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Posts Made By: Thomas Dey

May 30, 2018 09:55 AM Forum: Equipment Talk

ES 12" F5 Truss Dob Review

Posted By Thomas Dey
Hi, Rod et al. Interesting! That report on the other one doesn't strike me as too terrible. What's there is dominated by some spherical, astig, and a turned edge. [I see your point!] But otherwise smooth and the central hole gets blocked anyway. For some reason, I HATE astigmatism, probably just because its signature is so obvious. Stars are supposed to be round and crisp! I like knowing that we can still make superior mirrors at home... or pay a LOT to buy them!  Tom

July 2, 2018 10:43 AM Forum: Equipment Talk

ES 12" Part 1 Review

Posted By Thomas Dey
Hi, Rod, et al. Somewhat in context...

Over a decade ago, we had a Giant Holographic null made by an outside vendor, to do an independent certification of a GIANT convex Ritchey-ish SM for one of the major observatories. So, one of the engineers went over with a truck, to the shipping place. The attendant confirms that is is there... and says he'll go get it...

Our guys are out front, expecting either a fork lift, palate skidder or even a hand truck. From back in the warehouse they hear ... blam blam Blam Blam BLAM BLAM... and the guy appears at the double doors... big flat square crate with UP arrows all around, glass etc. markings all over. He had Tumbled the wooden 40x40-inch crate All The Way out! They decided to open it there... undamaged... and got it outa there as quickly as possible!

Nother anecdote. JMI shipped my giant 16-inch binos in this HUGE crate. To their credit, is had a shock-accelerometer attached to the outside of the crate, that would change color if it got unacceptably jarred anywhere in transit. That looked good, and the binos were wonderfully packed and in great shape.  Tom

July 5, 2018 10:04 AM Forum: Equipment Talk

Mirror identification

Posted By Thomas Dey
Hi. James!

I don't know how convenient this would be for you, but if you can form a good prime-focus axial image using the PM alone, then the configuration would be Classical Cass. On the other hand, if that image is LOADED with spherical aberration... then it would most likely be a Dahl.

There is another possibility... Ritchey... but that seems unlikely, given the probable vintage of the OTA.  Tom

February 10, 2021 09:29 AM Forum: Equipment Talk

Need to know how to sell properly on this site.

Posted By Thomas Dey
Yes! The most abiding rule is ~price to sell~ For the difficult to ship items, "pickup only" works, provided you make the selling price VERY attractive. I know some sellers try to squeeze every last dime out of the buyer, but that comes at the price of maybe/probably not selling it all. It's really as simple as that.    Tom

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