geeklee

This is correct. The only limit you have is not having too long a train between the rear of the scope and the sensor. Too much and you can't bring the focus in enough - it's still a generous distance though. You can bring the camera in close and the focus should compensate by having to move it outwards more. A DSLR with a standard setup would be the "typical" distance by default. This is why filters shouldn't make a difference either (as long as your train isn't too long!) I've typically aimed for "traditional" spacing and get the infinity mark (I think it is) close to the focus marker but I've been either of side of this with no difference seen (I use small sensors though). There's some good info (and diagram) on this site highlighting the flexibility. Number 4.

Great set of images Ben - love seeing the variety of different versions. Those last two for me 👍

That sounds like a very challenging time during those months, waiting to hear what would happen at work. On the kit side, with a few cables that looks ready to go. With a Bahtinov mask, you should be fine with the occasional check - focus seems to hold well. It's tricky at the moment - testing things out means staying up late and if there's any troubleshooting - that can be tough as the early hours come round (speaking from experience!) I was lucky to pick mine up second hand on SGL a while back. It's the vixen only one I have in the photo, so less cost than the dual one - which you shouldn't need with vixen dovetails only. I had intended it for another project but changed my mind... was just about to try and sell it on, when I put the Samyang on it. Good dual option from @Space Oddities above. There's also an all in one solution above by @desmcm although it requires 3D printed parts + other bits (all described on the link provided). I'm still thinking about switching to this 🙄 😁

Looks lovely @Rustang Any noise is well hidden in this sized image - the colours look superb. Agreed. It's good to see both versions sometimes.

Great image @Spongey What a fantastic FOV with that camera and the quality of stars for such a view is excellent.

Me too. My AZ EQ6 is quite stiff so I don't get that lovely easy to balance RA/DEC I see where a few mm makes the difference This setup is actually better as it's heavier overall which makes it easier to balance in RA. For DEC - it's balanced in two directions. It sits horizontal by default with scope pointing up (of course) and it's slid to the right significantly as you allude to above. The blue bit of tape in the top image is a marker for the right hand clamp in the saddle so the Samyang part ends up just off centre to the left. Then turn the DEC so the scope points to the left or right and balance by sliding the dovetails along their individual clamps. I could probably look at moving the clamps towards the centre of the bar more... 🤔 Weighing in at 4.2kg it's far within the AZEQ6 capabilities that I don't worry too much esp with the imaging scale being high. Same here 🙂 I've had it hooked up on the bench like this. Your mount must be one where those few mm make the noticeable difference. Is it one particular DEC axis it struggles with?

It's been a while coming, but I've finally pulled together the various bits to add a ZWO EAF to my Samyang. Thanks everyone for the inspiration and help on varied rigs and 3D printing! I currently have the Astrokraken rings, so I removed the top plate and designed a simple replacement that could hold the ZWO EAF with ability to raise it up for tensioning a belt. Then a - hopefully - robust way to get the belt tensioned around the lens. I've seen various designs and adapted a few ideas to create a two piece ring that would join with an M3 nut and bolt (rudimentary, I know). This was for a GT2 belt but the HTD 3M one I did worked fine too. The rig now looks like this. Excuse the right hand dovetail - I need to rework this. Here's the ZWO EAF mounted on the custom bracket (very solid): Here's the belt and geared rings: The gear meshing is good on the pulley and round the lower ring. The upper ring is tricky as it has to match very closely to get good mesh. Mainly I want to just keep the same distance as the pulley moves - a few earlier iterations of a half ring only proved a mistake. Hopefully someone finds this as useful as I've found the ideas in this thread. Testing it all out...and like a broken record as I have a similar image up above in the thread.... here's a 3 pane mosaic of the Sadr region during civil darkness in Ha (~F2.4). Each pane is 30 minutes (10 x 180s). I wasn't sure how to present it as vertical looks cool, but the below fits better...

Great first light @Daf1983 Lovely capture 👍 Dithering will temporarily send the RMS higher (depending on the dither size) but it should settle back down quickly. The later dev versions of PHD2 (v2.6.9dev3+) don't include dither recovery frames in the graph stats. During the dither the capture software should be paused and waiting for "settling time" so as long as you see similar stats afterwards when exposures start again, you should be fine.

Better multiply those 1000 up a bit more with all that 😅 That's a good idea adding a new step/piece of equipment each time. You'll notice the difference and be able to concentrate on the new stuff, while understanding what's gone before. If the lens of the scope looks clear, the dew strap could be doing its job - just wanted to raise it as a check point next time. Apologies, I should have gone into a bit more detail with the black point. Offset is a setting within the camera - if you can leave this at it's default then it's probably best when starting out - it's usually a number above 0. I'm not familiar with the Altair cameras regarding gain and offset, but any defaults offered - especially around "unity gain" are a good starting place. The black point I mentioned is found within the post processing and refers to the histogram of the image. At the left of the histogram is where all the data is, as it's stretched it can be tempting to pull the black level in to make the image dark and maybe hide some gradients we don't like. The cost of this is potentially lost, faint data that's "clipped" and gone forever. Here's an example histogram, with a gap to the left, giving some breathing room: Here's the same histogram, but I've pulled the black point in. New histogram at the top (clipped), the black point pulled in at the bottom but look at the number near "Shadows:" - That's the clipped pixel count, gone! You'll be able to see the histogram in GIMP too (this is PixInsight), but here's a quick example on the image above: The blue looks clipped, the red and green just on the edge. The colours in the image look OK, but the histogram suggests the channels aren't aligned. Of course, how dark we make the image is personal preference but if you can avoid losing that critical, faint data then try not to go too far. Hope this helps.

Great stuff 👍 You have every reason to be pleased with the outcome! Be careful of clipping the black point - it was marginally done in the first image, but seems more severe on this one looking at the histogram (primarily in the blue). Keep an eye on dew and/or flat calibration - I only mention this as there's a slight gradient and a brighter area in the middle. One more thing to add to the thousand other things we need to think about / learn about for each following session 😅

I wasn't sure if you meant 180s or 600s in the first post as you mentioned both but was going to say 600s on a CMOS camera in broadband is high. I think it's worth reducing it - there is some concrete calculations to work out the best exposure for your sky conditions, target and camera. Starting out, I'd just bring it down a bit - 5 minutes if you're happy with that, but even 1, 2 or 3 minutes in our non-astro dark skies should be fine. The satellite trails should get removed in stacking if you have enough subs - another reason to reduce the exposure + less reliance on perfect guiding over that whole exposure (although you have a solid mount). If you've not already seen it, one to watch over the summer / cloudy nights. https://www.youtube.com/watch?v=ub1HjvlCJ5Y&ab_channel=SharpCap

Absolutely. A job for a cloudy day/night and one you don't need to do that often. If you're grabbing 180s darks today, you just re-use them - I think it's typical to keep using them for 6-12 months. For tonight, I would stick with this FOV and just add more data of the same area (if possible to get the same framing with your current toolset). I don't think the barlow is going to do everything you want - it may increase the focal length, but at the serious detriment to speed, more challenging guiding and maybe more. I have to admit, I haven't seen anyone use a barlow for DSO imaging (it sounds too good to be true if you could!) but I'm sure there are exceptions... and if you like to experiment of course!

Great start @blameTECHIE Very challenging time of year to be going after these sorts of targets but you've got some great detail and structure in the galaxy. Sorry I can't help with GIMP, but for the darks, as you've hinted at, once you get exposure and temperature matched versions it should remove that amp glow fine.

😅 You've saved me the bother of doing something similar. In my head I was saying "Surely this will work fine".

This could be extremely well timed... I'll drop you a PM. I haven't a had a chance to post some photos but I've been busy configuring EAF on my Samyang based on your ideas and previous iterations and have done what you mention above (an HTD 3M and a GT2 2mm) Definitely. That setup is looking very compact and neat. The handle should finish it off nicely... for now Agreed, that's a couple of nights I've been out checking/refining. Wish I could start earlier than 23:00++!

Lovely Adrian. Nothing there to suggest it was anything other than a successful outing! Great seeing the starless version if only to focus my eye on certain areas I may have missed looking at the star filled one. It's only civil darkness up here and you can tell even at 23:30 it's still not that dark at all! I was out having a play with the Samyang (and Ha) in this area too last night.

Brilliant image Wim. The way you've brought out the faint very outer disc is excellent. So subtle, but clear. I think I prefer image 1, but switching between them at full resolution, perhaps a blend of both. The first image holds the faint stuff and transitions in and out of it really well (the second is also excellent!).

Excellent @tomatoAwesome close up of M27 and the initial sets of outer layers showing really clearly. Great still seeing images like this in late May... and the moon just to keep things interesting!

Very challenging conditions Paul - that's come out really well. Lovely structure inside M27.

Nice one Chris - you've picked a good time to get stuck into something while waiting for darkness again Be careful with the stretch on those galaxies, they're bright anyway - you might have some more detail if you take it back a little. M81 is looking great. I think the SX 694 has the same chip as the Atik 460EX - small yes, but great chips (I really enjoy using my 460 anyway).

Great stuff @DaveS Those tails are really coming out, even the fainter ones curling back on themselves.

Fantastic Paul - great image.

I've been waiting for this to pop up @Spongey since the teasers started appearing in the Samyang thread 😀 Great write up and really built up the excitement reading through and waiting to hit the image itself. Absolutely beautiful image and worth all the work you put in. Very moody colour palette with loads of contrast. The bigger mosaic must be a beast! So much to look at viewing the full resolution - just like you mentioned. I also like the rich starfield which in the small version feels almost non-existent, but at full resolution is right there but still enjoyable without distracting at all from the nebula detail. Fantastic. Will view this more closely again later where I can get it on a bigger screen.

That sounds like quite a change to almost every aspect of your imaging Damien! Great stuff getting it all running together so you can take advantage of methods that simplify the process. What a great FOV with the camera and scope - lovely image with lots of detail even in the smaller stuff.

Excellent Gerr, you've still grabbed a lot for 2 hours. As @DaveS mentioned, those tails peeling off from NGC 3718 just get fainter and fainter. I stuck ~11 hours on my version and still couldn't get as far as I'd have hoped. Looking forward to Dave's darker sky version though!