gorann

I have three ASI2600MC and use no dark or bias calibration frames (I initially made a dark library but using a master dark made no noticeable difference and I have repeatedly heard the same from others). And I do not dither. Still I rarely see a hot pixel. I think it has to do with the Image integration routine I use in Pixinsight (see below). In the rare case of a some hot pixels they are easily removed by the Dust & Scratches filter in PS (using a low setting that does not affect stars).

Looks really great and very inspirational Dave! Reminds me that it is high time give my Iris data the same treatment.

Thanks Olly! It shows that there are still a few rarely imaged gems out there. I am sure it would be even more ethereal on a moonless night with a more steady sky. My RSM was around 1.5" that night, while it is usually between 0.5 and 1.0".

Thanks Olly! I did not know about it either until I though I saw something there i a recent wide field image someone posted on Astrobin. A bit of research revealed that a few people had actually imaged it. So it bacame a RASA target for me and this image is the joint effort of the RASAs and the piggybacking Samyang 135. I could actually see a faint trace of it also in the 4.25 hours I got with the Samyang. Here is the RASA image of the SNR:

Thanks Rodd! Read my post and you find a link to that object😉

The Monoceros SNR is the enormous circle of mainly Ha emission between the Rosette Nebula and the Cone Nebula. Above it is the much smaller (but still relatively large) and very faint blue Oiii-emitting SNR only named G206.9+2.3. This is what my Samyang 135 caught piggybacking on my dual-RASA rig over two recent nights. I have added about 50% RASA data to the Rosette and the blue SNR. For more info on the blue SNR see https://www.astrobin.com/8wuzok/ Materials and methods: 51 x 5 min with Samyang 135 and an Omegon veTEC571C with IDAS NBZ filter, and 102 x 5 min with RASA8 with ASI2600MC and NBZ or Baader high-speed Oiii filter. So totally about 16.5 hours. Processed in PI and PS including all the XTerminators. Cheers, Göran

EGB 6 is a very faint planetary nebula in Leo. It was catalogued by Glenn Ellis, Earl Grayson and Howard Bond in 1984 after looking through prints from the Palomar Sky Survey. It is big (8 light years wide) and relatively close (2100 ly), so it is old (probably 50 000 years) and therefore so very dim. Even @Petergoodhew, who of course have imaged it, calls it extremely faint. I imaged it under 50 - 70% moon, so not ideal, but the RASA is a photon bucket. Dual-RASA8 rig with ASI2600MC. IDAS NBZ filter on one and Baader high-speed Oiii on the other. 102 x 5 min, so totally 8.5 hours. Processed in PI and PS including the XTerminators. Cheers, Göran

Or Dividing Cell Nebula? Yes, I see at least one rather clear Ha filament that lines up with the Oiii filaments.

This is a very rarely imaged and quite weak Supernova remnant a bit east of the Rosette Nebula. It was shot in the morning of March 2nd under 70% moon, which is not the best for Oiii, and seeing was quite bad that night. Still my dual-RASA rig picked it up (it cannot for example be seen in DSS2 images on Aladin Sky Atlas). I was using the NBZ filter on one RASA and the Oiii filter on the other. I was just pointed at a German site with some info about it: https://forum.astronomie.de/threads/14-woche-der-supernovarest-g206-9-2-3-im-einhorn.286227/ Dual RASA8 with ASI2600MC on Mesu200. 51x5 min IDAS NBZ (Ha+Oiii) and 51 x 5 min Oiii (Baader Hi-speed). So 8.5 hours in total. Processed in PI and PS including all the XTerminators. Cheers, Göran

Yes, if I stretch the image further I can see rings also on my screen. I am quite sure that the reason is Gradient XTerminator that I have seen causing rings like this before. I guess the image is rather ok for most screens as long as it is not further stretched. I could also desaturate the sky a bit. It would be good if Russ would make a new AI version of Gradient XT 😉

Let's hope for the brain hypothesis🤣

Beautiful! Never seen so much tidal streams around this galaxy. As you indicate, the RASA may find even more. Mi impression has been that StarXT is quite good at not moving galaxies to the star layer but keeping them in the background layer, so you were probably unlucky this time. Did you try Starnet2 on the image?

Thanks Steve! I do not see the rings. Good if you check it on another device and get back to me if you still see them. If they are artifacts I assume @wimvb would also have spotted them.

Great details there Wim, including all the Ha emitting regions! Here is what I came up with when merging our data. Nice details in the galaxy and a lot of IFN:

As you can see Coddington's nebula IC2574 is a galaxy! It is a dwarf spiral galaxy discovered by American astronomer Edwin Foster Coddington in 1898. At the time galaxies were not clearly distinguished from other lumps of nebulosity. It is an outlying member of the M81 group. For those that believe in dark matter this galaxy is made up of 90% of the stuff. Just like M81 and M82, this galaxy is surrounded by a lot of IFN (Integrated Flux Nebulosity), which is faintly shining dust energized by the collective radiation of the Milky Way. The RASA is great for disclosing IFN. This is 9 hours of RASA8 (ASI2600MC, no filter) data (see https://www.astrobin.com/8z3xtt/C/ ) and to the galaxy I have added 19 hours of LHaRGB data collected by Wim van Berlo @wimvb with his SW MN190 telescope and ASI294MM. Please zoom in - there is quite a bit of detail to be seen in the galaxy. Here is Wim's post showing his close up of the galaxy:

After CMOS took over I get the feeling that astrophotographers are less occupied with pixel scale. I see experienced astrophotographers using these new 3.76 µm pixel cameras on any focal length between 135 mm (like Olly, me and others) and 3.5 meters (like John Hayes with his 20" scope in Chile). So, my advice is just to get on with it. You can experiment with software binning after you taken your images. ASI 2600MC is a great camera (I have three) but there are other less expensive and good alternatives with the same sensor (I also have an Omegon variant of it that works great).

Thanks Simmo, that is where I also landed. A good compromise.

So the obvious is to go for a compromise. So here is a 33%:66% mix of A and B:

Thank you all! The vote appears to lean for version B. I think I may agree. More dynamic, making the nebulosity stand out a bit more.

This is a rather rarely imaged area in the busy Cephus that I imaged two nights ago with my dual-RASA8 rig. I ended up with a version with rather brownish dust that I quite liked, Then when I had a look at Astrobin for other images of the area, I found a striking variation in the colour of the dust. With a few tweaks of the curves of the three colour channels, I could get also a rather nice bluish shine on the dust. So, now I am confused about which one is more pleasing. Any opinion is much appreciated! Astroprocessing is clearly very arbitrary, Camera was ASI2600MC without filter. 183 x 3 minutes. Praoessed in PI and PS.

Aladin Sky Atlas is an excellent free source. Google and you find it. There is a web version and one you can install on your computer.

Great image, especially for 90 min, and you really reinforced the original selling argument from Celestron when they introduced the RASA line. And then, when you finally get a long clear night - aim it for something faint and it will blow you away (with or without star spikes)!

Thanks a lot Chris! Yes, Pink Floyd's Animals album immediately came to mind.

Yes, it is possibly a result of doing StarXT on the un-stretched image. I never tried that but like Dave and Olly I stretch the image first so I get the stars at a level I like and then run StarXT. That may be the reason why I never run into any blotch similar to yours. I have more hard to believe that NoiseXT would be the problem - it has been quite subtle on my images (I use the standard settings).