The Lazy Astronomer

Just as an additional note to the issues mentioned with the 294c, the mono version is better, but still has some issues with getting good flats. It doesn't make for a deal breaker, but it makes calibration more cumbersome than it needs to be. If I were you, I'd probably be looking at the 2600 if you could stretch to it, or the 533 (either osc or mono, depending on what you could afford/justify spending). In the OSC v mono debate, my vote would always go to mono.

Lovely delicate Oiii around the crescent showing quite nicely, plus you've got the soap bubble visible in the bottom right too. The only thing is the stars are quite funky - did you use Topaz denoise by any chance?

Now that is a seriously thick ribbon of Ha there - I'd say you've definitely succeeded in accentuating it. I may well copy your framing if/when I shoot for myself 😁

5 or 10 minute subs (or longer) may be needed with narrowband filters, or cameras with high read noise, or under very dark skies, but for broadband imaging under a typical suburban sky with a modern astro cam it's way overkill IMO.

Correct, choice of target has no impact, and yes, theoretically, once the optimal minimal exposure is reached, all the faint/dark detail has been recorded to a sufficient enough level and a longer exposure won't record any further detail.

No worries - the general idea is to expose until your light pollution "swamps" your camera read noise. To calculate your optimum minimum sub exposure time, you only need to know two things: 1. Your camera's read noise (at your desired gain/ISO setting) 2. Your light pollution rate, in electrons per pixel per second - this will vary depending on your equipment and the pattern of your local light pollution, so you'll end up with a different number with different cameras, scopes and, most likey, when pointing at different areas of the sky (e.g. my light pollution is worse in the east as I'm shooting towards London). I tend to sort of ignore this last variable and just use a generic light pollution measurement from the web. Getting the read noise figure is easy, decide on a gain and look up manufacturers spec. For the 533, ZWO state read noise for unity gain (100) is 1.5e- To get your light pollution rate is a little more involved. Our resident expert vlaiv has described several times how to calculate it experimentally using your own data, which is probably the most accurate way of doing it, but for life of me I can't remember how to do it! The other way is to calculate it theoretically - I use this tool: https://tools.sharpcap.co.uk/. Input your details and it'll spit out a number at the bottom. Once you've got the numbers, the formula is then: exposure = C*RN^2/P, where RN is camera read noise, P is the light pollution rate, and C is a factor to determine how much additional noise is introduced into the image. This can basically be any number you want, and the higher the number, the lower the amount of additional noise. A C-factor of 10 equals approximately an extra 5% noise and is generally a good figure to settle on (there comes a point where visually there is no real discernible difference in the noise for different C-factors and I think after 10 it becomes diminishing returns). When I did it last time using your details I think I just used the peak QE figure quoted by ZWO, but it might be better to approximate an average QE across all the colour channels instead, or even use the lowest figure. And by the way, this is by no means gospel - it just sets out an exposure time that ideally you shouldn't drop below. If you want to go longer and your mount performance/guiding is up to the job, then go for it, just be aware that once you reach the optimum minimal sub time, exposing longer is very much a game of diminishing returns.

This will all likely be very low quality, you'd be much better off looking into established astronomy brands instead (as advised above), but you pays your money you takes your chances.

If you're making your foray into dedicated astro cams, then definitely look for one with set point cooling - it is one of the main advantages of an astro cam, so I think it would be unwise to choose one without (assuming you're going down the long exposure DSO route, and not planetary or something more akin to EEVA).

I never really understand the issue people have with darks - reading the extraordinary lengths people go to and still suffer from light leaks - I simply don't get it. I don't even take the camera off the scope, whenever I need to shoot mine, I just do it at night with a jacket or two loosely thrown over the setup and don't see any problems whatsoever.

Not really a solution to your problem, but as you've only got a few lights, for a workaround you could apply the master flat manually to each one using pixelmath: light/master flat

Could you explain why, please?

Just to say, there is an advantage to the ghs script pointed out by one of the creators that you can stretch an image then run starnet/starXterminator/whatever, and do an inverse stretch (again in ghs, just use the same parameters as before) to go back to linear. Et viola, 32bit linear star removal

Starnet v2 does linear de-starring

GHS appears under utilites>script once installed. Link to install is here: https://ghsastro.co.uk/links-2/ Also a few video tutorials on how to use it - I'd recommend the recent one from the astro imaging channel as it's essentially a walk through from both of the script creators.

Skip? No, portable observatory!

Or surely an open tube design like a newt or RC would be liable to collect some new dust motes from time to time?

And for those of us without a permanent pier, maybe consider some weight training 😅 Seriously though, l don't consider myself particularly strong, but I leave my eqiupment permanently set up and just move the whole lot in and out of the garden in one go (100mm refracter on an eq6r*) - quick polar align in Sharpcap and l can be imaging in 10 minutes. *side note: what does the "r" denote? It seems like a naming structure oddly borrowed from the automotive industry

Not sure whether this will be of interest/useful or not, but, just for comparison, here is a single 3 minute sub with the mono version of your camera and a 6nm Ha filter. All I've done is calibrate, bin x2 and stretch a bit PI:

Halos present around the brighter stars. You'd have thought they'd have invested in a set of astrodons... 4/10 must try harder 😁

Hmm. Yes, I think I just assumed that when zooming on a phone it stopped at 100%, but I've just done a little experiment and I think it stops at something like 200% making it quite difficult to guess what the true full resolution is...

I think the 0.75 refers to the pitch of the thread

I largely access the forums on my phone, but I think l have the same issue when viewing on the PC, I tend to just right click and open image in new tab if I want to view at 100%

All my filters are Astronomik L3, RGB and SHO (6nm). I don't really have a bad thing to say about them, they work and they work well. The only slight things that stop them from being perfect: 1. Oiii is difficult to get flats right for, due to a central bright spot which shows up. This may be my light source, or some other internal reflection from the optics, rather than the filter itself, but the issue does not show up on any of the other filters. 2. I noticed a small halo with the blue filter on a very bright star. It was no issue to deal with it in processing and maybe I'm being a little unfair as it was Alnitak!

Thanks very much gents 😊

Well past the usual time for one of these images to make an appearance! It takes me a long time to get around to actually doing anything with my data... This is probably the region that got me into wanting to try astrophotography a few years ago, after a former work colleague showed me an image of this very object. I really couldn't believe that so much detail could be captured from a regular suburban back garden, and I guess that's what got me hooked on the idea of giving it a go for myself. Captured in Jan/Feb this year, just shy of 16 hours in HaLRGB (split as below) with a 294MM and Astronomik filters. Stacked in Siril and processed entirely in PI. Ha - 7h L - 4h 51m R - 1h 17m G - 1h 24m B - 1h 24m Ideally I'd have liked more LRGB, but various things conspired to prevent that from happening. The L data was ok, but the Ha was much cleaner, so the luminance channel is composed mostly of Ha, with L blended in larger amounts around features largely absent in the Ha capture, such as NGC2023. I wanted to retain the Ha stars, as they were obviously much tighter than the broadband ones - hopefully I haven't fudged their colours too much in my attempts to do this. Ha was also blended into the red channel using the PM formula described by Rogelio Bernal Andreo in his book Mastering Pixinsight. As usual, feedback and critique welcomed! Thanks