Qhy168c second light

[beren]

Had another go with the Qhy cam last night, read up a bit on getting the gain and offset done correctly and didn't seem to get the artifacts I had on first light. With guilt put aside went after the convenient targets the Horsehead and Eta again. With the full moon and shooting back south over the Perth CBD think the end result wasn't to bad I think......30x180s lights.....cheers for looking.

Astrobin https://www.astrobin.com/full/328131/0/
https://www.astrobin.com/full/328130/0/

[RickS]

They both look pretty good!

[beren]

Thanks Rick.......if you have time do you have any tips for colour correction on blue stars, seem to struggle with it....cheers

[RickS]

Here are a few thoughts, assuming PI...

Get a good colour calibration first. I really like PhotometricColorCalibration with average spiral galaxy as the white reference.

The new archsinh stretch is great for keeping and enhancing colour. I normally do an initial stretch with it and then a HT stretch to finish.

Applying a star mask and then pulling up the saturation curve in CurvesTransformation will boost star saturation in general. Use ColorSaturation if you want to selectively boost specific hue ranges, e.g. blue.

Apply a star mask and then use one of the multiscale tools, say MMT, and turn off the first few layers completely with target set to Chrominance. This will blur the colour in the stars. This helps fix coloured rings around stars and will also colour up white cores a little.

The hue curve in CurvesTransformation can be used to push cyans towards blue - set points to keep the ends of the curve straight and "lift" up the region from green to blue.

You can make a blue star mask by taking a ColorMask (blue) and a star mask. It generally helps to blur the blue mask and then stretch it a bit. Now apply PixelMath to the star mask: "iif(blue_mask<0.05,0,$T)". You might need to tweak the 0.05 value and otherwise play around to get a good mask. Then apply the mask and tweak the blue stars using your favourite tools, e.g. use CurvesTransformation to pull up blue, reduce red and/or green, lift saturation, reduce lightness at little.

Cheers,
Rick.

[rustigsmed]

super sharp and colour vibrancy sets them alight.

nice.

[beren]

Cheers Russell :thumbsup:

Thanks Rick for the detailed tips , appreciate it and will check it out in PI :thumbsup: