RGB capture quality

[johnrt]

I've been doing some RGB capture recently using a set of Baader LRGB filters (ones with ir cut) and my mono ATik 314l+.

I have found on several occasions my red channel has been of low quality (gradients especially) in comparison to blue and green.

Is the red more affected by sky conditions - seeing, light pollution etc etc???

[ollypenrice]

Can't help on LP but for what it is worth I have never found this from my dark site. If there is a tricky channel for me it is blue, which suffers relatively easily from scatter and bloat unless using premium optics, which now I do.

The only value of this post is that it might lead you to a process of elimination. I use the same filters and have used the same camera. I find the Baader filters to be highly parfocal, as claimed.

My suspicion would be light pollution. It might be an idea to time your red run to cross the highest part of the sky. From a very dark site I do the reverse, saving the highest elevation for luminance and blue if the object is on the low side.

Olly

[johnrt]

Olly,

I have also found the filters to be as advertised - parfocal.

The blue does suffer a little bloat, is there an easy way to combat this?

[shaunster]

I think the colour gradients must be introduced by LP

My green channel can produce gradients but red and blue are good, although blue produces bloated stars

My RGB data from a dark site doesnt show these gradients..

[ollypenrice]

Olly,

I have also found the filters to be as advertised - parfocal.

The blue does suffer a little bloat, is there an easy way to combat this?

Only using premium apos or reflectors can strangle blue bloat at birth, I think. However, in Ps try this:

Put a well feathered round marquee loosely around the offending star. In Curves, Blue channel, pin the curve at the background sky level (Cursor on the background, Alt Click.) Now grab the curve just above the pin and pull it down a bit, trying to keep the upper part of the curve close to standard. You may need to play the colour balance in shadows and or mid tones to settle it again. Or you could adjust the other colour curves individually but I never found I needed to.

This was part of my routine with the Meade 127 but forking out the price of a decent car for our TEC140 has disposed of that little task!!

Olly