This is data from the same dates as images in the three previous posts before this one. There were so many things I wanted to shoot in these sessions that were Ha, but needed 3 or 4 times more exposure to do them justice. I scouted for what would be brighter Ha targets and did some test stacks trying to get the feel of how much certain things would need.
This one was one of the bigger and brighter targets I tested, but I could tell the less than an hour’s worth of data would need lots of work to make it into a presentable image. Another one of those works in progress, I guess. I gave it nearly an hour but it really needed at least double that as a start and 4x that for something exceptional.
Two sessions combined to produce this shot. One was taken with the UHC filter and the other was taken with the Optolong L-eNhance filter. Total combined time is nearly 3.5 hrs. Not too bad considering the location where they were taken – a Bortle 8 Red Zone.
Well, my luck with the weather allowed me to keep my promise and try out the new L-eNhance filter on a galaxy, in this case, M33. It came out surprisingly well considering this filter is not really made for galaxies. M33 has enough H2 and OIII regions to make things interesting, however.
I used Unity gain (11) with 4 minute subs, captured and LiveStacked in Sharp Cap 3.2. I also kept all the individual frames and tried stacking them in IRIS, but the LiveStack was better in overall quality, so I did not go beyond stacking them and viewing the results and just discarding it.
Below is the combined data from the above with 10×120 sec sub-images taken with a UHC filter:
So far, the L-eNhance does well for any H alpha objects and has a much more uniform background than my cheapo UHC. The UHC filter has a red to green diagonal color gradient always present and is exaggerated by the degree of LP in the shot, with long exposure stacks suffering the strongest. Not fun to deal with, but I’ve managed. Probably a quality control issue with coating uniformity for the cheap filter, I guess.
Since there is no uniformity-caused gradients with the L-eNhance, it lets me see the scope’s vignetting with this camera setup. Looks like I’ll need to start using flats in SharpCap to compensate, since vignetting is now noticeable.
A mixture of 120×30 sec exposures taken with a L-eNhance filter and a mixture of 15, 30 and 1 minute exposures taken with a UHC filter. About an hour and 30 minutes total. The 120×30 set was at 30 gain and -20C.
I am starting to like the 30 gain setting, since it gives the best results with shorter exposures. Over 40 is too much noise and under 30 it is just too slow.
When the set began there was no matching dark to subtract, so I was using one at gain 20. I stopped after about 10 shots and took some darks and then restarted shooting. I’m glad I did since the amp glow was starting to show up bad on the right side of the frame. The new darks overcame it and the glow averaged out after a while of LiveStacking with ShapCap 3.2.
What luck! First light for new filter is the day I received it! Thanks to the clouds for staying away. What I wanted to test was my new Optolong L-eNhance dual-band nebula filter, which is similar to the UHC filter I already own but with a narrower bandwidth and a more even color rendition across the frame than the cheap UHC one I’ve been using. I got to try it out before the run of good weather we’ve been having ended.
I was a able to test it on the Veil, which I recently imaged, and the Cave Nebula, which I had never shot before. I am very pleased with the results. Even color and illumination and better rejection of LP.
The Veil nebula was shot like I’ve been doing – 30 sec sub images at high gain. The Cave was long exposures of 4 minutes and I managed to get 26 subs. The Veil is a finished image and the Cave Nebula is still a work in progress. It seems the long exposure, 4 minute darks I used were not too good of a match and there are numerous hot pixel trails left to manually repair or clone out still left to do.
I also tried it on two reflection nebulae, one being the Running Man in the image below, and it was not as good as my UHC filter. I also tried one star cluster, M35, and it is the last image below. No galaxies yet, so I’m not sure how well it will work for those. Maybe next time I will have to try for one and find out.
Here is an interesting experiment I did in shooting short, 10-sub x 30 sec “subs-stacks” with LiveStacking in SmartCap 3.2 and stacking the stub-stacks in IRIS. I used Fitsworks first to orient the 5 min stacks taken after the meridian flip with the first batch. Final post-processing was done in PS.
I squeezed in two other shots this night – one of the moon and a test for guiding I did on Mirach. The test involved changing the PHD2 camera selection to the Ascom Toupcam driver instead of the regular version I used that gave trouble in the last session. That solved a problem with the camera dropping and losing connection.
Similar to NGC 981 above, I did twelve 10-sub stacks of Mirach for 5 minutes each for a grand total of 60 minutes of exposure:
The moon was out and after shooting NGC 891, I captured it in a .SER movie with 100 frames. I used 20 to make a still with the AutoStakkert software. Here’s the result:
Very clear conditions this night, but seeing was mediocre, with strong LP and moonlight interference. Cold for Cajun country, too… it got down to mid-to-upper 30’s. Brrr…
I was testing a used i7 laptop for use with SharpCap 3.2 under a bright moon on Saturday night, Nov 9, 2019 and the session yielded two images so far from the data. I was also testing a different guide camera. I switched from the Orion StarShoot mono cam to my Rising Tech IMX224 color eyepiece cam.
I had mixed results in testing. It was promising at first, but after several hours, some instabilities with SharpCap and the guider cam means I still have work to do to debug some possible driver and compatibility issues. Oh, well. At least the new laptop seems to be able to stream the camera data better than the old Panasonic ToughBook I was using.
As far as the two images, the top one was the first object I imaged since I used it to do alignment and focusing . I really wanted to see the “ghost” since I missed out getting it on Halloween. It is a crop centered around the star and galaxy at 100% resolution.
The second one was in the muck and between the bright moonlight, the LP and the terrible seeing, I thought it would be hopeless, but I managed to pull out some data that at least shows some of the spiral structure of M81. It is the full field of the camera. The linked image is at 50% reduction from the full size, 20MP final image.
Pretty clear night but the seeing sucked bad. The moon, which I did not shoot this night, was at 89%. Normally, I would not shoot on a night like this, but I had some testing to do, which was a good enough reason to get out.
I am amazed at how much signal is in just 6 minutes of sub-images for this new camera, QHYCCD’s QHY183c. When you take the shot, there is really not much there without significant stretching of the image. But, since the noise is so low with this cam, it can be boosted beyond anything a DSLR image could keep up with.
Now, I did do quite a bit of noise reduction on the Veil image included here, but it had enough signal to preserve enough detail to make the image adequate for a display image. I reduced it 50% to smooth it out more, but the original size is OK, too, just quite large to be downloading on a mobile phone.
Clouds were why the session was so short. I was clouded out when it was in a prime position early on, then it went completely overcast at the end. In between, I manged to get the 6 x 1 minute subs . I gave up and tore down and stowed the rig after I couldn’t shoot anymore. Almost as soon as I had put away the last piece of gear, I went back out and it was totally clear, just like when I had started setting up. Sucker holes and I fall for them all the time. lol
I was actually just testing some tweaks to my laptop I did hoping that they would improve performance. I added memory and updated a few drivers. Stability was vastly improved, but the speed of the machine lacked. I could not do a, “live,” shot of the moon at the lower exposure needed. It would not stream with the exposure less than 350ms. Too many frames per second for it to keep up with, I guess. Means I need another field laptop. 🙁
I started this session at midnight on Sat/Sun, Nov 2nd/3rd, 2019. It was cloudy, but the forecast said it would eventually clear. I went to bed early and woke up at midnight and checked and sure enough, it was clear. I managed to get these two objects plus some other stuff that I haven’t had time to mess with.
The seeing was horrible when I shot the Crab and it shows. I decided to take that data and combine it with previous efforts to see how it would look. The image below is the result of 3 different sessions, 3 different cameras and 2 telescopes. Check it out:
I bought the adapters needed to mate my new QHY183c camera to my Canon lenses. I tried it out with the 200mm F/2.8 telephoto. No way to control the F-stop diaphragm, since it needs a Canon camera to do that, so I had to shoot with it wide open. BTW, this was from the light polluted metro area I’ve been shooting from lately.
Since this is one of the cheaper lines of Canon lenses, it suffers from optical imperfections like astigmatism. That makes the red focus to a line up and down and blue and green focus to a line left to right. It really messes up the star shapes and there is no way to fix it except to stop the lens down to F/3.5 or higher. Oh, well…
Images of Comets, Nebulae, Galaxies and Star Clusters