From: Jeff Phillips <imjeffp@mac.com>

Date: March 24, 2008 3:32:48 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] IR filter with a DMK color .AS camera?

From the TIS web site:

IR cut filter

The CCD camera DFK 21AU04.AS is equipped with an IR cut filter that blocks wavelengths above 700nm. Thus, its properties are similar to those of the human eye.

No IR cut filter

Although the astro CCD camera DBK 21AU04.AS has a color CCD, it does not have an IR cut filter. It is therefore possible that users of this astro CCD camera can fit their own filters, thus being able to set it up to their own requirements.

The short answer is, "it depends."

<http://www.astronomycameras.com/en/products/>

On Mar 24, 2008, at 4:29 PM, Alan Friedman wrote:

I believe the DMK cameras are all monochrome models without an IR cut filter. If you are using this camera with a color filter wheel for RGB imaging, it will be necessary to use filters with IR blocking or a separate IR block filter else the color will be skewed by the IR sensitivity of the chip. If you are imaging a monochrome subject (like the moon) in white light and have refractive optics in the system you will probably obtain sharper results by filtering out IR and UV wavelengths. 

If you are using a color camera (DFK, DMK) - I believe these do have an IR blocking filter before the chip - but I have never used one so I'm not certain.

best regards,

Alan