Saturn with (mostly) the 7.25" Schupmann
Since 2003, I have imaged Saturn whenever it was available with whatever camera and telescope I happened to be using at the time. In the picture below I show how the appearance of Saturn has changed from then until now. I have used my old Philips ToUcam, a DBK21 from The Imaging Source and a Flea3 from Point Gray. All were color cameras. I used my 10" Barlow Newtonian, my 12.5" Newtonian and my 7.25" Schupmann medial. When I started imaging Saturn we were looking at the south pole and the "underside" of the ring system. The earth passed through the plane of the ring system three times in 2009 and 2010 and now we are looking at the northern hemisphere and the "topside" of the ring system. This period is a bit less than 1/3rd of a Saturnian year and we see remarkable seasonal changes in the planet.
June 30, 2011. Saturn imaged using a Flea3 color webcam coupled to the 7.25" Schupman medial with a 2x Barlow lens to give an effective focal ratio of f/27. Seeing was poor to average and the altitude of Saturn varied from 29° to 27° from the beginning to the end of the session. 90 second videos were taken at 30 fps at a variety of shutter speeds (see captions) using the program FireCapture in raw undebayered y800 format. They were later debayered with FireCapture's debayer tool using the Adaptive Smooth Hue algorithm and processed with Registax6. Final images are stacks of the best 2000 of 3000 frames, sharpened with wavelets and then levels adjusted in PhotoShop.
July 16, 2011. Tonight I got several decent images of Saturn in spite of the low altitude, poor seeing, and evening twilight. North is up in the 6 normally exposed images, but south is up in the over exposed image showing the satellites Tethys and Rhea. As an experiment, I tried the new auto align feature in the Beta 2.0 version of FireCapture by Torsten Edelmann. The feature worked perfectly, keeping the planet centered in a small ROI. This results in much higher frame rates and smaller file sizes.
The great northern hemisphere electrical disturbance is still going on. It is the blue region bordered by lighter blue just above the dark North Equatorial Band.
July 21, 2011. This is probably my last Saturn image of this opposition. The planet is getting lower and lower into the evening twilight and becoming more amd more difficult to image. Taken at f/27 using the Flea3 color webcam coupled to the Schupmann with a 2x Barlow lens.
February 27, 2012. Saturn was imaged with the Flea3 color camera coupled to the f/14, 7.25" aperture Schupmann medial with a 3x Televue Barlow lens giving an effective focal ratio of f/45. 60 second videos were taken under less than ideal conditions, average seeing, but an altitude of only 48°. The video was processed in Registax6 and final adjustments made in PhotoShop Elements. Note how much more wide open the rings are than the last image taken in 2011.
April 20, 2012. Same equipment and setup as in the imaging session of Feb 27, but the seeing was considerably better. Flea3 Color webcam coupled to 7.25" f/14 Schupmann medial with 3x Televue Barlow lens to give f/45.
May 16, 2012. Predictions were for only average seeing and fair transparency, but I made the effort and opened up observatory #3 and set up the 7.25" Schupmann medial on Saturn around 10 PM EDT. After getting lined up using the 35mm Plössl and 2x shorty Barlow, I switched to the Flea3 which is parfocal with the eyepiece. This combination gives me about f/27, not enough for proper Nyquist sampling if the seeing conditions were perfect, but probably sufficient for these conditions. The lower focal ratio than my usual f/45 gave me a much brighter image with a much reduced noise level. I took several 90 second videos at full gain and exposures in the 80 to 100 ms range. The image to the left, taken at 10:19 pm (2:19 UT the next day) has sufficient resolution to reveal a remnant of the great storm of 2011 (blue-green band). Note prominent blue cap on the North pole of Saturn. This bears watching as Saturn's northern hemisphere becomes more tilted towards the sun and the earth. The hexagonal standing wave pattern imaged by the Cassini spacecraft in March of 2007 is located on the north pole of Saturn. The last time the North pole was pointed towards us was back in 1987 before webcams and Registax were in widespread use by amateurs for planetary imaging. Who will image it first when the pole points our way in 2014-2018? A Hubble Space Telescope image of Saturn taken in 1990 shows the hexagon and it was imaged by Voyager 1 and 2 back in 1980. See image below:
May 19, 2012. Seeing is predicted to be good tonight. I set up the Flea3 color webcam and 2x shorty Barlow on the 7.25" Schupmann medial and took eight 90 second videos at full gain and using various exposures in the 21 to 59 millisecond range. The videos were processed with Registax6 and final histogram adjustment, orientation, annotating and cropping was done in PhotoShop Elements. The image to the left is about the best one, obtained from the video taken at 11:01:55 pm EDT corresponding to 3:01:55 UT the next day. The blue irregular band in the northern hemisphere is the remnant of the great storm of 2011. North is up in this image.
May 28, 2012. I had brief imaging opportunity tonight. The sky was kind of murky and Saturn was even more dim than usual, but the seeing was a bit
above average so I could do longer exposures and get away with it. Still noisy, but including more frames smears the Cassini division too much. Last hear's storm still leaves its
traces in the NTZ.
June 6, 2012. Sky hazy, seeing poor to average. Flea3 color camera was coupled to the 7.25" f/14 Schupmann with a shorty 2x Barlow giving about f/28. Firecapture was used to take several videos of Saturn which was at an altitude of 42 degrees and almost due south. The videos were processed in Registax6 and enlarged 2x, cropped, and labeled using PhotoShop Elements. One of the images is shown at the left.
June 7, 2012. Taking advantage of a brief imaging opportunity, I set up the Schupmann medial with 2x shorty Barlow and Flea3 and took 5 videos at exposures ranging from 20 to 80 ms. Seeing did not support the longer exposures. The image to the right was obtained at 50 ms. Still not resolving Cassini's division all round the planet.
June 15, 2012. Seeing was relatively good tonight. I am guessing about 6/10 with a suspicion that it NEVER gets above 8/10 around here. I spent a while
examining Saturn with a 12 mm Plossl eyepiece, 2x shorty Barlow and my Mark I Eyeball. The latter piece of equipment has exceeded its warranty and is giving me a lot of frustration since,
at high magnification, the tiny exit pupil sometimes ends up right over my cataract and things go all goofy. Have to get that fixed. Anyhow, the combination gives me about 400x.
I could see Cassini's division quite well, and in flashes of better seeing, it appeared to go all round the ring. My overall impression of color was a very pale creamy yellow, with less
color in the rings which appeared almost white. The equatorial zone was the most yellow region and both polar regions had a distinct bluish cast to them. The broad NEB had a faint
hint of a rosy color.
I took eight videos over the period from 9:50pm EDT to 10:07pm. The seeing consistently improved over the course of the session. In retrospect, I should have waited a bit longer, but Saturn was getting lower and dew was forming on the glass. My impression of the color of Saturn as seen on the computer screen as taken by the Flea3 color webcam matched very well what I had seen through the eyepiece, so my white balance must be set pretty well. An image made from the last video is shown to the left.
If you look closely, you will see that the Cassini division is not completely black, ranging from a warm gray (110/95/102) to a cool gray (83/87/89). I believe this is an artifact of the not perfect seeing. The gap between the rings and planet is full black (0/0/0), but the shadow of the rings on the planet is not (39/34/64). I believe some of the color problems are simply artifacts of the seeing and how Registax aligns and sharpens the image from a 24 bit color video. When the seeing is excellent, all is well and all the colors get lined up together, however when the seeing is bad, what is good for green is not necessarily good for red or blue. This points up an advantage of the monochrome camera/filter wheel combination over one-shot color cameras. When the three separate monochrome videos are aligned and processed and later combined to give the final RGB image, each color channel has been processed properly.
June 17, 2012. Seeing was a bit better tonight than on the 15th and considerably better than last night when it was terrible. The image to the right was obtained from one of eleven videos taken between 9:28 and 10:06 EDT. Seeing was better towards the middle of the session when the video which gave this image was taken. The Flea3 color webcam was coupled to the 7.25" f/15 Schupmann medial with a 2x shorty Barlow giving f/28. The video was aligned, stacked and wavelet sharpened in Registax6 and then final adjustment of levels done in Photoshop Elements. I believe the light greenish irregular band at about 45 degrees northern latitude is a remnant of the great storm of 2011.
June 21, 2012. After a blistering hot day close to 100°F, the evening sky was free from clouds but quite murky and there was no wind. These conditions can lead to good seeing, and that in fact was the prediction of the Clear Sky Chart. I coupled the Flea3 color webcam to the Schupmann using the 2x shorty Barlow giving me f/28 and took seven videos over the period from 9:30 to 9:40 pm EDT and processed them before doing the next video using Registax6. There was considerable image motion and intermittent defocusing and distortion. Definitely not good seeing but better than my usual. The best image of the night is shown at the left, taken at 60ms exposure. It is a stack of 747 aligned and sharpened frames. Note darker blue band within the NEB and the persistent light blue green band in the NTB, the remnant of the great storm of 2011.
June 23, 2012. Had a little better luck tonight. Seeing was predicted to be average, but it was a little better than that, at least better than average for my
place. I took 8 videos between 9 and 9:30. The best was taken at 9:11pm EDT and is shown below, enlarged 2x in PhotoShop. This may be my best so far this season. It
certainly shows Cassini's division further into the narrow part of the ring than any of my other pictures. The division is not entirely dark and has a bluish tinge to it. Probably
because my blue layer is lousy as usual. That annoying orange cast to the rings where they approach the planet is still there and I saw it on screen while taking the videos.
I did a little fiddling with my telescope today. I moved my finder around to the same side of the scope that the eyepiece is on to make it more accessible at all positions of the telescope. Trouble is, that side of the tube has the hump where the meniscus corrector is mounted so I had to put it on a bit of a platform to clear the hump. Everything worked very well until I went to shut down for the night and rolled the roof back. Wouldn't clear the finder. Had to loosen the dovetail slide and take it off before I could close the roof. Not what I had planned. It was very convenient in that position.
I did a bit of experimenting with a video finder also. My DBK21 is now mounted on the side of the tube with a 75 mm f/1.8 lens on it. I can run that camera using IC Capture 2.2 at the same time that I run the Flea3 with Firecapture. With Al's Reticle (downloaded from the Ice in Space site down under) running I can position the double crosshairs over Saturn. It works out at 300% zoom that the little square in the middle of the crosshairs is about the size of the field in the Flea3, so I can easily reposition the telescope if the planet drifts out of the field of view without getting up and going back to use the optical finder.
April 30, 2013. I believe I actually had some good seeing tonight, possibly 4/5. I took a series of 100 second long videos of Saturn using the Flea3 coupled to the C-1100 Edge HD with my 2x shorty Barlow. The combination gives about f/23. This image is one of the best, obtained when Saturn was at 38 degrees altitude about 20 minutes after midnight, EDT. I processed the videos first in PIPP, keeping only the best 1000 frames out of 6532, then aligned, stacked and sharpened with wavelets in Registax6. Image was scaled 2x in Photoshop. Is it just my imagination, or is there a green hexagon at the pole?