From: Milton Aupperle <milton@outcastsoft.com>

Date: April 23, 2011 10:10:53 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Source for C-Mount to 1-1/4 Adapter?

Hi David;

On 23-Apr-11, at 9:23 AM, daffyddsant wrote:

Hello,

I have a C-mount to 1-1/4" barrel adapter for my Imaging Source FW camera (slides into the eyepiece tube on a diagonal, e.g.). I have no idea where I got it and I can't seem to find another for sale on line.

Search Google or Yahoo with the phrase:

C Mount 1.25 adapter astronomy

Their are some "low profile" models out there too

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Imagers-Opticstar.asp?p=0_10_5_0_3_103

which have a barrel that are around 15 mm long. I have both he longer and shorter type here that I use. Just make sure the adapter is threaded for a 1.25" thread on the 1.25" end.

Most will list themselves as C or CS. type. If you can get a CS that's usually better as its a few mm shorter.

I need for it to have female threads opposite the C-mount threads to accept a 1-1/4" screw-in filter.

So is this for your diffraction grating?

What is the maximum distance from the diffraction grating to the CCD you can go?

If anyone here knows of a source, would you please post it here?

I've never heard of anything like that, except maybe something custom machined.

I suspect your only options would like be a 1.25" filter wheel or filter slider, or maybe a short profile C Mount 1.25 adapter.

WIth a filter holder (which are usually TS female threaded) , you need to find a low profile C-Mount to TS adapter, then screw that into the male threaded TS adapter on the filter wheel / slider back end.

I use a very low profile CSMount to Thread (M42 x 0.75 mm thread)  female adapter :

http://www.sciencecenter.net/hutech/prices/borgparts/html/7526.htm

which minimizes the distance from my filter wheel to the C-Mount cameras.

Still, I suspect your going to have at least 10+ mm back from the Grating using a filter wheel, so it likely is cheaper to go with a low profile C Mount to 1.25" adapter.

HTH..

Milton Aupperle