Bubble Nebula (aka "Screw the math")

[raadoo]

Pairing an ASI183MC Pro (2.4μm) with a Skymax 127 at 1500mm native is not generally a recommended setup, especially not from a Bortle 6 inner city location. The pixel scale alone, at 0.33 arcsec/px, is so oversampled that you're essentially just getting a lot of blurry pixels. And I'm not arguing against it; that's absolutely the case here. Binning x3 will get the same level of detail without the hassle of dealing with 20MP subs.

But hear me out. I really wanted to get the Bubble Nebula. It was on my to-do list. And I'm in a situation right now where my next best scope is not in the cards in the foreseeable future. So I could either go for another wide field target or frankenstein some sort of setup with my only other scope: my Mak.

So I lifted the ASI183MC Pro + Altair Filter Holder w/ Antlia ALT-T + ZWO OAG off my wide field setup and through a lucky combination of adapters managed to stick it to the back of the Mak 127. For focusing I had to rely on the stock focuser without so much as a Bahtinov mask (that was ... uhm ... "fun"). Speaking of focusing, I soon realised that the Antlia filter, nice as it is, blocks so much light that I was unable to focus or polar align without going to 10s exposures, which wouldn't work because of drift. So the whole process was to do a first focus with no filter in the slot, polar align, enable tracking, then slot in the filter and refocus. Then refocus every ~30min because temp deltas at night are horrible right now in my location.

This whole song and dance went on for four nights these past two weeks or so and while I can take some credit for careful planning and choosing the best equipment I have for the job, credit where it's due: my beautiful red RST-135 tracked and guided like a champ. I was consistently getting ~0.3" RMS, sometimes going down as far as 0.2". It wasn't all perfect and I did throw away about 40 subs but what I ended up with were 133 decent subs that yielded the final result. So here I go piling on to the same age old advice: get a good mount.

If you want to throw a like or just a look, the image is also on Astrobin.

So, despite the math saying it's not the best setup to throw at a Mag 10 emission nebula and it certainly doesn't compare to what some of you have done with this target, I'm really proud of the result and I see it as a landmark in my own journey into astrophotography.

Thanks for reading!

[Elp]

This is what I like, just go out and do it and experience for yourself with what you may have at hand and not get yourself in a spin worrying about specs and stuff.

[Nik271]

Wow, imaging at F12 and 1500mm, pretty good result!

How long were your subs if I may ask?

Edited August 16, 2022 by Nik271

[raadoo]

1 hour ago, Nik271 said:

Wow, imaging at F12 and 1500mm, pretty good result!

How long were your subs if I may ask?

Don't forget about using a tiny 1" OSC sensor, on top of all that 😂

Subs were all 300s.

[powerlord]

top work fella! I'm of the same mindset - some folk like to get bogged down in the theory - fair enough, each to their own. I prefer to say 'stuff it', and just have a go - sometimes you end up coming away thinking 'yup they've got a point there', but more times than not I end up with something I am happy with, even if it's not good enough for the star peepers out there. 😛

I'd be well happy with that result. 👏

[old_eyes]

Yep! Sometimes just give it a go! Nice image from a very tricky setup. I admire both your boldness and your perseverance.