Atik Cameras

Author Topic: Question about 2" nosepiece  (Read 161 times)

Chicago Sky Ranch

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Question about 2" nosepiece
« on: September 13, 2017, 08:04:08 PM »
Sorry if this has been asked before, I actually couldn't find anything on the net...

I just took possession of a color infinity and would like to use a 2" TPO .5x focal reducer and possibly 2" filters down the road. I'm trying to stay away from 1.25" stuff to reduce the chance of vignetting.

How can I use 2" threaded items? Are the threads that the 1.25" supplied adaptor M48 x 0.75 (normal 2" scope threads? If so and I can thread the focal reduce right onto the camera, will I need tubes or a nosepiece to insert into the back of my refractor?

I'm kind of lost here and could use some advice :-)

Jeff

JimH123

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Re: Question about 2" nosepiece
« Reply #1 on: September 23, 2017, 03:24:00 AM »
The answer to your question can go several ways.  There is not a good agreement among eyepiece manufacturers as to what thread sizes that various eyepieces are going to use.  Here is a web site that spells out a number of them:

http://www.rudolf-reiser.de/astro_atm_gewinde_en.html

The Atik Infinity comes with a nose piece that can be unscrewed exposing a 42mm x 0.75 thread size.  In my case, I screw my 1.25" filter wheel right on to the Infinity.  The other side, I use a 2" adapter so that I can insert into the 2" focuser of my telescope.

As for focal reducers, I do have one that is 1.25", but I haven't been using it.  If I were to, it would be best to put the nose piece back on the Infinity and use a different adapter for the filter wheel.  The focal reducer produces different focal reductions based upon how far it is from the Infinity sensor and it wouldn't make sense to put it on the telescope side of the filter wheel.

Now in your case, you already have a 2" focal reducer.  Overkill for the Infinity, but should work OK.  You would need to have an adapter to go from 42mm x 0.75 to a 2" barrel so that the reducer can screw into the bottom of the barrel.  This can then be inserted into the 2" focuser of the telescope.  Or, you can use a 2" filter wheel which would go between the focal reducer and the telescope.

There is quite a step up cost in filter wheels and filters going from 1.25" to 2".