Teeter STS 11 f/4.3 Zambuto | XT8i | XT8g | XLT 150 | C90 | EON 80mmAT Voyager and Nexstar SLT mountsEyepieces: Mostly TeleVue and PentaxDenk II BV'er, Earthwin PFS-SE, Pentax 10x50 PCF WP II
David Cotterell Toronto, Ontario "If an observer actually sees an object, there is no point in referring to a formula to find out whether he ought to see it; and if he fails to detect it, no formula will ensure his success." - W.H. Steavenson 8" f/15.5 TEC Maksutov 16" f/5 Teeter/Zambuto Dob 66mm WO SD AT 65EDQ APO Refractor Astro-Physics Mach 1 GTO Mount iOptron ZEQ25 mount Canon 60Da
Too many scopes, not enough time...
APM/TMB 115/805 APO Celestron ED-80 9.25S - GT, Vixen Porta II Naglers: 17T4, 13T6, 3-6 zoom UWANs: 28mm, 7mm Pentax 10XW, 10mm Radian Misc EP: 50mm Parks, 42mm GSO, 2x TV Barlow, sundry plossls...
“I am the only person to ever ace a 1951 USAF resolution test. My 'to observe' list says 'done'. I do not use charts or atlases when I starhop; men do not use maps. One of my sketches won an SBIG deep sky imaging contest. I am the life of star parties I have never attended. I never say anything looks like a faint fuzzy - not even a faint fuzzy. Pilots aim green laser pointers at me. Don Pensack proofreads my CN forum posts.” - The Most Interesting Astronomer in the Universe
Compustar C14 Leo Henzl's Custom C8(VP Sales Celestron) Celestar C8 6" Refractor Adv. GT mount 6" F5 Omni XLT Newt. LXD-75 F4 Imaging SN8 Meade 8" F6 Newtonian Dynamax DX6 Criterion RV-6 ETX-90 Astro Meade 2045 4" SCT B&L 4000 Vixen/Celestron 80mm F11 JC Penny 60mm AZ/ALT Refractor 1963 60mm 15-60 B&L Spotter Binos 25x100 8X40 20x80 Arcturus Bino-Viewer
Quote:Also, try to pick a 2nd or 3rd magnitude star that is *not* a double to collimate and/or star-test on. Very interested in what the lines in picture 2 turn out to be!
Quote:I must admit I was parroting what I learned from Ed Moreno's excellent "Guide to SCT collimation" on that "other site". He recommends a 2nd to 3rd magnitude star and a 6mm to 8mm EP. I note that others differ; Thierry Legault suggests a 0 to 1 magnitude star. Our own Uncle Rod advocates a 'medium bright star'. So two out of three advocate a 2nd/3rd mag star. Personally I like that because I find 0/1 mag stars rather blinding when only slightly defocused (as they should be).Incidentally, the arc-like appearance sounds like mis-collimation to me. I suspect that when you get the collimation perfect, you will be totally wowed by your scope.
I lost count of my scopes. Now I just want mobility. I came, I saw, I bought some interesting accessories, and put names to faces: NEAF 2012, ASAE 2012, SWAP 2013, ASAE 2013.
Quote:If seeing is not that good or if you are not trying to get perfect collimation, then the magnitude of the star does not matter.For the first round of collimation, the brightness of the star is not that big of deal. But after that when you are trying to really fine-tune collimation on an IN-FOCUS star, you really need something that is not super bright. You are looking for an airy disk surrounded but a well defined diffraction ring. If a star is too bright, the airy disk and first diffraction ring just get blurred together and you have a bigger, fuzzy star.
Quote:Star test generates new false indictment on scope, yet again.Consider looking at something in focus. My own C5 does best with a sharp collimating and sharp focus. -Rich
George You know you're getting on when the equipment you farmed with is showing up as suburban lawn ornaments.