AbsolutelyN

Looks great, like the hint of blue. Nice to hear you're getting some clear skies. Eventually cleared here last night but not until 2 or 3am - too late for me. 

Unfortunately sky didn't clear until after Jupiter and Saturn were below horizon did manage this before clouds roll back in a couple of hours later. This image needs more exposure really as quite noisy - lots of noise reduction applied. 3.8 hours with RASA and 2600MC - 5 mins subs.  

https://www.astrobin.com/vtrhgu/

2 hours ago, Allinthehead said:

We were pointing at the same stars last night, beautiful clear night in East Cork. That's one of the finest shots of M45 I've seen, not over cooked and it's full of detail. Excellent 

Thanks, much appreciated. Think we had a lucky brief clear corridor, rain to both north and south

5 hours ago, Adreneline said:

An excellent image Tristan - well done. The RASA8 and 2600MC has produced an outstanding result - you must be delighted.

Thanks for sharing.

Adrian

Thanks Adrian, just pleased to get a clear sky if only for a few hours. Colour camera makes a big difference to productivity, I was using rgb filters and mono and kept ending up with just one or two channels then cloud for a month making it hard to ever complete a pic.

45 minutes ago, gorann said:

That is really nice Tristan! With a RASA 8 you do not need many hours of clear sky (but over the last weeks I have not even got a minute). So far I have not found any need for using flats of darks with the ASI2600MC - maybe I was lucky with mine. Yes, there is a little bit of vignetting with the RASA 8 but that is why there is a DBE in PI or a Gradient Exterminator in PS😉

The second camera still has the banding but it's more like yours - you have to dig really deep to find it. Just tried stacking this M45 image with no flats and no darks and you can't see the banding even with a strong DBE. Previous camera it would have been obvious banding. So although I think all the cameras have it to some extent the first copy I got had it particularly bad. Glad I managed to return it and exchange cameras. 

41 minutes ago, CraigT82 said:

Superb! So smooth. Can hardly believe that's only 3 hours data 👍

Thanks Craig, fast scopes pays off with this weather. Love the new solar setup.

Don't go with the 18-135 or 18-55 lenses. Get a prime lens of fixed focal length and fast aperture (f/2.8 or 1.8 etc).  The Samyang 135 is perfect but if out of budget there are some good cheap canon lenses that will do much better than the zooms and are brilliant for general photography too. 

https://www.mpb.com/en-uk/used-equipment/used-photo-and-video/used-lenses/used-canon-fit-lenses/canon-ef-50mm-f-1-8-stm/

https://www.mpb.com/en-uk/used-equipment/used-photo-and-video/used-lenses/used-canon-fit-lenses/canon-ef-85mm-f-1-8-usm/

4 minutes ago, ollypenrice said:

Beware of dual rigs (ie on one mount) at high resolution. Most who try it find it is difficult/impossible without recourse to Peter Goodhew's solution of an AO unit on the slave scope. We found it worked sweetly at 3.5"PP but is a pain at 0.9.

Olly

Thanks Olly - if I was ever to make the RASA dual I think I'd just mount it separately - much simpler and have option of imaging different targets at the same time. 

I bought a ZWO 2" EOS filter draw and have had no issues with it at all. Really impressed with it actually, much better than other ZWO EOS adapters I've tried. I've got a 200mm 2.8 lens mounted on it and have had no issues with tilt or anything and the lens is just attached to the adaptor with no other support. 

https://www.firstlightoptics.com/zwo-accessories/zwo-filter-drawer-for-canon-eos-lenses.html

40 minutes ago, gorann said:

I made some modifications to the Artesky adapter. In this image you see the side attaching to the scope. I have drilled two holes so I kan use a tool like the one in the image (found on ebay) to uscrew it safely from the camera since I realized that it could easily get stuck on the camera. Especially when I have a filter in there centrally I could not get a grip on it since the threaded ring from Celestron (not in this image) will just rotate freely (if you see what I mean). The second modification is the brown adhesive teflon tape (also ordered from ebay) that provides low friction so that the camera hopefully can be easily rotated. The tape is only 0.13 mm so it should not have much impact on the sensor distance. Further up in this thread you can see the wire ring I will introduce  between the Artesky adaper and the threaded Celestron ring so that it cannot wobble sideways. Now I just have to get a clear night to test it all.....

Brilliant, hope it does the job. Certainly looks a lot more precise than the Celestron one with it's soft foam backing! You'd think Celestron themselves might bring out some kind of advanced version of the adaptor making some of this stuff easier.  

1 minute ago, Dinglem said:

@AbsolutelyNdid you use any filter during the captures?

No ... I only use filters for narrowband. To me they just block out light. Can’t speak for worse light pollution than bortle 5 though.

3 minutes ago, tooth_dr said:

Amazing!  Cant wait for my 2600MC to arrive.

Thanks - a 2600MC in such capable hands will be quite something, look forward to seeing the results. Only issue I had with it was weird banding but it calibrates out with flats. This has no calibration other than flats. I returned the first - second camera still has it but doesn't seem to be as prominent

2 minutes ago, Dinglem said:

@AbsolutelyNthat can't be M45 it looks nothing like the one I took of it 😟 on a serious note that is amazing, I suspect my 450D doesn't quite grab as much signal as your 2600.

Thanks  .... I think it's just the sheer light grasp of the RASA. It's a light bucket. Was starting to wonder if it was worth it as never seems to get any use but when you can pull in so much light makes it possible to take images with only a few hours break in clouds which is really nice.  I had a 1600mm shooting with a 200mm at about f/3.5 at same time and didn't get anywhere close to the rasa. Your 450 can do - just needs more exposure time but that's hard to come by in the UK. 

7 minutes ago, gorann said:

Thanks Tristan! Yes, I have the same experience - focus remains spot on between days, and I have so far not lost a sub due to focus drift. The weak point is the sensitivity for sensor distance and any tilt, but that is probably inevitable for such a fast system.

Yes I'd love to be-able to rotate camera for framing but dare not touch it as currently have reasonable stars. Will have to try that Artesky adaptor at some point. 

Finally had a break in the clouds for a couple of hours last night. Managed 3 hours on M45 before clouds swooped back in. Taken with RASA 8 and 2600MC, 96x 2 mins subs.
https://www.astrobin.com/n8regq/0/

23 hours ago, gorann said:

I never used a Hyperstar but from what I have read the RASA is something quite different especially when it comes to collimation issues. My RASA was perfectly collimated and have stayed like that. It is my impression that this is the norm for RASA. It also holds focus very well over the night. I think the Hyperstar concept is a bit of a compromise while the RASA optics are designed for fast imaging from the start. The RASAs (except the first generation of RASA 11) have a much better focusing mechanisms than the ordinary Celestron SCTs and there is no tendency for movements in the mirror. Apparently it is so good that a mirror lock system like I have on my SCTs is not needed and is not there.

Can confirm the focus holds very well indeed. Set mine up and focused 2 days ago but clouds rolled in so covered the scope but left it setup. Finally cleared and stopped raining last night and started imaging without refocussing as focus was still as good as I could get it.  Also played with idea of dual rasas but uk weather so hopeless currently having second thoughts about spending more on something that only gets occasional use. 

Fantastic images by the way!

It was unexpectedly clear here too, none of my weather apps said it would be clear. Also skipped as didn't notice till late on. 

1 minute ago, souls33k3r said:

This I'm sure is such a welcome news for Esprit owners. Slightly on the expensive side of things don't you think? 

I thought the price was quite good. Looked at a few options for a reducer on Esprit 100 last year and they were in region of double this price and needed various adapters. Never got one as was too expensive and felt risky regarding not knowing if backspacing would be spot on and how good stars would be.  

Nice. Any idea if there will be version for the Esprit 100 and 80 scopes?

again please let us know how the new adapter performs, almost bought one a few months ago but no stock. 
I got my best stars with 1600mm with starizona filter adapter and a baader 0.3 metal spacer

1 minute ago, gorann said:

yes, and rotate it around until I get the right corner lifted and all stars round. If the thickness is not enough I just fold it a bit more. I hope it could be quick and simple, maybe have the handle inside a rubber band around the camera. That is my theory at least - cannot test it yet.

Let us know how it goes. I always felt it was centring and getting precise back focus causing star sharp Issues but I guess that was all I could control. Hope it works.

9 hours ago, wimvb said:

This pattern reminds me of newton rings. And since newton rings are caused by thickness variations in a thin film, it may very well be that there is a natural thickness variation somewhere in the light path. lThis can be a cover glass that is not perfectly flat, or a deposited film on the sensor itself. Maybe even thickness variations in the microlens layer. Since it also shows in the flats, and because flats can remove it, it must be optical in origin, not electrical.

I'm certain that you can adjust your workflow to minimise the banding, but that will be limiting your process and your final results. As always: try to eliminate unwanted artefacts as early in the workflow as possible, i.e. by using flats.

To lessen the impact of the bands during processing: use a mask when you saturate the colours in the galaxy. Or in PS speak: use layers. (Did I just mention PS? the horror 😬)

That's absolutely fascinating thanks - love your rendition of the image too. 

23 minutes ago, Spongey said:

That's very kind, thank you!

This explains a lot! But yes, your star shapes aren't the best around the periphery of the frame for sure, do you have the backfocus 100% nailed in? I feel like more of the image should have round stars than it does...

Again that's the rasa, it's tricky to get good stars with 4/3 sensor, never mind aps-c. It was just a test shot so I've not yet spent time trying to tweak the back focus and centre camera and doubt I'll ever get it perfect. How camera attaches is not great - each time you remove or rotate the camera it ends up in a different position and impossible to centre it perfectly. With my 1600mm I spent hours getting it as good as possible and then dared never touch it again ... 

29 minutes ago, Spongey said:

Hi AbsolutelyN, I just had a quick go at processing your file for fun, and agree that there is some banding in the background visible after DBE. Once stretched and setting the background to a good level though it wasn't too visible, and adjusting the background (minus stars) saturation helped eliminate it.

It's far from my best work but shows that the problems you have are certainly manageable with careful processing!

Not sure your flats are correcting properly as the very corners are quite dark indeed compared to the rest of the image after stretching. I cropped them out for this process.

Cheers

That's great, you've done a great job there, prefer it to my version. That file had no flats - it's taken on a rasa 8 so it does not fully cover the chip size. Cropping corners is to be expected.  The banding is manageable but I'm not sure it should be so visible in the first place. Thanks for  taking the time to have a crack at it. 

6 minutes ago, gorann said:

Here is my flat run through the Equalize command in PS, which is used by many as a diagnostic tool to find banding and gradient problems and I see nothing there.

Just been digging in the stacked M31 image and flat in PS and I can't find any banding at all.  However I can see it in the Esprit 80 flat I took this morning in PS. So I think it is actually in the file and DBE is just bringing it out much stronger. Looking like nothing wrong with camera though and I just need to alter my workflow to work around it.