StarTools

Finally finished my first SHO image of NGC 2070 Tarantula Nebula using the 2600MM and Antlia 3nm filters.
Very happy with the result under Bortle 8 skies and Full to first quarter Moon.
It’s taken just over a month due to persistent cloudy nights but managed to put together about 5 hours of data. I only have a window of less than 2 hours on this object during the night due to my roof , my TV antenna and a big tree obstructing its ascending view.

Bortle 8 City suburban skies
Full moon to first quarter
Seeing average
8” f5 Klaus Helmerich Carbon fibre Newtonian
Skywatcher EQ6-R pro mount
ZWO 2600MM cooled to -10C , Gain 100
TS Optics GPU coma corrector
ZWO EAF
ZWO EFW 7 x 2”
Antlia 3nm filters
Orion 60mm guide scope with helical focuser
ZWO 120MM guide camera
Ha 34 x 3 min dithered subs
Oiii 30 x 3 min dithered subs
Sii 29 x 3 min dithered subs
Full calibration suite ( Flats, Darks and Bias )
Tracking and Goto EQMOD and Stellarium
Captured using APT
PHD2 Multistar guiding ( guiding over all sessions was excellent, lowest numbers ever achieved on this mount in 4 years , 0.37 arc sec total rms. )
Stacked in ASTAP ( ASTAP produced a much cleaner , lower noise stacked image than with DSS )
Processed in Startools V1.8 via Compose
In colour module used various SHO matrix blends and tweaked saturation and colour bias amounts
It should be noted , this is the first image where I didn’t use any Startools gradient reduction ( Wipe module ) When I hit the colour module , Startools gave me a warning about not using Wipe and may experience an issue with colour ( I had no problem with the colour module and producing some nice SHO blends ) For only 5 hours of data I expected more noise but the stacked image was very clean before loading into Startools.
I’d certainly like to add more data and see what 10 or 12 hours would produce but by the time this cloudy weather clears this object will limit my window to less than an hour. I’ll have to wait until next year.

Link to Astrobin below for full resolution image ….
https://www.astrobin.com/s8umvh/

Comments welcome
Thanks for looking

Martin

Here’s 2 more versions
Another SHO ( blue dominant )
Synthetic Luminance equivalent in SHO

Clear Skies
Martin

Congratulations on your first SHO image, Martin It looks great and I really can't say which version I like best. And I'm not sure if more integration time would add any significant benefit. The full res version on AB still looks slightly oversampled (?). I wonder if you could trade some resolution for improved SNR using the BIN module. But of course, that's just to say something

Startrek wrote: ↑Tue Nov 21, 2023 3:12 am ASTAP produced a much cleaner , lower noise stacked image than with DSS

Yeah, I recently had the same impression while experimenting with our beloved DSS SBPTZ check box . I don't remember the difference being so obvious in the past when I switched to ASTAP. But maybe ASTAP has improved even more since then and I just haven't noticed it over time.

Startrek wrote: ↑Tue Nov 21, 2023 3:12 am It should be noted , this is the first image where I didn’t use any Startools gradient reduction ( Wipe module ) When I hit the colour module , Startools gave me a warning about not using Wipe and may experience an issue with colour ( I had no problem with the colour module and producing some nice SHO blends )

According to ST documentation using WIPE is important (and mandatory) to set background levels. (Of course, you succeeded well!) If you feel like there's nothing to wipe, you still could use the gentle NB preset and/or less aggressive settings.

Best regards, Dietmar.

P.S.: Oh, I just decided I like the blue dominant version best. But maybe that's just because I like blue colour in general

Hi Dietmar,
Thanks so much for your reply and comments
I’m sure any image can benefit from more integration time due to the fundamentals of SNR , it definitely reduces noise but the level of improvement in resolution and detail is limited by seeing etc…Under heavy light polluted skies like I image under , integration time is paramount especially imaging broadband.

I did Bin these images at 71% preset so some improvement or trade off in res to noise reduction.

My rigs sampling is calculated at 0.77 arc sec per pixel , so well over sampled.
The way I judge Sampling and Binning is to zoom in from 100% to 400% and see when my smaller stars ( with obviously less pixels in their profile ) start turning “blocky”.
Depending on the quality and amount of data captured, my images have the best balance of SNR between 65% to 75% Binning.

If I Bin below 65% when I use SV Decon my smaller and sometimes medium sized stars morph into square blocks of solid pixels which is ok at normal frame size but as soon as your pixel peep , it becomes obvious and looks ridiculous.I’m always zooming in to check my processing.

I haven’t upgraded to the latest DSS as folk are still experiencing issues every day, I’m still using 4.6 and it’s working fine.
ASTAP is working extremely well so far , it does produce a slightly lower noise cleaner stacked image. However I am stacking with both DSS and ASTAP at the moment so time will tell which one I settle on moving forward.

I did reprocess this data set using Wipe NB preset and the results were similar to the non Wiped image ( at least I couldn’t see any significant changes )
I’m not going to skip Wipe again but it was an interesting exercise. Yes Wipe is important to give your stretches and other modules the correct baseline.

The blue dominant image is spectacular but lacks a little bit of contrast IMO. It’s version 2 for me

Thanks again and Clear Skies
Martin

Absolutely marvels, all of them. I think i prefer the blue/reddish the most...but maybe only today, tomorrow i might choose another one

I am sitting here and waiting for clear skies to come, but when will that be....cause i want to make my first SHO too...i just bought the filters and have the mono cam...what i don't have is good weather...it has been raining for weeks, too much water in Belgium...some people have flooded houses in a particular region of Belgium...very bad

super lovely, for me SHO v2 it has the most billowing structure height

fmeireso wrote: ↑Wed Nov 22, 2023 10:07 am Absolutely marvels, all of them. I think i prefer the blue/reddish the most...but maybe only today, tomorrow i might choose another one

I am sitting here and waiting for clear skies to come, but when will that be....cause i want to make my first SHO too...i just bought the filters and have the mono cam...what i don't have is good weather...it has been raining for weeks, too much water in Belgium...some people have flooded houses in a particular region of Belgium...very bad

Thank you for your kind comment
Each version has its own features

My wife and I traveled through Europe years ago and stayed in Bruges along the way. Lovely City
Belgium is very flat so I can understand why there’s flooding in areas
Hopefully the rain stops soon and you can get back to our wonderful hobby
Cheers
Martin

happy-kat wrote: ↑Wed Nov 22, 2023 11:14 am super lovely, for me SHO v2 it has the most billowing structure height

Thank you
What makes this capture so challenging is that I only had a small window of time between obstructions ( less than 2 hours ) My roofline , a TV antenna and a big tree.
The weather down under on the east coast has been cloudy for over a month and managed 1 clear night to capture Oiii and Sii data so I could finish off the image.

Clear Skies
Martin