Saturn, Recent Observations
July 7, 2016. Seeing was reasonably good when I imaged Saturn near the meridian tonight. The above image is the derotated stack of 5 images made from videos taken between 2:56 and 3:01 UT. Each was the best 10% of 7144 frames. Note extreme blowup of the north polar region at the right. There seems to be a vague hexagon there, not nearly as contrasty as it was in my image taken in 2013.
May 12, 2016. Seeing was fairly good when I recorded the video for this mosaic. The background showing the satellites was taken with a gain of 600 (maximum) and an exposure of 100 ms. Saturn was grossly overexposed in the image from stacking the 50% best frames of 601 in the 60 second video. The correctly exposed overlay of Saturn was made from the 25% best frames from a 60 second video of 6566 frames taken at a gain of 484 and a 9.1 ms exposure. Enceladus is just peeking out from the glare of Saturn on the right and Dione, Tethys and Rhea form a triangle southwest of the planet. South is up in this image. The north polar hexagon is less apparent than it was in the image taken in July of 2013 in spite of the more favorable tilt.
April 24, 2016. Seeing was about 4/10 when the 60 second video from which this image was made was taken. The image below was obtained at 2:58 AM from a 60 second video. No prominent storms visible, and the northern polar hexagon is not visible like it was in 2014.
April 14, 2016. I had a nice clear night with at least average seeing tonight. Was able to get decent images of Mars, Jupiter and Saturn. I
used the ASI224MC color camera, a 2x Barlow with a spacer giving about 3x, my atmospheric dispersion compensator (see Saturn, current webpage about 2/3 down at wa2guf.org) on the
CPC-1100EdgeHD. Effective focal ratio = f/30.3, 0.0904"/pixel.
I put together the montage above from my results. Seeing was a bit better when Saturn and Mars were imaged than when Jupiter was earlier in the evening.
The North polar hexagon is not as visible this year as it was last year. Mars shows clouds over Hellas (top) and over Elysium (just below center near terminator on the left).
July 7 2015. The sky was reasonably cloud free but very murky tonight, seeing only fair. I imaged Saturn with the ASI174MC at the f/10 focus of the
CPC-1100EdgeHD, taking 90 second videos. I deliberately overexposed Saturn to bring out six of the brighter satellites, Titan, Rhea, Dione, Tethys and Enceladus using 0.250 second
exposure. Mimas is right at the edge of the overexposed area around Saturn between Enceladus and Tethys. An overlay of a properly exposed Saturn image was also obtained at 0.003 sec
exposure. The resulting composite image is shown below and an enlarged image of Saturn is shown above.
June 7, 2015. Got this image of Saturn from a 90 second video with the ASI174MC, 3x Barlow and CPC-1100EdgeHD under somewhat soupy conditions, patchy light overcast. Processed with
AS!2 and Registax.
April 26, 2015. Got up at 2:15 am this morning, a bit before Saturn crossed the meridian at only 30 degrees altitude. I set up the ASI174MC at the f/10 focus of the
CPC-1100 EdgeHD and lined up on Saturn. I took a set of fifteen 60 second raw undebayered videos and two at 180 seconds. With a ROI of only 120x80 pixels, I was getting 330 fps with
an exposure of 3 ms. The 60 sec videos gave me 19,839 frames and teh 180 sec videos gave me 59508 frames. This camera is fast, mostly because of the USB 3.0 connection to the
computer. Unfortunately, seeing was poor, no better than 2/5. No clouds, a bit hazy. I processed the videos using AS!2 with 3x drizzling to recover the color from the raw
undebayered video. The TIFF files from AS!2 were then wavelet sharpened in Registax6. The image taken at 6:48 UT is shown above. Including more frames (50% instead of 10%)
or using the 180 second videos did not give a significant improvement. Image soft, North Polar Hexagon not visible. Seeing limited, as usual. This camera is going to be tough
though if I ever get some good seeing.
July 27, 2014. I took my 150 mm Maksutov to west Texas with me along with my ASI120MC camera. The vacation site was Mano Prieto, a residence near Fort Davis and McDonald observatory which some friends and I rented for 6 nights. Very dark skies here. A series of 60 second raw undebayered videos of Saturn were taken at the f/15 focus of the little Mak with a 58 ms exposure at full gain. A good breeze was blowing causing a great deal of image movement. Didn't think I would get any useful results. Videos processed with AS!2 using 3x drizzling to compensate for undersampling. Surprisingly, the image movement was nicely cancelled out by the alignment software. The above is a stack of the 50% the best frames of a 5346 frame video. Not that great, but the 9 degrees lower latitude of the west Texas site at least gave Saturn a high enough altitude for decent imaging.
December 6, 2013. The above movie was taken by cameras on the Cassini spacecraft of the hexagonal feature at the North pole of Saturn. This is the bluish region on the bottom of my images of Saturn below.
July 27, 2013. When I lined up on Saturn tonight, seeing appeared to be a bit better than my last imaging opportunity. Probably 3/10 with transparency being above average, around 7/10. I set up the ASI120MC camera directly on the f/10 focus of the C-1100, not using any additional amplification. Using Firecapture 2.3 beta build 12 drag a rectangle selection of ROI, I was able to get to 10ms exposures and a frame rate of around 100fps. The ROI was only 160x96 pixels, but there was ample room to keep Saturn in the window. I took 23 sixty second long videos, leaving the debayering function turned off so I would record raw 8bit avi files. I then used AutoStakkart!2 to align and stack with 3x drizzling and sharpened the results using Registax6 to give 23 images taken from 8:52 to 9:23 EDT.
See the images below for a comparison of one of these 23 images with the result of first debayering the same avi with Firecapture's stand-alone debayer utility (HQLinear algorithm) and then using Registax6 (not using Registax's drizzle function which I have not been able to make work) to align, stack and sharpen. Note that the conventionally processed image (not using AS!2) has sampling artifacts and poor resolution compared with the drizzled image.
All 23 images were then processed in WinJUPOS to derotate and stack them. The stack was sharpened in Registax6 and the result is shown above left.
July 24, 2013. Conditions very poor tonight. Hazy sky, scattered clouds but Saturn visible. Was able to take two 60 second videos before the cloud cover became compete. Seeing was also poor, estimate only 2/10. I used the ASI120MC camera coupled with a 2x shorty Barlow to the C-1100. Videos were taken with Firecapture 2.3 beta in raw undebayered form for processing using AutoStakkert!2 to drizzle in the color information. The resulting images were sharpened and color channel shifted to reduce the effects of atmospheric dispersion and then derotated and stacked in WinJUPOS and finally sharpened again. The result is shown at the right.
July 23, 2013. After a thunderstorm at sunset, the sky cleared, but was not very steady when I began imaging Saturn around 9:15 pm EDT. I used the ASI120MC color camera attached to the C-1100 EdgeHD with a 2x shorty Barlow. This combination gives f/23. I took 11 raw undebayered videos of 60 seconds duration. I then processed them in AutoStakkert!2 using 1.5x drizzling to recover the color information without debayering. The stacks from AS!2 were sharpened using wavelets in Registax6 and then derotated and stacked in WinJUPOS. The image was then sharpened a final time in Registax6 and annotated in Photoshop to give the result shown at the left. Because of the poor resolution, I cannot confirm the presence of the white spot seen in the image taken on July 19 even though the region where the spot was is near the limb on the lower left.
July 19,2013. Seeing was a bit poorer than last night, estimated 3/10 and transparency was also below average, 4/10. Light haze. Tonight I am testing a new camera: the ASI120MM, the monochrome version of the color camera I had been using since late May. The first target of the evening was the moon for which I had fitted the camera with two filters: a #25 red and the usual NIR blocking filter. This passes a narrow band of red light that is less subject to seeing and atmospheric dispersion than white light imaging and is very useful for lunar imaging which does not have much color to begin with. I mounted the camera at the f/10 focus of the C-1100, no Barlow amplification. The lunar images obtained tonight are on my Lunar Images page.
I kept the same setup when I moved over to image Saturn. f/10 would not normally be my focal ratio of preference for planetary imaging. I have used f/23 to f/30 with the color camera and f/12 to f/15 should be needed for 3.75 micron pixels and f/10 should give an undersampled image. Good chance to try AutoStakkert!2 drizzling. Firecapture 2.3 beta build 12 was used to capture eight 60 second videos using an ROI of 160x96. The lower focal ratio permitted the short exposure of 16ms. This and the small ROI gave me a frame rate of 62 fps and allowed 3779 frames to be captured in one minute. Direct processing of one of the videos with Registax6, keeping the best 50% of the frames gave the (enlarged) result shown below on the left. The same frame processed with 3x drizzling in AS!2 and then wavelet sharpened in Registax6 is shown below on the right. Note the presence of sampling artifacts and failure to resolve Cassini division all the way round on the left image and the better resolution with no sampling artifacts on the right image. All eight videos were processed the same way as the lower right image and then combined by derotation and stacking in WinJUPOS to give the final result shown above and to the right. Much improved contrast between Cassini division and the A and B rings, North polar hexagon shows up nicely. Note that there is a light colored storm trailing to the west and slightly south for about 25 degrees of longitude in the same region as the big storm of 2010-2011. I measured the coordinates of the spot in WinJUPOS and got L2=20.6°, B'=48.5°
July 18, 2013. Sky was clear when I started imaging aroung 9 pm EDT. Seeing was not as good as last night, I estimate about 4/10. The ASI120MC camera was coupled to the C-1100 with a 2x Shorty Barlow. This combination gives me a focal ratio of f/23. I took 11 sixty second videos between 9:05 and 9:20 pm EDT using Firecapture set to debayer using the HQLinear algorithm (that'st he one NASA uses on the Curiosity rover's color cam). I used a 460x256 pixel ROI to minimize file size and maximize the frame rate. Each video was 2400 frames in length. These were preprocessed in PIPP, cropping, centering, sorting and rejecting the 1200 worst frames and saving as new files. The new videos were then processed in Registax6, derotated and stacked in WinJUPOS and finally sharpened once more in Registax6.
July 16, 2013. Excellent seeing was predicted for tonight and the Jet Stream forecast indicated it was well to the north with winds overhead in the 0 to 10 mph range. Saturn was easy to find in the twilight, just 4 degrees north of the nearly half moon. Seeing at the 38 degree altitude of Saturn was not excellent, but still pretty good. I am estimating 4/10 for the seeing. I set up first with the ASI120MC camera hooked up to the C-1100 EdgeHD with a 2x shorty Barlow. This gives me a focal ratio of f/23. I took 17 sixty second long videos with this configuration using Firecapture with HQLinear debayering turned on. I then removed the Barlow giving me the native f/10 of the C-1100 and took two more sixty second videos, one of the raw undebayered and the other debayered with HQLinear to be used with AS!2 as described below.
I processed the f/23 videos in PIPP, centering, cropping, sorting and discarding the poorest 50% of the frames giving me 1200 frame avi files which were much smaller than the originals. I then processed them with Registax6, keeping all frames and finally derotated and stacked all 17 images using WinJUPOS to give the result shown above.
I next turned to the videos taken at f/10. As I understood it, AutoStakkert!2 was capable of taking undersampled images (even raw undebayered color images) and processing them using the drizzling technique to provide super resolution. The technique relies upon the frames being dithered with respect to one another by seeing. This lets the camera get samples between the cracks of the pixels and obtain information which would normally only be obtained if the pixel size was much smaller. I first processed the debayered video using Registax6. This gave the tiny image shown at the left. I magnified it 3x in Photoshop to reveal the artifacts created by undersampling in the top large image. These show as "jaggies" in the image. I then processed the raw video in AutoStakkert!2 selecting "force bayer GRBG" under the color menu and selecting a drizzle setting of 3.0x. After analyzing and stacking I sharpened the stack in Registax6 givng the second large image. This image does not show sampling artifacts and is essentially as good as the individual images obtained at f/23 see the fourth large image for an example. I then processed the debayered f/10 video in AutoStakkert!2 using the RGB setting in the color menu and 3.0x drizzling. The result is shown as the third large image. It is a definite improvement over the result of simply processing it in Registax6, but not as good as the result from processing the raw video. I guess having the interpolated values created by the debayering interferes with drizzling. This is a promising technique which I will investigate further. It offers the possibility of using low focal ratios which give short exposures and much smaller ROI. Together these mean lots more frames taken in the same time.
July 14, 2013. S up Skies very murky tonight, but by 8:30 pm the crescent moon and brighter stars were showing through the haze so I set up the C-1100 on Saturn with the ASI120MC and a 2x shorty Barlow giving f/23. At the low altitude of ~37 degrees, the seeing was pretty bad, the image was constantly in motion and distorting its shape and only occasionally could I get glimpses of Cassini's division out in the ansae, never on the narrow part of the rings over the planet. I used Firecapture2.3beta to take nine 60second videos between 9:14 and 9:29 PM EDT of 2400 frames each. These were preprocessed in PIPP to quality sort and keep the best 1200, cropping and centering each frame. These were then processed in Registax6, stacking all frames and sharpened with wavelets. Two of these images are shown below. All were derotated in WinJupos, stacked and then sharpened again in Registax6. The result is shown above, South up.
July 6, 2013. Sky was very murky tonight, but appeared reasonably steady. I set up the C-1100 with a 2x Barlow and ASI120MC. The combination gives f/23. I took 6 videos of 2350 frames each from 9:27 pm EDT to 9:32 pm. PIPP was used to center, crop and stack the best 1200 frames from each video. These 1200 frames were then processed in Registax6 and finally WinJUPOS was used to derotate and stack all six images. The final sharpened stack is shown at the left.
June 22, 2013. Boomer and I went out imaging saturn again last night and took 14 sixty second videos of Saturn at f/23 with the ASI120MC, 2x Barlow and C-1100. Not too bad, not too good results after PIPP and Registax6 processing. I really need to build my atmospheric dispersion compensator. In my Schupmann, atmospheric dispersion is automatically compensated for perfectly by adjustment of the micrometer screws that tilt/tip the field mirror and align the image of the objective onto the mangin mirror. Slight misalignments create a linear spectrum which will cancel that caused by atmospheric dispersion. The only thing wrong with my new, C-1100 is that it is not a Schupmann. The compensator (drawing below) that I plan to build around a couple of 2 degree refracting wedge prisms should let me make the same adjustment of the image that I did with the Schupmann. To the right is the result of derotating, stacking and sharpening all 14 images of Saturn I got last night. Considerable improvement over the resolution and s/n of the individual images, but still not up to the quality of the June 1 image. Firecapture, PIPP, Registax6, WinJUPOS and Registax6 (one mo time) was used to obtain and process the images. Seeing should be better tonight because of lower strength jet stream winds overhead.
June 4, 2012. Seeing was expected to be above average tonight, but when I went out a bit after 10:30 PM and opened up the observatory, it was a disappointment. Saturn was difficult to focus and only glimpses of Cassini's division could be seen in the ansae, not at all in the part of the rings crossing the planet's disk. I took four 60 second videos anyway using the ASI120MC camera and 2x shorty Barlow on the C-1100. The combination gives f/23.3. Processed in PIPP, keeping only the best 1200 out of 2399 frames and then aligned and stacked using Registax6. The best of the four results is shown at the left.
June 1, 2013. Seeing was good considering the low altitude of Saturn. Cassini's division could be easily seen at the extrema of the rings and almost into the narrow part closest to us just looking at the live image on the computer monitor. I took 12 sixty second videos using Firecapture 2.3 beta 10 to run the ASI120MC camera attached to the C-1100 with a 2x shorty Barlow giving f/23.3. Camera settings were 24 ms, 100% gain and 73% max gamma. Videos were pre-processed using PIPP, keeping only the best 2000 out of 2500 frames, then processed in Registax6 to align and stack all 2000 frames. Wavelet sharpening gave 12 individual images, some showing Cassini's division almost all the way round. After derotating and stacking in WinJUPOS and a little more sharpening in Registax6 the image to the right was obtained, clearly showing Cassini's division throughout the visible part of the rings. Ring C shows up nicely where it passes in front of the disk of the planet and the North Polar hexagon is well defined within a yellowish polar region. Encke's division remains elusive. Above this text is an animated GIF from the 12 individual images.
May 31, 2013. The combination of low jet stream velocities and Clear Sky Chart prediction of 4/5 quality seeing suggested this might be a good night. While not 4/5 seeing at the low altitude of Saturn, the seeing was definitely above average. Using a shutter speed of 24 ms, full gain and gamma increased to 73%, I took a series of 60 second videos with Firecapture 2.3 beta7 and my ASI120MC camera coupled to the C-1100 with a 2x shorty Barlow. Debayering with HQLinear algorithm was selected. While taking the videos the image on the screen showed hints of the Cassini division going all the way round, but not distinctly. The videos were pre-processed in PIPP, keeping only the best 1200 frames out of ~2500 obtained, then they were aligned, stacked and wavelet sharpened in Registax6. The 16 images were then run through WinJUPOS, derotated to a common CM and stacked. Finally, the derotated stack was sharpened again in Registax6 and annotated with Photoshop. This is probably my best image of the season. Much detail visible in the cloud band structure, and the North Polar hexagon is well defined, along with the yellowish band around it. Could be better though, there is no hint of Encke's division.
May 27, 2013. Skies were clear when I went out a bit after midnight this morning. Boomer was with me, having taken over from Noah as night assistant and bear detector. I set up the ASI120MC camera on the C-1100 using the 2x shorty Barlow to amplify the f/10 focus of the C-1100 up to f/24. That focal ratio was probably not justified, since the seeing was below average, probably no better than 3 or 4 on a scale of 10. I took two videos of 60 seconds duration, pre-processed them in PIPP, keeping only the 2000 best frames which I aligned and stacked in Registax6 and then made final adjustments in Photoshop. Resolution was considerably poorer than last week's image with the Cassini division not resolved on the near portion of the rings and the polar hexagon only visible as a darker blob at the pole. No bears detected, Boomer slept through the session.
May 22, 2013. Seeing was below average and hazy with a bright moon. I did some disappointing imaging on the moon and then a double exposure on saturn at f/10 to get
the brighter satellites. Got them all except Mimas which was too close to the glare and Hyperion which was too faint to see against the sky glow. See below. Exposure was 100 ms
for the satellites and 5 ms for Saturn.
You can see from the lack of detail on Saturn that even f/10 was way oversampling for the quality of seeing. Note how big the satellite image blobs are. I am finding that for pretty good seeing, f/22 is sufficient, and if it ever gets really good, I am prepared to go up to f/30 which should be close to Nyquist sampling.
So far, I am quite pleased with the ASI120MC. It is definitely more sensitive than my Flea3 and far far better than the DFK42 from TIS.
May 21, 2013. I took 17 sixty second videos from 3:19 to 4:03 UT last night of 2400 frames each using my ASI120MC color video camera attached to the C-1100 EdgeHD telescope with a 2x Barlow. Seeing was definitely above average, around 6/10. Each video was run through PIPP to center, crop and quality sort the frames. Only the best 1200 were saved from each video for processing by Registax6 with which i aligned and stacked all 1200 frames and sharpened them with wavelets, and partially corrected atmospheric dispersion by shifting the red and blue layers a few pixels. The resulting 17 images were then operated upon by WinJUPOS to derotate them to a common central meridian and then all were stacked and the result again wavelet sharpened in Registax6. The final result is shown At the left. The north polar hexagon is clearly defined. One of the sides is facing us, the two adjacent ones are angled back towards the polar limb, and three sides are over the curve of the planet beyond the rim. While Cassini's division is seen all the way round, I don't see any sign of Enke's division, so I should eventually do better if I get better seeing. A light colored zone marks the location of the planet wide storm of 2011 in the northern hemisphere. If the seeing would support it, I should be working at around f/33 using my 3x Barlow for proper sampling. The ASI120MC has 3.75 micron pixels, effectively 7 microns considering the reduced sampling frequency imposed by the RGBG Bayer filter mask. I believe the colors are accurate, compared with the true color images from the Cassini Spacecraft.
May 8, 2012. Testing the ASI120MC CMOS video camera. The seeing was terrible tonight, the USB cord that came with the camera was too short, there were scattered clouds, but all in all, I got a good test of the new camera AND Firecapture 2.3 beta build 7 which was needed to run the camera. I have a couple of USB extensions running under the observatory floor, but plugging the cable from the camera into one of the extensions was a disaster: a latticework of beige colored lines with vertical strips dominated the image in Firecapture with the actual subject seen through the blinds. The five foot cable supplied with the camera was not quite long enough to reach back of my C-11. Putting an extension tube on the back of the 2x shorty Barlow moved it back just enough to reach. When hooked up this way I got a usable image of Saturn, but way over-magnified. Radio Shack being closed, I went with it. Because of the long focal ratio for the conditions (~f/30) I had to use longer exposures than I would have liked. 39 ms was needed to get the histogram up to 44%. F/20 would have been better. I took a couple of 100 second videos of 2500 frames each, preprocessed in PIPP, keeping the best 2000 frames and then finished up with Registax6 and Photoshop. The best of the images is at the right. The image is not much to look at because of the poor seeing, but getting anything with a decent s/n from Saturn at f/30 is pretty good, particularly for a CMOS camera. This is the first CMOS camera I have seen that is worth what you pay for it if planetary webcamming is your thing. Cost me ~$300 with shipping.
May 4, 2013. Another good night, again maybe as good as 8/10. Took 5 videos of 100 sec duration using Firecapture 2.2, Flea3 color video camera, 2x shorty Barlow lens and my C-1100 EdgeHD telescope. All were processed in PIPP to center and crop the image and keep only the best 2500 frames out of 5000. The processed video were then aligned, stacked, R/B adjusted to correct atmospheric dispersion and finally wavelet sharpened. The image at the left taken at 1:48 am was slightly better than the others. Note that the Cassini division can be seen pretty much all the way round the planet. The North Polar Hexagon is also prominent.
May 3, 2013. There was a short period of pretty good seeing around 1:05 to 1:15 am during which I used Firecapture to take a 100 sec video from which the image to the right was obtained. The original video contained 4928 frames. Preprocessing in PIPP saved only the 2500 best frames. The resulting video was aligned, stacked, R/B shifted to remove atmospheric dispersion and sharpened in Registax6. Again, the North Polar Hexagon is evident.
May 2, 2013. Seeing was not as good compared with yesterday, perhaps 5 or 6 on a scale of 10. I obtained 8 videos of 100 seconds duration using the Flea3 color video camera attached to the CPC-1100 Edge HD SCT with a 2x shorty Barlow lens. The combination gives about f/23. The videos were first processed with PIPP to give cropped and centered .avi files which kept only the best 2000 frames of the original. PIPP's quality sorting is more reliable than what is used in Registax6 (IMHO), so I will be routinely presorting and discarding bad frames in PIPP. The resulting videos were then aligned, stacked, R/B shifted to tune out atmospheric dispersion, levels adjusted and wavelet sharpened in Registax6. Seeing varied a bit over the course of the imaging session and the picture from the video taken starting at 5:01:31 UT was the best. It is shown at the left.
May 2, 2013. Tonight we have a rare evening of better than average seeing, possibly as good as 7 or 8 on a scale of ten. I obtained 13 videos of 100 seconds duration using the Flea3 color video camera attached to the CPC-1100 Edge HD SCT with a 2x shorty Barlow lens. The combination gives about f/23. The videos were first processed with PIPP to give cropped and centered .avi files which kept only the best 2000 frames of the original.The resulting videos were then aligned, stacked, R/B shifted to tune out atmospheric dispersion, levels adjusted and wavelet sharpened in Registax6. Seeing improved over the course of the imaging session and the picture from the video taken last starting at 2:20:08 UT was the best. It is shown at the right. The image is notable in that the famous north polar hexagon discovered by the Cassini Mission is visible at the top. I see a distinct polygonal appearance that seemed to rotate over the course of the imaging session. Perhaps an animated GIF would show this better.
April 27, 2013. Still testing the DFK42 on the CPC-1100 EdgeHD. Seeing was poor.
April 26, 2013. First Saturn image of the 2013 apparition. I am using the new CPC-1100 EdgeHD SCT with the DFK42 CMOS color camera. Although seeing conditions were poor, I took three 100 second videos, processed them in PIPP and Registax6. The best of the three is shown at the right. The CMOS camera is not as sensitive as the Flea3 CCD camera. Exposure of 45 to 65 ms was needed to get sufficient s/n for realistic imaging compared with the 15 ms which suffices for the CCD camera. This results in far less frames for stacking.
June 24, 2012. This picture was taken last year using the Flea3 coupled to the 7.25" Schupmann with a 2x shorty Barlow. It is included to show the significant change in tilt this year compared to last.