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Posts Made By: David McGough

August 6, 2007 05:52 PM Forum: Refractors

Re: Refractory history question

Posted By David McGough

I think an added factor that determines how well a telescope can "see" is resolution. If the 72" mirror was well corrected the image of a star would be much smaller and therefore more intense than a 20" modern telescope, so the limiting magnitude should be better in the larger lower % reflective instrument than converted aperture would indicate.


December 15, 2008 06:34 PM Forum: Takahashi

Mewlon 210 dovetail fastener?

Posted By David McGough


I just picked up a used Mewlon 210! Can anone confirm if the fasteners to replace the standard dovetail with a Losmandy DUP are M4.0x0.75? Thanks!


March 15, 2009 05:01 PM Forum: Camping and Outdoors

Good telescope spots in Zion National Park?

Posted By David McGough

Anyone have a good recommendation on a good, dark drive in spot in Zion National Park to set up a telescope for stargazing? I'm going there in late April but staying in a B&B in Springdale, UT. I prefer overlooks or picnic areas where I can set up right near the car as it saves a lot of carrying but like to be somewhat isolated from traffic.

I haven't decided on which scope to bring, but my old orange C8 might be a front runner for small packing size and decent aperture compared to a TV85. Galaxies need more than 85mm, Thanks in advance!


May 3, 2009 12:10 PM Forum: Equipment Talk

Re: Electric Plug Older Orange-tube C5

Posted By David McGough

Hi Mike,

Try Mouser Electronics ( The part you need is a Jones type 302 socket (not the plug, the plug has the prongs and is in the drive base). I've made a few replacement cords fr my C8 and older C10 with these and some lamp cord.


Mike Morea said:

Hello folks: I've just acquired an older C5 Orange-tube with cutout holes in the fork arms. Optics are gangbusters with sharp lunar images using the supplied .965 6mm. Problem. Mo power cord. The plug is an unusual configuration. It is a dime-size round rather than oval hole on the side of the drive base just under the fork arm with the manual dec control in it. Projecting from the hole are two prongs, aligned horizontal to the ground, and made of what looks like aluminum. The upper prong is a bit narrower than the lower. SN looks like 214346. Any idea just how difficult it's going to be to get a cord or rewire? Thanks. Mike.

March 5, 2012 04:34 PM Forum: Astro-Physics

Crystalline structures in lens?

Posted By David McGough


In ad 768077 for an old 5" f6 NASA glass triplet, there is mention of "VERY beginning amount of crystalline structures in the lens".

What is this referring to, devitrification of some sort? Is this something peculiar to this old NASA glass and that those of use with later EDTs and the like never need to worry about?


July 18, 2013 01:35 AM Forum: AstroMart FAQ

Logon issues with IOS devices/Safari browsers?

Posted By David McGough


Since the latest rollout I have been unable to login from my iphone and just get reload of login screen after entering username and password. My access with PC is still OK. Anyone else run into this?


January 23, 2014 07:53 AM Forum: Equipment Talk

Re: Orange tube C-90

Posted By David McGough

The focusing is just screw threads machined into the rear housing and on the front barrel. They are always loose and there is slop, so nothing to do other than get used to it. Sometimes a thicker grease can help. To do thta, you need to pull the tripod plate from the bottom and back out a screw hidden under it, then the front section can unscrew all the way.

The other cap screws on the side are for covering the holes where the fork mount for the C90 Astro version attached. The single cap screw opposite from that was for screw in counterweights to help with tracking (the fork was a one arm and unbalanced)


July 24, 2004 08:12 PM Forum: Celestron

c11 weight reduction

Posted By David McGough

Hi Paul,

Late reply, but no one else jumped in. I had a C11 orange tube with the fork mount for a while, and the tube dismounts from the fork rather easily, but with an allen wrench required. There are 2 1/4x20 by 5/8" long socket head set screws in the "saddle plates" that connect the tube to the forks. If you point the tube upwards, and remove those 4 screws, the tube can be lifted straight up. The first time you do this, have help, when I got mine, the stops in the tube were not installed (you can't see them until you slide the tube forward) The stops are shorter socket head set screws which slide into channels on the inner side of the saddle plates aligning the holes for the mounting screws, and preventing the tube from sliding too far aft. Once you get the hang of this it is quite easy, and doesn't require butchering up the tube or mount. Heaviest pieces are in the 30 pound range whn broken down like that. The real caution is to not use screws longer than 5/8" to mount the tube to the saddles, as they will hit the mirror, so if you need extras, order a box of 50 from Good luck!

December 26, 2004 11:20 AM Forum: Equipment Talk

My new Televue 60, Yehaw!!!

Posted By David McGough

Great gift! You should check Tele Vue's web site as they are selling an adjustable bracket for the TV 60 and the Starbeam that fits the sliding rail on the TV60 and bolts to a C8, Meade 8, etc. where the finder bracket normally attaches. The tapered body on the TV60 would not fit any rings from losmandy very well. Tele Vue calls the item the X-Y Adjustable Mount System and it can be found under "Observing Accessories" on

May 30, 2005 05:31 PM Forum: Equipment Talk

AC for Old EQ mounts

Posted By David McGough

Hi Jon,

I actually had that problem with the line current in Camarilli, CA, my old C5 and C8 made quite the racket. An old Vogel drive corrector solved that, but has recently failed.

I found a very compact inverter at Best Buy which has a modified sine wave output good for small timing motors and such. This unit is a Vector model VEC041, good up to 95 Watts max and works well with my old scopes, and silent motor operation on my 1965 Celestron 10".