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Posts Made By: David McGough

February 15, 2008 07:33 PM Forum: Off Topic Discussions

Stray Voltage? What the . . . ?

Posted By David McGough

Sounds like a real life Ren and Stimpy. The one with the "don't wizz on the electric fence" jingle!

Dave

February 26, 2008 09:21 PM Forum: Equipment Talk

polaris alt-az vs. giro et al

Posted By David McGough

Hi George,

With a counterweigt (2 actually!), I find the GR-3DX very usable with an AP130 EDT f8, which is a over 40 inch long, 20 pound scope including finder, rings, and plate. Hand tracking is very smooth even at 360x, although focusing can require a delicate touch at that power.

I'm using a Stellarvue TSL5 stand for mine since I have a long and heavy scope. The center column lets my diagonal clear the legs just to look overhead. For your setup, the Oberwerk or similar tripod should be plenty and the mount rock solid.

Dave

March 23, 2008 05:19 PM Forum: Reflectors

Spiderless Reflector

Posted By David McGough

What you most likely have is the Schmidt camera "nose" of the convertible version of the Celestron 10 from mid 1960s. The SCT front end inclusing its corrector and secondary came off, and this piece mounted instead. The glass at the front is a Schmidt corrector and not flat, altough deviations are too small for the eye to readily see. Design was for F2 primary (spherical) with image plane halfway between primary and corrector (internal to the tube).

Dave

Oren Soffer said:


I have an old Celestron 10" f1.5 Camera that has no primary but it does have the front 10" round (optical flat?) glass window. Is that glass considered to be flat enough so I can glue a seconday in the middle and add a good 10" f/4 mirror and a focuser and have a reflector with no spider of a good quality? I know those cameras were made for low power imaging, so will it take high power ok with that glass in the way?

Thanks, oren.

April 28, 2008 07:43 PM Forum: Beginning Astronomy?

STUCK

Posted By David McGough

Sometimes it is hard to hold a strap wrench on something as narrow as a filter. Try a big fat rubber band wrapped around the filter cell until it stays (ie not loose) and grip on that.

Try to avoid spray oils and lubes, AR coatings and the dielectrics on the filter could easily be damaged by these. When you do gte them apart use a tiny bt of graphite lube on the thrads (the powdered stuff for locks works nice). Be patient and careful!

Dave

May 11, 2008 02:20 PM Forum: TeleVue

Gibraltar mount

Posted By David McGough

Tom,

See if you can find some of the spray can teflon lube to apply to the inner surface and top flange of the bushing.

Dave

May 25, 2008 09:11 PM Forum: Equipment Talk

Microfocuser for C8 orange tube

Posted By David McGough

Werner had told me that the old scopes aren't compatible as there is nothing to keep the focus threaded rod captive. Newer C8's had a snap ring at front of the central baffle tube that kept you from moving the mirror too far forward and thereby disengaging the threaded rod from the Feathertouch micro and letting the mirror slide off the baffle tube but my old orange tube C8 (CA1974-75) does not have this as it had a washer screwed at the rear of the focus rod that acts as the stop.

Dave

July 14, 2008 07:38 PM Forum: Equipment Talk

SCT for the high-power crowd?

Posted By David McGough

Keith,

You mean like this? 1965 Celestron Pacific C10, 10" f15, 27% obstruction.

Cool down is a bear but optics are SWEET!

Dave

November 30, 2008 04:54 PM Forum: Equipment Talk

Starlight Focusers

Posted By David McGough

Correct. The drawtube doesn't fit same way as on a usual focuser for the 2" model, it is actually rolling against the bearing wheels on stainless rails fitted into the sides of the drawtube. Very slick design and no lubrication required.

Dave

December 15, 2008 07:43 PM Forum: Takahashi

Mewlon 210 dovetail fastener?

Posted By David McGough

Never mind, I found my small metric ruler and figured a M5.0 12mm flat socket head screw would do it and, pitch is 0.8mm only for M5.0. The other giveaway was M5 uses 3mm hex key and M4 is 2.5mm. McMaster should fix me up in no time!

Now if only the rain and clouds would go away (in fairness, I drove to get the scope in the rain so the curse started before purchase. That means it should clear up sooner, right?

Dave

David McGough said:

Hi,

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!

Dave

December 25, 2008 09:05 AM Forum: Refractors

1.25 diag for eon 120 ed

Posted By David McGough

I found the TV Everbright is slightly better than the standard enhanced for reducing scatter around a bright planet. It isn;'t that much more money and the coatings are supposedly more durable. I say supposedly as I did notice some very slight sleeks on mine. Both of the TV 1.25" diagonals are machined from single piece of aluminum (angled body and both inlet and outlet tubes) and plate on back holdsthe mirror, so alignment is pretty much spot on.

The Takahashi prism still has the plastic body I believe, presumably the added price is a more precise prism and the clamp ring collet. The prism s do supposedly have some effect on correction but that all depends on what the objective was designed to optimize for. My TV85 works much better with the Everbright mirror than a prism.

The best prism out there is the Baader T2 but ends up being quite expensive by the time you add the focuser and eyepeice adaptors.

Dave

itz marcus said:

Hi,
I would like to buy a high quality diag. for my Eon 120. It will be a 1.25 diag. My oices are the TV enhanced for $140 or the TV Everbright for $190. Is the Everbright worth the extra 50 dollars. Also, I am looking into the Tak 1.25 prism diag. for $115. I know that prisms sometimes work better with ed scopes and I have found that to be the case but I'm not sure if its the prism or the fact that my mirror diag is a cheaper make. I have been satified with it but collimation seems to be slightly off. Anyway, your input really counts.
Thanx
clear skies