The Lazy Astronomer

I believe the extra spacer/shim should go between the filter and the camera. In my mind (and I may well be wrong!), the extra fraction of backfocus is needed after the light path has been slightly altered by passing through the filter.

Amp glow really does not matter. It is completely calibrated out with darks. The 294mm is somewhat of a fussy camera when it comes to calibration though, so if it's an easy life you want, I'd look elsewhere. There's been some talk of the possibility of mono version of the 533, if that comes to fruition it might be the one for you.

It's cheating if you crop out Alnitak! 😅 It is very nice though 👍

Out of those 2, my vote would be the 533 as well. If you could stretch to it, the 2600 would be the best choice.

I like the straight RGB image - I've got around 16hrs in narrowband on this region and l think your image has inspired me to attempt a more "true" colour look when l get around to processing it.

To identify the UV/IR cut filter, would it be possible to use a common household IR source (like a TV remote) and a camera which detects IR? So, put the filter over camera sensor, get a live view going, and point and shoot the remote at the camera. If the camera detects the flashes, then it must be the clear filter. Repeat with other filter to confirm. Might even be able to do it with a phone camera as well - I know my Samsung does detect the flashes from a remote, but my partner's iPhone doesn't.

An autofocus routine should be highly repeatable if the settings are properly configured. As has been mentioned, it may be the miscollimation throwing the focus measurement off, but if you get that sorted and still have autofocus issues it's likely that your focusser step size or backlash compensation settings aren't quite right.

Ah, the joys of mono imaging! 🙃

Disclaimer: woefully underqualified to be providing advice! 😁 Nevertheless: nice detail, and the background looks good (maybe a tad dark, but much better than I managed on my first attempt). I wonder if there's something more that could be had in terms of colour? There's some lovely subtle reds and blues to be had in Andromeda.

Someone's been busy!! That's a nice collection you've got there 👍

My take on it is to ask the following question: are you looking change your camera anyway? If yes, then sure, go for a newer generation CMOS, for all the reasons mentioned above. If no, then your money is probably better off in your pocket (or spent elsewhere!). I don't think there's really anything in it in terms of the final image quality when it comes to CMOS vs CCD these days - I see fantastic results with both. The CMOS might make it easier on the mount, and be a bit faster than a CCD, but if you're getting results you're happy with - in a timeframe you're happy with - is it worth the £2k or so to buy a new CMOS?

You can basically do anything that doesn't involving stretching the histogram.

Haha. I'm currently trialling Pixinsight, and to be honest I quite like it actually, but I know what you mean about applying for the licence - it seems a little OTT. @69boss302: on the subject of darks and flats, you may even be able to get away without them entirely with the 2600mc (how's your vignetting and dust bunny situation?). There's a guy on here (can't remember his username right now) who uses that camera with no calibration frames and seems to get good results. Just worth bearing in mind as sub optimal flats can introduce more problems than they correct.

Nice - it's got something of a funky psychedelic look to it 😁

My, oh my, that full resolution version really is something quite special!!

Actually, the opposite 😁 I took the advice of @vlaiv which is to ignore the histogram, use high gain, and very short exposure (around 5ms) to take 1000's of frames. Individual frames will look terrible but the stacked and sharpened result is very pleasing indeed (seeing conditions allowing). Never imaged Venus though, so I'm not really sure what sort of detail is visible (if any?) in the cloud tops.

I appreciate your frustration somewhat, however people on the forum are free to choose what they like and comment on. If they don't happen to do so with something you post, accept it and move on - it's not healthy to count views and likes. Personally, the images I produce are for me, because I enjoy the process of making them. If someone else happens to like it too, then great, and if someone is able to provide feedback that helps me improve then that's even better (and is in fact the main reason I post my efforts here). If not, then no worries, I still had fun creating it.

I do very much enjoy your images Göran - you always go after such interesting and different targets. l have a processing question for you (if you don't mind sharing your secrets 😉): what's your technique for bringing forward these very faint nebulous regions and maintaining that nice dark grey background?

I like the little rainbow, it can be your signature on the image 😁

Library of darks: yes, super easy, just take them and reuse however many times you want. Library of flats: yes, but only if you leave the imaging train intact between sessions. Even then, eventually you'll get some new dust bunnies (or they'll shift slightly) and new flats will be required. You should be able to get a good few months out of them unless you have an unusually dusty environment.

What reducer do you have? I think the reducers sold for the ZS71's were reducer/flatteners. You mention imaging with a DSLR (I assume this is with the ZS71) - how are the star shapes near the corners? If they're good, then no need for a separate flattener. As for the barlow: it has no place in deep sky astrophotography. This depends on the required backfocus from your reducer/flattener. Typical backfocus requirement is 55mm to the camera sensor. For a dedicated astro cam you very likely will need spacers. Absolutely yes, proper image calibration is not really optional. An advantage of a camera with set point cooling is you can create a library of darks and reuse them. That calculator is concerned only with pixel sizes and sampling rates. It makes no judgement at all as to whether one camera is better than another, and indeed there are a multitude of other factors to consider. In typical conditions, it is unlikely you'd be able to actually achieve the sort of resolutions that calculator might have you believe. An example from personal experience: I image at 1.7"/px. However, based on the measured FHWM of my images, I find I can usually bin x2 in processing with no loss of actual detail (this effectively makes my sampling rate/resolution 3.4"/px). There is also a way to attempt to recover resolution in undersampled images through the use of drizzle integration (provided you have adequately dithered data). I've never personally tried it, although it's on my list of things to do.

It's another vote for the 200p from me. By all means do a comparison on one panel between the 2 scopes though, but the theory says the 200p would be the clear winner. Just looking at optimal sub exposure time for the barlowed 72 actually: sub exp time = C * read noise^2 ÷ sky background in e-/px/s For a 1.5e- read noise mono cmos with 3.8um pixels and 60% qe, in fairly typical suburban bortle 5 skies with a 7nm nb filter you'd be looking at almost 20 minute subs for the sky background to swamp the read noise (C factor = 10). That puts quite a lot of pressure on the mount. In contrast, the with the 200p, you'd be looking at subs of just under 4 mins in length to swamp the read noise by the same factor. Then there's also the resolving power of the scope (maybe not the correct terminology here) - a barlowed small scope will certainly give you a larger image, but will it record twice as much detail than at native focal length? I doubt it.

It's a very specific question and has piqued my curiosity: what are you planning to do? The actual probe is 20mm long and 4mm in diameter. There's also some heat shrink sleeving around the cable which extends about halfway down the probe, this adds about 1mm to the diameter.

Definitely contact the council, that light must shine onto so many bedroom windows it's a prime candidate for shrouding. If that doesn't adequately reduce the light intrusion into your garden, you could try fashioning some kind of retractable shield from plywood or something?

I am one of those multi coloured swap shop image fans 😁 I like this - I think it looks a bit like a heart (an anatomically correct one), so the natural colour rendition suits it well.