Deep Sky Imaging
July 21, 2022 I finally added M31 and M33 to my collection of galaxies in the local supercluster. I used the Astro-Tech semiAPO 70 mm f/6 to capture the images. The image scale of the smaller telescope was just right for these nearby galaxies.
January 19, 2022. This is an image of the Crab Nebula, M1, taken using the Live Stacking tool of SharpCap with an ASI294MC coupled to my C14 with a Starizona 0.63x focal reducer, efr=f/7. The image is a 480 second stack of 8 second exposures, 4x binning, darks subtracted. This nebula is a remnant of the supernova of 1054 CE. The pulsar remnant is the brighter of the two close stars in the center of the nebula. It rotates at a rate of 30 revolutions per second. A searchlight like beam of radiation sweeps past the earth causing a brief spike of light. For most of the revolution period the star actually disappears!
June 30 2021. The two images below were obtained by live stacking in SharpCap with the ASI294MC at the f/6 focus of my 72mm semi-APO AstroTech refractor.
May 17, 2021. Along with the more picturesque spiral galaxies I have been imaging using the LiveStacking tool in SmartCap, I attempted to image elliptical galaxy M87 and its jet with the C14/ASI294/0.63x focal reducer. I was able to image it, but the jet did not show up very well. I suspect it was a combination of undersampling (2x binned 4.63 micron pixels at f/7) and the relatively high brightness of M87 as well as the fact that I had to use 8 second subs. Shorter exposures did not work because the LiveStacking tool refused to stack the subs. Could be lack of alignment stars bright enough to work at the shorter exposures. See image of May 16 below.
May 16, 2021. I used the live stacking tool in SmartCap to obtain long exposures without any guiding with the ASI294MC, 0.63x reducer and C14. Images of M109, M102 and M87 are shown below. The polar jet from the massive black hole in the center of M87 can be seen as the tiny streak on the edge of the galaxy at 2 o-clock.
May 14, 2021. Seeing was good tonight and the sky reasonably dark after the crescent moon went down. Got these images of M51, M104, M61 and M101 by live stacking. I used the C14, 0.63x reducer and the ASI294MC.
May 13, 2021. Seeing was pretty good tonight. Star blobs are significantly smaller than my earlier attempts at imaging M101 and the red streaks that reveal ionized hydrogen in star forming regions are partially resolved in the arms of the galaxy.
May 12, 2021. Although the seeing was unsteady, the skies were clear tonight. I was able to get better images of the 6 galaxies shown below than any so far. Dark frames as well as flat frames were used to calibrate the images as they were taken and stacked by the Live Stacking tool of Smart cap. The C14, Starizona 0.63x focal reducer and the ASI294MC were used for these images of M100, M64, M91, NGC4565, M101 and M106.
April 13, 2021. Below is a live stack with full calibration of 90 ten second exposures of M51 taken with 2x binning of the ASI294MC, 0.63x focal reducer and the C14. This is the full frame of the camera. The sensor is 13x19.2 mm in size and the unvignetted field is a circle about 10 mm in diameter. Note how well the daytime flat dealt with the severe vignetting. The noise around the border edges is the only sign of a poor s/n way outside the fully illuminated field.
April 13, 2021. After constructing a full aperture diffusing filter from a wooden hoop and a sheet of translucent Lucite, I prepared a daytime flat, calibrated with the appropriate dark and saved it for the night's adventures. Below is a live stack with full calibration of 47 ten second exposures of M42 taken with 2x binning of the ASI294MC, 0.63x focal reducer and the C14. This is the full frame of the camera. The sensor is 13x19.2 mm in size and the unvignetted field is a circle about 10 mm in diameter. Note elimination of vignetting.
April 6, 2021. An experiment to see the effects of using dark subtraction on live stacking. Not much effect. Looks like the ASI294MC does not have a lot of thermal noise. I might get more help from applying flats. I think I see some vignetting, possibly from the focal reducer.
April 5, 2021. Last night we had one of those rare events in New Jersey: a clear moonless night with relatively low wind velocity so I could actually open up the fold-off roof of the observatory. I used the time to get Live Stacked images of several galaxies as well as both live stacked and lucky imaging pics of the eskimo nebula. For the latter, I took a video of one second frames and used AS!3 for stacking. All the rest using SharpCap's live stacking tool.
March 21, 2021. I got a nice image of M42 tonight. It is a live stack of 50 four second images taken with the Live Stacking tool in SharpCap. I used the Starizona 0.63x focal reducer and the ASI294MC camera. Focal ratio is reduced from f/11 to f/7. Total exposure was 200 seconds. Could have gone longer if it were not for the moonlight. Note: unguided exposures. No darks or flats.
September 21, 2019. This morning I took a set of 19 ten second unguided images of M42 with the ASI-1600 at the f/14 focus of the 7.25” Schupmann. Darks were subtracted.
January 27, 2017. The image of the belt and sword region of Orion is a 25 minute integrated exposure taken with the ASI174MC camera and a 55mm camera lens working at f/4. The gain was set at 179 which corresponds to unity gain in this camera and the exposure time was 20 seconds per frame. A total of 75 frames were combined in Autostakkert and processed in Photoshop and Photomatix to give the above result. Some haze was developing towards the end of the exposures and prevented further imaging. The camera was attached to the Losmandy rail on the G11 mount of my C14 and simply tracked. No guiding corrections were made. In addition to M42 in the lower right we see the Flame Nebula and Horse Head Nebula in the upper left.
May 27, 2016. Testing new ASI-1600MM camera without cooling. Set of 294 images of 0.54 seconds exposure. Aligned and stacked in MaximDL. No darks or flats. CPC-1100EdgeHD, f/10.
March 18, 2015. Tonight I tried out the new ASI120MC CMOS camera from ZWO. I attached it to my 80mm, f/5 guide scope and took a 300 second raw avi file of 10 second
exposures and aligned and stacked it in Registax6.
January 22, 2015. After a lot of lost motion after losing my computer to the cold weather (I turned it off over Christmas and it got very cold and the mother board failed), reinstalling all my software on a new computer and learning how to use the full version of MaximDL with my Orion StarShoot Pro Deep Space Color Imager, I am back in business. Above is an HDR version of a 25 minute integration time image of M42, the Orion Nebula. It is a stack of fifty 30 second images taken at the f/10 focus of my Celestron 11inch EdgeHD with the SSDSCI. Below is a normal image, showing the outer nebulosity but with the Trapezium region blown out completely.
M74 reprocessed as HDR image
M31, The Andromeda Galaxy
M42, The Orion Nebula
November 27, 2014. Thanksgiving Day. Downloaded Photomatix Essentials and used it to create a HDR (High Dynamic Range) version of the image of the Orion Nebula and The Andromeda Galaxy, M31. Note that the Trapezium is visible in the middle of the brightest part of the Orion Nebula and that the faint outer detail is also visible.
November 21, 2014. Calm and clear tonight, but cold. I set up the CPC-1100EdgeHD with the Orion SSDSI at its native f/10 configuration (no focal reducer) and took a
set of thirty unguided 10 second exposures of the Orion Nebula. Star images stayed reasonably round for no guiding. I took a set of five darks and five flats, also at 10 seconds
exposure. MaximDL was then used to calibrate, color convert and stack the individual exposures to give the result shown above.
October 27, 2014. Tonight I imaged M27 again, but this time using the new 0.7x focal reducer giving me f/7 from the CPC-1100 EdgeHD rather than the native f/10. I managed a slightly longer exposure, 92 minutes vs 80 minutes in the image of September 26, but the big improvement in image density is the faster focal ratio, about 1-1/3 stops faster.
October 24, 2014. Orion was high this morning when I got up to observe the eclipse of Callisto by Io, so I spent a little time taking this image of M42 using the SSDSI at the f/7 reduced focus of the CPC-1100 EdgeHD. The above image was obtained from four light exposures of 1 minute each and a single dark. No flats. Obviously, needs more integration time. We'll do better.
October 16, 2014. My 2" sky fog filter came from Orion today. I installed it on the nosepiece of the SSDSCI and re-oriented the camera so that south would be to the left in the images. When twilight was nearly gone, I set up on Altair, did a good focus with the Bahtinov mask and pointed the telescope at NGC6960. I set up the Orion autoguider on the bright central star in the nebula and set the camera to acquire eighty 60 second images. Unfortunately, the sky became partly cloudy after the 32nd exposure and I had to quit after taking a set of five 60 second darks, five 20 second darks and five 20 second flats. After calibrating and stacking and extreme histogram stretching I got the result shown above. Obviously I am going to need a lot longer integration time than 32 minutes. The Veil is beginning to show up, however, and the color is nice. I don't know why the overexposure halo around the central bright star (52 Cygni) is off center. Have not noticed that before. I wonder if the new filter is tilted?
October 12, 2014.
October 8, 2014. My 0.7x focal reducer came in from Celestron today. I mounted it directly on the 3" threaded hub on the backplate of my CPC-1100 EdgeHD and threaded the Baader motorized Crayford focuser directly on the back of the lens. The optical path taken up by the focuser was almost a perfect match for the spacing recommended by Celestron, needing only a half inch extension on the drawtube of the focuser to make it perfect. The system is shown above. The image below is the result of stacking 30 one minute guided exposures, calibrating and converting to color before stacking. Note the contrasting colors of the two brightest stars in the image. The one near the upper edge is a type A2 blue giant and the one in the lower right is a much closer K2 orange dwarf.
October 5, 2014. Although the moonlight was much too bright for good deep sky imaging, I made the attempt on the spiral galaxy M74, for practice guiding if nothing else. The SSDSI color camera was used at the f/10 focus of the CPC-1100 Edge HD telescope. Scattered blue light from the moonlight gave a pronounced blue hue to everything. The image above is the result of removing the blue channel entirely and converting the red and green channels to monochrome. 19 five minute exposures were calibrated, color converted, aligned and stacked to give this image with a 95 minute integration time. I will do better on a good dark night. The actual color image is shown below. The blue background is moonlight scattered off the atmosphere just like sunlight makes the sky look blue in the daytime. M74 is only 32 million light years away. Practically in the neighborhood.
October 4, 2014. Here is an image of M13 taken with the Orion StarShoot Deep sky imager at the f/10 focus of the CPC-1100 EdgeHD telescope. It is a stack of 78 images of 40 seconds exposure for a total integration time of 53 minutes. Calibrated, color converted, aligned and stacked in MaximDL
September 26, 2014. Tonight everything worked very well. Guiding was spot on and I managed to take 120 forty second exposures of M27 with the Orion SSDSI one shot color camera at the f/10 focus of the CPC-1100 EdgeHD. I also took a set of 5 darks at 40 seconds exposure. The next day I got a set of 5 flats at 3 seconds exposure and the darks to go with them. Processing in MaximDL gave the result above. The faintest stars are approaching 18th magnitude and quite round all the way to the corners of the giant 25x18mm CCD (3040x2024 pixels) of the camera. The above image is a cropped 1479x1379 pixel region around the nebula.
September 23, 2014. Here's the improvement obtained by 480 seconds integration compared to only 120 seconds in the picture taken on September 18. Again, taken with the Orion StarShoot Pro Color Imager II at the f/10 focus of my C-11 EdgeHD telescope. 18 exposures of 30 seconds each were calibrated and combined in MaximDL6.
Above is an image of M57, the Ring Nebula taken with the same equipment with an integration time of 540 seconds.
September 18, 2014. I am slowly learning how to use my Orion StarShoot Pro Color imager with the CPC1100EdgeHD and the Orion Autoguider. The above image is a stack of only six 20 second guided exposures at the f/10 focus of the telescope. When I could keep the guider working, it did well, but eventually lost the guide star after only a few exposures. I took flats today and used them in processing the raw color images with MaximDL (boxcar flats). Only 5 of the 20 second images were used to make this final result. What would this look like with an hour of integration rather than only 100 seconds?