Helix - over-processed but I'm happy.

[Drac0 (Mark)]

This is Ha+LRGB image of NGC 7293, the Helix Nebula.

While it is a bit over-processed, the stars are terrible, I'm happy with it compared to an earlier effort I had made at it with a OSC. On that occasion I just couldn't bring the nebula out at all - just a field packed with stars & a blurry fuzz in the centre.

102mm ED with x0.8 reducer.
ASI294MM Pro
L = 112 min
R = 47 min
G = 60 min
B = 57 min
Ha = 300 min

I thought initially the Ha would be total overkill but was surprised when my red had almost no data, so was glad to have the Ha to fill it out.

Cheers,
Mark

[Startrek (Martin)]

Mark,
That’s a great image of the Helix with a relatively short focal length rig
It’s a really faint object
What sub lengths and Gain did you set ?
Looking at the charts for this camera Gain 120 ( HCG ) is where you achieve the highest dynamic range for the lowest read noise , so you can really push those sub lengths pending mount tracking and guiding limitations.

Well done !!

Martin

[Drac0 (Mark)]

Thanks Martin.

What sub lengths and Gain did you set ?

Lum were 120 secs
RGB were 5 min one night & 3 min on another
Ha were 10 min
Gain was of course 120 for all.

All done over 3 nights:
Night 1 - Ha+LRGB
Night 2 - Ha only
Night 3 - LRGB

Cheers,
Mark

[Startrek (Martin)]

Mark,
As the Helix is primarily a narrowband target ( emission ) and at magnitude 7.8 ( very faint ) theres not much value in capturing LRGB with a short focal length rig as it only assists to achieve some colour balance
To pull out the finer detail I would shoot purely Ha , Oiii and Sii with 5 mins subs with at least 8 to 10 hours of data integration

I’ve captured the Helix many times both in OSC RGB and OSC narrowband ( L Extreme) on my newts and the narrowband data is the key to pull out fine detail even with a OSC

Just my 2 cents ……….

Attached image of Helix from 2020 using 6” newt ( focal length 900mm ) under Bortle 8 Sydney LP with L extreme filter , waxing moon and neighbours lights. 2600MC OSC with 135 x 3 mins subs dithered (inc calibration )

Cheers
Martin

[Drac0 (Mark)]

the narrowband data is the key to pull out fine detail

Sadly right now the Ha is the only narrowband I have right now, will be good to attack this target again next year with OIII & SII to see what a difference it makes.

[Startrek (Martin)]

Originally Posted by Drac0

Sadly right now the Ha is the only narrowband I have right now, will be good to attack this target again next year with OIII & SII to see what a difference it makes.

Definitely the Oiii filter and to a lesser extent the Sii
Narrowband does play some havoc with your colour but extracting detail is what we all aim for , the colour can be subjective but good fine detail is paramount IMO

Your Helix is excellent , I’m sure NB will improve it

Cheers
Martin

[Dave882 (David)]

Mate this is a great shot! I also agree with Martin the narrow band will help greatly to increase contrast and some more detail in particular those outer areas. But I’m really impressed with what you’ve presented. Well done!!