22" f/4 Sayre Monocular, Tom Osypowski Equatorial Platform (since 1995), Assorted small telescopes 76-152mm; 25mm ES100°, 20mm ES100°, 13mm Ethos, 9mm ES120° (serial #18), 9mm ES100°, 8mm Delos, 6mm Ethos, 4.7mm Ethos, 3.7mm Ethos SX, 2.5mm Nagler Type 6, 2" 2X Powermate, 2" 1.5X Proxima Barlow, 2" GSO Coma Corrector, 18mm BCO, 10mm BCO, 6mm BCO and other 1.25" eyepieces. Zhumell 8x42 Nova Phase-coated ED Binoculars, Burgess 25x100 Binoculars
ALL my posts should be considered as opinions shaped by MY experiences and understanding of the facts.
Quote:Sounds like a Jones-Bird design. Google it. Not an easy scope to collimate and not a design that is known for good optical performance.
Quote:That image does show coma, of pretty uniform degree and orientation. The system is very far from collimation. Reversed lens elements by themselves will not necessarily be the culprit for this aberration.When adjusting the secondary alignment, I gather the entire unit housing the mirror and lenses tilts? If so, I wonder if there is a means to alter the tilt of the secondary mirror by itself, with respect to the 'Barlow'.Do you have a laser collimator? Place a white paper projection screen surrounding the laser's exit hole, with the smallest hole in the paper possible. Place a small mirror beside the secondary assembly so that you can sight up into the focuser tube from the front of the scope, and thereby observe the reflected spots on the white surface. I should think that the 'Barlow' lens surfaces can send back sufficiently bright reflections, at least in dark conditions. Ideally, all spots should fall on the laser's exit aperture. The more dispersed the reflections, the poorer the alignment.The brightest spot by far will be that returned by the primary. Each of the four lens surfaces should send back a very much dimmer spot, with the possibility of one or more being enlarged somewhat due to the curvature of the surface and additional refraction upon return.It might be better to do this with the secondary adjustment screws well loosened, so that you can wiggle the secondary assembly by hand and observe the relative movement and disposition of the spots. If there is no point at which the group all occupy at least nearly the same place, after further adjustments if the primary as well, things are likely out of whack with that secondary housing.
Quote:No luck with http://www.zhumell.com/contact-us/ ??Try warming the barrel of the collimator gently with a hair dryer. It might expand enough to get the stuck battery out.
Quote:I trust you know to check the collimator's collimation by spinning it on a V-block...
Quote:Instead a of V block, four nails in a block of wood is an option... An option I will exercise when I get my collimator...
Quote:Any thoughts of removing the barlow and seeing what happens? (Is it easily "unscrewable"?)
Quote:Also......It may be advertised at 600X, but I don't believe any claims over 2X the aperture in mm, (508X max), and, at least where I live, getting a clear view at 500X with my 10" is a tall order. My atmosphere conditions seem to dislike anything over 250X with an occasional, rare, fleeting, pristine view over 300X. (But those nights are like a once every three year occurrence for me.)I call it a great night if I can go over 250X at all......Peter T.