Chris

Thanks Priesters! It's great to have some positive feedback from yourself, you very much sound like my target audience! I'm pleased my little GIMP tutorial helped out I must admit I took a deep breath before posting as I know how divisive the subject can be! However, I'm happy to see it's been a largely positive and educational thread with lots of great points and resources touched upon, and agree it would be great to see others post their techniques so we can all learn what we don't think we're missing. It's all too easy to think you're doing things the best way until someone points out a better way lol

Nice one, that looks really good! My PC runs a Ryzen 5 processer and 8GB of RAM and crashes when it reveals the final stack It only gets as far as applying the stack to the top left section of the image. It's nice to see the results you can get when using the non converted files. The conversion process really messes things up in summary. I managed one version where the core was well controlled, however the stars look better using the RAF files here for sure. Lovely tight stars from the StellaMira 90 EDT also. The Fuji is a real beast for astro considering it came out in 2014. Shame it's a pain but good to see it's potential

I have version 4.2.6 and although it opens the files, the finished stack only applies itself to a fraction of the image area on my machine at least, almost like it crashes. I tried a number of things before I went the file conversion route a few months back. Most Fuji's use an Xtrans sensor, however I used to own one of their entry level cameras with a Bayer filter and that has the same issues. I believe GIMP uses dcraw, I can open RAF files in GIMP ok, stacking really is the sticking point but Sequator might work?, I've not tried that yet.

I was guessing the conversion process was to blame, so thanks for confirming it!

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Well it would be great to see what you get out of the data Vlaiv I'm going to try the 32bit floating point approach also but I'm all processed out tonight and might just have a beer instead I've just checked and have 55 RAF files, and I stacked the best 80% in DSS to make up the master tiff file. The 55x RAF files take up 1.71GB and the SGL limit is 1GB. I'll attempt uploading here in two parts as I'm not keen on disturbing the Drop Box files for the video. Here are the first 30 RAF files: DSCF0057.RAF DSCF0058.RAF DSCF0059.RAF DSCF0060.RAF DSCF0061.RAF DSCF0062.RAF DSCF0063.RAF DSCF0064.RAF DSCF0065.RAF DSCF0066.RAF DSCF0067.RAF DSCF0068.RAF DSCF0069.RAF DSCF0070.RAF DSCF0071.RAF DSCF0072.RAF DSCF0073.RAF DSCF0074.RAF DSCF0075.RAF DSCF0076.RAF DSCF0077.RAF DSCF0078.RAF DSCF0079.RAF DSCF0080.RAF DSCF0081.RAF DSCF0082.RAF DSCF0083.RAF DSCF0084.RAF DSCF0085.RAF DSCF0086.RAF

Thank you, I think I've got the gist of what you're saying but I'll check out the thread, and I look forward to comparing 32bit to 16bit Tiff files and seeing how much difference it makes. It might be a good idea for a video if I had two tabs open and performed the same processing steps on both 16bit and 32bit data to see how and where they differ. Just to check we're simply talking about saving as 32 bit in DSS rather than 16bit right? I tried stacking Fuji RAF files in DSS with no luck unfortunately and this lead me to paying for one of the online file converters. I did wonder how Siril enabled you to perform changes before stretching, it's a shame GIMP doesn't have a preview mode but I'm looking forward to checking out SIRIL anyway. I had heard of it and it would be good to try something new. I use 3 bits of software for processing planetary and Lunar so the extra step for DSO's wont be a problem.

Thanks James! and it's good to hear that SIRIL which Onikkinen recommends is free also I know the paid versions have many more tools, but I feel a lot of people starting out would be happy just getting a recognisable image and the discerning part comes later. A bit like how we don't notice optical aberrations as much when we start out observing.

Thanks! and I don't mind at all I'm a complete Jack of all trades and master of non so I posted in full knowledge that it might be scrutinised by the more discerning hardcore imagers out there. I've never used SIRIL so I can always look into it and do another tutorial involving that once I've got to grips with it. It does add a nice surprise element getting a different result every time though, I might miss that as I like getting different versions from the same data 😆 Well this is the thing like you say, when using DSS and going straight to GIMP you need to stretch the data to see something that you can actually work on. I probably should get another Canon camera for tutorials though because the Fuji has some weird quarks: one of which is that when you import the stacked image into GIMP it looks super bright like a flat panel, whereas a Canon camera looks much darker and you can hardly see anything. I had to move the histogram to the left in DSS to make it usable in GIMP, but I've provided both the RAWS and master tiff so people can take the process from the start if they wish. I recommend they use the slightly tweaked master Tiff though as working with Fuji RAW takes some getting used to in DSS. Ah yes see my previous point, however I've got to disagree with your point that people won't be able to work with this tutorial with a freshly stacked image. You can pull up an invisible image using levels adjustments as I do in this tutorial. The only difference is that you an see a faint galaxy to begin with here. If I had made the image even darker in DSS to emulate a Canon Camera for example, I would have just made more adjustments to the levels but in the same way. I've been using GIMP for years now so pulled up plenty of black images to reveal DSO's using the levels. I honestly didn't know using 32bit would help with a 14bit camera. It should be around 40 files your right, but I downloaded the free version of Drop Box for the purpose of this video and maxed out the storage with 17 RAF files converted to RAW, and a Master Tiff. Yes when stacking Fuji converted files in DSS they come out very over exposed for me also. This is using just 2 minute subs as well! The data is far from ideal with only light frames and no LP filter used under Bortle 6 skies. I can imagine people would have an easier time with better data but I just wanted to give beginners an Idea about using levels, curves, and colour balancing etc. So to summarise, would you say the main take away would be to use SIRIL and maybe not use a Fuji camera for tutorials as they are very much their own beast? It's possible that the RAF to Tiff converter doesn't do the Fuji data any favours. It's a shame DSS wont accept Fuji RAF files as they are, but the Fuji's inherent Ha sensitivity is almost worth the hassle. I would love to know more about using 32 bit files, can this really help if the camera is 14bit? Thanks for taking the time for such a thorough reply and feedback, it's much appreciated

I think GIMP is great for people starting out with image processing as it's absolutely free and simple to use. I'm by no means a master at processing images but I think I know enough to give beginners a leg up. Here's a beginner friendly tutorial I put together, I could have done a better job on the core but the key steps are there: If you want to follow along I've placed a master stacked tiff in the video description on Youtube.

Thank you! Unscrewing the knurled M48 adapter on the camera side buys you an extra 5mm and reveals a 63mm male thread on the reducer/flattener. The TS version appears to come with an additional adapter on the telescope side, whereas the StellaMira ends with another male M63 thread for attaching directly to the StellaMira 90 EDT. I would like to do some full frame testing, I just need a full frame camera firstly. I may look on MPB.com to see how much their most affordable Full frame is, hmm? : ) Cheers Chris TS: StellaMira:

Another crack at the StellaMira data... The core was a bit blown out on the first rendition:

Quick first light image with StellaMira 90 EDT + 0.8 RF + Fuji XT1 - Triangulum Galaxy M33 1) Single 2 minute exposure 2) 30 x 2 minutes processed in GIMP (no flats darks, filters etc so fairly rustic)

Congrats on first light, your observations sound promising so far

I need to get a full frame camera on StellaMira at some point, however hopefully this quick video gives some idea of how well the dedicated 0.8 reducer/flattener works when simply used with a T-ring and APS-C crop sensor camera. No messing with spacing.

Congratulations Michael, that really is a wonderful looking combo! I really like how the Starfield simultaneously pulls of being a modern yet classic looking refractor. Very much looking forward to your thoughts regarding the optics : )

Very nice indeed! Both the scope and the Lunar shot. Lots of great sights ahead with that scope I should imaging

I think this is a good point, I will check with colleagues to see if there are any plans for a dedicated flattener without any reducing effect. Otherwise, I'm curious how well the OVL field flattener would work with the StellaMira 90 EDT? After all it is optimised for f/5.5 to f6 scopes. The only initial down side would be that it's push fit and a lot of people prefer a more secure screwed connection: https://www.firstlightoptics.com/reducersflatteners/ovl-field-flattener.html

The flange to sensor distance for the ASI 533 is 17.5mm, so you would need 37.5mm of M48 spacers to make up the 55mm back focus.. Now it so happens that the ASI 533 comes with M48 to T2 16.5mm and T2 21mm extension tubes which add together to make this 37.5mm! You should be all set

As Andrew said, it's an M63 thread and the 0.8 RF screws on smoothly. Annoyingly my EXOS2 mount decided to stop working when I tried to test the scope, however I have another mount on the way so hopefully I'll have some luck in the next couple of weeks : )

You've not seen my neighbours Christmas lights yet!

Congratulations! I've said this a million times and I'll say it again - there is something special about classic long focus refractors.... and the ladies find them irresistible too!

My wife Bella asked me what I wanted for my birthday, I'll send her a link 🤣🔭🤦‍♀️

Nice report, thank you for posting! Corners look good and I can't see much in the way of vignette.

No problem Adam, here you go