Quote:Wow that's a lot of reading. Unfortunately for me it will take reading this thread quite a few more times before I can begin comprehend it all.But I applaud you for taking the time to help newbies like myself!THANKS!
Quote:Jason D, or Don P, or guru surrogate ,In this post #3635872 from within this very thread, Jason outlines an alternate method from what the catseye website outlines using the 2-pupil XLK.My question...is the CDP used when performing any of the steps in Jason's alternate method? Or just get a decent collimation, then the hotspot is simply centered as precisely as possible using the cheshire, then insert the XLK and proceed with the steps. There is no CDP while stacking P+2...correct?p.s. I have 50 posts per page. Less pages, but more scrolling . But seriously, how can anyone who wants to use AC's and cheshires not love this thread. Truly a great thread! My thanks to Jason, Don, Vic and Jim for a really outstanding presentation. It has admittedly taken me a while to absord the intracacies. Still, I learn from a rehashing of it every time. But it is sinking in a lot more lately...the science of it that is. In fact I just sent Jim Fly my Infinity XL to upgrade to the XLK because I am now empowered with confidence that I can do better with collimation, and do it easily. I am believing that Don's words will ring out in the night...it's amazing how much better the seeing got with my better collimation.
Quote:I don't mean that to sound obtuse, but the tools we use for collimation of the mirrors and focuser ARE doing optical, as well as physical, collimation.
Quote:...I am asking this question as the claims for accuracy for placing the center spot are getting down into the 0.1mm range, so it seems prudent to ask center of what? Are the mirror blanks round enough for such levels? If the reflective portion of the mirror is being used is the bevel consistent enough on the round enough mirror for such levels of accuracy?
Quote:Quote:My personal opinion is that a decently placed center works fine provided one obtains a good star test when done, but that's just my opinion. Or, another way to state it:If the tools used to collimate yield good star images, round with concentric diffraction rings, then collimation is good, and no improvement will be made by collimating using a star test.
Quote:My personal opinion is that a decently placed center works fine provided one obtains a good star test when done, but that's just my opinion.
Quote:...The issue with using the lateral pupil of the AC, as I understand it, is that is makes certain the primary and secondary optical axes are parallel, but not necessarily coincident. Hence, it is possible to see good cheshire alignment, and well-aligned stacks in the lateral pupil, but not have the secondary reflections perfectly stacked in the center pupil's image.However, if the central pupil, lateral pupil, and cheshire all agree the instrument is collimated, it is.
Quote:...I have used CDP to align the scope and taken my time only to find the lateral pupil still shows some unresolved secondary/focuser axis anomalies....So there is no question in my mind the lateral pupil reveals secondary/focuser axis errors of smaller size than the central pupil.
Quote:Using Jason's technique in that post (and I start from much closer, where the central pupil jumble is almost collimated), a couple iterations and all tools and pupils agree the scope is collimated.
Quote:...And that's why the technique jason outlined in that post results in better alignment for the focuser axis than does CDP. If you had an autocollimator with only the central hole, you'd use CDP. With the XLK, Jason's method is just a bit easier.
Quote:I hope you will find switching to the Hotspot was worth it.
Modified Megrez 90 FD with digital motorized Feather touch focuser Vixen GP DX partially regreased with Superlube Astro Electronic FS2 Atik 314L+
10" Sumerian, Webster D18, solar scope, small 'frac, Vixen Foresta 8x42 Take action against Light Pollution. Together we can make a difference.
Quote:Could one simply take, say a 'BB' or small bearing, and place it softly very near the center of the mirror and let it come to rest in the exact center of the parabola (bowl).
Then, using a template or tweezers, place the donut, triangle, or hotspot over the said object.
Am I missing something?
XT10 classic with premium optics Tri-knob CR2 focuser
Catseye + Glatter collimation tools
StarBlast 4.5" & 6"
Round Table Platform
Quote: Could one simply take, say a 'BB' or small bearing, and place it softly very near the center of the mirror and let it come to rest in the exact center of the parabola (bowl).
AD10, NoName8, DS-16 with Spooner primary.
ES, Sterling, Parks, Baader, TV, GSO EP's and a lone Nagler.
Nikon, Celestron binos
Quote:What am I doing wrong?
Quote:You were right (as usual)the Farpoint AC I purchased was poorly made. the mirror is glued to a thin plexiglass disk and sandwiched in between the cap and body of the AC with the small cork pices there to keep it from rattling around
Quote:That is why it is getting sent back on Monday. I'll be giving Jim Fly a call.
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:Squaring the AC mirror to its case is critical. Without precise squaring, the AC will not be useful. I do not see how Farpoint design can achieve and maintain this a critical alignment. That is why it is getting sent back on Monday. I'll be giving Jim Fly a call. Jason do you think the Infinity XLK is a must have for my f4.9 dob or is it more aimed at the imaging crowd with their f3-4 newts? Thanks again Rob.
Quote:Quote:That is why it is getting sent back on Monday. I'll be giving Jim Fly a call. Better yet, give Howie Glatter a call. His Blug/Tublug combined with his laser and barlow work exceedingly well any time of the day or night for an acceptable price.
Quote:Jason do you think the Infinity XLK is a must have for my f4.9 dob or is it more aimed at the imaging crowd with their f3-4 newts? Thanks again Rob.
Home-built Dob 10 F6/Zambuto/Osypowski Platform Starmaster 7 Oak Classic- Zambuto Discmount DM-4 w encoders Stellarvue 80ED Stellarvue 70ED Stellarvue 60 Finder Tasco 50 refractor (1966 birthday gift) Orion 80ST Lunt 60 Double Stack Bogen with Dwarfstar mount AT Voyager mount Celestron SLT mount Astro Physics 15x70 Binos Orion Parallelogram mount
Quote:P.S. Is the CAM amendment absolutely necessary and if so is it available?
Quote: But it is a VERY rare scope that can move up and down over a wide range without seeing collimation changes in an autocollimator