Grey stars in M45

[blinky]

I think this is due to the L channel, but the bright stars in my M45 image seem to be very grey, the screenshot below shows this, left is L, middle is RGB and right hand side is LRGB.  You can see in the RGB image the star look OK, Ive not pushed saturation or anything here, just a combine of RGB and a stretch but it does appear to have colour, the LRGB image just shows grey round the star.  Ive attached the individual stacks in case anybody can help.

BaseLUM.xisf BaseRGB.xisf LRGB.xisf

[vlaiv]

Would like to give it a try, but I don't have software that works with xisf files.

Maybe fits for us poor souls?

 

[blinky]

Think I fixed it - but have also added fits files

BaseLUM.fit

BaseRGB.fit

Edited January 12, 2022 by blinky
uploaded wrong file

[blinky]

[vlaiv]

52 minutes ago, blinky said:

but have also added fits files

Thees seem to be already stretched.

Do you stretch your data prior to channel composition?

[blinky]

Yeah I do stretch them prior to combining,  is that the wrong way round to do things?

[vlaiv]

1 hour ago, blinky said:

Yeah I do stretch them prior to combining,  is that the wrong way round to do things?

Well yes. Stretching R, G and B individually will cause them to be stretched differently and that impacts colors in the image.

Even regular combined stretch alters colors in a way (usually desaturates them a bit) - but separate stretch causes hue shift as well.

[blinky]

What is do is linear fit the rgb channels then combine and stretch, then stretch the lum and finally do LRGB combination by replacing the RGB L with the actual L data