tomato

Nice to see this lively thread maybe ending on a remarkable image of M51, although I have to say it is not to my tastes. The faint nebulosity looks a bit over processed to me and has a painted on look but perhaps that how it is in reality. I prefer images with (dare I say it) more detail in the actual galaxies. I agree with Olly that amateurs can really only break new imaging ground by going deep and off the beaten track, but if your favourite objects are galaxies then you can only strive to get the best detail you can with the kit and location you have. And I’ve obviously not got the message as I have just ordered a camera with 2 micron pixels….😉

It does look like moisture on the camera sensor window to me. If you can remove the camera you will be able to see it for confirmation. I’m not sure why you are getting this if you have a functioning heater on the camera, though.

Great detail in the body of the shark, 20 hrs of integration has made all the difference.

I use Affinity Photo and followed the method in Dave Eagle’s excellent book on using AP for Astro image processing, I would never have got there on my own.

I have been frustrated by cloud and my RASA optical train falling apart recently so I thought I would look at an area of processing that has not come easy to me, namely the use of layers. I reprocessed this M78 data to try and improve the overblown core of the Nebula using masked layers, it definitely works. Mind you, if folks feel uncomfortable using BXT, why don't they get equally uneasy using this methodology? New version Old Version

You should be happy with it Dave, it's another top notch mosaic from your widefield set up.

It will be difficult because the tapered wedge is incorporated into the body of the camera, I’m not sure how close to the sensor mounting we would get if drilled and tapped the body to permanently mount a threaded adapter. You could of course leave the wedge connection alone and carry out tilt adjustment elsewhere but it already consumes quite a bit of back focus. It is worth a look though.

You are pretty close Olly. I’ve since decided it’s not very helpful to not immediately publish the cause of an issue such as this so without further ado: A while back to help fix tilt issues with the QHY268c/RASA camera adapter I introduced some quarter circle shims between the camera and adapter. For speed and convenience these were cut from some 0.3 mm thick clear acetate. Last night it looks like one of these shims came adrift as the scope slewed and ended up across the centre of the secondary lens and in front of the sensor. The transparent nature of the shim has caused a refraction/reflection resulting in duplicate stars in the centre of the image and the sides remaining unaffected. The offending shim fell to the floor as I removed the camera, but a test tonight should confirm this. The problem is certainly exacerbated by QHY’s rather dubious design of mating the OSC camera to the adapter by means of a tapered flange and three clamping screws. It is very hit and miss and makes it difficult to provide a compression between the two mating surfaces, hence the shim being free to float around. Why they don’t supply the camera with a simple m48 thread connection like their mono version, beats me.

I captured a batch of subs with my RASA8/QHY268c/NBZ combination in an unattended session last night, they all have a curious aberration. The stars through the central region appear to be duplicated or maybe triplicated(?) whereas those on the vertical edges are unaffected, although they show some elongation in the corners. Guiding was within tolerable limits throughout the session (~0.5 arcsec total RMS) and every sub was affected. This is a single stretched sub, so it is not a registration or stacking effect. I think I have found the cause but wondered if anybody would like to take a stab at what it was? (Hint: it was something I introduced to fix a previous problem).

I set up and took down a Mesu 200 Mk 1 for 5 years before building a permanent observatory. Note the Mk 1 has more user friendly alt/az adjustment than the Mk 2, which I think is designed to be used with a dedicated 3 bolt wedge, I can’t comment on how easy this is to adjust. I always put the tripod in the same place and could polar align with Sharpcap in about 10 minutes. Putting it up was always OK (motivated by the imaging session to come) but taking down at 2 or 3 in the morning when I was cold and tired was getting a bit of a bind.

C4 documentary on the Virgin Orbit story airing now…

Great detail right into the core. For my taste I would boost the saturation a bit, to get more distinction on the blue star fields and red Ha regions.

When I was young and single I was into Drag Racing. On a good weekend if we went deep into eliminations we could get 6 or 7 runs in, so about 70 seconds of racing, if it rained then nobody turned a wheel all weekend. Must be something in my genes when it comes to picking hobbies.☺️

Single intrusive lit areas in an otherwise dark site can be a pain, especially for visual observers. I once went on an astro themed holiday to a dark location, it was a superb dark site but there was a floodlit farm yard about a quarter of a mile away which killed your night vision, I was very glad when they were switched off around 23:30.

Yes, Bortle 4/5 is pretty good for a home location, I estimate my back garden is Bortle 5/6 with a pesky LED street light right opposite, but it doesn't bother me one bit. I just keep on taking subs if I am near it and let the LP removal software do it's thing.

For inspiration take a look at @Lee_P’s images on here. He images from Bristol city centre (Bortle 8 ) and gets phenomenal results, although he does have quite a high end setup. And +1 for LP removal software. Sometimes my raw stacks can be completely washed out but after applying the LP removal tool, the nebulosity and contrast are all there.

Yes, I was going to pursue this further but when I could see it had no adverse impact on my imaging I let it go. It would be a real PITA if I was a regular visual observer though.

I have an LED streetlight opposite my back garden which looks like it would give me a real problem when imaging due South: The council should switch it off after midnight according to their policy but it stays on all night. I considered all kinds of screens including making a light weight box shroud which would be dropped over it by drone and then removed at the end of the session. Using GPS this could have been incorporated into the automated run so I wouldn’t even need to get out of bed! However, even with the scopes in the orientation shown in the photo, the subs were not affected by stray light so I just carry on regardless.

Certainly if you go by the number of scopes being used for DSO imaging, then an 8’ Newtonian must be close to the top of the list, but there are a lot of 80mm refractors out there also. However, I think they tend to be favoured by nebula imagers, small galaxies, it seems to me, are a less popular group of targets to image. Perhaps the title of my original post was misleading, I did mean it to apply to DSO imaging (all objects) only. I tried DSO imaging originally back in the 80’s and 90’s with an 8’” F4 Newtonian, and the frustrations I experienced with that scope persuaded me to buy a refractor when I took up the hobby again 35 years later. Another great DSO imaging scope which I think deserves a mention as a candidate for a one stop scope is the MN190, but I will stick stick with the RASA11, aperture is good.

Wonderful Panavision image.👍I have never heard of the Rotting Fish before, it's aptly named.

Take Olly and Paul's 3 panel RASA8 mosaic of the Ghost and Iris Nebula region: If I tried to get as deep and wide with this with an Esprit 150/IMX571 set up here in the UK I could forget imaging small galaxies for a whole season , but each of these RASA panels is only 55 minutes integration. Wide and deep images from an RC or Edge HD are as rare as hen's teeth for a reason, folks aren't prepared to devote the clear sky time to them. But IMHO the RASA can produce reasonable images of small objects (though never as good as an RC or SCT) so that's why I would chose a RASA11 if I could only have one scope.

Both images were run through the same workflow which included BXT. We all know the F7 6” APO should be better on detail than the RASA, the point I was trying to make is the RASA can do better than I would expect on small targets so if you had to go for just one scope for your DSO imaging, the RASA could be the best choice: RASA 11 £4315 Esprit 150 £4999

I don’t think I have done any “proper science” but I have tried to capture the jet from 3C 273, the JWST heading out to L2, and produce an animation of the M1 pulsar, but these are more technical exercises in how far the setup can be pushed to it’s limits. These experiences have been equally if not more satisfying than producing Astro images.

Certain sections of the press keep saying it has landed on the Dark Side of the Moon. Pink Floyd have a lot to answer for…

Just looked at the images again, where did the small background galaxy at 3 o’clock disappear to on the RASA image?🤔