wimvb

Of course the Empire strikes back. 😉

It could be a reflection. Tension (pinched optics) often shows itself as misshaped stars.

The mini is a mono cmos, which is more straightforward than the colour version. I too used the asi120 (Mono) binned past season, and had fewer ”star lost” events.

With a mono ccd camera, binning will bring the noise down and change the sampling scale (arcsecs/pixel). With a mono cmos camera, you change the sampling scale, but there is less gain in signal to noise ratio. But there is some, so it's still a good thing to do. With a colour camera, it's a bit more complicated because if you bin, you average over the colour pixels. There's probably still some noise advantage, but not as much as with a mono cmos/ccd. There's really only one way to find out if it makes a difference: try it. But do the test in a patch of sky where there are few guide stars; you'll probably get clearer results.

As long as you use zwo products, it should be a smooth ride. Zwo have included all adapters and spacers you need with their cameras, oag and filter wheels. But if you deviate from their path (dslr, other astrocam), you’re very much on your own. That being said, zwo also have published a chart with all possible variations, on their web site.

That makes the choice easier. Filter, or rather, rim thickness can be an issue. Compare the filter characteristics of the various brands. Then study reviews and look at images. Look out for reflections. In the end, such things will matter more than exact colour balance, you will find out. I know it’s more expensive, but if you keep the filters with the camera, you can create a workflow for each. Unless you can just swap cameras of course, without having to fiddle with spacers or adapters.

Astrodon markets a set optimised for the kaf chip, and one for Sony chips. They seem to work ok. iow, what’s your budget? 😉 I believe most manufacturerers have the same pass band on all three filters, ie 100nm per filter. It’s diffucult to taylor filters to all sensors. Where filters differ is in the gap between G and R (light pollution rejection) and the overlap between B and G (Oiii passband). I believe that Astrodon filters have a much wider gap between G and R, which is likely part of their colour balance strategy. If I were you, I might look into the zwo set for the asi1600 and adjust my process to also fit the Atik.

A light pollution filter. Idas filters get good reviews, generally.

Probably. Eventually you may want to try mono imaging or get a cooled camera anyway. If you have the funds, then why not now?

Have a look here https://www.astrofotoblog.eu/?p=856#more-856 cc review, only one with a distance larger than 55 mm

Very likely rebranded from the gso factory

Yes. 45 mm is inside the dslr. 10 mm is the t-ring adapter between the cc and dslr. There are some coma correctors that allow/need more than the standard 55mm distance. But I believe, these are more expensive. If you have a working oag solution, you can use it on basically any telescope. But imo, you'll get tired of swapping guiders around. Once you find a stable, functioning configuration, you probably don't want to disturb it. But take that hurdle in due course.

In ABE and DBE, check "normalization" in the corrections tab. This maintains the median background value.

It's not just quantum efficiency, but also sensitivity. A photon generates an electron (+ hole) = qe The electron creates a voltage on a "capacitor" = sensitivity. The larger that voltage, the more sensitive the camera.

There is an "imaging with the sw 130pds" thread, with plenty of users that have a guidescope or a finder guider. The 130pds has a focal length of 650 mm. For 1000 mm fl, an oag is probably better. Otoh, seeing in large parts of Europe can be so bad that it hides less than optimal guiding. Other things to consider: A large guide scope on top of your imaging scope increases the load on your mount. It can make balancing trickier. An oag is a heavier load on your focuser. May cause focuser to sag. A finder guider collects less light, but has a large field of view. Easy to find stars. But you have to find a way to attach it to your scope. The finder shoe is not up to that task, imo. It can also be harder to focus.

What scope? I've seen this kind of pattern with sct's occasionally. And when someone had dew on the front element of the scope. Check your subs. You can fix most of it with dbe, and desaturating the background. In dbe you plaster samples all over the image. Large (25 pixel radius or more) samples avoiding stars and galaxies. Increase tolerance. Forget about ifn, just flatten that background all you can.

Here's an interesting reference, albeit a bit old https://pixinsight.com/forum/index.php?threads/how-does-one-interpret-the-noise-evaluation-statistics-in-imageintegration.1933/

Phd has an accuracy measured in the tenths of a pixel. But how accurate can the mount move? Besides that, even with longer exposures, it's often the seeing that limits guiding. A larger aperture guide scope will gather more light and give you better/more stars to guide on. With my oag, I can always find a star, but very often that star is so dim, I seem to be guiding on noise. That's with an ASI120MM-S. Hopefully, my newly ordered ASI290 will be more sensitive. I have had good results with a skywatcher ST80 scope and asi120 camera, fixed to a top dovetail on my scope. Now with a longer focal kength reflector, I'm more concerned about mirror movement (flexure), hence the oag.

Pixel scale = 206 * pixel size (micrometer) / focal length (mm) arcseconds/pixel. Eg 5 um pixels, 1000 mm fl: Pixel scale = 206*5/1000 =1.03 "/pixel

As for which guidescope to use: 1. The guidescope must be firmly connected (bolted) to the main scope. Otherwise you will have an additional source of flexure. 2. The pixel scale of your guide solution shouldn't differ too much from your imaging solution. You should aim for achieving a guide rms that's about half your imaging pixel scale (arcsecs/pixel). 3. More aperture means more light on the guide cam, so easier to find a star, and better signal to noise ratio. If you already have a scope you can use, why not start with that?

The AZEQ5 has freedom find, so using the clutches during alignment is definitely a no-no. You absolutely need to use the synscan hc for this. Use a low power eyepiece first, then refine with a high power eyepiece, if you want better accuracy. After 2-star goto alignment, use the polar alignment routine on the hc to improve PA. Then do a new 2-star alignment. After that, you can play with the clutches all you like, because the mount will remember its position. Note: this assumes eq mode.

Check normalization in the correction tab. This maintains the median background (as well as any colour cast, so you need to do background neutralization afterwards).

Getting polaris in the polar scope or finder scope of a new mount is no guarantee for correct polar alignment. With a goto mount, you will need to do a 2 star alignment first, then a polar alignment using the hand controller. Sw synscan has an all star polar alignment feature that is quite accurate and fast. You don't even need a polarscope on your mount. They're back breakers anyway. Use a compass to find north, and sight along the parked telescope tube to get altitude roughly correct. Then go to star alignment. Btw, when doing a star alignment, the first star can be "miles" off, but once centered, any subsequent stars are much closer to alignment.

Nice! The background is a bit too blue for my taste, but an easy thing to fix. Neutralising it should also give more punch to the red.

Deconvolution is a wonderful tool, but I would hold off on it until a later time. Once you have the data, you can process it over and over, as you learn pixinsight. For a novice, background extraction, background neutralization, colour calibration, stretching, noise reduction, and perhaps star reduction, are quite enough to wrap one's head around and avoid . Just my 0.02€