Who you jivin' with that Cosmic Debris? "all science is either physics or stamp collecting" -- Lord Rutherford
10" OO VX, 6" iOptron Mak-Cass, Orion 100ED
ALL my posts should be considered as opinions shaped by MY experiences and understanding of the facts.
My eyepieces are made from the waste product of exploding stars. 10XTi 102XLT ST80A(2" Focuser) XW: All; XO: 2.58 Televue: Naglers-T1 Smoothside-full set, 17T4,12T4,Ethos 17,4.7; plossels-40,32,20,17,&7.4mm; Pans-22,24mm; Delos-6,8,12,17.3mm ES100: 5.5,9*,14,20 ES82: full set ES68: 16,20,24,34 NLV: 5,9,10,15 Ortho: HD-7,9; OPS-9,12 Meade RG 7mm Other: Pentax 12.5K(.965), 10mm Parks Zoom: Nag3-6 *=on b/o DAS Dark Site
Dark Arts Observatory - Brockport, NY - Skyshed POD XL5 with iOptron iEQ45 Mount
Scopes: C8, C5, SV110 ED, EON-72 ED, ST 80, ATRC6, Megrez 90
Quote:Alas, if you want to focus there's gotta be *something* that's not locked in place. In SCTs, when you twist that focus knob you're actually sliding the primary mirror forward/back in the tube, for example.
Quote:So why all this collimation? If components are rigidly mounted, aligned, and then locked in place, what's going to change? Is it necessary, or do amateur astronomers just like to fiddle with stuff?
Quote:Newtonians require attention to collimation .. There are couple of reasons for this... - Mirrors cannot be held tightly, they deform under even slight pressure, they need to be free to move.
First and foremost observing love: naked eye.
Last but not least, telescopes.
And I sometimes dabble with cameras.
Quote:If that's true for Newtonians, why isn't it true for SCTs of the same aperture? After all, the primary mirror of an SCT is roughly f/2, so its collimation tolerances are truly critical, much worse than for an f/5 Newt. Yet as noted, SCTs go out of collimation less fequently than Newts.
I ache, therefore I am
Orion XT10i Dobsonian
Celestron 80mm EQ Refractor
Paint brushes, canvas
Happy owner of-- A Mag 1, 12.5 inch Porta Ball A Dual Axis Equatorial Platform A PST Double Stack
Yeah, but ...
If that's true for Newtonians, why isn't it true for SCTs of the same aperture? After all, the primary mirror of an SCT is roughly f/2, so its collimation tolerances are truly critical, much worse than for an f/5 Newt. Yet as noted, SCTs go out of collimation less fequently than Newts.
You know you are there when you start thinking in terms of EXIT PUPIL rather than Magnification..