Astronomy Astrophoto Gallery

Milkyway Mosiac in Sagitarius

Paul Walker — Sat, 14 Aug 2010 22:56:58 -0400

by: Paul Walker

Description: I had to resize the original image by 62 percent to meet the 2400 x 2400 requirement, didn't loose too much detail in the process. Wide Field Sagitarius, Southern Ophiuchus 2010-08-06 and 2010-08-07 Taken from Springfield, VT (Stellafane Convention) Constellation - Sagitarius, Ophiuchus 3 image mosaic 3mim X 7, 3 min X 6 and 3min X 6. ISO 1600 50mm f/1.4 lens at f/3.5 Field of view: 16 x 25 deg (each image) Field of view of mosiac approximately 25 deg heigh x 28 deg wide. Cameara Orientation - Portrait w/ north up Camera Canon Rebel XT (350D) (8 mega pixel) with Orion Broadband Light Pollution Filter Used darks and flats. Southern Ophiuchus (right image) 9:48 - 10:13 PM EDT Temperature - 52 degree F Transparency 20.7 mag/arc sec at target (Sky Quality Meter) Transparency 21.3 at zenith Seeing 5 (1-10) Sagitarius (west) (middle image) 10:21 - 10:39 PM EDT Temperature - 48 degree F Transparency 20.7 mag/arc sec at target (Sky Quality Meter) Transparency 21.3 at zenith Seeing 5 (1-10) Sagitarius (mid) (left image) (cropped almost half of this image for aesthetics) 11:03-11:24 PM EDT Temperature - 52 degree F Transparency 20.8 mag/arc sec at target (Sky Quality Meter) Transparency 21.3 at zenith Seeing 5 (1-10)

10 comments

Milkyway Mosiac in Sagitarius

Paul Walker — Sat, 14 Aug 2010 22:56:58 -0400

Clavius

Paul Walker — Thu, 12 Aug 2010 14:51:55 -0400

by: Paul Walker

Description: 2010-07-31, 4:58 AM EDT Middlebury, Vermont 20 day old Moon 10" f/5.6, 24mm e.p., Canon HD camcorder (afocal setup) Image is approx 400km across By far my best Clavius shot to date. Seeing: 8

Jupiter and Io

Paul Walker — Thu, 12 Aug 2010 14:39:39 -0400

by: Paul Walker

Description: 2010-07-31, 4:54 AM EDT Middlebury, Vermont 10" f/5.6, 24mm e.p., Canon HD camcorder (Viixia HF21) Afocal Setup Seeing: 8 It's the best shot of Jupiter I have so far and shows Io as a distint disk. It is a stack of 249 frames from 1 minute of high definition video (1920 x 1080 resolution). Not that the HD resolution actually helped. Stacked and wavelet sharping and color registration in Registax; color histogram stretch and unsharp mask sharpening in Picture Window; noise reduction in Noise Ninja, levels; +25% color saturation and color balance in Picture Window.

3 comments

Green_Flash_Sequence from Marathon Key

Paul Walker — Sat, 05 Jun 2010 16:29:29 -0400

by: Paul Walker

Description: I managed to see and capture the "green flash" while in the Florida Keys. Shortly after we got on the Keys, Saturday, May 22, the Sun was setting. Just as the Sun was starting to disappear below the waterline, I remembered the one of the best times to see the "green flash" is when the Sun is setting over water (or when viewed from a tall mountain with the horizon slightly below you). Jan pulled over where we had a clear view and sure enough, the "green flash" appeared just before the last sliver of Sun slipped below the water. We watch for it 6 times and saw it 3 times. The best was Monday, May 24 when I saw it for about 2 seconds. That was the day this image sequence was taken. The first 2 times I watched without optical aid, the other times I viewed the last few seconds through 8x21 binoculars. Time between top image and 2nd image is 2-3 seconds, and 1/2 to 1/3 second between the rest. The "green flash" occurs because the atmosphere strongly refracts lights of objects low on the horizon, just like a prism. With red on the bottom and blue on the top. The atmosphere also has to be nice and clear for the best views because it absorbs and scatters blue light more than red light. That's why the Sun gets redder as it gets closer to the horizon. I'm not sure, but if it is particularly clear near the horizon it may be possible to see a blue flash but normally too much blue gets absorbed and the eye is more sensitive to green than blue. Canon Rebel XTi 55-200mm zoom with polarizers (the polarizers were not needed I just didn't bother to take it off. Set at 200mm f/5.6, iso200, 1/640 sec. I was using 2 XTi's, the other was to 1/800 sec. and was too dark. The file is made of full resolution crops of the original images. I did noise reduction to smooth out the sky background and histogram stretch to brighten things up a bit. I video taped it as well but I can't see it on the video.

4 comments

Green_Flash_Sequence from Marathon Key

Paul Walker — Sat, 05 Jun 2010 16:29:29 -0400

M51 (The Whirlpool Galaxy)

Paul Walker — Sun, 18 Apr 2010 13:19:13 -0400

by: Paul Walker

Description: M51 (The Whirlpool Galaxy) 2010-04-14 21:55 PM EDT to 4/15/2010 01:01 AM EDT Middlebury, VT Constellation - Canes Venatici M51 is another interacting galaxy pair. The pink spots are clouds of hydrogen and dust where stars are being born. The blue spots are clusters of hot young stars that were born only a few million years ago (the galaxy is billions of year old). Just below the pair there are 2 distant background galaxies faintly visible. Exp 15 x 720 sec (3hrs total) (12min subs) ISO 1600 75 percent crop Scope Rotation - position 4B Camera Orientation - 1P North - lower left 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter with Baader Coma Corrector (MPCC) Start to Finish: Temperature - 46 to 33 degree F Transparency at target 20.92 to 21.07 mag/arc sec (Sky Quality Meter) Transparency at zenith 20.88 to 21.07 mag/arc sec (Sky Quality Meter) Seeing 4 (1-10) Autoguider- Meade Pictor 201XT on custom off-axis guide setup. Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing Steps: Stacked 15, 12 min exposures with 20 darks (taken at 39 deg F) and 30 flats. Color histogram stretch to darken and color balance the background. Selective color correction on background. Unsharp mask sharpening using a mask so only the galaxy details were sharpened. Color histogram stretch to fine tune background brightness and spiral arm color. Slight blurring using another mask to preserve galaxy and star details. Selective color correction on background. 75% crop. Added grayscale bar and text. M51_15x12m_10inF5_2010-04-14_wav2-chist-cc-1-unshpR5wmsk-chist-blurwmsk-cc-crop0.75-text -med.JPG

M51_15x12m_10inF5_2010-04-14_wav2-chist-cc-1-unshpR5wmsk-chist-blurwmsk-cc-

Paul Walker — Sun, 18 Apr 2010 13:19:13 -0400

by: Paul Walker

Description: M51 (The Whirlpool Galaxy) 2010-04-14 21:55 PM EDT to 4/15/2010 01:01 AM EDT Middlebury, VT Constellation - Canes Venatici M51 is another interacting galaxy pair. The pink spot are clouds of hydrogen and dust where stars are being born. The blue spots are clusters of hot young stars that were born only a few million years ago (the galaxy is billions of year old). Just below the pair there are 2 distant background galaxies faintly visible. Exp 15 x 720 sec (3hrs total) (12min subs) ISO 1600 75 percent crop Scope Rotation - position 4B Camera Orientation - 1P North - lower left 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter with Baader Coma Corrector (MPCC) Start to Finish: Temperature - 46 to 33 degree F Transparency at target 20.92 to 21.07 mag/arc sec (Sky Quality Meter) Transparency at zenith 20.88 to 21.07 mag/arc sec (Sky Quality Meter) Seeing 4 (1-10) Autoguider- Meade Pictor 201XT on custom off-axis guide setup. Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing Steps: Stacked 15, 12 min exposures with 20 darks (taken at 39 deg F) and 30 flats. Color histogram stretch to darken and color balance the background. Selective color correction on background. Unsharp mask sharpening using a mask so only the galaxy details were sharpened. Color histogram stretch to fine tune background brightness and spiral arm color. Slight blurring using another mask to preserve galaxy and star details. Selective color correction on background. 75% crop. Added grayscale bar and text. M51_15x12m_10inF5_2010-04-14_wav2-chist-cc-1-unshpR5wmsk-chist-blurwmsk-cc-crop0.75-text -med.JPG

M51_15x12m_10inF5_2010-04-14_wav2-chist-cc-1-unshpR5wmsk-chist-blurwmsk-cc-

Paul Walker — Sun, 18 Apr 2010 13:19:13 -0400

NGC4038 & 4039 (The Antennae)

Paul Walker — Sat, 17 Apr 2010 21:46:43 -0400

by: Paul Walker

Description: NGC4038 & 4039 (The Antennae) 2010-04-12 22:25:13 PM EDT to 4/13/2010 01:24:50 AM EDT Middlebury, VT Constellation - Corvus Magnitude 10.7 and 10.3 interacting galaxies about 60 million light years away. The strings of bright spots in these galaxies are not individual stars but huge clusters of stars and glowing clouds of hydrogen and dust in which new stars are forming. There are 2 very faint streams of stars that have been tidally pulled from the galaxies and flung far into intergalactic space. I thought for sure the debris streams would show up better than this, with 3 hours of 12 minute subs. Exp 15 x 720 sec (3hrs) ISO 1600 50 percent crop Scope Rotation - position 3 Camera Orientation - 1P North - upper left 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter with Baader Coma Corrector (MPCC) Start to Finish: Temperature - 33 to 27 degree F Transparency at target 20.42 to 20.52 mag/arc sec (Sky Quality Meter) Transparency at zenith 20.81 to 20.96 mag/arc sec (Sky Quality Meter) Seeing 4 (1-10) Autoguider- Meade Pictor 201XT on custom off-axis guide setup. Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 The Antennae_15x12m_10inF5.6_2010-04-12_wav1-chist1_NR-chist2-levels-cc-unshp-50crop-creg_NR1-hist-sat+18-unshp-w-mask-1.jpg

NGC4038 & 4039 (The Antennae)

Paul Walker — Sat, 17 Apr 2010 21:46:43 -0400

Early morning at Clavius

Paul Walker — Sat, 17 Apr 2010 21:26:20 -0400

by: Paul Walker

Description: Early morning at Clavius By Paul Walker 2010-03-24_8:41 PM EDT #9 of the Lunar 100. Made from 82 high definition video frames stacked using AviStack (not that the HD video improved the final resolution).

M81 and M82

Paul Walker — Sun, 21 Mar 2010 21:08:19 -0400

by: Paul Walker

Description: M81 & M82 2010-03-17, 10:39PM EDT to 2010-03-18, 1:08AM EDT Middlebury, VT Constellation - Ursa Major Exp 11x720sec (12min) subs (2hr 12min total) ISO 1600 Focus was soft. By the time I managed to find a star the autoguider could lock onto I didn't want to go back to re-check the focus. The seeing was poor and the tracking was problamatic, had to use 5sec integrations and that's a little too long for my setup. All the subs had a little trailing and could not use 4 of them. 12 minutes may be pushing it with my setup as well, though the previous night I got some sharp images of what I hoped were "The Antannae" with 12 minute subs using 1sec integration time on the autoguider. Turned out to be 2 rather non-descript 14th mag galaxies, NGC4285 & 44279 (Ididn't want to disturb my wife to find out what they were, my computer is in the bedroom). North - left 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter Temperature - 38 to 34 degree F Transparency 20.83 to 20.93 mag/arc sec (Sky Quality Meter) 20.83 to 21.01 at the zenith Seeing 4 (1-10) Autoguider (Meade Pictor 201XT) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing Steps: Stack of 11, 720sec subs using darks (20) and Flats (30). Small amount of wavelet sharpening in Registax. Regular historgram stretch. Unsharp Mask sharpening. Selective color correction. Historgram stretch (to darken background). M81 & M82_11x12min_10inf5.6_2010-03-17_wav1_chist_hist_unshp-cc-hist-(medium).jpg

M81 and M82

Paul Walker — Sun, 21 Mar 2010 21:08:19 -0400

by: Paul Walker

Description: M81 & M82 2010-03-17, 10:39PM EDT to 2010-03-18, 1:08AM EDT Middlebury, VT Constellation - Ursa Major Exp 11x720sec (12min) subs (2hr 12min total) ISO 1600 Focus was soft. By the time I managed to find a star the autoguider could lock onto I didn't want to go back to re-check the focus. The seeing was poor and the tracking was problamatic, had to use 5sec integrations and that's a little too long for my setup. All the subs had a little trailing and could not use 4 of them. 12 minutes may be pushing it with my setup as well, though the previous night I got some sharp images with 12 minute subs using 1sec integration time on the autoguider. North - left 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter Temperature - 38 to 34 degree F Transparency 20.83 to 20.93 mag/arc sec (Sky Quality Meter) 20.83 to 21.01 at the zenith Seeing 4 (1-10) Autoguider (Meade Pictor 201XT) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing Steps: Stack of 11, 720sec subs using darks (20) and Flats (30). Small amount of wavelet sharpening in Registax. Regular historgram stretch. Unsharp Mask sharpening. Selective color correction. Historgram stretch (to darken background). M81 & M82_11x12min_10inf5.6_2010-03-17_wav1_chist_hist_unshp-cc-hist-(medium).jpg

M65, M66, NGC3629 (different processing)

Paul Walker — Sat, 20 Mar 2010 20:36:03 -0400

by: Paul Walker

Description: Different Processing of previous image Is is bluer and brings out the fainter portions There are just too many processing options!!!!!! M65, M66, NGC3629 2010-03-16, 10:59PM EDT to 2010-03-17, 12:23AM EDT Middlebury, VT Constellation - Leo Exp 11x480sec (8min) subs (88 min total) ISO 1600 North - right 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter Temperature - 26 degree F Transparency 20.80 mag/arc sec (Sky Quality Meter) 20.86 at zenith Seeing 7 (1-10) Autoguider (Meade Pictor 201XT) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing Steps: Stacked 11, 480sec images using darks and Flats. Since the master dark frame didn't exactly match the temperature of the "lights" I brightened the dark slightly. Moderate wavelet sharpening. Noise reduction. Color Curves (separate RGB channels histogram stretch) to correct background color while doing initial stretching. Noise reduction. Color curves. <--same as 1st image / different from 1st image--> 2 Regular historgram stretches. Color Curves. Increased color saturation by 15 percent. The master dark frame still didn't remove all the thermal noise so I selectively darkened part of the lower right. Burned in (selectively brightened the outer portions of the galaxies. Selective color correction. Noise reduction. M65,66_NGC3629_11x8min_10inf5.6_2010-03-16_moddrk_[wav1] _NR_chist2_NR_levels_hist_chist_sat+15_dodge_burn_cc_NR_(Medium).jpg

M65, M66, NGC3629

Paul Walker — Sat, 20 Mar 2010 20:36:03 -0400

by: Paul Walker

Description: Different Processing of previous image There are just too many processing options!!!!!! M65, M66, NGC3629 2010-03-16, 10:59PM EDT to 2010-03-17, 12:23AM EDT Middlebury, VT Constellation - Leo Exp 11x480sec (8min) subs (88 min total) ISO 1600 North - right 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter Temperature - 26 degree F Transparency 20.80 mag/arc sec (Sky Quality Meter) 20.86 at zenith Seeing 7 (1-10) Autoguider (Meade Pictor 201XT) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing Steps: Stacked 11, 480sec images using darks and Flats. Since the master dark frame didn't exactly match the temperature of the "lights" I brightened the dark slightly. Moderate wavelet sharpening. Noise reduction. Color Curves (separate RGB channels histogram stretch) to correct background color while doing initial stretching. Noise reduction. Color curves. <--same as 1st image / different from 1st image--> 2 Regular historgram stretches. Color Curves. Increased color saturation by 15 percent. The master dark frame still didn't remove all the thermal noise so I selectively darkened part of the lower right. Burned in (selectively brightened the outer portions of the galaxies. Selective color correction. Noise reduction. M65,66_NGC3629_11x8min_10inf5.6_2010-03-16_moddrk_[wav1] _NR_chist2_NR_levels_hist_chist_sat+15_dodge_burn_cc_NR_(Medium).jpg

M65, M66, NGC3629

Paul Walker — Sat, 20 Mar 2010 20:36:03 -0400

M65, M66, NGC3629

Paul Walker — Sat, 20 Mar 2010 20:22:08 -0400

by: Paul Walker

Description: M65, M66, NGC3629 2010-03-16, 10:59PM EDT to 2010-03-17, 12:23AM EDT Middlebury, VT Constellation - Leo Exp 11x480sec (88 min total) ISO 1600 Seeing and transparency were exceptional as was the autoguiding. North - right 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter Temperature - 26 degree F Transparency 20.80 mag/arc sec (Sky Quality Meter) 20.86 at zenith Seeing 7 (1-10) Autoguider (Meade Pictor 201XT) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing Steps: Stacked 11, 480sec images using darks and Flats. Since the master dark frame didn't exactly match the temperature of the "lights" I brightened the dark slightly. Moderate wavelet sharpening. Noise reduction. Color Curves (separate RGB channels histogram stretch) to correct background color while doing initial stretching. Noise reduction. Color curves. Regular historgram stretch. Selective color correction. Historgram stretch. The master dark frame still didn't remove all the thermal noise so I selectively darkened part of the lower right. Burned in (selectively brightened the outer portions of the galaxies. M65,66_NGC3629_11x8min_10inf5.6_2010-03-16_moddrk_[wav1]_NR_chist2_NR_chist3_hist_cc- hist_dodge_burn-(Medium).jpg

M65, M66, NGC3629

Paul Walker — Sat, 20 Mar 2010 20:22:08 -0400

M65, M66, NGC3629

Paul Walker — Sat, 20 Mar 2010 20:22:08 -0400

Horsehead Nebula

Paul Walker — Thu, 18 Mar 2010 20:30:09 -0400

by: Paul Walker

Description: Horsehead Nebula 2010-03-16 7:59 to 9:29 PM EDT Middlebury, VT Constellation - Orion Exp 9 x 480sec (8min) subs (72min total) ISO 1600 North - left 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter Temperature - 30-25 degree F Transparency 20.12 - 20.02 mag/arc sec (Sky Quality Meter) 20.73 mag/arc sec at the zenith Seeing 7 (1-10) Autoguider (Meade Pictor 201XT) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Horsehead Neb 9x8min_10in f5.6_2010-03-10_NR_chist-chist-unshp-hist-cc-(Medium).jpg

3 comments

Leo 1 Dwarf Galaxy and Regulus

Paul Walker — Thu, 11 Mar 2010 21:29:29 -0500

by: Paul Walker

Description: Leo 1 Dwarf Galaxy, right of center Another image taken more recently. 8 minute subs verses 5 minute for the previous image. Regulus is the bright star. IC591 and another fainter gallaxy below, a few faint galaxies to the far right. Leo 1 is a dwarf galaxy in our local galaxy group. It is though to be one of the most distance of our own Milkyway Galaxy's satelite galaxies at about 820 million light years distance. Some of the brighter spots in this image may be red giant star in Leo 1. 2010-03-06 10:49 PM EST to 12:01 (on 03-07) AM EST 3:49 to 5:01 UT on 2010-03-07 Middlebury, VT Constellation - Leo Exp 10 x 480sec (80 minutes total) ISO 1600 North - right 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera Canon Rebel XTi (10 mega pixel) unmodified Temperature - 22 to 19 degree F Transparency 20.55 mag/arc sec at target (Sky Quality Meter) 20.70 at zenith Seeing X (1-10) Autoguided (Meade Pictor 201XT) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Stack of 10, 8 min exposures with 30 flats and 20 darks. Slight wavelet sharping in Registax. Color histogram stretch (color curves) in RGB color space. Moderate noise reduction. Histogram stretch (brightness curves). Unsharp mask sharpening. Color histogram stretch (color curves) in RGB color space. Leo 1 Dwarf Gallaxy_10x8min_10inf5_[wav1]_chist1_NR1_hist1_unshpR3T5_chist-(med)- rotated.JPG

2 comments

Horsehead Nebula, IC434, NGC2023 NGC2024

Paul Walker — Sun, 07 Mar 2010 21:01:55 -0500

by: Paul Walker

Description: Horsehead Nebula, IC434, NGC2023 NGC2024 2010-03-06 Middlebury, VT Constellation - Orion The bright star in the upper left corner is the middle star of Orion's belt and of coarse the one just to the left of the Horsehead is the left most (eastern) star of Orion's belt. Exp 14x180sec (42min total) ISO 1600 North - left 4.25 inch f/3.9 (422mm fl) reflector Field of view: 1.9 x 2.9 deg. German Equatorial Mount (Super Polaris model) Camera - Modified Canon Rebel XT (350D) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter with Baader Coma Corrector (MPCC) Temperature - 27 to 22 degree F Transparency 20.10 mag/arc sec (Sky Quality Meter) Seeing 5 (1-10) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Horsehead Neb_14x3min_4.25in f3.9_2010-03-06_chist-chist-unshp_NR2-hist2-cc (med).jpg

Wide Field Mosaic, Jupiter, Sagitarius, Scorpio

Paul Walker — Sun, 28 Feb 2010 21:51:14 -0500

by: Paul Walker

Description: Wide Field Mosaic of the Milkyway, Cropped Jupiter, Sagitarius, Scorpio 2008-06-03 Taken from Alto, New Mexico The light pollution in lower right is from Ruidoso (where we were staying) Exp 5 X 4min ISO 1600 28mm f/4.5 Camera Canon Rebel XTi (unmodified) Transparency 21.7 mag/arc sec (Sky Quality Meter) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processed with 6 darks and 10 flats.

3 comments

Wide Field Mosaic, Jupiter, Sagitarius, Scorpio

Paul Walker — Sun, 28 Feb 2010 21:51:14 -0500

by: Paul Walker

Description: Wide Field Mosaic, Cropped Jupiter, Sagitarius, Scorpio 2008-06-03 Alto, New Mexico The light pollution in lower right is from Ruidoso (where we were staying) Exp 5 X 4min ISO 1600 28mm f/4.5 Camera Canon Rebel XTi (unmodified) Tracking was with a homemade Hiag (or Scotch) mount with a stepper motor drive on top of a camera tripod. Transparency 21.7 mag/arc sec (Sky Quality Meter) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processed with 6 darks and 10 flats.

The Dwarf Galaxy, Leo 1

Paul Walker — Mon, 22 Feb 2010 21:43:59 -0500

by: Paul Walker

Description: Leo 1 Regulus below and IC591 and another faint gallaxy to the right, a few faint galaxies above 2009-03-14 Middlebury, VT BEST VIEWED IN A DARK ROOM 10x5min (50min total) ISO 1600 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.80 x 0.50 deg. Homemade Wooden Split Ring Equatorial Mount Camera Canon Rebel XTi (10 mega pixel) Manually guided. North is up West is right Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing: Stacked 10, 5 minute exposures useing darks and flats (do not have a record of how many darks and flats). Wavelet sharping in Registax before saving. Noise reduction. Histogram stretch in HsV color space, twice. Historgram stretch in RGB color space. Color Correction on selected color. Unsharp Mask sharpening. Slight crop. Leo 1_5mx10_wav1_NR-HSVhist_HSVhist-RGBhist_cc-unshp_crop.jpg

2 comments

Leo_1_5mx10_wav1_NR-HSVhist_HSVhist-RGBhist_cc-unshp_crop

Paul Walker — Mon, 22 Feb 2010 21:43:59 -0500

by: Paul Walker

Description: Leo 1 Regulus below and IC591 to the right a few faint galaxies above 2009-03-14 Middlebury, VT 10x5min (50min total) ISo 1600 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Image scale- 0.0405 deg per mm Large Wooden Split Ring Equatorial Mount Camera Canon Rebel XTi (10 mega pixel) (sensor 22.2 x 14.8 mm) (approx 1.6 x 35mm film form factor) Manually guided. Off Axis guider info: Optical axis 3.54 degree from main optics axis. Field available for guiding, approx 2x3 degree. Image orientatioin: Portrait North is right West is Down Image Exp ISO Subject 5m 1600 Leo 1 Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing: Stacked 10, 5 minute exposures useing darks and flats (do not have a record of how many darks and flats). Wavelet sharping in Registax before saving. Noise reduction. Histogram stretch in HsV color space, twice. Historgram stretch in RGB color space. Color Correction on selected color. Unsharp Mask sharpening. Slight crop. Leo 1_5mx10_wav1_NR-HSVhist_HSVhist-RGBhist_cc-unshp_crop.jpg

The Dwarf Galaxy, Leo 1

Paul Walker — Mon, 22 Feb 2010 21:43:59 -0500

Horsehead Nebula

Paul Walker — Fri, 19 Feb 2010 23:14:56 -0500

by: Paul Walker

Description: Horsehead Nebula 2010-02-11 Middlebury, VT Constellation - Orion Exp 16x8min (2hr 8min) ISO 1600 It took a while to figure out why this image has reflections of the bright star and an image taken 2009-11-17 (see my earlier posting) does not. For this image I used the coma corrector and the light pollution filter, for the earlier one I only used the light pollution filter. I will have to experiment to determine whether it's the combination of the two or only the coma corrector. So far this is the only image with a bright enough star for the reflection to be noticeable. There is also a faint, very large image of the primary mirror near the center of the picture which is not present in the earlier image. North - left 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera Canon Rebel XT modified (8 mega pixel) (sensor 22.2 x 14.8 mm) (approx 1.6 x 35mm film form factor) With Baader Coma Corrector (MPCC) with Orion Broadband Light Pollution Filter Temperature - 19, 16, 13 degree F Transparency 20.25 mag/arc sec at target (Sky Quality Meter) Transparency 20.5 mag/arc sec at zenith Seeing 5 (1-10) Autoguider (Meade Pictor 201XT) Stacking - Registax 5 Other - Picture Window Pro 5 Stacked images with darks and flats. Stacked mages in 4 sets of 4 images. I did sets of 4 so I could combine them with the set of 4 I took on 2009-11-17. Because the temperature changed quite a bit during imaging I used 3 sets of darks from 3 tempertures (23 deg F, 22 deg F and 13 deg F). Saved stacks as 16 bit TIFF. I then stacked the the 4 sets of stacked image (no darks or flats of coarse). I had enough images to reduce the signal to noise enough that I did no noise reduction this time. Did color curves (histogram stretch). I then did something I have never tried before, I used the color curves function in HSV color space (hue, saturation, value) (I was using RGB color space before). This allowed me to shift the color balance, saturtion and brightness at the same time. I did unsharp mask (sharpening) and a minor histogram stretch (contast). There are 3 types of nebulae here, emission, reflection and dark (all part of 1 huge cloud of dust and gas). Ultraviolet light from the bright hot star ionizes the hydrogen gas it strikes causing it to emit red light (similar to a neon sign). Reflection nebulae are seen when smaller less energetic stars simply illuminate part of the dust cloud. Dark nebulae are portions of the dust cloud that are not lit up and are blocking most of the light from behind them. Horsehead Neb_2010-02-11_10inf5.6_16x8min-chist_HSV1_unshpR4,T7_hist2.jpg

1 comment

Horsehead_Neb_2010-02-11_10inf5_6_16x8min-chist_HSV1_unshpR4_T7_hist_hist

Paul Walker — Fri, 19 Feb 2010 23:14:56 -0500

by: Paul Walker

Description: Horsehead Nebula 2010-02-11 Middlebury, VT Constellation - Orion Exp 16x8min (2hr 8min) ISO 1600 It took a while to figure out why this image has reflections of the bright star and an image taken 2009-11-17 (see my earlier posting) does not. For this image I used the coma corrector and the light pollution filter, for the earlier one I only used the light pollution filter. I will have to experiment to determine whether it's the combination of the two or only the coma corrector. So far this is the only image with a bright enough star for the reflection to be noticeable. There is also a faint, very large image of the primary mirror near the center of the picture which is not present in the earlier image. I had to keep that part of the image dark sto keep the image of the primary from being too noticeable. North - left 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera Canon Rebel XT (8 mega pixel) (sensor 22.2 x 14.8 mm) (approx 1.6 x 35mm film form factor) With Baader Coma Corrector (MPCC) with Orion Broadband Light Pollution Filter Temperature - 19, 16, 13 degree F Transparency 20.25 mag/arc sec at target (Sky Quality Meter) Transparency 20.5 mag/arc sec at zenith Seeing 5 (1-10) Autoguider (Meade Pictor 201XT) Stacking - Registax 5 Other - Picture Window Pro 5 Stacked images with darks and flats. Stacked images in 4 sets of 4 images. Because the temperature changed quite a bit during imaging I used 3 sets of darks from 3 tempertures (23 deg F, 22 deg F and 13 deg F). Saved stacks as 16 bit TIFF. I then stacked the the 4 sets of stacked image (no darks or flats of coarse). I had enough images to reduce the signal to noise enough that I did no noise reduction this time. Did color curves (histogram stretch). I then did something I have never tried before, I used the color curves function in HSV color space (hue, saturation, value) (I was using RGB color space before). This allowed me to shift the color balance, saturtion and brightness at the same time. I did unsharp mask (sharpening) and 2 more minor histogram stretches (contast). There are 3 types of nebulae here, emission, reflection and dark (all part of 1 huge cloud of dust and gas). Ultraviolet light from the bright hot star ionizes the hydrogen gas it strikes causing it to emit red light (similar to a neon sign). Reflection nebulae are seen when smaller less energetic stars simply illuminate part of the dust cloud. Dark nebulae are portions of the dust cloud that are not lit up and are blocking most of the light from behind them. Horsehead Neb_2010-02-11_10inf5.6_16x8min-chist_HSV1_unshpR4,T7_hist_hist.jpg

Mars_2010-02-12

Paul Walker — Sun, 14 Feb 2010 20:12:56 -0500

by: Paul Walker

Description: Mars 2010-02-11 11:45 PM EST (2010-02-12, 04:45 UT) Disk size 13.55 arc seconds Nothing to write home about but it's the best I've got so far. Better than any I have from the 2003 opposition. Stack of 1827 video frames 10 inch f/5.6 (1407mm fl) Newtonian Sony CyberShot DSC-W80 point and shoot camera in video mode (640x480 pixels) (at appox. 2x optical zoom) 10mm eyepiece, 3x barlow (420X). Seeing 6 (1-10) Included on the labeled side is the approximate locations of the Viking 1 lander, Pathfinder lander and rover, and the Opportunity rover. The info for the labeled features came from a free applet called Mars PreviewerII. Before doing the video I viewed Mars at 530X (17mm eyepiece combined with a 2x and a 3x barlow). I tried 840X (10mm eyepiece with the barlows) but that was too much magnification. I could make out most of the features in the image. Processing: Registax - Stacked, color registration (alignment)(had some chomatic abberation due to the camera lens). Wavelet sharping, histogram stretch. Picture Window - color histogram strecth (for some color correction), color correction (color balance) for addition color tweaking, cropped, rotated, a little more color registration. I had tried stacks of 250 and 500 of the best frames but liked the results of stacking all 1827 as it gave a noticably smoother result with no noticable loss of detail. Mars_stkof1827_2010-02-12_rgb align_wav4_stch40-235_chist-cc-crop-rotate-color reg.PNG

4 comments

Mars_2010-02-12

Paul Walker — Sun, 14 Feb 2010 20:12:56 -0500

M42 (The Orion Nebula) and The Running Man Nebula

Paul Walker — Sun, 07 Feb 2010 18:29:35 -0500

by: Paul Walker

Description: M42 (The Orion Nebula) and The Running Man Nebula 2009-11-21 Middlebury, VT Constellation - Orion Stack of 6 images Exp: one each - 240s, 90s, 60s, 30s, 14s, 6s, (1,3,4,6,8,10) ISO 1600 North up 4.25 inch f/3.9 (422mm fl) reflector Field of view: approx 1.7 x 2.0 deg. German Equatorial Mount (Super Polaris model) Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) Orion Broadband Light Pollution Filter Baader Coma Corrector (MPCC) Temperature - 33 degree F Transparency 20.5 mag/arc sec (Sky Quality Meter) Seeing X (1-10) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Stack 6 images in Registax, one each of the following exposure times- 240s, 90s, 60s, 30s, 14s, 6s. No Dark frames or Flat Field. Saved stack as separate red, green and blue grayscale images. Histgram stretch on each of these. Combined into color image. Noise reduction. Historgram stretch. Color histogram stretch (has separate control over the red, green and blue portions). Cropped and rotated. Sharpened using unsharp mask function. Noise reduction. Manually removed hot pixels (there were lots of little triple stars for some reason ;) ) M42_stkof6_Rh_Gh1_Bh1_NR-hist-chist-crop-rotate-unshp_NR2-(medium).jpg

M42 (The Orion Nebula) and The Running Man Nebula

Paul Walker — Sun, 07 Feb 2010 18:29:35 -0500

by: Paul Walker

Description: M42 (The Orion Nebula) and The Running Man Nebula 2009-11-21 Middlebury, VT Constellation - Orion Stack of 6 images Exp: one each - 240s, 90s, 60s, 30s, 14s, 6s, (1,3,4,6,8,10) ISO 1600 Cameara Orientation - Portrait w/ north left 4.25 inch f/3.9 (422mm fl) reflector Field of view: 1.9 x 2.9 deg. German Equatorial Mount (Super Polaris model) Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) Orion Broadband Light Pollution Filter Baader Coma Corrector (MPCC) Temperature - 33 degree F Transparency 20.5 mag/arc sec (Sky Quality Meter) Seeing X (1-10) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Stack 6 images in Registax, one each of the following exposure times- 240s, 90s, 60s, 30s, 14s, 6s. No Dark frames or Flat Field. Saved stack as separate red, green and blue grayscale images. Histgram stretch on each of these. Combined into color image. Noise reduction. Historgram stretch. Color histogram stretch (has separate control over the red, green and blue portions). Cropped and rotated. Sharpened using unsharp mask function. Noise reduction. Manually removed hot pixels (there were lots of little triple stars for some reason ;) ) M42_stkof6_Rh_Gh1_Bh1_NR-hist-chist-crop-rotate-unshp_NR2-(medium).jpg

M42 (The Orion Nebula) and The Running Man Nebula

Paul Walker — Sun, 07 Feb 2010 18:29:35 -0500

Rosette Nebula

Paul Walker — Sun, 07 Feb 2010 14:03:13 -0500

by: Paul Walker

Description: It's no prize winner but I was surprised I could get this much out of 2 minute exposures. Rosette Nebula (NGC2244 [open cluster in center], NGC2239, NGC2237, NGC2238, NGC2245) 2010-02-06 Middlebury, VT Constellation - Monoceros The Rosette Nebula is a star birth region just east of the constellation Orion (about 1 hand width to the right of the red giant star, Betelgeuse, in Orion's shoulder). The young open star cluster in the middle is slowly blowing a bubble in middle of this large cloud of gas and dust. The narrow dark fingers or lanes above and the the right of cluster are denser clumps with new born stars hiding inside. Exp 11x2min (22min total) ISO 1600 Landscape, North down in original image, North up in final image. Had difficulty focusing, finally obtained a good focus. Had tracking issues. Planned on 4 minute exposures had to settle for 2min. I had 12, 4 minute exposures that were unusable. Even at 2 minutes the tracking was a bit of an issue an had 2 unusable images (the ones I kept were not all that good but at this scale it is doesn't show much). Then the clouds came in and put a halt to everything. 4.25 inch f/3.9 (422mm fl) reflector Field of view: 1.9 x 2.9 deg. German Equatorial Mount (Super Polaris model) Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter with Baader Coma Corrector (MPCC) Temperature - 6 degree F with 5-10mph wind Transparency 20.2 mag/arc sec at the Rosette, 20.45 at zenith (Sky Quality Meter) Seeing 7 (1-10) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Stacked in Registax with dark frame (from 7 images) and Flat Field (from 30 images). Histogram Stretch using color curves in Picture Window (for adjusting the histogram of the red, green and blue separately within one function). Noise reduction with Noise Ninja. Another Histogram Stretch (color curves). Unsharp Mask (sharpening) with Picture Window. Another Histogram Stretch (color curves). Cropped the sides off. Rotated for north up. Rosette Neb_11x2min_2010-02-06_4in-f4_hist_NR_hist_unshp-hist-crop-rotated-(medium).jpg

2 comments

Rosette_Neb_11x2min_2010-02-06_4in-f4_hist_NR_hist_unshp-hist-crop-rotated-

Paul Walker — Sun, 07 Feb 2010 14:03:13 -0500

by: Paul Walker

Description: Rosette Nebula (NGC2244 [open cluster in center], NGC2239, NGC2237, NGC2238, NGC2245) 2010-02-06 Middlebury, VT Constellation - Monoceros The Rosette Nebula is a star birth region just east of the constellation Orion (about 1 hand width to the right of the red giant star, Betelgeuse, in Orion's shoulder). The young open star cluster in the middle is slowly blowing a bubble in middle of this large cloud of gas and dust. The narrow dark fingers or lanes above and the the right of cluster are denser clumps with new born stars hiding inside. Exp 11x2min (22min total) ISO 1600 I was surprised I could get this much out of 2 minute exposures. Landscape, North down in original image, North up in final image. Had difficulty focusing, finally obtained a good focus. Had tracking issues. Planned on 4 minute exposures had to settle for 2min. I had 12, 4 minute exposures that were unusable. Even at 2 minutes the tracking was a bit of an issue an had 2 unusable images. Then the clouds came in and put a halt to everything. 4.25 inch f/3.9 (422mm fl) reflector Field of view: 1.9 x 2.9 deg. German Equatorial Mount (Super Polaris model) Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter with Baader Coma Corrector (MPCC) Temperature - 6 degree F with 5-10mph wind Transparency 20.2 mag/arc sec at the Rosette, 20.45 at zenith (Sky Quality Meter) Seeing 7 (1-10) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Stacked in Registax with dark frame (from 7 images) and Flat Field (from 30 images). Histogram Stretch using color curves in Picture Window (for adjusting the histogram of the red, green and blue separately within one function). Noise reduction with Noise Ninja. Another Histogram Stretch (color curves). Unsharp Mask (sharpening) with Picture Window. Another Histogram Stretch (color curves). Cropped the sides off. Rotated for north up. Rosette Neb_11x2min_2010-02-06_4in-f4_hist_NR_hist_unshp-hist-crop-rotated-(medium).jpg

M13, IC4617, NGC6207

Paul Walker — Fri, 29 Jan 2010 19:13:14 -0500

by: Paul Walker

Description: M13, IC4617, NGC6207 2008-08-31 Middlebury, VT Constellation - Hercules Exp 29x1min ISO 1600 North - right 10 inch f/5.6 (1407mm fl) Newtonian Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera Canon Rebel XTi (10 mega pixel) Not Guided. Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5

M13, IC4617, NGC6207

Paul Walker — Fri, 29 Jan 2010 19:13:14 -0500

by: Paul Walker

Description: M13, IC4617, NGC6207 2008-08-31 Middlebury, VT Constellation - Hercules IC 4617 a 14th magnitude gallaxy halfway between M13 and NGC6207 Exp 29x1min ISO 1600 North - right 10 inch f/5.6 (1407mm fl) Newtonian Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera Canon Rebel XTi (10 mega pixel) Not Guided. Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5

4 comments

M13, IC4617, NGC6207

Paul Walker — Fri, 29 Jan 2010 19:13:14 -0500

Paul Walker's Off-Axis Guide System

Paul Walker — Sun, 17 Jan 2010 17:32:10 -0500

by: Paul Walker

Description: Off Axis guider info: Field available for guiding is approx. 3 degree in diameter, centered about 3 degree from main optical axis. I started with the 2" diagonal because wanted as much light as possible to work. I switched to a 1.5" to bring the focal plane in a little and decrease the offset from the main optical axis a little. I did not notice any difference guiding switching to the 1.5" even though it does not provide 100% illumination even in the center of the field of focal plane. The guide diagonal can tilt and rotate (the blue part is an 11:1 reduction device) to center any star in the 3 degree circle. It only take about 15 seconds to install or remove (most nights the seeing is bad enough that it has little or no visual affect on planetary viewing). For "visual" guiding the whole 3 deg field is usable, the stand alone autoguider for the most part can only use half of this. Those familiar with optic know as one moves farther from the scope's optical axis coma spreads the starlight into a "V" shape making the image much dimmer. For "visual" guiding I use a low light video camera on a pc board (0.001 lux sensitivity), a so called spy cam, and a video monitor and can use stars down to about 11 mag. The autoguider works best with 5th or 6th magnitude stars no more than about 3 degrees off axis. I have used stars down to about 7th mag. The autoguider also works best using exposure times that produce a brightness readout of 10-20 (out of 0-100). This probably renders only the apex of the V shaped star image visible to the autoguider. It also guides best with exposure times of 5 seconds or less. Longer than that and I get some elongation for the star images. I expect a newer more sensitive autoguider would allow me to use fainter stars. I can rotate the telescope tube to access more potential guide stars. I currently have 2 positions marked on the tube. I typically orient the long axis of the camera either north/south or east west and currently have registration marks on the focuser only for the 2 marked tube rotation positions. This limits my guide star fields to 2 locations on either side of my target object, 180 degrees apart. There is a little flexure in the system, but not enough to bother exposures of 10 minutes or less. Steps for autoguiding: After focusing the camera and locating my subject I place a 60x eyepiece (1 degree field of view) into the guide focuser. Tip and rotate the mirror until I find suitable guide star. Place a 120x reticule eyepiece into the focuser, center and focus the guide star. I put a ring on this eyepiece so I could make it parfocal to the autoguider. Place the autoguider in the focuser, check the brightness and position readouts and adjust them if needed. This whole process can take an hour or so. I spent a lot of time thinking about the details of how to make the off axis guider and wondering if would even be usable knowing that the stars would look like little comets. At first I planned on having control knobs on the outside of the tube but decided that would be somewhat complex and difficult to remove for doing planetary work. The final design requires I reach inside the front of the tube which can be a little awkward, but that�s' what they make step stools and ladders for. I have a Little Giant stepladder that extends up to 11 feet that I have had to use on occasion and works quite well. I place it right over part of the mount.

5 comments

Paul Walker's Off-Axis Guide System

Paul Walker — Sun, 17 Jan 2010 17:32:10 -0500

by: Paul Walker

Description: Off Axis guider info: Field available for guiding is approx. 3 degree in diameter, centered about 3 degree from main optical axis. I started with the 2" diagonal because wanted as much light as possible to work. I switched to a 1.5" to bring the focal plane in a little and decrease the offset from the main optical axis a little. I did not notice any difference guiding switching to the 1.5" even though it does not provide 100% illumination even in the center of the field of focal plane. The guide diagonal can tilt and rotate to center any star in the 3 degree circle. It only take about 15 seconds to install or remove (most nights the seeing is bad enough that it has little or no visual affect on planetary viewing). For "visual" guiding the whole 3 deg field is usable, the stand alone autoguider for the most part can only use half of this. Those familiar with optic know as one moves farther from the scope's optical axis coma spreads the starlight into a "V" shape making the image much dimmer. For "visual" guiding I use a low light video camera on a pc board (0.001 lux sensitivity), a so called spy cam, and a video monitor and can use stars down to about 11 mag. The autoguider works best with 5th or 6th magnitude stars no more than about 3 degrees off axis. I have used stars down to about 7th mag. The autoguider also works best using exposure times that produce a brightness readout of 10-20 (out of 0-100). This probably renders only the apex of the V shaped star image visible to the autoguider. It also guides best with exposure times of 5 seconds or less. Longer than that and I get some elongation for the star images. I expect a newer more sensitive autoguider would allow me to use fainter stars. I can rotate the telescope tube to access more potential guide stars. I currently have 2 positions marked on the tube. I typically orient the long axis of the camera either north/south or east west and currently have registration marks on the focuser only for the 2 marked tube rotation positions. This limits my guide star fields to 2 locations on either side of my target object, 180 degrees apart. There is a little flexure in the system, but not enough to bother exposures of 10 minutes or less. Steps for autoguiding: After focusing the camera and locating my subject I place a 60x eyepiece (1 degree field of view) into the guide focuser. Tip and rotate the mirror until I find suitable guide star. Place a 120x reticule eyepiece into the focuser, center and focus the guide star. I put a ring on this eyepiece so I could make it parfocal to the autoguider. Place the autoguider in the focuser, check the brightness and position readouts and adjust them if needed. This whole process can take an hour or so. I spent a lot of time thinking about the details of how to make the off axis guider and wondering if would even be usable knowing that the stars would look like little comets. At first I planned on having control knobs on the outside of the tube but decided that would be somewhat complex and difficult to remove for doing planetary work. The final design requires I reach inside the front of the tube which can be a little awkward, but that�s' what they make step stools and ladders for. I have a Little Giant stepladder that extends up to 11 feet that I have had to use on occasion and works quite well. I place it right over part of the mount.

Paul Walker's Off-Axis Guide System

Paul Walker — Sun, 17 Jan 2010 17:32:10 -0500

M33 (The Pinwheel Galaxy)

Paul Walker — Sun, 17 Jan 2010 11:53:18 -0500

by: Paul Walker

Description: M33 (The Whirlpool Galaxy) 2010-01-12 Middlebury, VT Constellation - Triangulum Slightly Cropped Combined images from 2 sessions Exp 9x8min (2010-01-12) Exp 10x8min (2009-11-17) Total exp 2hr 32m ISO 1600 North - right 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) (sensor with Orion Broadband Light Pollution Filter with Baader Coma Corrector (MPCC) Autoguided with Meade Pictor 201XT thru custom offaxis system. Conditions for 2010-01-12 session: Temperature - 1-3 degree F Transparency 19.8 mag/arc sec (Sky Quality Meter) Seeing 5 (1-10) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Processing steps: Stacked with darks and flats. Saved in FIT with separate red, green and blue image files. Did slight noise reduction and histogram stretch on the separate files, recombined into rgb image. Color curves (histogram) stretch, unsharp mask, targeted color correction on particular areas. M33_9x8min_iso1600_10in f5.6_2010-01-12_NR-hist-comb-hist,rgb1-unshp-cc_NR.tif Combined with image taken on 2009-11-17: (M33_2009-11- 17_10x8min_iso1600_10in_f5_27degDrk _R1r2NRr5_G1g2g3(27d)g3_B1b2NRb5-cc_NR.TIF Did additional processing on combined images: Additional dark frame subtraction (there was residual heat signiture from the chip readout circiut). Targeted color correction, historgram stretch, unsharp mask sharpening, a little noise reduction, more tageted color correction Final image: M33_19x8min_iso1600_10in f5.6_2010-01-12_...hist,rgb1-cc_NR+B1b2NRb5-cc_NR_B_-dark-1-cc-hist2-1_unshp_NR2-cc3.TIF

M33 (The Pinwheel Galaxy)

Paul Walker — Sun, 17 Jan 2010 11:53:18 -0500

M33 (The Pinwheel Galaxy)

Paul Walker — Sun, 17 Jan 2010 11:53:18 -0500

M81 and M82

Paul Walker — Tue, 05 Jan 2010 21:49:29 -0500

by: Paul Walker

Description: M81 and M82 2009-04-29 Middlebury, VT 10x5min (50min total) ISO1600 10 inch f/5.6 (1407mm fl) Newtonian Field of view: 0.90 x 0.60 deg. Large Wooden Split Ring Equatorial Mount Camera Canon Rebel XTi (10 mega pixel) (not modified) Hand guided with off-axis video guiding setup. Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Stacked images with darks and flats. Did wavelet sharping in Registax after stacking. Noise reduction, slight historgram stretch, noise reduction, slight histogram stretch. Blended with a single 60 sec exp with the idea of increasing the detail in the core of M82 and purhaps a little color saturation. Did color saturtion (didn't record how much), slight hist stretch, target color correction (color shift) on a few spots in the core of M82 to bring out the reds (this also brought out the dust lanes in the center of M81 a little more), slight hist stretch to darken background while trying to maintain the faint arms of M81. M81,82_10x5min_wav2_NR_stch_NR_strch_comb60sec_sat_hist_cc-hist-Large.jpg

2 comments

Coma Corrector Comparision, with and without

Paul Walker — Sun, 03 Jan 2010 11:40:17 -0500

by: Paul Walker

Description: Using a Baader Multi Purpose Coma Corrector. They were taken through the 4.25� f/4 scope. The top image is without the coma corrector, the bottom with it. Mostly look at the stars (though some of the difference in the nebula is due to the corrector). These are crops of larger images. The center of the frames are near the rigth. The comparison isn�t quite apples to apple as the top image is slightly out of focus, taken on a slightly hazy night (the day I got the corrector), is a stack of 3 verses 7 (4 min) images for the bottom and no dark/flats for the uncorrected image. Many more stars are visible in frame edge of the coma corrected image and they are round, not oval. ---------------------------------------------------- This summer I starting thinking about getting an apochromatic refractor and a f/ratio reducer/field flattener. I was looking at a Borg 80mm f/3.9 setup. I wasn�t so keen on spending $2000 though, so I got to thinking about cobbling together a short focus reflector instead. I have three 4.25� f/4 finder scopes that I had build over the years for my 10� scope and a 4.5� f/8 (source of the 2" diag) that I built as a guide scope for the 10� (none of these were currently being used). Among them I had one good 4.25� f/4 mirror and one good 2� diagonal mirror and 2 good tube assemblies. A couple years ago at the Stellafane swap tables I bought a 2� Crayford style focuser with dual speed focus for $80 and this year a couple 8x50 finders with dovetail mounts for about $30 each. Taking images with the resulting 4.25 f/4 scope (f/4.4 equiv. with the 2" obstruction) worked well except for the coma. Coma correctors range from about $150 to $250. I purchased a Baader Multi Purpose Coma Corrector (MPCC) (the astrophoto setup only) for $145. It is optimized for f/4.5 optics and does not change the focal length (does not reduce or magnify the image). FYI, the same image brightness requires only 4 minutes in the 4� f/4 (f/4.4 equiv) compared to 7 minutes in the 10� f/5.6 (f5.8 equiv). I extracted this from an article I wrote for our local club's Winter newsletter.

4 comments

Coma Corrector Comparision, with and without

Paul Walker — Sun, 03 Jan 2010 11:40:17 -0500

by: Paul Walker

Description: Using a Baader Multi Purpose Coma Corrector. They were taken through the 4.25� f/4 scope. The top image is without the coma corrector, the bottom with it. Mostly look at the stars (though some of the difference in the nebula is due to the corrector). These are crops of larger images. The center of the frames are near the rigth. The comparison isn�t quite apples to apple as the top image is slightly out of focus, taken on a slightly hazy night (the day I got the corrector) and is a stack of 3 verses 7 (4 min) images for the bottom. Many more stars are visible in frame edge of the coma corrected image and they are round, not oval. ---------------------------------------------------- This summer I starting thinking about getting an apochromatic refractor and a f/ratio reducer/field flattener. I was looking at a Borg 80mm f/3.9 setup. I wasn�t so keen on spending $2000 though, so I got to thinking about cobbling together a short focus reflector instead. I have three 4.25� f/4 finder scopes that I had build over the years for my 10� scope and a 4.5� f/8 (source of the 2" diag) that I built as a guide scope for the 10� (none of these were currently being used). Among them I had one good 4.25� f/4 mirror and one good 2� diagonal mirror and 2 good tube assemblies. A couple years ago at the Stellafane swap tables I bought a 2� Crayford style focuser with dual speed focus for $80 and this year a couple 8x50 finders with dovetail mounts for about $30 each. Taking images with the resulting 4.25 f/4 scope (f/4.4 equiv. with the 2" obstruction) worked well except for the coma. Coma correctors range from about $150 to $250. I purchased a Baader Multi Purpose Coma Corrector (MPCC) (the astrophoto setup only) for $145. It is optimized for f/4.5 optics and does not change the focal length (does not reduce or magnify the image). FYI, the same image brightness requires only 4 minutes in the 4� f/4 (f/4.4 equiv) compared to 7 minutes in the 10� f/5.6 (f5.8 equiv). I extracted this from an article I wrote for our local club's Winter newsletter.

M33 (Processed to bring out the dust lanes)

Paul Walker — Sat, 02 Jan 2010 21:15:51 -0500

by: Paul Walker

Description: M33 (same as submitted 2010-01-01 but processed to show dust lanes better) 2009-11-17 Middlebury, VT Constellation - Triangulum Exp 10x8min (80 min total) ISO 1600 North - right 10 inch f/5.6 (1407mm fl) Newtonian (Homemade with Coulter Optics) Field of view: 0.90 x 0.60 deg. Camera - Modified Canon Rebel XT (350D) (8 mega pixel) (modified by Hap Griffin) with Orion Broadband Light Pollution Filter Autoguider (Meade Pictor 201XT) Temperature - 26 to 23 degree F Transparency 20.7mag/arc sec (Sky Quality Meter) Seeing 4 (1-10) Stacking - Registax 5 Noise Reduction - Noise Ninja 2 Other - Picture Window Pro 5 Stacked images with darks and flats. Saved as 16 bit FIT (separate Red, Green and Blue files). Did histogram strecth on Red, Green and Blue images, did 2nd hist stretch on R, G + B, then noise eduction on R + B, hist stretch on R, G + B (took several tries on R and B to get the desired color balance and boost to H-alpha and young star cluster regions), combined into color image, performed selective color correction, did noise reduction, increased saturation +5%. Addition histogram stretch. Re-balanced the color to bring out dust lanes by doing color curves histogram stretch. M33_2009-11-17_10x8min_iso1600_10in_f5_27degDrk_R1r2NRr5_G1g2g3(27d)g3_B1b2NRb5-cc_NR-cc_NR-hist-cc-chist3-Large.jpg

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