From: Alan Friedman <alan@greatarrow.com>

Date: October 25, 2005 12:03:19 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Color Filters :(

Hi Duane -

Do your RGB filters block IR? The camera is very sensitive to IR - including this wavelength in the R,G and B streams will skew the colors significantly. If the filters are not coated to block IR you will need to add a UV/IR cut filter in front of the wheel. 

The focus will vary in the different colors of light. The amount will depend on the type of scope and the various refractive elements (barlows, etc) you have in the equation. It doesn't vary that much between R and B, but enough to make it important to refocus if the seeing is good. You might try to focus in green light and see if this is OK for R and B too. If you image with an IR pass filter you will need to refocus at this wavelength.

Alan

On Oct 25, 2005, at 1:40 PM, Duane wrote:

OK, I tried the new B&W Firewire camera this morning. First light (yay)

I need some more time using it. This morning was pretty quick and dirty.

However, my question today is, why are my colors not turning out right? I did RGB through 

the Apogee filter wheel and the image comes out like this:

http://groups.yahoo.com/group/Astro_IIDC/files/Planetary/Mars1.jpg

All the images were shot one after the other, the only change being the flip of the wheel. 

In a new photoshop image I placed each one in their corresponding channel. Not until 

after doing this did I sharpen.

What's up with this color?

Also, is it normal that each of these colors have a little different focus? This particular 

image I didn't adjust anything (just took the shots). But I noticed on subsequent images 

that the filters had a different focus.

A big peeve I have of this filter wheel is the threading. It does not match the standard filter 

thread. I have an IR filter I wanted to put in the fourth slot and it won't go. I looked at the 

threads on the included filters and compared to my IR filter and they are not the same. I 

didn't use IR on any of these.

Any ideas on what I'd doing wrong? I took several shots and even have a very sick looking 

Saturn to do with my ill Mars.

Thanks for the help.

Duane

YAHOO! GROUPS LINKS 

▪  Visit your group "Astro_IIDC" on the web.

▪  To unsubscribe from this group, send an email to:

 Astro_IIDC-unsubscribe@yahoogroups.com

▪  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.