Pseudo colour - any suggestions?

Folks - given the really great run of weather we've had the last few days, I did a bit of recreational imaging.

I've a bunch of images of M38 taken through BVRI and clear filters.

I've yet to process them - the calibration, registering etc is easy peasy. What I need to know is how to combine them to give some sort of colour image.

So there are two things I need to know:

1. What is the process to get filtered images into a "colour" space using either Maxim and/or Photoshop (I use V7 because I know it)
2. What are the respective weightings for BVRIC filters? And given that I'd presumably be mapping to RGB, I'd have to let one of the filtereds images go *or* do a CMYK mapping?

Thanks
Dave

p.s. I have 2.5 GB of data to process - sometimes a good run of weather is a curse...

Dave,

Once you have your Master Red, Master Green and Master Blue, load all three of them into Photoshop and make sure they are monochrome (Image -> Mode -> Monochrome). YOu then click on the Channels tab (within the Layers Window) and choose Combine Channels.

A small window will pop-up and you will choose 3-channel RGB and which will lead to a new window popping up asking you for the respective R, G and B.

You also inquire about colour weighting for combining the three channels. The challenge here is not the colour weighting itself but the determination of the proper colour weights themselves. Do you have these? If not, proceed with a G2V calibration of your images against a standard image of the same field of view extracted from Aladin. I do all of this using exCalibrator. In order for exCalibrator to work, you must perform a plate solve on the master Red using, for example, PinPoint (via Maxim D/L).

You may be able to bypass the plate solve using PinPoint if your Master Red FITS header already has some key information such as the RA and Dec of the center of your image, the image scale etc.

Anthony.