Hello. I took on a small project of making a better finder than my Cracker- Jack finder that came with my kit. I saw some web pages that described how some...
In a message dated 4/1/03 11:06:13 AM Eastern Standard Time, ... Is this an achromat lens? To be color corrected it must have at least two elements for...
... and ... least two ... a ... number? ... Here's the info from the web page, http://www.surplusshed.com/pages/Lenses.html. Item No.: L2167 Coated plano...
In a message dated 4/1/03 1:51:00 PM Eastern Standard Time, ... Well, that lens will go into your experimenters bin. Go to Surplus Shed and enter 'achromat' or...
... Mark... What you have purchased is commonly called an "Ant burner". It would be very difficult and expensive to make it usable as an objective lens for a...
Hello All, I'd like to first thank all the atmers who have responded to my posts and have provided me with valuable advice. Without which I would surely never...
Hello I'm looking for examples or advice for constructing a holder for a 8 inch secondary. The secondary weighs 6.5 pounds. I need an idea as to how wide and...
John wrote, ... What are the radii of your zones? ... Unless you're using something like Zerodur for your mirror, it's not a good idea to test without letting...
David, Next time you are at the Home Depot or Lowes etc look around the lumber area and see if they have any steel banding or strapping that is used to band...
The numbers in your foucault test do not represent your central bump. Sometimes you cannot trust numbers... especially when they try to represent a complex...
David Take a look in the links section of this group, I placed a link there awhile back on a easy to make and very affordable spider and secondary holder...
Hi, just joined the group. I've been making a lot of add on parts for my telescope out of Al. I was wondering if anyone knows how to anodize Al, either clear...
Hi David, I too have a large secondary 7.25" minor axis which I'll be used for my 25" scope. I'd appreciate receiving any good advice you manage to pick up. My...
I've used the Orion 9x50 RACI finder and liked it. I'm considering the Orion 6x30 RACI for another scope due to its lighter weight (10oz vs 18oz). Can anyone...
... for ... anodize ... Mike, Also consider alodining, much easier than anodizing, especially when followed by a coat of paint. If you have a store nearby...
Thanks for the replies to my query, I will give alittle more information on the 8inch mirror. I realize now that Foucault measurements without zone sizes mean...
I have read a post where someone mentioned mixing old pitch with new to change the temper of the pitch. Is it safe to recycle pitch melted off of a pourstone...
John, That 'pimple' is small enough that much of it will be hidden behind the secondary. If I remember correctly, your Strehl ratio is calculated to be .893....
Hi John, It is possible to recycle it. It can be strained through 4 or more layers of cheesecloth. I have never tried it, and I am concerned that there...
Hello friends, I have created a yahoo group for OSLO LT optical design software user group. Amature telescope optics designers are welcome to join. ...
Hello Peter The secondary holder design at http://www3.bc.sympatico.ca/gwolanski/SPIDERS.HTM looks interesting. i haven't found a design specifically to hold...
... From: "David Thomas" <ferncliff23@...> To: <atm_free@yahoogroups.com> Sent: Tuesday, April 08, 2003 8:54 AM Subject: Re: [atm_free] large secondary...
Hi John, Just a couple quick notes. Both sets of readings show a total correction of 0.100, which is close for a 8 inch F5 (or so). Like Richard said, though,...
John, I used cement or plaster tools on a regular basis especialy for large mirrors and recycled my pitch often, but I took very important steps to do this....
