I was wondering if you ( or anyone else) has had the same problems with their Antares finder. I recently bought a 10X50 right angle finder with the dovetail base and I am very disappointed overall with it. First, there is a huge amount of parallax. I can move my head around and the crosshairs move w.r.t the field almost 1/8 of the field!. Secondly, the reticle eyepiece will not reach focus when fully inserted. It must be pulled back out a few millimeters to reach focus. I think this might explain problem #1. Lastly, and most frustrating, I bought the dovetail mount for my C8. The thing was so poorly designed that there is almost 1/2 degree of slop in the mount when the set screw is tightened. DO I just have a lemon or is this what you get for $140?
Antares finder - Lemon?
Started by joe B, 10/02/2002 05:06PM
Posted 10/02/2002 05:06PM
Opening Post
Posted 10/02/2002 05:24PM
#1
Mine was okay, but the mirror diagonal was crap. What kind of diagonal does yours have? It's possible the tube lengths are different for the correct-image and regular RA models, which could lead to the reticle eyepiece focusing problem that you noted if they were mismatched. I'm assuming you are already using the diopter adjustment of the eyepiece to focus and are just running out of travel. The reticles per se are probably focused by nudging the crosshair insert inside the barrel to move them. If the crosshairs AND the view are focused, then the parallax is a mystery. Just needing to pull the eyepiece back a little wouldn't explain it.
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Mike
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Mike
Posted 10/05/2002 04:56AM
#2
I recently bought one and find the optics to be fine. My problem is that with an Intes-Micro 50mm bracket I can't get the crosshairs aligned properly. Looks like the root cause is that the crosshairs in the removeable eyepiece are not properly centered. That any the amount of adjustment available between the rings and finder isn't all that great. Kinda bums me out but it still blows away the original 6x30 thingee on my MN56.
Bob
Bob
Posted 10/05/2002 08:56PM
#3
Hi,
I'd like to make an unorthodox suggestion about crosshairs for visual use. I'm not trying to be rude either:
Rip out your crosshairs. Remove them. Some crosshairs are so fat they get in the way!
I was trying to focus them in my UO 8x50 when I first got it and broke them accidentally. I was so upset. I observed without the crosshairs a few times and realized I didn't need them. It's a 4 - 5 degree field. If you put a star or DSO _anywhere_ near the center of the field, it will show up in an eyepiece that has a 3/4 to 1 degree FOV.
Just an idea. And trust me, I get downright jiggy with my finder! DSO's can't hide from the asterisms of stars that take you there. But a nice, fat set of crosshairs'll blot 'em out sho'nuff!!
Regards,
Matthew Sherman (the finder freeek!)
NGC ME!
I'd like to make an unorthodox suggestion about crosshairs for visual use. I'm not trying to be rude either:
Rip out your crosshairs. Remove them. Some crosshairs are so fat they get in the way!
I was trying to focus them in my UO 8x50 when I first got it and broke them accidentally. I was so upset. I observed without the crosshairs a few times and realized I didn't need them. It's a 4 - 5 degree field. If you put a star or DSO _anywhere_ near the center of the field, it will show up in an eyepiece that has a 3/4 to 1 degree FOV.
Just an idea. And trust me, I get downright jiggy with my finder! DSO's can't hide from the asterisms of stars that take you there. But a nice, fat set of crosshairs'll blot 'em out sho'nuff!!
Regards,
Matthew Sherman (the finder freeek!)
NGC ME!
Posted 10/06/2002 01:04AM
#4
I've got two Right Angle 8x50 Antares Finders; one is erect image, the other isn't. Both display significant spherical aberration but I can easily live with it. The erect image version is dimmer by about a half-magnitude (just a guess) but much nicer to use.
The way I understand it you first focus for a clear cross-hair image with the e.p. diopter ring. You then focus for a clear target image by moving the e.p. up and down in the diagonal's draw tube and tightening the thumbscrew when in focus. Because of the spher. aberration, focus at edge of field is reached at a different point than at center field. Both finders reach center-field focus with the e.p. about 5mm from being bottomed in the tube.
I remember briefly trying a 20mm plossl in the normal, non-erect finder in place of the cross-hair e.p. I recall it reached focus about the same location...image was no better or worse. Makes Matt Sherman's recommendation for getting rid of cross-hairs an easy thing to try...which I think I will next time out.
Both finders are mounted in Losmandy 65mm(?) finder rings...An EXCELLENT setup. Screws are non-marring plastic; return to zero after remove & replace (from dovetail) near perfect. One is mounted on a C9.25 using the Losmandy dovetail, the other uses the TVFAB plastic dovetail base and is mounted on my TV102's tube ring. Thought I was crazy to spend the extra money for the Losmandy rings; but they're well worth it.
These appear to be good utilitarian finders. I'm quite happy with them in spite of their optical flaws.
Bob Young
The way I understand it you first focus for a clear cross-hair image with the e.p. diopter ring. You then focus for a clear target image by moving the e.p. up and down in the diagonal's draw tube and tightening the thumbscrew when in focus. Because of the spher. aberration, focus at edge of field is reached at a different point than at center field. Both finders reach center-field focus with the e.p. about 5mm from being bottomed in the tube.
I remember briefly trying a 20mm plossl in the normal, non-erect finder in place of the cross-hair e.p. I recall it reached focus about the same location...image was no better or worse. Makes Matt Sherman's recommendation for getting rid of cross-hairs an easy thing to try...which I think I will next time out.
Both finders are mounted in Losmandy 65mm(?) finder rings...An EXCELLENT setup. Screws are non-marring plastic; return to zero after remove & replace (from dovetail) near perfect. One is mounted on a C9.25 using the Losmandy dovetail, the other uses the TVFAB plastic dovetail base and is mounted on my TV102's tube ring. Thought I was crazy to spend the extra money for the Losmandy rings; but they're well worth it.
These appear to be good utilitarian finders. I'm quite happy with them in spite of their optical flaws.
Bob Young
