Lyra
Taken with a Canon EOS 550D with an 80mm lens on an equatorial tracking mount, under Bortle 4 skies. 30 thirty second lights, 50 darks, 50 flats.
Stacked in Siril following the manual pre-processing tutorial. Stretched also in Siril using Asinh Transformation. I set the stretch factor to 30, and the black point to 0.005, then exported the image as a jpeg.
I think she looks a bit better than my attempt at Orion. You can sort of make out the Ring nebula.
Also, I'm pretty sure that's a comet over to the right of Sulafat. Tiny green cloud of consistent size, drifted a few arcminutes over the ~20 minutes I was capturing these images
Looks like you have a collimation error you might want to look into. What is your setup?
It's a DLSR mounted to the top of my scope. Variable focal length lens, was set to 80mm. I don't really know if collimation is possible with this kind of lens. The focus could probably have been better, though
Ah right, that's just not a stiff enough setup, that's probably causing the issue.
Any reason for not using the telescope as a lens? That was my first setup and I used it for years till I bought a proper camera for my telescope.
Tiny FOV. I can't bring the focuser close enough for the camera, so it needs a Barlow lens, but that turns the 650mm scope into a 1300mm lens. So I basically don't have anything between 90 and 1300 mm.
At some point I'm gonna 3d print a new focuser. There's files on thingiverse. Maybe I start working on that tonight so it's ready by the weekend
Cool! Let us know how you get on.
I think if you stiffen up your current setup it will be a lot better as well.
It’s not a perfect answer, but halving your exposure time and taking twice as many can help mitigate tracking and stiffness issues. You still have the same total exposure time, and the exposures tend to be sharper because they’re not trying to track for nearly as long. And if an exposure or two get funky shaped stars, you can toss them out without impacting your total data set as much.
There’s a few downsides… each time you read data from the sensor introduces noise… but modern CMOS sensors are reasonably low noise, so this isn’t as much of an issue as it was with CCD’s from back when. You’re also processing twice the number of subs, so your stacking and calibration can take longer.
The trade-offs might make it worth it though. You can play around and find out.
Annotated version pointing out the maybe-comet