Elephant Trunk Nebula Ha Oiii Sii

[tooth_dr]

This is a bit of mismash of misaligned data, from the past couple of years, the most recent data captured in October.  I used my ED80 and Epsilon 180, along with the QHY9 and 383L+, and Ha Oiii and Sii filters.

Ha = 10.25 hours

Oiii = 3.5 hours

Sii = 2.0 hours

I left a bit of green in the image, as I quite like the transition between yellow and blue.  It lacks a bit of clarity and is noisy too despite over 15hours, which I attribute to collecting the data with the moon and hazy skies.

 

Thanks

Adam.

 

 

Edited December 2, 2020 by tooth_dr

[Xiga]

Very nice Adam. FWIW, i completely agree on the green front. 

The noise is probably down to the level of stretch. The Ha is so dominant here, that it's often enticing to try and bring the other channels up to the same level. 

Recently, i've started to go the other way, and actually tone down the Ha stretch quite a bit. This way, you don't have to boost the other 2 (usually noisier) channels quite so much. The result it usually a darker, moodier image overall (personal choice of course, but i quite like that, even though it's taken me quite some time to realise it). If you aim for a roughly similar Mean value in PS for each channel, that's usually a good starting point for combining the colours. 

[Miguel1983]

nicely done !

[MartinB]

13 hours ago, Xiga said:

Very nice Adam. FWIW, i completely agree on the green front. 

The noise is probably down to the level of stretch. The Ha is so dominant here, that it's often enticing to try and bring the other channels up to the same level. 

Recently, i've started to go the other way, and actually tone down the Ha stretch quite a bit. This way, you don't have to boost the other 2 (usually noisier) channels quite so much. The result it usually a darker, moodier image overall (personal choice of course, but i quite like that, even though it's taken me quite some time to realise it). If you aim for a roughly similar Mean value in PS for each channel, that's usually a good starting point for combining the colours. 

Great framing and, for me, the colour is perfect.  It is surprisingly noisy.  I don't know if you used a luminence.  I normally do and my normal routine is to stretch the 3 channels and have a look to see whether the SII and OIII are pulling out any features that aren't present in Ha.  In the majority of instances they aren't!  Where they are, e.g OIII in the Jellyfish or the Crescent, I use a lighten blending mode in PS to combine.  I never bother with a super luminance since I think this actually degrades the SNR.  I might be completely wrong on this and there maybe something I've missed, it's just what I've decided on from experimenting really.  Once you have a luminence in place you can take all sorts of liberties with the combined colour image to kill the noise!

 

[tooth_dr]

14 hours ago, Xiga said:

The noise is probably down to the level of stretch. The Ha is so dominant here, that it's often enticing to try and bring the other channels up to the same level. 

This is what I did, the Ha was my baseline and I adjusted the other channels up to that level.  But the Ha was noisy too, so perhaps I just stretched that too much as well.

[tooth_dr]

57 minutes ago, MartinB said:

I use a lighten blending mode in PS to combine.

I did use a 50% 50% blend of Oiii and Sii, and then added it to the Ha at 15%, but I didnt use lighten, just normal combine!  There is so much to learn.

[MartinB]

1 minute ago, tooth_dr said:

I did use a 50% 50% blend of Oiii and Sii, and then added it to the Ha at 15%, but I didnt use lighten, just normal combine!  There is so much to learn.

There certainly is and there seems to be so many ways to achieve the same result!