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Posts Made By: David Simons

January 30, 2010 10:37 PM Forum: Equipment Talk

ATS Pier

Posted By David Simons

Just got my hands on a ATS pier this weekend. (8"x48")

I tried to get info on these piers, but it seems like their website is no more.

Any tips or tricks on these things ?

Also there are a couple of pieces I could not identify. Anybody know what these are for ?

February 4, 2010 11:37 PM Forum: Reflectors

Re: Maksutov Telescopes

Posted By David Simons

Hi Neil,

I think we may have the same type mirror.

I took a Ronchi picture, and it does not look too spherical.

I heard these were used for infrared rooftop telecommunication systems

I'm thinking or re-grinding mine someday.

Neil Backus said:

I picked up a 16" F/1.2 spherical mirror with ~3.5 hole in the center. Using a ~4" secondary mirror. I was thinking of making a Maksutov telescope. Anyone have any experience making one of these type? ...or maybe have another suggestion? I didn't really think a 'classical' dobsian would be a wise choice, but as this is my second telescope that I will have made, I still have a lot to learn. Thanks, -Neil.

June 23, 2010 12:29 PM Forum: Equipment Talk

Unitron 166 is in the house

Posted By David Simons

Just acquired a well used pedestal mounted 100 mm Unitron with the weight driven clock drive.

I will try to assemble everything this weekend, however I am not sure if all the parts are there.

Does any body have any links to an instruction manual ?

Thanks in advance !

July 5, 2010 11:02 PM Forum: Refractors

Damaged Unitron Case

Posted By David Simons

Hi folks,

I have a Unitron 4"f15 ota case that also houses a guide scope, rings, etc. that was damaged in a car accident. I believe this was a 166 setup.

Any ideas on how to get a replacement case, or a reproduction made ?

Thanks !

October 1, 2011 10:37 AM Forum: Equipment Talk

C14 and AP900

Posted By David Simons

Finally got all the pieces together for this setup.

Now if only the clouds would clear up.

May 17, 2002 03:03 PM Forum: Celestron

Need help with C9.25 micrometer focuser

Posted By David Simons

It locks the focuser shaft from rotating. You would most likely never need to do this.


April 14, 2004 01:09 AM Forum: Equipment Talk

eyepiece turrets for reflectors

Posted By David Simons

Hi Douglas,

Apogee has something like this, but my guess is the adapter uses a lot of back focus.

David Simons

April 19, 2004 12:34 AM Forum: Telescope Making

Cutting a large hole from a thin wall 12" od Tube

Posted By David Simons

Thanks for the suggestions everybody.

I tried a small battery circular saw first. It was good for getting started, but the cut line was too wide. Then I switched to a "Sawzall" with a universal blade, which really worked well, but then I had to switch to a saber saw with a very small blade for the end radius.

Here is the results. This is the oval cutout on the side of my tube to let the light hit the steering flat for what I call a reverse newtonian. The aluminum was really pretty easy to cut. Although the Sawzall gave the cleanest line.

The open end of the tube is where the primary will go.
The focuser end shows the tilted mount for the steering flat that has the hole in it.

Previous experiments:

David Simons

May 13, 2004 11:41 PM Forum: Equipment Talk

Off axis experiment

Posted By David Simons

and I REALLY enjoyed that unobstructed, accurate color view. Anyone put curved spider vanes on an 11", f/5.6, 1.83" secondary Starmaster?

Hi Tom,

Here is my attempt at getting decent aperature, small obstruction (11%), and no spider diffraction! It's a 10" scope with a perforated flat mirror and a normal 10"f6 parabolic mirror. The light path sketch shows the external light entering from the side, reflecting toward the parabolic, then the focussed image exits the hole in the flat mirror.

With two big mirrors to cooldown I have had mixed results. I will be adding some fans to see if that helps.

David Simons

May 13, 2004 11:47 PM Forum: Equipment Talk

Off axis experiment

Posted By David Simons

So, I have a question: Anyone know where I can get an 11" APO? wink

I was wondering what to do with this 11" triplet : )

(It's a relay lense, and only good for low powers)

David Simons