What is causing this then....

[Shelster1973]

Making the most of a clear night here and when getting towards the end of my image session (well its still going as we speak, but has 11 mins of pics to grab) decided to image the Garnet Star.

Am a bit confused as to why I am getting two 'spectrum' lines in addition to my normal diffraction spikes.

Quick crop of the image is below so you can see what I am on about

[johnrt]

Internal reflection perhaps?

[Shelster1973]

Tis a possibility.  May be from either the coma corrector or the LPF that are in the image train.

May do an experiment next time out and remove the LPF 1st and see if that cures the issue.

[Chris]

My guess is that it's coming from your coma corrector. 

If you could see the absorption lines you could do imaging and spectroscopy at the same time! 

[ollypenrice]

I think lens as well.

To fix it in Ps I'd make a bottom copy layer active in Ps, clone stamp out the entire aretefacts wholesale with a chunk of background sky then make to the top layer active and erase the spectral pattern.

Nice colour in the star!

Olly

[Cath]

Yesssss, that looks sooooo much like a prism (glass) effect

[Shelster1973]

Olly take it be lens you are refering to the coma corrector?  Would have thought the Baader would not have had any artefacts / effects like that with it

Cheers for the PS advice.  Will be processing it this weekend, so will give that a go when all is done.

Am happy with the colour too.

Did take some varying length subs on this one, did 30s, 60s and 90s so that I can get a decent range for blending.

[Shelster1973]

Is also present in this image of the Leo Double (may have missed the third one...but as Meatloaf says, 2 out of 3 aint bad).

This time it is in a different area of the image.  The one from the Garnet Star is dead centre where as you can see in this, while central in the frame, it is in the top third of the image

That is just a straight JPG conversion of a single sub of 120s ISO 800.  Have 30 of them to stack at the weekend

May reframe on my next image session with it and centre on HD98388, hopefully will get them all in then