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Posts Made By: Larry Thaxton

October 19, 2003 11:00 AM Forum: Equipment Talk

Home Remedy

Posted By Larry Thaxton

I have a G-11 with a long ( 6 foot) cord on the hand controller. Handy with a long focus refractor. Unfortunately I snagged the small plastic lock lever on the plug and "removed" it. How does one go about fixing it?



December 27, 2003 08:24 AM Forum: Chinese Optics Imports

AP Lens Corrections

Posted By Larry Thaxton

Hi Jon,

Roland's lens correction per AP website:

Optical Production and Testing Standards
Every production run starts with optical glass purchased to our specifications. Each blank is inspected and tested by our suppliers to meet our homogeneity and quality standards. These blanks are then processed in our computerized facility and hand-figured by experienced opticians. Each surface is polished to a fine sphere and tested by test plate interferometry. Three elements are then matched and assembled as a set. Final figuring on the front and rear surfaces is done using our green light Fitzeau interferometer which checks the wavefront accuracy. The interferometer immediately shows when a polishing lap is worn when zones develop on the glass surfaces. A new lap can then be made without guesswork to again produce a smooth surface.

The finished lens is then coated and assembled in a precision cell which is fully temperature-compensated. The cell is attached to the tube assembly and the optical alignment is checked at high power on an artificial star. The lens is serialized and all test data including final interferogram are stored in a computer file along with the customer's name. Our extensive hand-figuring techniques and the use of high quality blanks allows us to guarantee that all production lenses will meet the 1/50 RMS (98.4% Strehl ratio) minimum limit.

March 5, 2004 12:18 PM Forum: Equipment Talk

Information on Planetary Scopes

Posted By Larry Thaxton

I am considering shifting around some of my equipment in yet another step toward finding "the best planetary scope." Living near Los Angeles limits deepsky opportunities to the occasional road trip so this is to be an in-town scope. At the moment I am using an AP 6" F/12 Superplanetary and a D&G 8" F/12, both of which have excellent optics. An observatory is being considered and I am balking a bit at the size I will need to house the D&G on its HD 150.

The scopes that I have been looking at are the TEC 250 F/20, Tak Mewlon 250 (love the 300 but $$ has to be considered at some point!), TOA 170 (someone say something about $$??) and the TEC 180 APO. The AP 10" Mak would be on the list but after three years on their list for a 155, I am aready a bit tired of waiting.

Anyway, has anyone had a chance to compare the various 250s? Thoughts on performance of the TOA or TEC APOs v the 250 maks? I have been looking at some of the dark sky sites I frequent but have yet to have a chance to view through either the 250 Tak or TEC.

May 2, 2004 03:32 PM Forum: Pictures of Me and My Telescope and........

Re: My Pet Refractor

Posted By Larry Thaxton

D&G 8" F/12 on a Parallax HD 150 with 60" tall, 10" diameter pier, AP focuser and Takahashi 11x70 finder(hidden behind main tube). In-town planetary scope!

May 6, 2004 08:21 PM Forum: Equipment Talk

EQ Platform Question

Posted By Larry Thaxton

I have an ET platform set up for my latitude here in Los Angeles (34 degrees). I was wondering if ET Platforms still exists (can't find their website) or if Terry Hubbert is still around. Alternatively, what is required to "adjust" the latitude to 40 degrees or so?



May 22, 2004 05:31 AM Forum: Binoviewers

Your Thoughts - AP Baader v Denk II?

Posted By Larry Thaxton

I have a Denk I that has given great service and images but am ready to move on to another binoviewer. The AP Baader Mk 5 and Denk II seem to be the top contenders. TEC 140, D&G 8" F/12 are the scopes at present.
Any experiences/thoughts on differences in performance or ergonomics?

July 11, 2004 03:23 PM Forum: Equipment Talk

Help With Collimating a Classical Cassegrain

Posted By Larry Thaxton

I recently picked up a Cave 6" classical Cassegrain and need to collimate it. Anyone out there know how to do so? This thing has adjustments on everything- three screws to center the mirror in the cell, push-pull screws on the primary, collimation screws on the secondary and even adjustments on the focuser. Where does one start? Is there a best tool to use in trying to set it up?

THANKS in advance!!

July 22, 2004 09:51 PM Forum: Antique/Classic/Vintage Optical Instruments


Posted By Larry Thaxton

I am trying to determine the history/origin of a scope I recently acquired. Here is the description I posted on the Cave Yahoo Group site:

"It is a 6" F/15(?) cassegrain. The tube is fiberglas pigmented white though kind of yellowed from age, has a heavy aluminum end ring in front and a plate at the rear that is set back 1/4" or so to allow cooling. The mirror is ground flat on the back, has a "PANCHRO" sticker with the date of "1-8-68" and there are two marks indicating "#1" written in pencil. The secondary is convex and also has two pencil marks indicating "#1". I have owned three other Cave mirrors and am familiar with the habit of inscribing them though I do not know when that practice started. Anyway, I carefully examined the primary and secondary but found no other markings or inscriptions. It had a finder at one time and retains teh holes for the finder rings but no rings. The scope is adjustible for EVERYTHING and I am finaly starting to get it properly collimated thanks to a few folks directions and the Tectron tools/collimation booklet. What I am hoping to do is determine it's history. I recall 8" and larger cassegrains and think I remember seeing a picture of a 6" cassegrain in a Cave catalog in the 60s but am not sure. Any help would be greatly appreciated!"

It also has a sticker of the focuser that has faded a lot but still has part of the name Cave Optical and the Anaheim Street address in Long Beach.

Given the "#1" written on both mirrors, this may be the prototype or the first production scope. Heck it may be the first and last- or it may be something other than a Cave. Any ideas or sources to help me figure it out?

September 18, 2004 08:32 AM Forum: Takahashi

FS152 Case Options

Posted By Larry Thaxton

Any suggestions on a hard case for the FS 152? At the moment it looks like ScopeGuard is the likely choice.


October 28, 2004 08:31 AM Forum: Astro-Physics

AP 160 becomes a reality.

Posted By Larry Thaxton

Take a look at AP's website for specs on the soon-to-hit-the-streets 160mm air-spaced triplet.