M20 Day of the Triffid

[TrevorW]

Had a window of opportunity over 2 nights- 8 hrs in 4 minute subs QHY269c OSC


Went to do a third night and the laptop decided not to play ball - Windows and Ascom errors- I recently updated the HDD to SSD in the laptop, cloning the HDD to SSD- it seems in the cloning process something may have got corrupted.

[TrevorW]

and here is one in Hubble pallet

[Startrek]

Trev,
I’ll be the first to comment

Well I’ve never seen a Hubble palette applied to M20 , that’s a first !!

The image is absolutely fine but colour is a bit subjective ? Only my opinion and as always colour is always subjective and each to their own !!

Hubble palette works best on the larger Ha emission nebula like Lagoon , Prawn , Tarantula, Carina , Orion , Lobster and many others that generally emit hydrogen alpha , oxygen 3 and sulphur 2 emission lines.

I’m assuming you captured M20 using a OSC dualband ( Ha and Oiii ) filter ?

As M20 is primarily a Broadband target with reflection nebula ( blue ) , emission nebula (red to pink) and Dark nebula ( black to brown ) you may have been better to use a filter like the Antlia Triband RGB 2 or similar which would give you much better results on this particular target in relation to detail and colour. This target generally should be processed as a Broadband LRGB , however can be also processed as an Ha LRGB ( Mono data ) or in the case of your OSC , something similar to the Antlia Triband RGB 2 which is ideal for light polluted skies.
Alternatively you could use a luminance filter ( UV/ IR cut ) for your LRGB and use a second Ha filter to accent the main target as there loads of nebulosity in the interstellar background. However the luminance filter is not ideal for heavy LP like my Sydney location.
I was considering to buy the Antlia Triband RGB 2 and use it as a luminance filter for my Sydney B8 skies only , however that would mean every time I head south to my Dome under B3 , I’d have to open up my filter wheel and swap filters. My filter wheel hasn’t been opened since I originally loaded the filters in August 2023 and they are virtually dust free, so I ditched the idea and put up with my Lum filter for Sydney.

For OSC , the Antlia Triband RGB 2 is certainly a versatile option for Broadband and some Narrowband.


Please send some clear skies over to the East , cloudy for the next 2 weeks, May is a wash out . Hopefully June will be better.

Cheers
Martin

[strongmanmike]

Looking good Trevor :thumbsup:

The colours of the Trifid is one of the more debated, in the challenge to get true colours, when it comes to looking for the most accurate rendition. I wrote an article (https://pbase.com/strongmanmike2002/image/163616284/original) about the colours of the Trifid, for Sky & Space magazine some years ago, which was proof read by Dr Malin. While the articles accompanying image was close (rendered pretty poorly through the less than ideal magazine printing process and the mobile phone photo that it is, it should have looked like this (https://www.pbase.com/strongmanmike2002/image/82479275/original)), the best representation I have seen of how the Trifid should look though, based on the science, is this one (https://app.astrobin.com/u/morefield?i=vz4yir#fullscreen).

Mike

[TrevorW]

Thanks for the feedback Martin and Mike, Perth is experiencing some unusually warm Autumn weather (very little rain) although its full moon time.



Another filter can my wallet be pried open again :)


Mike, I wasn't expecting to win any prises with this one, not in the same league as yours.:)

[strongmanmike]

The super duper M20 I linked to was a 56hr exposure, taken by Kevin Morefield, using a CDK17 and APX60 on PWL600 mount from Chile :) So its high res and beautifully processed but the final colour palette/balance was what I was pointing too, it is spot on and matches well with the various physical/atomic processes going on :thumbsup:

Mike