I've looked into wood for scopes and mounts and noted that woodworking requires more tooling than working with metal tubing and pipes. Why? because the metal...
I have a 4" takahashi FS-102 and a C14 and a TV-85, and shorly will have a 152ED Meade refractor. Im a big fan or refractors, but my big C14 always gives...
This is not ture. Art Ciampi ... From: "Phil Jones" <jediwebwarrior@...> To: <Refractors@yahoogroups.com> Sent: Sunday, July 27, 2003 6:55 PM Subject:...
Dwight You make some good points about the pros and cons of apo and achromatic refractors. I have owned and constructed an ota with a 6 inch f-12 D&G lens and ...
(Note: If you're also a member of the Chinese Refractors group you'll hear an echo here.) I notice that Celestron seems to be promoting their short tube 80 as...
... Actually, this is *not* always true with Powermates. Greater distance between an eyepiece and a Powermate can actually yield slightly *less* magnification...
... as ... Hi, George. The 80mm f/5 Celestron "telescope" is very much alive and well and lives on as the Nexstar 80GT (one of Celestron's biggest sellers, ...
Comments interspersed. Kevin Barker wrote in part: <SNIP> ... A point well taken. Shorter f.l. scopes have problems with some simpler (but excellent) eyepiece...
John Beyrau wrote in part: ============================================ <SNIP> I don't have the space to do the objective grinding and finishing process in my...
Hi Dan, This is getting complicated! I realize the group members are largely visual observers, but I sure wish someone could tell me what the 5X Powermate...
Hi Dennis, Perhaps you can work it out for yourself using Stephen Tonkin's excellent (recently updated) page on the subject (from his website). Might come in...
I have had a home robbery, among items stolen is an Astro-Physics Traveler - serial #155EDF444- sure appreciate if anyone if anyone hears or sees such scope...
Ever since I saw a film photo of B72 in Kepple and Sanner's "The Night Sky Observer's Guide" I have wanted to image it. The Barnard dark nebula B72 is...
Mike Thanks for the reply. I incorrectly put the word length rather than ratio to explain focal ratio. I meant to say the focal ratio should be at least twice...
Hi, D&G discuss the choice between f/12 & f/15 on their website and downplay the difference if I read it correctly. If memory serves the f/18 minimum for a 6"...
Alan I am also very aware that our eyes response curve peaks in the green region where chromatic aberration is corrected to a greater extent. Yes an apochromat...
... Kevin, Yes, the eye is far more sensitive in the green. That's probably a good thing, since out of focus color would be much, much more annoying if our ...
Alan Yes and your point is a good one. I guess my point is that D&G make a good lens. And spherical aberration and spherochromatism is also an issue for a lot...
Kevin, The D&G achromat is a doublet and the Astrophysics apo's are triplets. That's how they can correct the color and also why they are more expensive. There...
AP's middle lens element is a type of ED glass that has virtually the dispersion index as fluorite. It is expensive, but works well with the other two...
Rich N.
rnapo@...
Aug 5, 2003 9:29 am
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Call your area pawn shops and watch eBay. I had a racing bicycle stolen. Had it back within 2 hours because I called area pawn shops. -Phil ... Traveler - ... ...
Chuck KzF2 and BK7 was used in later AS lenses so I quess the glass type in this old lens would be similar if not the same. My lens is from the late 1950's to...
Thanks Rich and Don I am aware how they do it and was merely stating amazement in a reflective tone. I have a couple of triplets with oil spaced lenses too!! ...
Kevin, James Baker wrote an article for Applied Optics in 1963, called Planetary Telescopes (some say it is the "standard" for optic discussion). In it he ...
