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Posts Made By: Vahe Sahakian

November 15, 2003 07:48 PM Forum: Equipment Talk

Which 2 of 3 AP scopes you will choose.

Posted By Vahe Sahakian

It all depends what you want to do with these scopes, if you want an apo for planetary observations then the 6" is the best choice, I have one, and it is borderline in size if you are expecting any serious planetary detail.
As for your question, I will choose the 155 and skip the others, or, buy a heavy mount with the price of the second scope.

Thanks,
Vahe

December 7, 2003 07:49 PM Forum: Equipment Talk

Color and the Orion 80mm ED - is this normal?

Posted By Vahe Sahakian

You can try one simple experiment to convince yourself what is the cause of the color in your 80mm ED. Find a Newtonian reflector with roughly the same f/7.5 or closest cone of light, the reflector is simply color free, that is the nature of the beast, now try all your eyepices in the reflector and see what happens, if you see color in the reflector you know that it is eyepice problem and not the scope.

Thanks,
Vahe

January 5, 2004 05:31 PM Forum: Equipment Talk

Seeing Encke

Posted By Vahe Sahakian

Number of prominent planetary observers claim the the Gap can be seen with a 6" aperture, I tried for eight years using my 155 f/9 AP with absolutely no luck and that with every eyepiece combinatins plus a binoviewer & powers up to 360x.
The only time that I got a glimpse of this feature and it lasted about 10 seconds, never to be seen again, was with a TEC 250/20 with a binoviewer operating at about 420x.
If I have to guess, a high quality 14" aperture would be the minimum if you expect a fighting chance of "really" capturing the Encke long enough to really enjoy the view.

Thanks,
Vahe

January 8, 2004 07:32 PM Forum: Equipment Talk

Wavefront error of an average C8??

Posted By Vahe Sahakian

If you have access to ap-ug, check out a set of interferograms that Roland just placed there, number of scopes are tested including a typical 8" SCT, the iterferogram clearly shows the rough optics, this particular one tested at PV 0.57 and Strehl of 0.80, this one is really a good representative of what you can expect if you bought one.

Thanks,
Vahe

February 8, 2004 12:12 PM Forum: Equipment Talk

Thermal equilbrium ideas

Posted By Vahe Sahakian

Try this, over and above everything that is suggested;
After you set up the scope on the mount point a household electric fan towards the rear of the ota and let it just blow air at the scope.
I started doing this in the hot and humid Houston for my own comfort and to blow away mosquitos, but then discovered its additional benefits in speeding up the cooling process of my cat.

Thanks,
Vahe

March 5, 2004 07:19 PM Forum: Equipment Talk

Information on Planetary Scopes

Posted By Vahe Sahakian

"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."

The TEC250/20 in my opinion is probably the finest 10" planetary scope out there, it is designed for high power use, it is a special purpose instrument with very limited applications, but what it does it does it real well. Cooldown is the only issue that need be considered with this instrument

March 6, 2004 12:26 PM Forum: Equipment Talk

Crazy Eyepiece Prices

Posted By Vahe Sahakian

"AP eyepieces- $249?!
Monocentrics- $200?!
Pentax XOs- $339?!

What am I not understanding about the construction of these that would warrant their prices other than disproportionately high margins and marketing BS?"

After reading all the replies so far, there really is no standard reply to your question, the answer should be on a personal level, if you feel, for instance, that a UO ortho is every bit as good as a Zeiss AO, then you have answered your own question, why spend all that money if both eyepieces perform the same, as seen by your own eyes of course.

Thanks,
Vahe

March 6, 2004 05:41 PM Forum: Equipment Talk

11" EL handles 1000x

Posted By Vahe Sahakian

"At 1000x the image is so sharp its unreal"

Could you see the Encke Gap?

Thanks,
Vahe

March 13, 2004 09:56 AM Forum: Equipment Talk

why not a "premium" SCT

Posted By Vahe Sahakian

"i have often wondered why Meade and Celestron havn't taken a marketing hint from the Russian mfgs of mak scopes and produce a "standard" and a "deluxe" version of their SCT optical tube assemblies."

This topic comes up regularly, and yes, there is room for impovement for Meade & Celestron SCT's, one thing that I hope that they never do is the introduction of carbon fiber tubing, given the insulating qualities of this material and the cooling problems associated with all sealed tube "cats" all that you will accomplish with this material is slowing the cooling process, terrible idea.

Thanks,
Vahe

March 14, 2004 07:16 PM Forum: Equipment Talk

D&G 5" vs AP 130 f/6

Posted By Vahe Sahakian

"I am wondering how much difference there is between a D&G 5" and an AP 130mmf/6 on planetary/lunar viewing."

For planetary viewing the AP 130 f/8.35 would be preferable to the f/6 version.