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I've been doing some experimenting to try and find the right values for gain and offset, having watched a video done by Cuiv. Sharpcap sensor analysis shows that gain 300 is where the S/N ratio drops so I understand that, though this translates to gain 150 in NINA with HGC enabled due to the way that Sharpcap calculates it for Altair TEC cooled cameras. Do the below figures look to be the right ballpark? Cooled to -5 on the bench Gain 150 with HGC mode enabled Offset 260 Exposure is 0.0001 (is this to fast?) Minimum pixel value is 6 Thanks Ed

I'm struggling to get hold of documentation at the moment, the altair website requires a login and that's not working for so.e reason. Being investigated apparently but does leave me a bit sparse on docs for this camera / chip combo. They have just sent me the latest software though while I wait.

Thanks for the heads up Woldsman. this camera does indeed have dual gain so I will double check what was used, though it sounds from what you say that Sharpcap would default to that high gain? I didn't realise that gain changed between applications though, I knew it did between camera manufacturers, but assumed that if optimum gain was determined in Sharpcap that it would be the same in NINA (albeit making sure HGC is turned on to be 100% like for like). Reading that article, does this mean that if 290 is the optimal gain as reported by Sharpcap I should set it as 145 in NINA?

Actually, that's a good point... full well depth is significantly lower at 300 than at 100, is that figure of 16k ish still OK? Apologies for all the questions, lots to learn!

I've just done a sharpcap sensor analysis on it and the results are as follows. Does this mean that the best gain to use is 300 (significant drop in read noise)

Thanks for the tips regarding NINA. I too had forgotten about offset! Thanks for the reminder. And thanks for the above diagram, I think its refreshed a memory as to why I removed the 2mm ring as well. I'm using a 130PDS telescope, and they are renowned for focus tube protrusion in to the OTA, especially when using a DSLR. My solution was to get the CC as far in to the focus tube as possible and to utilise a low profile DSLR adaptor. That way the DSLR is literally only 2mm out from the end of the FT. If I were to fit this ring I don't think that would allow the CC to go all the way inside the FT as its a wider Dia?? If that is the case then I presume I just need to include the extra 2mm in the spacer I order?

Didn't realise about sharpcap, that's a shame as I only renewed a few weeks ago. I currently can't register on the AA site, some error message comes up which they are looking in to, I did get a disk with it but would assume the site is the only place to get updated drivers etc.

Hi, I've never understood what that ring is for? I've always used the CC at the full 48mm width with the DSLR and removed the ring. Will I need it for the 26C then?

Hi All, I went to the PAS 2024 over the weekend and finally purchased my first dedicated astro camera - an Altair Astro 26C (Sony IMX571). So now I'm excited to try it, but a bit apprehensive as the documentation that comes with it is a bit more sparse than I would have imagined. I've just worked out the spacer I need to purchase to get the right distance to my Baader MPC Mk3 but a few thoughts have occurred to me, so advice on any of the following would be great! Focussing - I usually use live view at 10x zoom on the screen on the back of my EOS 600D coupled with a Bhatinov mask on the main scope. Whats the approach with a dedicated camera? is it live view in NINA or sharpcap on the computer screen instead? (I don't have an auto focuser) Correct Gain - How do I find out what is the correct gain to use? I did find another thread on here about the AA 26C which I think suggested gain of 200 as thats when the S/N ratio changed significantly. I would like to understand how to come about this though, do I run a sensor analysis in sharpcap? If so does that have to be done with the camera/telescope together and focussed or can that be done on the camera alone on the bench? I use NINA - long shot but does anyone know if this camera is plug and play with NINA? Is there anything else I need to be aware of in making the jump from DSLR to dedicated camera? Many thanks Ed

To the OP you may know this already, but for the 600D the best ISO to use is 800. Have a look at the explanation on this site below. Been using 800 with mine for a few years now and very happy with it (though I have this weekend just purchased my first ever dedicated astro camera!) https://dslr-astrophotography.com/iso-dslr-astrophotography/

What software are you using to stack? I had horrible horizontal banding on my EOS 600D that I spent ages trying to get rid of. Changed USB cables, tried battery power an mains for the camera and capture laptop, different ISO's and all sorts of changes to calibration and DSS settings. Nothing shook it off until I switched from DSS to APP for stacking. Never had an issue since.

If you enjoyed that, wait til you get the first long exposure image pop up on the DSLR screen of a Galaxy or something bright like the Orion Nebula, it will take your breath away and you will be hooked!

Exactly what I did, certainly with a Canon camera there is no need to chop the focus tube in order to reduce protrusion, though you do need to spend £20-£30 instead. 1 Low profile camera adaptor (1mm rather than 11mm) 2 Spacer between CC and camera to suit (width of which fits inside the FT) so all the spacer & the CC are inside the FT. In the case of the Baader this also moves that annoying shoulder out of the way of the locking screws, thus also helping CC and camera tilt! 3 Move the primary mirror up the OTA (10mm spacing from the rear plate leaves plenty of thread on the adjusters on mine) Result is a protrusion of approx 5mm in to the OTA at focus (mine was originally 25mm+) and completely reversible. No more pacman stars Thanks Ed

I've got a primary heater but mounted it around the OTA at the secondary end and have never had humidity issues since (either with the secondary or primary), so that may be a simpler alternative as its a lot less hassle than fitting a secondary heater.

Hi, I know APP isn't the most commonly used stacking software but I've usually found it to be very very good until now, but I'm getting a strange issue when trying to stack some data I have taken this week of the Soul nebula. The resulting stack has odd coloured pixel artefacts in clusters over the image, red and blue predominantly but some green as well. Its a 2 panel mosaic but I don't think its to do with that as the artefacts are over both panels, not just the overlap. Any thoughts / suggestions as to what could be causing this would be greatly appreciated! Thanks Ed

Thats a very tidy cap you have over the mirror end, where did you source that from?

You're absoluely right - that 44mm relative to the 6.5mm you quote for some ZWO cameras means the FT is 37.5mm further towards the OTA in real terms. So its no wonder there is no happy medium that suits both dedicated astro cameras and DSLRs. I think the rule of thumb is to get the CC and any spacers down the FT as much as possible in order to move the FT outwards, after that you have to look at other areas or a different CC to improve things further.

You don't have to do the focusser mod to almost completely eliminate the FT protrusion in to the OTA. Currently available CC's either keep the native Focal length but have the disadvantage of OTA focus tube protrusion, or increasing focal length/ratio which in turn eliminates the protrusion. I too was not keen on taking the hacksaw to my scope, or spending £200+ more on another CC having bought the Baader MPC Mk3 so came up with an alternative. This is for DSLR though so your mileage may vary for a dedicated astro camera! Bear with, its difficult to explain so the sketch may show it more clearly! The protrusion I had into the OTA was about 25mm at focus with a DSLR and the Baader mk3. A significant amount to hacksaw off! so..... Basically I bought a low profile DSLR adaptor (1mm thick rather than 11mm). To keep the CC to camera spacing the same you then need a 10mm extension tube between the DSLR adaptor and the CC. There is an added benefit here of both the CC and the extension tube sitting inside the focus tube and therefore gets the horrible shoulder of the Baader out of the way of the clamp screws (therefore eliminating some of the tilt I was also experiencing). This mod gives you 10mm. Next I looked at the screws holding the primary mirror to the OTA, they are (on my scope at least) plenty long enough that the mirror can be moved up the OTA to about a 10mm gap from the back plate (they were almost touching the back plate from the factory). So I moved the mirror up the OTA and re-collimated. Just to be sure I also did some maths and worked out that this shouldn't cause light loss around the secondary mirror. That gave me another 10mm off my OTA protrusion, which now is about 5mm and has negligable effect on my images, certainly way less than my rubbish processing skills lol Here's the sketch showing the difference at the camera end of my setup, the thing to note is how much further out the end of the focus tube is relative to the focus point while keeping the CC to focus point exactly the same. Hth!

Used one with my 600d for several years without issue (if it goes wrong on the next session I'm blaming this post!) But I do house that, my old laptop which runs my rig, the dew heater psu, the mount psu.....basically everything in a suitably sized plastic storage box next to the rig. That also acts as the storage box for everything once I break the rig down for the night.

Ah of course! Not been using fits for long so still getting used to it. Thanks for the reply Ed

exactly this! I'm getting results that I'm happy with (way better than I could in photoshop) but don't know how to improve from here. It seems to be a case of fumbling around in the dark, or should I say processes, and just trying things, which feels really hit and miss.

Hi, Given the eeeennndless cloud cover where I am I thought I would give it a go processing some data from the above. I want to start with RGB though to remind myself of how to process anything. That would include using SPCC though and I have no idea what the pixel size, focal length etc of the targets are for doing that. How can I fond this out? There doesn't seem to be anything (that I can see anyway) on the posts for the competitions. Another question though, there doesn't seem to have been any data posted for a couple of years now, are either of them still going? Thanks Ed

ask 100 people this question and you'll get 100 different answers. I think you have to find your own path to be honest, and there is a fine line between battling on with one piece of software because you are picking up the odd bit of extra 'goodness' out of it and chopping it in to try something else. For me that was photoshop, I know my round photoshop pretty well as a 'normal' photographer but REALLY struggled to get anything I was happy with out of it astro processing wise. I stayed with it probably 18 months longer than I should have because I didn't want the expense of using Pixinsight. I finally bit the bullet on PI and it was probably the single biggest jump in my processing results I've had. The interface can be a little querky but to be honest I don't find it that bad at all. FWIW my journey so far is as follows: DSS & Photoshop - all sorts of issues stacking DSLR images in DSS (EOS600d) Astropixel processor (APP) - the muts danglies for stacking as far as I'm concerned, all my issues went away, but didn't really like it for processing. APP & photoshop - this is where I was for ages! APP for stacking, photoshop for processing Siril - didn't like it that much, interface wise etc Startool - Just don't like the results, or the interface. As others have said, too much of a black box. The stars look fake to me no matter what I try. I can tell a startools image at 1000 paces! APP & Pixinsight - APP for stacking PI for processing. My word what a jump in output that was, instantly better images (though still nowhere near as good as many others on there!). I intend to try PI for stacking at some point but TBH it scares me - I read all the questions about it on facebook and in forums and it seems really complicated, so I tend to stick to APP for that! HTH and no offence intended to any that like the software I've not got on with, its such a personal thing that I think everyone has to find their own path by trying them and seeing how they get on. Ed

Thanks Gary, very useful info. There seems to be very little on the camera when you start searching for reviews so real world experience is always a good guide as to whether there are issues lurking. Ed

Just resurrecting this thread as I'm interested in the Altair 26c. How are people finding this camera? Rob - did you get to confirm your checkerboard was sorted with the changes made? This camera seems a LOT cheaper than the 2600 from ZWO, so naturally draws my interest, but don't want to be considering buying a bit of a lemon if thats what they have turned out to be! Thanks Ed