Hi Richard & Mike,
Quote:
Originally Posted by strongmanmike
Astronomik has released a new product - a Ronchi eyepiece, with it you can easily test any scope you care to put it in, for all the major aberations that can plague an optic, so it will be very usefull and easy to check any telescopes optics 
Mike |
This may be a new product to Astronomic, but they have been available for donkey's. You can make one if you like with a bit of 1 1/4 brass pipe and a grating. I bought one about 15 years ago from Jack here:
http://schmidling.com/ez-testr.htm
when they were about $16 and I figured it would cost me nearly that much to make it.
A simple but effective tool that will pretty easily show all but subtle aberrations like localised dog-biscuit or lemon-peel that are best seen with a knife-edge. If the mirror is a true dud, this thing will show it pretty quickly. Gross errors are pretty easy to see.
If you'd like to become the most un-popular person at your next star-party, take a wander around the field at night and ask to look through various people's 'scopes. After a quick peek at what they're looking at, tell them you bought an eyepiece of your own and ask if you can I use it -- or you can slip it in when they're not looking and put it on a bright star.
Then tell them exactly what is wrong with their optics. Repeat with the next person ... and the next etc etc.
Pretty soon you'll be the most un-popular person at the party ...
Best,
Les D