SAC color filter wheel questions

In my search for a low cost color filter wheel, I see that SAC imaging has
such a unit. Has anyone here had any experiences with it and how do you
like it? My camera has a C/CS thread. Anyone know if the SAC wheel will
couple to it?

My other question concerns the optical train length. How do color filter
wheels, like this one, change the focal length of the system when I am using
a standard 3x barlow also, along with the wheel and ccd camera?

Thanks,
BS

"Uncle Bill" wrote in message
nk.net...
In my search for a low cost color filter wheel, I see that SAC imaging has
such a unit. Has anyone here had any experiences with it and how do you
like it? My camera has a C/CS thread. Anyone know if the SAC wheel will
couple to it?

Not sure what a c/cs thread is. I have an SAC IVD camera, and it has 1 1/4 inch
extension (like the barrel on a 1 1/4 inch lens. The adapet that his threads
into also comes off the front of the camera so the camer baody itself is
threaded. I have a konus 200 reflector which has male threads (if you unthread
the 1 1/4 inhch adapter) that will allow this camera to threat to the
telescope. I would think that the SAC color filter wheel has at least one of
these threads to allow it to attach to an SAC camera. I hope this helps. I
looked at an image of it on the internet, and it looks like the filter wheel
will allow a 1 1/4 inch adapter connection.

My other question concerns the optical train length. How do color filter
wheels, like this one, change the focal length of the system when I am using
a standard 3x barlow also, along with the wheel and ccd camera?

Thanks,
BS

I don't think these filters change the focal length much at all, since they are
pretty much optically neutral in that they don't magnify the light, merely
filter it.

"Uncle Bill" wrote in message
nk.net...
SNIP
My other question concerns the optical train length. How do color filter
wheels, like this one, change the focal length of the system when I am
using
a standard 3x barlow also, along with the wheel and ccd camera?


The magnification you get from a Barlow depends on the distance from the
Barlow lens to the eyepiece/camera so if putting the filter wheel between
camera and Barlow changes that distance, the magnification will change.
(The greater the distance, the higher the magnification) Note that your
spacing might not be the same as the design spacing anyway so you may
already not be getting the standard 3x magnification.

Robin
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Robin Leadbeater
54.75N 3.24W
http://www.leadbeaterhome.fsnet.co.uk/astro.htm
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"Uncle Bill" wrote in message
nk.net...
In my search for a low cost color filter wheel, I see that SAC imaging has
such a unit. Has anyone here had any experiences with it and how do you
like it? My camera has a C/CS thread. Anyone know if the SAC wheel will
couple to it?

I have the SAC filter wheel and it has male T-threads on one side and female
T-threads on the other. The filter wheel is about 13/16" thick. I had some
trouble getting my 1.25 inch filters to thread, but SAC sent me a new one
which works better.

One problem that I do have with it is that the clip used to hold the spring
on the registration pin interferes with the filters as you turn the wheel,
so it tends to "stick" as it turns. This means I have to give it an extra
push, which sometimes causes the whole wheel/camera setup to move a bit.

Mark