geeklee

It doesn't, excellent capture @Wiu-Wiu. A reminder of the skies, equipment and time you need to capture these challenging areas... or at least the trade off between the three that you pick if you don't tick all the boxes!

That's looking superb so far @Sp@ce_d Definitely an area of sky I'd like to capture, but with the RedCat! Mosaics always sound like a great idea until you remember our skies 😅 (except with fast lenses!) Is the plan four panes in the end to cover everything or would you get it with less?

Typically for spacing on this lens, you will need to account for the filter if it's between lens and camera - usually add 1/3 the thickness of the filter like you would on a scope. I have found these to be very good: M42 https://www.firstlightoptics.com/adapters/baader-t2-fine-adjustment-rings-aluminium.html M48 https://www.firstlightoptics.com/adapters/Baader_M48_adjustment_rings.html You will also have got thin spacers with your ASI camera - one of these might just be thin enough, I can't remember. Whether you'll still get an iffy corner, I'm not sure If you want to break away from that adapter, you could get the Canon Samyang M48 adapter that FLO sell, use your filter drawer and make the rest up with what you have and additional spacers.

It's unlikely but I was thinking could a bigger slew be moving something in the focuser / imaging train. You're right, you should be able to go to wherever you like to focus and back without an issue. If you look through your Lobster subs, they'll likely start fine and start to drop off if it's temperature so at least something you can check (if not done already of course). I understand and sympathise. With the lack of clear skies, everything can become doubly frustrating and can (for me in the past anyway) keep nagging away at me until I can test again the next clear night.

Was there a different process you took each time. For example the times you've had issues with focus you slewed to a star far away to pick as your focus star, then slewed back to target? Whereas (for example) the "good session" your focus star was very close to your field... or do you put the mask on the field you're targeting and pick a star+pattern you can see there? For now, just add the sub check or two after you've done focus, it'll save you a wasted night. If the focus looks off you can put the mask back on then and double check - maybe adjust in and out of focus using the other methods mentioned above (FWHM, HFD etc). It'll give you a shot at getting focus for the night while learning some new focus methods and hopefully figuring out what's going on. Silly question, but the imaging train after the focuser is all good? Is there an adjustable flattener that's not tight or non-screwed connection that's likewise?

When you tighten the focus lock, do you then set off another focus check sub? As you mention above, whatever process you end up being happy with definitely needs the extra check when the mask comes off. Just fire off a 30s sub to check, then if all looks good run a longer one too. I don't think the scope is that fast so surprised you see such an out of focus image from using the bahtinov mask that might be a tiny bit off - as you've said before, it's served you well. I remember on my ED80, I got used knowing which way the focuser lock would nudge the focus (ever so slightly) so got used to leaving it a tiny touch off, then locking, then checking focus again. It's definitely locking and there's no slippage?

Nice challenge and good write up Stu. No point in wasting any clear skies! Hopefully some/all of those are keepers for more data another night.

No problem - 5/6 with the usual street lights helping out too 🙂

Yep, I realise this 👍 I was just offering my experience up as that was a scenario spoken about by the OP.

I find the 183MM with the Samyang 135 an excellent combination. The small pixels with fast speed produce some surprising detail for the focal length. Even resampling later still produces good output with modest integration. I've also used the ASI533 with the Samyang. On one occasion I remember using a dedicated Ha filter in front of the camera and wasn't impressed - as mentioned above, that inefficiency with the OSC (compared to mono). In general though, the ASI533+Samyang was a very easy relationship. My Astrobin page has images from both these combos - the 183MM images (the latest ones) were done during summer (so no astro dark)

Sorry David, I can't help with the NINA side of things but I do have my encoders off as well. Thinking back a couple of years when I set this I'm sure I'd read it was recommended when imaging. It was something I did in the early days so can't say if it makes a difference. I do get successful flips using my main imaging software - it does similar and goes past the meridian ~10 minutes then does the flip, plate solves etc and carries on. If NINA is controlling things, it maybe thinks the mount hasn't passed meridian - are all the time / date and daylight saving offsets OK?

Fantastic news @Rustang and cracking image 👍 Really clear detail in the crescent - good luck with the OIII.

There's no need to be confused, just use the defaults to get started . I'm fairly sure the last thing you'll be thinking about or noticing is what that offset was set to. I'm guessing ZWO were just playing it safe, knowing that the value they set still provides ample dynamic range - perhaps they'll change it at a later date, but the camera has been out for 18months+ already... I used darks with mine and dark flats instead of bias and it all calibrated fine alongside my flats. I would recommend dithering. On the face of it, I don't think there's anything to set straight - there's just people doing different things with the camera that all work. Maybe we all need some clear skies so we can get out and use our technology rather than worry about it 😅

From 13th August (yeah, it's been that cloudy since!) the best 20 of 30 180s Ha subs (1 hour) of the Heart and Soul. Taken while testing my Samyang + 183MM (~F2.4) on an AZ-GTI in EQ mode with ASIAIR Pro. Not processed much except to reduce the stars. Some nice detail for 135mm in the heart of the Heart:

Yeah, it's frustrating and I sympathise. When I saw your thread title, I knew exactly what you meant! I find the lack of clear nights exacerbates that feeling of urgency/frustration for issues that require testing. All you can do next time out is have a plan - try the tools suggested in Apt first, maybe get it bang on according to the Bahtinov Aid, then check using the Focus Aid as a reference, take a frame or two and check them zoomed in etc. If you're happier all good, if not, start to tweak the focus through the zone and keep checking the frames. Ensure to check back with temp changes or just every 30/60 mins maybe (I like to focus on filter change too)

Sorry, I don't. It will only be testing out of focus, in focus, out of focus and back will you see the best values. One thing I noticed is the screen view and peak value looking like 8bit, in the Apt manual it says you have to switch to 1:1 preview mode to use the raw FITS data for calculation. Just double click the image to get this 1:1 view. https://astrophotography.app/usersguide/focusing_aid.htm

Apt has another tool that lets you put a box over an area and get x3, x5 and maybe something higher (I think I have that right but am going off memory) The Bahtinov Aid is worth using and those spikes look clear. The WO masks with the clear material do seem to create bright spikes.

Did you eye ball the bahtinov mask focus? To my eye the centre line looks too high (but very close) but if you used the Bahtinov Aid in Apt then it's my eyeball at fault 😉 When not using auto focus I've found the Bahtinov Aid in Apt to produce good results but perhaps not as consistent as a good autofocus routine.

Absolutely 👍. I recently put together a light weight rig I hoped to run my Samyang 135 on - an AZGTI with EQ wedge and ASIAIR pro. As always, it wasn't exactly simple, nor inexpensive 🙄 and the jury is still out on the performance. I didn't want another full size mount - even a "light" one like a CEM26/28 where you still have considerable counterweight and tripod. The only night I've had a chance to use both rigs at the same time was still a bit of a pain getting each fully setup and imaging... but was a great feeling when they got separate data sets ☺️ - felt like free data...😉 (couldn't be further from the truth ... it was expensive data! 😅)

Depending on your goals.. if you had a camera and fast lens you could use a Raspberry Pi or ASIAIR Pro (v1 or Pro) and just use them to focus and snap images - throwing away the ones where your main camera might be dithering etc. This likely works better if your main camera is taking long exposures so your fast lens combo can snap many more subs in the time so throwing away less @Adreneline has tried something like this approach with a Samyang 135. For full rigs you'd likely need just what Tristan suggests!

I don't think it would make a difference. As long as everything is rigid, the guiding is for the components on the mount. Frustrating! I was about to say, what about a cheaper CLS CCD or equivalent but when looking they weren't as cheap as I thought for a clip-in That was Astronomik. I'm always keeping an eye for a miniPC, but running at 12v Tristan. What was the appropriate cable in this instance - a typical 5.5x2.1?

If you have a camera and lens, that sounds like the best way to get started if you wanted to. At least you could price up the bits needed to mount them together without extra camera and scope etc!

From dabbling myself, like normal but with a more obvious "2-way DEC". So RA on overall weight, DEC with scope either side of saddle and DEC at 90 degrees to this (so you're balancing the scopes along their dovetails I guess is another way to think about it). They would be pointing slightly off yeah. There's a few discussions going on right now on SGL about dual RASAs and Esprit 150s. With these big scopes there is a dedicated saddle (or two) to help pointing but it would probably be overkill in weight and price for what you suggest. I've seen scope inside rings (like some guide scopes are done) used too. There are probably a few DIY solutions out there as well! Maybe simple shims or slight misalignment of a saddle would be enough - all depends on how precise you want them to match. A widefield lens + a scope probably doesn't need to be too close if their FOV are vastly different. Think about the whole weight of two rigs as well plus all their extras and any extra "metal" you use to get those rigs put together Vs the HEQ5 Pro recommended maximums. You've also got the control mechanism of a dual rig as well (if it's not a DSLR). Not only additional USB and power but software and do you want to tie them together for focusing, dithering etc (again, more relevant to matching scopes than a DLSR and lens). Plenty of members that have done this will probably provide more concrete info!

Sorry, I don't but they look very similar. If you measure the diameter of the collar location with calipers, you should be able to check which collars will fit. There are a few mentioned in the 135 thread like the RedCat collar or cheaper alternatives from Amazon. All list their sizes so you'd know if it will fit and whether a little felt or foam padding might be needed.

HI Adam - if it's a Canon EOS EF fit lens, something like this from ZWO for the camera? It lists the "ASI-120" with 12.5mm backfocus (what I think your camera has with the black lens bit removed - revealing M42 threads?) https://www.firstlightoptics.com/zwo-accessories/zwo-adjustable-eos-lens-to-t2-adapter-for-all-asi-cameras.html A few other vendors make similar items. From the mount - given the camera is small and light, it might be easier getting a collar for the lens that can attach to a dovetail (or that has a foot already). ZWO have holder rings but only for cameras with with wider diameters. If you check out the "Imaging with the Samyang 135" thread, there are a lot of similar solutions there where the collars used might fit your lens - it will at least show you a lot of ways a lens is used! You may also need some small spacer rings to allow best performance (depending on the lens and if a filter is used e.g. UVIR cut) but the above is a good start. Hope this helps get you started.