gorann

In my experience, the lost hours are virtually allways down to computers (and USB) or their inability to accept the smallest error of us. Very rarely down to the optics or mount. So I just try to keep the involvment of computers to a minimum.

Thanks, much appreciated!

Thanks a lot! There is no special secrets. I mainly use PS (but calibrate and stack in PI) and start by stretching the image in many iterations, at least 7 - 10 times (I attach a typical curve), so the bright parts slowly emerges from the dark sky. I have the idea that many minor stretches preserves the dynamic range better than a few large ones (maybe someone knows if that is true but it works for me). Then after those initial stretches I have recently started using the Star Xterminator filter (in PS but you can also get it for PI). The starless image produced allows me to give the faint nebulosity an extra stretch without being overwhelmed by the star field. Then I bring the stars back using a layer in PS (blend mode lighten) and control the stars size with a curve (takes some trial and error to avoid dark ringed stars). I hope that helped. There are a lot video tutorials, many of which I believe use similar approaches, that once got me going but it was a long time since I watched one. CS, Göran

Thanks a lot Colm! Dark is in the eyes of the rig! So, with a photon bucket, there is no darkness anymore😉

Thanks a lot! The universe is 4D at least so the aim should be to at least capturing some 3D😊

LBN and LDN means Lynd's Bright Nebulae and Lynd's Dark Nebulae from his catalogues. These particular ones are quite faint molecular clouds / dark nebulae, about 1,000 light-years away, and they make up part of a complex of dark and bright nebulae in the Cepheus region. The image is based on data I collected about a year ago and now processed using the new Star Xterminator filter in PS to stretch the nebulosity before I brought the starfield back. Interestingly, with a light bucket like the RASA 8 at f/2 many of Lynd's dark nebulae are revealed to be quite bright, lit up by neighboruring stars, except for their darker brownish cores. Collected with a RASA 8 and ASI2600MC (Gain 100, offset 30. -15°C). 67 x 5 min, so about 5.5 hours. No filter. Cheers, Göran

Thanks a lot guys! CS, Göran

Thanks so much Steve! That oil painting feeling struck me to but it was not intended, it just came out that way. CS & Cheers, Göran

Thanks a lot Jamie! It is all in the mind of the beholder😉

Nice Wim! According to some animal physiologists, Brontosaurus could not even lift up their neck very far to grase on trees since it would have demanded a rediculously high blood pressure to provide the brain with blood, and even if they had a heart that could do this that would probably blow the arteries in their legs. It may be that they used their long neck for grasing under water.

Thanks a lot! Yes, our brains are obviously wired to see cretures in even the most chaotic structures. CS, Göran

Thanks Roy, much appreciated!

Thanks a lot Andy!

Clouds have moved in and settled, and the moon is getting back, but Friday night was clear. After some initial problems of getting PS2 to calibrate (the star did not move enought at 81° N so I had to move the scope to calibrate), I aimed my dual-RASA 8 rig at this area with numerous, but faint and rarely imaged Molecular Clouds / Integrated Flux Nebulosity and reflection nebulae in Cepheus, containing MBM 163 - 165 (Magnani, Blitz & Mundy) and LBN 569 (Lynds' Catalogue of Bright Nebulae). There is also a background of very faint Ha nebulosity, so a mix of everything possibly except galaxies (I did not spot any while processing). Processed in PI and PS. After some initial stretches I made a starless image using the Star Xterminator filter before stars were brought back. This greatly helped to suppress the starfield that otherwise can easily overwhelm these quite faint nebulae. Two RASA 8 with ASI2600MC (gain 100, offset 30, -10°C) on Mesu 200. 221 x 3 min, so 11 hours. No filter used. Is it only me that see one or two chickens in there? Cheers, Göran EDIT: I said rarely imaged but I now found this thread on CN with an image of a similar FOV: https://www.cloudynights.com/topic/630969-faint-molecular-clouds-in-cepheus-mbm-163-165-magnani-blitz-mundy-lbn-569/ That image made me realize that I needed to flip my image as the one-mirror system of a RASA produces as mirror image, so the second image is the correct one, sorry...

So Vlaiv, what method do you think is best for my ASI2600MC? So far I have only tried superpixel when debayering in PI, which seems to work well (but generally I do not bin). I seem to remeber that the ASICAP program that I use to run the camera also have a "binning" option but I never used that.

These two quite faint objects from the Sharpless catalogue were once thought to both be supernova remants (planetary nebulae) but now only Sh2-224 (the one to the left) is recognized as a supernova remnant, with the typical blue Oiii mixed with Ha emission. Sh2-223 does not contain any detecatble (Oiii) and is now thought to be a Ha emitting nebula energized by the star BD+41 1144. For those that want to read more about thes objects a good start is, as allways, to read Gary Imm's description of his rendention of these objects (https://www.astrobin.com/380492/F/), where also BD+41 1144 is pointed out. To me Sh2-224 looks like some kind of flying creature. or rather gliding, coming in for landing on Sh2-223. Data collected 10 Nov 2021 with my dual RASA8 rig on a Mesu200. ASI2600MC (gain 100, offset 30, -10°C) with IDAS NBZ filer (Ha and Oiii dual band). 110 x 5 min, so 9.2 hours. Processed in PI and PS. After some initial stretches I made a starless image using the Star Xterminator filter before stars were brought back. This greatly helped to suppress the starfield that otherwise can easily overwhelm these quite faint nebulae. Cheers, Göran

Thanks a lot Martin!

Sorry that you did not want to keep it but it seems it is heading for Russia now 😉

I think it is a very good idea to have a tilt adjustible camera, even with an f/5 scope (and how knows what scopes you may have in the future). The ASI2600 has a built in adjustible tilt plate but it can only be adjusted from the front end so it cannot be reached when it is sitting on a RASA and it will be very cumbersome to adjust it as you will have to remove the camera back and fourth. I do not know how the adjustment works on the ATIK but if it is adjustable from the side that would be great. I think QHY has some model where that can be done.

Thanks Olly & Tom, yes, for me the RASA 8 and the ASI2600MC has been a game changer. A lot of signal and very little fight against noise. The fight is against the fast focal ratio allowing decent star shapes over a 18x24 mm image. Celestron's camera attachment system with a rather flimsy retention ring, and the lack of a good (accessible) tilt adjustment can be a bit frustrating. CS, Göran

Thanks a lot Carole! The UK has lately been sending the bad weather our way but now it looks like two clear nights may be comming up😉

Thank you all! Not sure Tom I would agree that it is over-processed, but I agree that it is brighter and shows more colour and structure in the dust than in most shark images. Nearly 10 hours with a RASA 8 brings out much more structure and colour, especially in dark nebulosity, than I ever have seen with my refractors. I think it has to do with the large aperture combined with f/2 (and the high dynamic range of the ASI2600). I have not done any sharpening routines like deconvolution that often introduce artifacts. So I am rather sure that what is seen in the image are for real. I also took care in avoiding the often seen dark ringed (panda eye) stars when I brought back the stars after having stretched the starless image. Cool that you spotted the spiral galaxy Steve! Cheers, Göran

This fantasy provoking object, a mix between reflection and dark nebulosity, probably needs no presentation. It is very faint so f/2 and my dark (Bortle 2-3) site helped. This is a merger of two datasets collected 13 - 17 September in 2020. I used Star Exterminator to bring out as much nebulosity as possible and then brought the stars back at a controlled level, since the starfield is quite rich and can overhelm the weak nebulosity. Again, the combination of RASA and ASI2600MC is really good at going deep and bringing out colours in the nebulosity. So, RASA 8 and ASI2600MC without filter. 146 x 4 min (Gain 100, offset 30, -15°C), so nearly 10 hours. Put together in PI and processed in PS and PI. Cheers, Göran

With my ASI2600s or ASI6200 I have never seen any need for dithering. I thought that was to suppress things like walking noise and they do not have that as far as I can tell, even if I often stretch my images really hard to catch IFN. The images still move a little bit over the night and I usually have about a hundred frames to stack so maybe that creates some natural dithering since I do not see hot pixels either after stacking and integrating (Linear Fit Clipping in PI).

I do run my Mesu 200 and PHD2 on a Win 7 laptop (that is never on the net) but for the cameras I use Win 10 laptops and have them in airplane mode (since I have had them shutting down to upgrade). Then of course, to complicate it all I do all my processing on a Mac.......