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M42

Started by The Thing, Feb 18, 2021, 10:22:44

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The Thing

I am a bit mystified by the flatness of the Ha on the right of the picture.

137x60s 2h17m Gain120 Offset 4 Temp-5C 10xDark, 10xFlat, 10xDarkFlat Processed in PixInsight using Weighted Batch Pre-Processing v2 (as easy as DSS!) and EZProcessing scripts with a tweak using Curves Transformation.

Image date, time and location:   2021-02-10, 20:22-00:17, Manche, France
Telescope aperture and focal ratio:   Sharpstar 61EDPH F4
Camera and filters used:   ZWO ASI294 MC Pro, Optolong L-eNhance Ha, Hb, OIII filter
Processing applied:   PixInsight (WBPP2, EZ, CT)


Carole

That's come our really well Duncan.

Very nicely processed except I think the brighter part of the nebula is a bit bright and obscuring detail, did you take any shorter subs to combine?

QuoteI am a bit mystified by the flatness of the Ha on the right of the picture.
As regards your comment above, I had a feeling that Ha was a bit lacking on that side of the nebula and did a search and found this one below.  Whilst there is Ha on that side, it's no-where near as bold and detailed as on the left side.

https://www.astrobin.com/340230/?nc=user

Carole

The Thing

Thanks Carole. Noted about the Ha.

I used a PI function called Masked Stretch, probably need to ratchet it up. The well depth of my asi294 and so it's dynamic range means at 60s I can see the trapezium stars on my main pc. I think conversion to jpeg has lessened the range somewhat, 32 to 8 bit🙁

RobertM

Nice one Duncan and very pleasing colours, pretty good stars in all four corners - I presume this is using the reducer ?

Are you autofocusing yet or is this with a Baht ?

JPEGs are always a PITA when it come to dynamic range.

Robert

The Thing

Thanks Robert. I'm using PhotometricColourCalibration in narrowband mode with the passbands entered.

It is using to the flattener which makes it a 5 element apo. The focus is automatic but I think I need to tighten the grub screws and glue them as it's gone sloppy! The autofocus often fails but it's pretty  good anyway. More tweaking.

Roberto

That's a cracking shot Duncan.  I love the nebulosity and framing.

Roberto

The Thing

Thanks Roberto, high praise much appreciated.