The Lazy Astronomer

I very much like the idea of a similarly advanced species somewhere in Andromeda taking pictures the Milky Way for fun - both of us never knowing that some strange aliens are watching them.

Like I said, it is huge!! With the same scope and same sensor size, I got almost all of it in a 3x2 mosaic, but 3x3 does frame it better.

Are you doing a mosaic, or were you imaging a particular area of it?

The spaghetti nebula is very faint, and also HUGE. I was playing around a few months back and I think I had to shoot a 6 panel mosaic to get most of it - 9 panels would frame it nicely (with almost the same equipment as you: esprit 100 & 294MM). I think l deleted the data because it was poor (lots of passing and high cloud), but I'll see if it's still sitting in the recycle bin to show you an example when l get back from work. You also don't mention the use of any filters, this target really benefits narrowband imaging, Ha particularly.

Starnge it has such a hard edge to it. Aliens must be the explanation 😁

At high dec and decent-ish seeing this should be achievable. At celestial equator, values around 0.8" are more realistic.

Yes, it will work fine over usb2. Be aware though, that the usb2 b type connectors are different to usb3 b type connectors, so you may need to use a usb3 cable - although usb2 type b cables do fit in a usb3 type b connection, I'm not sure they actually work properly and I've never been inclined to try. Edit: I've actually now read your post properly and realised you already know the connectors are different, haha!

This holds true so long as you kept the camera and lens connected between nights. Flats map the illumination of the sensor as well as any shadows from dust particles so the lights can be corrected during calibration. If you've disconnected and remounted the lens (or significantly changed the focus), it's likely that the 'map' of the flats won't match the lights and it can lead to more issues than it resolves. That said, it can't hurt to try anyway - you might get lucky!

Wow, surprisingly high number of fellow Berkshirians here. And you're not wrong there!! 😁 Welcome to the forum.

If you're sharing to this forum, just attach the unprocessed stacked FITS file to your post. Meridian limit reached would be my guess - EQMOD has a safety setting to prevent expensive things clattering into tripod legs, but by default I think NINA continues for some minutes past the meridian before initiating a meridian flip. The EQMOD meridian limit can be changed, or indeed disabled (not recommended), to prevent conflict between the two softwares. Beat me to it - I was going to suggest that too! Much better than a B. mask.

I don't use APT (NINA all the way for me!), but I imagine the process is broadly similar: 1. Polar align (via prefered method) 2. Use Stellarium to locate a target 3. Import target coordinates from Stellarium into NINA 4. Command mount to slew to the target 5. Plate solve to centre target in frame No need for any additional alignments - just use Stellarium to find targets, and repeat the process from step 3 when you want to move to another target. Further info for plate solving in APT can be found in the manual: https://www.astrophotography.app/usersguide/pointcraft_and_plate_solving.htm?ms=AAAA&q=UGxhdGUgc29sdmU%3D&st=MQ%3D%3D&sct=MA%3D%3D&mw=MzIw

Looking at the green channel you've posted up there, I'd say you did a good job processing it out - it's not really that visible, and doesn't detract from the overall image.

These are really nice for such short integration times 👍 Processing is a skill, and like all skills, you improve the more practice you get. There are plenty of tutorials out there to read/watch and learn from, or, feel free to post up a raw stack and ask the kind people of this forum to show you what can be done with your data. ☺

Just looking at the screenshot you posted above, it looks to me like the stars everywhere but the centre are affected by coma (I had a similar issue when I tried imaging with my (non EdgeHD) SCT) - DSS won't identify them as stars, so stacking might be difficult or even (as in my case) impossible.

Good seeing certainly helps. My experience with this mount is at high dec, guiding RMS is about 0.4 - 0.6", near the celestial equator, more like 0.8 - 1". That's with a 100mm refracter mind, as you're seeing this with a big ol' newt, maybe you did win the equipment lottery!

I'll caveat this by saying I've never done astrophotography with a DSLR, and am very, very far from being an expert, but generally I see the advice to not bother with darks with a DSLR, and just use bias frames, and dithering between lights.

🤑 Grow it faster, grow it bigger, sell it quicker

In DSS, calibration files in the group tabs are only applied to lights in the same group, anything in the main group is applied to all other groups as well. So put darks (or pre-stacked master dark) in the main group tab. Put lights, flats and flat darks from session 1 in a new group tab. Put lights, flats and flat darks from session 2 in another new group tab (repeat as needed). Stack.

Darks can be shared between different scopes, but flats cannot. The purpose of a flat is to provide a 'map' of the illumination of the sensor, as well as any dust in the optical path so it can be corrected during image calibration. This 'map' is certain to be different between different scopes. Some will advise taking flats after each session, but if you keep the camera on the scope, flats can be reused between sessions.

With maybe a couple of exceptions, DSLRs do not record video in the full sensor resolution, so you lose a lot of detail compared to the live view screen. Dedicated astro cameras will net far superior results for planetary imaging due to their ability to record video at full resolution.

Would be nice just to be able to see the sky at some point...

0.5 - 0.8" RMS is the typical guiding I get with my EQ6R Pro. The guiding performance you need depends on your image scale. What camera will you be using with the C9.25? Also, be aware that 1"/px is generally accepted as the limit for long exposure astrophotography due to the atmosphere, and even then, that will only be on the nights of the best seeing.

I watched that the other the day too - it was very surprising, and I'm now a bit paranoid about my own filters! Although they're not high speed ones, so won't have been bandpass shifted, I'm hoping that means they're fine...

I was going to add balance by reporting positive experiences with my ZWO stuff, but it seems like there's more people coming to report good experiences than bad, so I'll need to add balance back the other way! Most of the things l have from them are good: 2 cameras, filter wheel and eaf (huge backlash notwithstanding). But, their rgb filters were poor - huge reflection halos, particularly in the blue channel, plus other edge artifacts (these do calibrate out with flats though). I didn't expect greatness, because they were only a cheapo set originally bought for planetary imaging, but still the halos are quite severe; to the extent where they prevent me from extracting a synthetic luminance to add to the real luminance channel, which is slightly annoying. This is probably one of the best reasons to not buy ZWO (unless you are Chinese, of course!) but I feel the two main issues with this are: 1) Astronomy equipment is quite pricey anyway - building an AP setup runs into the thousands even if you stick to the 'cheaper' manufacturers like ZWO. There's just no way many people, myself included, could afford to do this without buying from them. More people in the hobby can't be a bad thing! 2) From what I can tell, companies like SX haven't really done any new product development in recent years, and I think they've been a bit left behind by the recent developments in CMOS sensors (uh oh, have I just started a CMOS vs CCD debate?! 😈)

Personally, I would say definitely upgrade your computer hardware. It is unfortunately not the cheap option, but if you can buy a high spec machine, you'll probably get another 10 years of use out of it. As an example of the speed of Siril and a decent spec PC: I recently calibrated and stacked 360 frames (23mb), which I also drizzled (so ~92mb per frame). I did the whole process manually, and from start to finish, it took about 30 mins. The actual stacking part took <5mins. This is with an i9, 32gb RAM, and an M.2 NVMe SSD. This is probably just my personal bias here, because I loathe working on laptops, but I think you get more for your money if you go for a desktop.