IC5148 "Spare tyre" planetary nebula

[Pilgrim]

Finally got around to processing this material. This nebula was filmed over many nights from October 2021 to early January 2022 when I hadn't switched to an off-axis guide yet, and the guider's fixture was flimsy not allowing really long subs. Therefore, I shot mainly with 3-minute sub-exposures even for narrowbands. Fixed that in January and made few 10 min oxygen frames then.

The image is color balanced bi-color composition of Ha+OIII+OIII with RGB stars. Was taken during 31 night between 6.10.2021 and 3.01.2022, on my balcony in Brisbane (Bortle 7 city sky)

Telescope is TAL-250K (Klevtsov's system 10" reflector + 0.7x special NPZ reducer/flattner Mk2)
Mount EQ6R, camera ZWO ASI2600MM Pro, guider SVBony 60mm + ZWO ASI290MM, filters ZWO RGB and Antlia 3nm Ha+OIII

Non cropped full resolution here:
https://www.astrobin.com/1js2lz/


Total accumulation time ~50h (H-alpha 31h, OIII 17h, RGB 1h26m) with sub-exposures:
Ha: 615x3 min
OIII: 287x3 min + 15x10 min
R: 15x2 min
G: 14x2 min
B: 14x2 min

[Dave882]

That’s a fantastic shot! Really detailed view of this tiny PN! Looks to be some remnants of an outer shell coming through?

[AdamJL]

Yeah that's beyond spectacular. Awesome work, Igor!

[petershah]

Not one I get to see normally....it looks super difficult.....really nice work

[rustigsmed]

really nicely done Igor. excellent detail and depth.

[strongmanmike]

Great result Igor! Those outer faint shells are very rarely captured, they are faint!... in fact, I think you are only about the 4th or 5th person to do so (https://pbase.com/strongmanmike2002/image/161316786/original), as far as I can tell...? :question: :thumbsup:

That's a lovely sounding scope too... reducing it to F6 would have helped too.

Mike

[Addos]

you are the planetary nebula man igor, great shot once again!

[Pilgrim]

Thanks David, Adam, Peter, Russel, Michael and Adam for Very kind comments! :)

I aimed to get some more details of the outer shell, but it appeared very slightly. Later I got an off-axis guide and now 20-minute exposures are not a problem but during the shooting of this frame I was yet limited by 3-min subs with flimsy guider mounting.



:question:It would be interesting to take additional several hours via 20min subs and compare SNR with same total time sum of 3min subs. It was is about 20% difference measured by bright objects SNR, but I suspect strong non-linearity for faintest details in heavy light pollution conditions because mathematics became non ideal suffering from all accumulated errors (non ideal calibration, non constant non flat sky background, etc)

Yeah, this OTA has it's own story. In 2007-201x I was kind of NPZ's Ambassador & volunteer tester and they provided it to me. I visited them in Novosibirsk several times, so had a chance to personally got acquainted with Yuri Klevtsov, and developer engineers of TAL telescope series Lev Parko and Anatoly Ageev.
The factory at that time had produced a small series of 0.7 reducers/flatteners "Mk1" explicitly calculated for TAL-250K and APS-C matrices. I tested them on the sky, and then I got a new Mk2 for tests, which was a prototype (never sold, only few items produced and some distributed to amateurs).

[Stephane]

Igor, you have shown some real determination to spend 50h on a planetary nebula. I am yet to spend 50 minutes on one. Your efforts have certainly paid off and inspired me to give one a fair shot some day. Well done.

[strongmanmike]

Nice, lucky guy! Sounds like a great OTA and corrector and results seem to confirm this :thumbsup:

Mike

[markas]

Spectacular:thumbsup::thumbsup:
Mark