XT10 classic with premium optics Tri-knob CR2 focuserCatseye + Glatter collimation toolsStarBlast 4.5" & 6"Round Table PlatformTV EPs
Jim Fly - Manufacturer
Indiana for two more weeks...
14.5" Teeter w/ Richard Fagin mirror, TT #66
EON 120ED on CG-5 ASGT
Lunt LS60THa/B1200 Sky Guy Porta II
Denk Super System with A45 OCS
Explore Scientific 127mm ED APO Orion 100ED Orion 90mm Achro Explore Scientific 80mm ED APO Orion ST80 Celestron SP-C6 Newt Orion XT10i Meade 12X60Orion Ultra View 8X42---------- Super Polaris CG-5GT ES Twilight I Skyview AZ Paragon Plus ---------- Torrance,CA
If it weren't for physics and law enforcement, I'd be unstoppable.
Rob 18" f/4.3 Starmaster 8" Meade LX200 Classic Celestron 15x70 Skymaster Binoculars
Z10 dob, flocked
"When I consider your heavens, the work of your fingers, the moon and the stars, which you have set in place, what is man that you are mindful of him, the son of man that you care for him?" --Psalm 8:3-4
DON'T PANIC!-Hitchhiker's Guide to the Galaxy Don Wyman
woody a parsec farther out...
12.5" f/4.8 custom truss dob, EQ platform
Tele Vue-85 Meade 8" SCT Nova Hitch Berlebach UNI 24 Meade 12" LightBridge Orion ED100 Losmandy GM-8 Orion SVP Quarter Hitch
Quote:The pictures and explanations as this topic progresses are truly excellent, Jason. Nice work.
Quote:Then we get to the table (what many readers are going to take away from this), and I have to wonder about a few things there:
1) Minor quibble, the cheshire in a combo tool can also be calibrated to a primary mirror mark, so could also earn an Excellent.
Quote:2) Was interested to see that there are no Excellent FAE tools(?)
Quote:3) Was interested to see that the CAM AC did not get promoted into the PAE row at all, since I thought its intent, one of them, anyway, was to make a cheshire completely redundant.
Quote:4) There ought to be some reemphasis that PAE and FAE are really the only two collimation axes. CAE and LAE are interesting to help talk about AC theory only.
Quote:Quote:2) Was interested to see that there are no Excellent FAE tools(?)Correct. Getting the “Excellent” rating has high standards. It should involve visual cues that are parallax-free, sharp, and highly-readable. Stacking P+1 does not meet this criteria....Jason
Quote: There ought to be some reemphasis that PAE and FAE are really the only two collimation axes. CAE and LAE are interesting to help talk about AC theory only.
Quote:What about stacking P & 3 in the CDP?
Quote:Indeed true - IIRC CAE=2*PAE+FAE and LAE=2*PAE+2*FAE (vector sums), and thus, the CAE and LAE should perhaps not be seen as "fundamental" in the sense of being independent of the others (you could, in principle, derive PAE and FAE from CAE and LAE, but this would be pointless).
It could also be made clearer that the PAE and FAE are indeed independent of each other - you may have accurate collimation of one axis and still have some miscollimation of the other (even if that's what you try to avoid). It is only the PAE that causes coma in the center of the FOV, the FAE will cause a tilt of the focal planes but no error in the center of the FOV.
Quote:Quote:What about stacking P & 3 in the CDP?
It depends on the focal length of the scope. For my 1200mm scope, it is hard to see reflection 3 primarily because of its fuzziness.
The left photo is what I see and the right one is with the camera focused at infinity.
Those with longer focal lengths scopes, reflection 3 will be clearer.
For a reference to others, the following posts explain the relationship between focal length and reflections 1&3 fuzziness:
But the trend seems to be moving towards scopes with shorter focal lengths (< F3.0 scope). Not to mention that imaging scopes tend to have a short focal length – the very scopes that require more accurate focuser axial alignment.
Quote:.... Therefore, eliminating LAE with P+2 stacking and CAE with the CAM with great accuracy implies both PAE and FAE are also eliminated with the same great accuracy.
Quote: Using a cheshire like Catseye’s with a triangle and a ring does add more reading accuracy than the sight-tube/combo tool with the distracting cross-hairs. I am speaking from experience since I have used both tools extensively.