Hello, I am making a 10" f/5 scope. I want to use it with a 30mm and 24mm eyepiece of 82deg AFOV. What size diagonal should I use for visual use, to get a 75%...
In light of warnings of oil production shortfalls and climate change, a good approach to this problem - and really the right one anyway - is to point out how...
You can use Mel Bartel's convenient Newtonian Diagonal Calculator: http://www.bbastrodesigns.com/diagonal.htm Your 30 mm eyepiece has a field stop of around 40...
Well Mel kindly told me about the Newt program, and I came up with some figures he approved! But I was hoping for direct experience with the visual appearance...
What numbers did Mel "approve"? I'd be interested in knowing so that I can learn. Also, why do you need a 6" + 2" + 2" to the image plane? Ok, 12" ID for the...
Hi Robert, Please excuse my ignorance, but why look at the 0.8 inch position and 0.6 inch positions for the 30 mm and 24 mm eyepieces, respectively? Thanks, ...
Hi Have been considering Tech2000's Dob-Driver II for my new Orion Optics UK 14" dob with 99 strehl mirror which should be ready in about 5 weeks time. I'm not...
Tim, A 30 mm 82 deg eyepiece has a field stop of about 40 mm (1.6 inch) diameter. The edge of the field is at half this diameter or about 20 mm (0.8 inch) from...
Hi John, They are a little slow in responding. I was looking at the same system for 18" DOB. You are right there prices look pretty good. Since I'm in Ohio...
Hi Dave At least I know now it's not just me they're slow in responding to. I intend to use the belt drive for the alt bearing, but for the Azimuth the rim...
Has anyone in this group tried a Mylar membrane mirror - that is, aluminized mylar stretched over a shallow pan and sealed, then a partial vacuum is pulled in...
Howdy John; I am in the process of installing a DDII for my 16 inch. The friction drive is much better thn the belt. A strip if nylon or aluminum makes a great...
Hi Jamey Thanks for that. Nope the picture didn't show, looks like you will have to post it. I would really like to see exactly how you installed it. The more...
... A google search found a few articles (one of which I've seen before). While the idea could be used for a rough mirror, getting optical quality is a very...
This is just a brief announcement to say that I have added a new product to my Accessories website for Obsessions and other Big Dobs. The product is a Basic...
Large mirrors (1 to 2 meter diameter) have been made by rotating a shallow pan of mercury. Of course, this means the scope direction of view is only directly...
Hi Well after gathering more info (and some personal messages from members of this forum) I've decided to forget about the Dob Driver II and go for the...
I posted pictures of the modified Dob Driver II drives for my 16 inch Dobsonian. The photo album is called Dob Driver II by Jamey I will reintall on the...
Hi, Just polling for opinions ... I have a 8" f/6 Starsplitter with nice Zambuto optics. Still waiting on 1st light ... 2 weeks of rain and counting! It...
... Hi Rob, I can't imagine that anybody on this list would have an opinion (LOL)!!! My suggestion would be to begin doing homework on DSC's. The scope will ...
Hi Rob, nice to hear from you again... indeed the smallest scope that a CAT is on is an 8" - a gentleman in Michigan has 4 (or was it 5) ServoCAT's from his 8"...
Hello everybody, A new update of the Mirror Edge Support Calculator is available: http://www.cruxis.com/scope/mirroredgecalculator.htm This tool allows you to...
This is a cheap way to have a mirror but not to make one. The problem with this is that you can make just so many mirrors like this and all that penny savings...
... aluminized mylar stretched over a shallow pan and sealed, then a partial vacuum is pulled in the pan to allow the membrane to settle into a parabaloid...
But what about the quality of the surface? Yes, there are versions of aluminized mylar good enough to be used for solar filters, but the required surface...
Having problems with message search?
Fill out this form to ensure your group is one of the first to be migrated to the new message search system.
