LodestarC X2 Colour Rendering by Starlight Live

[Bill S]

Hello

 

I've been having a look at the colour rendering from the colour Lodestar X2. I did a comparison of a non-astronomical scene (certainly not a standard test card!) using a C/CS lens mounted on the LodestarC X2 recording the picture using Starlight Live and the LodestarC software. The colour seems more realistic using the LodestarC software although producing the colour image seems more of an event (i.e. it does not appear instantly like Starlight Live).

Does this suggest that to get good colour rendering it's best to collect FITS files with Starlight Live and post process in something like Nebulosity.

See for instance the earlier discussion:

https://stargazerslounge.com/topic/263891-post-processing-lode-star-x-2-c-images/

Thanks for any comments. (Looks like I need to clean the camera sensor!)

Bill

 

 

[Martin Meredith]

Hi Bill

There should be no need to dump FITS to Nebulosity. How much adjustment of the colour channels did you do for the SLL shot? I've not used the LodestarC software (I don't think it runs on my Mac), but perhaps it has some kind of automatic colour balance built in, whereas with SLL you will need to do some manual adjusting. 

Martin

 

 

[HiloDon]

Bill,

Make sure that your exposure using the SLL software is greater than 250ms.  Unless Paul has change this, I don't think it will render proper color with fast exposures.  I recall having run up against the same thing a while back when doing similar tests.

Don

[Bill S]

Thank you very much for the helpful guidance - Martin and Don. Very useful.

I was using very short exposures with SLL even with the lens I was using stopped down to f16 because of the excellent sensitivity of the Lodestar camera .

I'll take into account the comments when trying things out.

Bill

[Paul81]

Decoding the CYGM (Cyan, Yellow, Magenta, Green) colour matrix of the Lodestar to RGB colour space is actually quite tricky. I had several revisions of the algorithm and bias it towards astronomical imaging as opposed to natural daylight colour reproduction.

Paul

[AKB]

51 minutes ago, Paul81 said:

Decoding the CYGM (Cyan, Yellow, Magenta, Green) colour matrix of the Lodestar to RGB colour space is actually quite tricky. 

Paul, do you have any recommendation for this when using third-party software to do this when post-processing with saved FIT files?  I use Nebulosity which has a CYGM option but also a matrix where you can play with the coefficients.

[Martin Meredith]

Check out this matrix here which Dr D sent me some years ago.

Martin

 

 

[AKB]

36 minutes ago, Martin Meredith said:

Check out this matrix here which Dr D sent me some years ago.

Yes, that looks like the one in the Nebulosity manual too.  I had wondered if that was just a generic stab at the problem, or whether the were any tweaks specifically for the Lodestar C.   I guess you've answered that, thanks!

[nytecam]

Bill - your demo of SX v SLL s/w shows the differences !   I've used SX colour s/w for over a decade before Paul's excellent s/w with the Lodestar-C and SX MX7 cams etc and the s/w includes some powerful if clunky options.  Under my severe London LP the SX s/w filters are invaluable and remove my hideous sodium yellow skies to neutral grey by pre-checking appropriate boxes in the colour menu !  Colour balance and saturation over a wide range included.  The s/w also allows auto dark and flat calibration etc

Play and you'll see what's possible - I'm still learning

Nytecam

[Bill S]

Thanks for the useful comments and guidance Nytecam.

Just to be sure we're talking about the right / same Starlight Xpress software (as distinct from StarLight Live), the one I am using for the colour Lodestar X2 is called 'LodestarC software' on the Starlight Xpress website. Is that right.

I've only used it a little bit and then only when I've located and focussed an object with SLL.

Thanks again.

[nytecam]

Yes that would seem correct - the name has changed over time !

Nytecam