Does anyone one this forum have any experience with flat-lapping graphite-epoxy composite parts? I don't have any first-hand experience working with...
Have you contacted Peter Chen? http://iacs.cua.edu/people/chen/ He's done lightweight optics work and had some posts on the ATM list I believe. Not sure if...
James I Think you are going to like it. I just poured a 14" lap and I love the stuff--no smell / dosen't boil no black mess / The wife didn't even know that I...
Thanks for the suggestion, Mike; I remember meeting Peter at Stellafane a few years back, where he gave a fascinating talk and demonstration of the composite...
I'm currently in the process of designing an 8" f/6.8 dobsonian scope. I'm planning on going with a square tube made out of 1/4" Baltic Birch plywood. The...
I'm not in favor of indiscriminately lightening a scope unless there is a valid reason for doing so. A more massive scope will have a greater inertia and will...
... attached ... I made my 10" also with 14" BB. and glued all seams with urethane waterproof glue. Since you are also using 1/4: BB which is quite ...
Consider using thinner plywood and slightly larger pieces for the reinforcing. Don't use quarter round as that has excess material that doesn't do anything...
I see no problem with you design but you could go much further. For Instance I was able to reduce my 8" F7 50 lb square tube dob to 30 pounds total. Here is a...
Instead of 1/4" baltic birch, try door skin. It is even lighter. Also, consider lightening the mirror by drilling holes in it. You don't need the center...
Ron: Sounds promising. Unfortunately the link to Salem isn't working. I tried Google and get the same link. Their site may be down temporarily. Do you have a...
From: Ken Hunter [mailto:atm_ken_hunter@...] ... A more massive scope will have a lower oscillation frequency and will damp out slower after any...
Krajci, Thomas J
KrajciTJ@...
May 4, 2004 5:40 am
3791
Tom, Practically speaking, a Dob needs lightening when it is too heavy for you to carry easily. Is your 8" in that category? An ultralight top end (thin ...
James: They must be changing it, I couldn't get on either. Salem distributing Company Inc Tel 1-800-234-1982 - 1-336-766-1104 Fax 1-336-766-1119 Ask for Randy...
Hi! Does anyone know of any plans on the net on how to make a cheap, light, simple, carryable mount/tripod for a small (3") refractor? Kind Regards, Søren...
From: Stuart Hutchins [mailto:stuart452@...] ... Remove the shroud and weathervaning is greatly reduced. I advocate 'no shroud'...instead, use a...
Krajci, Thomas J
KrajciTJ@...
May 5, 2004 9:05 am
3796
Stuart, I am still in the process of designing this scope. My ultimate goal is to use as little wood in the base as possible. All other design considerations...
... just ... the ... shorter ... The height of the sides of the rocker box are partial determined by the balance point and ultimately by the radius of the...
Well, your objectives are very clear. ... That is something of a challenge with an 8" mirror, which isn't really very heavy. I found the secondary, spider,...
... I believe you have inadvertantly exchanged "prolate" and "oblate". ... There are surely optical applications of the oblate spheroid, certain Cassegrain...
Soren, It is very hard to beat a good photo tripod with that particular scope, granted "cheap" is not necessarily one of it's points... An alternative is to...
From: Ken Hunter [mailto:atm_ken_hunter@...] ... That's because I was thinking in terms of cross sections of 3-D objects...which results in a 2D shape....
Krajci, Thomas J
KrajciTJ@...
May 7, 2004 8:22 am
3803
Greetings All, As usual, I was playing yesterday and stumbled on to an interesting observation. I took a bunch of pictures of a white paper towel laying on a...
Hi, I am a new member, joined a few days ago. I have been collecting parts to build a portable f/4, 6 inch reflector. Being an impulsive buyer, I bought a...
... From: "Prasad Agrahar" <prasad@...> ... I use a Wal-Mart red-dot finder on my Bino-scope, and I'm fairly satisfied. Instead of putting a dimmer in...
