Adam J

They are not rectangular pixels.

I think you are looking at it the wrong way. That QE is just for light of that frequency so that amount of 530 odd nm light that is converted to electrons. But there then there is fall off either side of that peak frequency, so yes the real figure averaged across the green is probably about 10-20% less if you stick to the same band as you would get for a typical set of LRGB filters. Red 64% Green 64% Blue 53% But we also have to consider that there are only 25% red pixels 25% blue Pixels and 50% Green pixels. So we get the following absolute figures (approximately): Red = 0.64 x 0.25 = 0.16 Green = 0.64 x 0.5 = 0.32 Blue = 0.53 x 0.25 = 0.1325 Compare that to mono in the form of an ASI183mm pro (Peak =83%): Red = 0.664 Green = 0.8 Blue = 0.71 Lum = (0.664+0.8+0.71) / 3 = 0.725 But all pixels are active and you can also use luminescence so we get the following absolute efficiencies: Red = 0.664 x 1 = 0.664 Green = 0.664 x 1 = 0.8 Blue = 0.71 x 1 = 0.71 Lum = 0.725 x 1 = 0.725 Now the OSC does have one advantage, all subs will collect all channels at the same time. However typically Lum will collect date at three times the rate of RGB so lets see how that leaves us over 120 subs assuming a 50/50 split between Lum and RGB for the mono camera. Starting with the OSC we get: Red = 0.16 x 120 = 19.2 Green = 0.32 x 120 = 38.4 Blue = 0.1325 x 120 = 15.9 TOTAL OSC = 73.5 Next for the Mono Camera using LRGB: Red = 0.664 x 20 = 13.28 Green = 0.8 x 20 = 16 Blue = 0.71 x 20 = 14.2 Lum = 0.725 x 60 x 3 = 130.5 TOTAL Mono (LRGB) = 173.98 Next the Mono without the luminescence filter. Red = 0.664 x 40 = 26.56 Green = 0.8 x 40 = 32 Blue = 0.725 x 40 = 29 Total for Mono (RGB) = 87.56 So in conclusion Mono LRGB vastly outperforms OSC and Mono RGB still outperforms OSC in terms of signal collected . But this is not the full story, you will note that the filters are better balanced and there is no excess Green in the Mono RGB that you get in the OSC RGB. Another thing is that you will get a noticeable increase in resolution with the Mono camera over the OSC camera due to the bayer matrix on the OSC. Hence the answer is if you want best performance for imaging you still need a mono camera. Adam

The 80% is just the peak in green it will not be that high across the entire spectrum.

You will be fine with the 80mm just dont be tempted to move upto the Esprt 100 with that mount. I speak from personal experiance. Adam

I really want one of these when are they going to get here!

In almost all cases the 533 will be the better camera. I assume you mena MC Pro as I dont think there is a non pro version of the 533 without cooling, at least not yet.

There are better bebayer algorythems in some other stacking programs like APP. Might be work having a go with the free trial and see if it improves things.

Dont buy new. I got a 450d for £100 and modified it myself when I started. Using an OSC for guiding is not optimal anyhow if you mean to switch it over at a later stage. A 1200mm focal length scope is not a good idea when starting astro imaging either. Especially with no guide scope initially. You will need to plate solve to find deep space targets with that focal length and such a small sensor too.

A badder replacement filter can cause red halos but they are not normally blue. It may be the Bayer matrix itself showing up. Do you do a per channel alignment?

Shoot lots LRGB, as a reflection nebula nothing is going to show up in narrow band at all as its not emmiting at those specific wavelengths, but to be honest even in LRGB not seeing much in indevidual frames does not mean that you wont get something with sufficient intergration. Youu just need lots of frames, the read noise on your camera is low, 2 min subs are the most you will ever need. You need 100's of subs not just a few dozen. Adam

You mean a reflection nebula.

Its latteral chromatic aberation, a problem with all two element coma correctors.

Pritty sure that all ZWO ASI OSC cameras have an IR cut on the window its only the mono cameras that have not IR cut. Adam

Yes those are great cameras, very small sensor but at the same time very sensitive. It wont be sutied to nabula imaging as the sensor is too small for that but galaxies are possible for sure and some planetary nebulas and planets and the moon and sun with a solar filter. If you really want to image nebula though, things like the M42 and M45 then you will be better served with a modified DLSR at your price point. Adam

Not the best target to judge from. Try Vega or another bright star. Also acceptable is decided by the individual.

Yes I would bin 2x2 or even 3x3 if you are taking narrow band images with that camera.

I think your best bet is to join your local club and take the scope to a meeting but at the moment that may not be possible.

by rasing the left hand adjustment on a levels stretch too far to the right in most cases, but I am not really familiar with star tools. Everyone finds processing difficult at first.

You will only need a large sensor if you want to image wide feild nebulas and the two largest galaxies m31 and m33. Some smaller cooled sensor cameras like the QHY178m and QHY290m will be very good for imaging smaller indevidual galaxies. ZWO used to make cooled cameras based on those sensors but they are no longer avaliable. You dont really need cooling for solar system imaging so uncooled cameras are usually your planetary cameras. With a 130PDS the QHY178m is a excerlent choice for galaxy imaging and if you want to do nabulas though a ASI1600mm pro or a ASI183mm pro or I even like the looks of the new Moravian C2-12000a. If you are looking for a one shor color OSC then I like the looks for the ASI533mc pro at the moment. Adam

Looks like you got some good data, but i think you have clipped the black point quite badly so your probably missing out on additionally detail that is avaliable in the image.

those are caused but the alignment of the filter wheel changing between the light frams and the flat frames slightly moving the dust along with the filter.

That is a very odd imaging train you have, looks like you are going from the reducer to a t-adaptor to a camera lens adaptor to the filter wheel to the camera. That is extreamly sub optimal. Why not just just t-2 extenders to make up the correct back focus as that camera adaptor is a potential source of tilt. Adam

Yes the red channel is worse on mine too even with refocusing. Sometimes gives faint red rings around blue stars.

My auto focus is reasonably consistent. So the range on each filter if you repeat it is no more than 3-4 steps if you exclude rare outliers.

You can't but in general if red is longer than greeñ and blue on one scope it will be the same on another.