GuLinux

I know.. same old easy targets.. But perfect test for my new gear. I've always been more of an itinerant stargazer, trying to do astrophotography with my star adventurer and camera lenses from dark places, but since the lockdown I've been wondering on how to better use these rare and amazing clear nights. In particular for this shot I used an iOptron CEM40 mount, with a small 50mm autoguider scope, and a slighly larger (1mm!) Redcat as primary scope. I also used an Optolong L-Enhance light pollution/narrowband filter, and I wasn't expecting to give such amazing results so close to London Center (Ealing!) The CEM40 and the L-Enhance are brand new, the Redcat almost a year old, but barely managed to do anything with it, the camera is an ASI094MC Pro. I also bought an Esprit 100ED and some narrowband filters for my mono camera (ASI183MM), to be tested after I get more confident with smaller scopes (blog post, FYI: https://blog.gulinux.net/en/blog/2020-06-01-backyard-deep-sky-north-america-and-pelican)

Ditto. Plus, I'm a bit wary of these full frame sensors. Great on paper, sure, but a lot more difficult to deal with (need for a bigger flat field, more sensitive to misalignments, etc)

Hi @Dantooine and welcome And as everyone else said, thank you very much for all your precious work! Aaaand, yes, me too 😂 just spent a massive amount on new mount, apo, narrowband filters (well, we can't look for dark places, so might as well get started in NB) etc etc. I feel a little less guilty knowing I'm not alone

AstroPhoto Plus.. mainly because I wrote it 😅 I often use KStars/Ekos too for the missing features, usually I use the two of them in tandem

Yes, of course, I merely meant the illumination issue

I'll try that, thanks. I often wondered exactly how to find the direction for the tilt, this is indeed a useful suggestion. I still have to learn how to properly do flats (I've read the "cling film" procedure before, I think I've tried it once, but I wasn't really satisfied by it, but I don't remember why. Have to give it another go)

Yes, I already followed that one (the second process, subtracting the blurred image). The image I posted is after I already reduced the uneven illumination, it was a lot worse before 😅

Following with interest, as I have the very same problem. I still have to try flats, but I did buy a tilt adjuster, which definitely helped with the newton rings, but the camera is now partially out of focus. It's quite visible in this picture, the centre is quite sharp, while the borders are visibly out of focus, and the illumination is quite uneven.

Nice little Star Adventurer trick I'm testing this evening: Instead of using sandbags to stabilize my tripod, I bought a few of these: https://www.amazon.co.uk/gp/product/B07RTRHVRB/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Regular pegs might be alright as well, I thought these should offer a better grip, particularly if the cord is well tensioned.

Great review, happy that you joined the club! And I really hope you're getting better skies than here in the UK, it's been ages since I could last use mine

Quick question. I'm currently undecided between trying a dual camera setup (with a second camera + lens on the other side of the dovetail, in place or in addition to the counterweight), or to just get a second SA (which would also imply using a second tripod though). Surely the second might prove to be more stable, but the first setup is tempting, particularly because it would greatly reduce the need for a counterweight. Did anyone try the first setup? Would you recommend it?

I typically use an Intel Compute Stick (or equivalent), with USB3. I used a Raspberry Pi in the past, but they are way too underpowered, download time extremely long with a full frame ASI camera. As for the software, I'll just leave this here... https://astrophotoplus.gulinux.net/ (working on autoguiding support at the moment)

These compute sticks are really handy. I bought a couple of these, and measuring power usage with camera and filter wheel attached I barely got to 1 amp. I had a test indoors, with the camera continuously shooting, and changing filter every now and then. The power bank lasted for nearly 48 hours. Of course battery performance outdoors (in cold weather) might suffer quite a bit, but it's still gonna last a while, I'd think

WOW! ? I'm a bit skeptical though. It might be something that happens only on my setup, but I need to be very careful and delicate with tightening the RA lock, otherwise I risk messing with the polar alignment. I think that wrench might take it a step further..

Interesting thread. Sorry if I go slighly off topic, but do you know from where I could draw a 5v power line from the SA circuit? directly from the regulator perhaps? I'd like to to a minor modding, adding an embedded polarscope illuminator instead of using the external one.

Really stunning, congrats I really have to get myself up to work, I need to catch up with these results ?

Hi, I couldn't find specific information about that scope OTA weight, but my guts say it's probably too heavy. Additionally, although these newtonians are excellent first scopes, they're not very useful as astrophotography scopes: there's probably too much coma, and I doubt you'll be able to get focus with a DSLR, as the focus excursion is typically very short. Furthermore, a focal length of 500mm starts to be way too much for a star adventurer, particularly if not autoguided. And of course, adding an autoguider will add even more weight.

Just be aware of what version you get: the "Super Takumar SMC" (super multi coated) is probably ok, and I've seen gorgeous pictures done with it, but I got the older version instead (I think it's called only "Super Takumar", non SMC) and I got massive chromatic aberration and stars bigs as baloons.

Slightly off topic, I'd really like to understand how reliable is the load capacity rating on tripods. Sometimes they just feel like they put random-ish numbers on them, sturdy tripods rated at 5/10KG, and much cheaper and lightweight tripods rated at 15. Mine (neweer carbon fiber) is rated 15KG, and although it's quite stable, I don't think that number can be taken too seriously.

Wow, that's really amazing!

Usually bad polar alignment.. happens to me all the time. Often after you polar align, everything you touch, from pointing the telescope to even tightening all the equatorial wedge screws can lead to a shift from the polar axis. You just have to learn being very, very delicate (and I'm still learning ?)

Quoting that. I did the same, and it really improved the wedge stability a lot (though it's still certainly not the very best it could have been)

Sorry, it might be a silly question, but why do you need the thermistor? I can't see any usage in the code, except for just showing the temperature

I wasn't clear, sorry I was just asking @alcol620 what he does, as that might explain his tracking issues, I wasn't asking for suggestions ?

Sorry if I might ask the obvious, but do you align by putting Polaris on the center of the polarscope reticule, or do you use a polar finder app to get the actual position of Polaris? There's almost a whole degree difference between Polaris and the actual pole, depending on the target declination that might account to a lot!