We mostly come out at night... mostly.
GSO Z8 Degree Circle & Digital Level
Celestron 4"(102mm) SLT 660mm f/6.47
2" 30mm GSO WideView
9mm GSO Plossl
ES 82's : 4.7mm, 8.8mm, 11mm, 18mm
BGO's 5mm, 6mm, 9mm
2" 2X ED Astronomics Barlow & GSO 1.25" 2x Shorty
8-24 Baader Zoom III
Baader M&SG, Semi-Apo
Quote: Quote:A cam lever when flipped down can provide vertical pressure on the plate or ring that prevents rotation, without creating any torque. It would probably apply a bending moment though.Jon
Quote:A cam lever when flipped down can provide vertical pressure on the plate or ring that prevents rotation, without creating any torque.
Celestron 8SE Dobstuff 13.1": Swayze refigured Coulter mirror, 6 pt mirror cell (2 pt edge support) and CF focuser board made by me StarBlast 4.5 ST80/PortaMount II Zhumell 20x80/Oberwerk 15x70 on a Seronik-style tripod boom mount Hubble Optics 18 inch F/4 mirror.
Quote:...But isn't all of this secondary mirror tilt exactness predicated on employing the best use of the best AC currently available? With the rest of us who don't have one of those AC's, setting the secondary tilt as a: do it correctly and for the most part, just forget it?
-DannyMy warehouseMy Channel
SteveCarpe NoctemBushnell 10x50 Seymour solarized binoculars.Bushnell 12x32 moon and terrestrial binoculars.Celestron: 102-GT Refractor OTA on a CG-4 GEMAstro-Tech Value Plössl 32mm, 20mmZhumell Z series 14.5mm, 9mm, 5mm+42° 18' 37.39", -122° 52' 3.76"Never argue with a fool. Onlookers often can't tell the difference.
My eyepieces are made from the waste product of exploding stars.
10XTi 102XLT ST80A(2" Focuser); President, Eypieces Anonymous, Denver Chapter (Hello, I'm an eyepiece junky, what's your excuse?)
DAS Dark Site
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 - TEC 140 - AT 65EDQ APO Refractor - Astro-Physics Mach 1 GTO Mount - iOptron ZEQ25 mount - Discmount DM6 - Canon 60Da
Clear skies - Jim Crazy PNW imager !
A-P Mach1 on 12" concrete pier - ROR structure.
Tak FSQ85-EDX, Tak FS-128. Orion 8" f/3.9 w/MoonLite motorized - MPCC MkIII CCD:
SBIG 8300M/FW8, Astrodon 36mm LRGB, 5nm Ha, 3nm SII, OIII - Canon EOS 6D unmod SSI3, SSAG,
Skytools3pro, MaxImDLpro, PSCS5, PSPpro, TheSkyX, TheSky6, BYE, StarTools
Orion XX14g -for visual- diags, ep's, accy tubes, Binocs .
Quote:The thing that gets my pants in a twist is the flex of the thin spider vanes. Collimating is a frustrating exercise in moving the screw, bolt or nut past the correct point and hoping the spider springs back to the right position when you let go.
I totally understand the reason for thin spider vanes but when a force from outside the telescope (i.e. your fingers or a wrench) is applied to anything attached to the spider it moves temporarily out of place.
If a system of tiny motors could be applied to these various screws, bolts and nuts the forces would be applied from inside the structure and there would be no 'spring and rebound' to worry about.
Quote:...One question for anyone, does the tilt action of the secondary along the short axis, I call it side to side, accomplish the same as rotation?
Quote:The thing that gets my pants in a twist is the flex of the thin spider vanes. Collimating is a frustrating exercise in moving the screw, bolt or nut past the correct point and hoping the spider springs back to the right position when you let go.I totally understand the reason for thin spider vanes but when a force from outside the telescope (i.e. your fingers or a wrench) is applied to anything attached to the spider it moves temporarily out of place.If a system of tiny motors could be applied to these various screws, bolts and nuts the forces would be applied from inside the structure and there would be no 'spring and rebound' to worry about. Dave
StarStructure 24" f/3.3 | ServoCAT/Argo Navis
Astro-Physics 175EDF | AP1100GTO | ATS Portable Pier
Psalm 19.1 - A Psalm of David. "The heavens declare the glory of God, and the sky above proclaims his handiwork".
Quote:How about instead of the collimation screws applying forces some what tanget to the 2ndary face, have them perp to the 2ndary face like a lot of european 2ndary holders.
Quote:but with standard secondary holders we're adj'ing tilt to a plane [top of the stalk] that has nothing to do with the face we care about.
Jeff Morgan - Wile E. Coyote School of Telescope Making
Quote:O.K. Bill, no big secret - I'm working on a Newtonian secondary mirror mount idea, that, to my surprise, someone already posted a picture of in a thread here. He took the picture at NEAF this year, but I've had that prototype installed in my scope for a few years. The idea does not have to do so much with this particular "embodyment" (patent lawyer-speak) of the holder, but with the principle of motion of the adjustments. In my opinion, the adjustment axis of most conventional Newtonian secondary holders are slightly insane.
Quote:...What am I missing?
Quote:It's a similar problem to pursuing an offset secondary mirror alignment with a centered spider. If the focuser is "square" to the OTA and the primary mirror is centered in the OTA, the intercept angle ends up a bit more than 90-degrees and the presentation of the screw heads changes (the secondary mirror is tilted slightly outside of the cylinder). We could change the "squaring" of the focuser to bring the intercept angle back to 90-degrees (or we could pursue a centered/no offset secondary mirror alignment), but it's pretty common to accept the best available alignment with the given geometries and call it "close enough".