Free Mirror Testing: Is your scope not performing as good as it should with fuzzy images? There could be many possible causes; seeing, alignment, tube currents, etc. as well as the optics quality. If you think all the other possibilities have been addressed then you might want to have me check you optics for free. I use a Zygo GH with a modified Offner null system and can check mirrors up to 20 inches. (http://www.telescope-optics.net/offner_null_test.htm)
Secondary Mirrors: The most common cause of an astigmatic image in Newtonians is from a poor diagonal mirror. I can check diagonal up to 4 inches major axis on my Zygo and for larger diagonals I can check them using the Raleigh water for any size diagonal you might have or optical flats up to 12 inches or more with no danger of scratching.
Refiguring: If needed I can refigure your mirror up to 20 inches if need and will beat any price you will find. Contact me for pricing. You might think I offer free testing to get business but quite the contrary. I’d rather not have to refigure your mirror as I am quite busy already and am simply offering this service to ATMs. Also please do not send me your mirror to get numbers just for the sake for bragging; interferometry is the most rigorous of tests and will most likely test worse than you think.
Contact: Please do not send me you optics for testing before contacting me. Please follow these directions for properly shipping your mirror: http://www.spectrum-coatings.com/Telescope-Mirror_Packing.htm
1071 Terrydel Lane Cincinnati, Ohio 45245