Monday, February 25, 2008

Antares 8*50 illuminated RACI finder

My Celestron C8 scope had only a plastic and flimsy red dot finder in original configuration. I needed a better magnifying finder, that will also help to spot dimmer objects on the night sky. There are no detailed measurement reports here, only a personal thoughs and ideas. Hope they will give you some idea about this Antares finder. The configuration looks like following:
Antares finder is attached the SCT frame with Baader finder bracket Rel4 -model. Maximum tube diameter that it can hold, is 72mm. I chose the larger model insteadt of Rel3, because of the larger "dewshield" tube in Antares finder. I was really amazed with the mechanical build and quality of this Baader product (with small cons, see comments). It is very sturdy and can hold bigger finderscopes also, maybe even small guiderscope (I have not tested this yet...). Supplied aluminum block between finder dovetail and finder bracket is removed to get finder more close to SCT.

Antares finder gives correct image in up/down and left/right directions because of 90 degree prism used. The image quality is good for the price, not perfect though. For higher optical quality the price would go very high, so I stay on this level now. Image quality is lower on the edge of field. Currently I did not had possibility to compare this Antares to other finders, so my comments are based on the actual (and short time) use. I've noticed that It takes some time to get familiar with the use of prism finder. I've noticed myself watching between the sky and finder EP, even when the finder is pointed to the right part of the sky :-) When scope position changes, there comes also an issue with finderscope viewing angle. In some directions it is facing sideways. It is possible to rotate finder in Baader bracket (by loosening setscrews a bit). Another method is to loose setscrew on Antares prism and rotate it (requires modification to allen screw). Finder eyepiece has double crosshairs with adjustable illumination (standard 1.25" size)

Antares finder - pros / cons
+ image quality decent/good for the price
+ correct / right angle image
- rear and front caps always dropping
- eyepiece focusing is jamming in low temparatures
- no separate focuser (eyepiece has to be moved)
- loose fit in lens hood tube (need to be attached again)

Baader finder bracket - pros / cons:
+ very good mechanical build and quality
+ feels sturdy
+ disconnected quickly from scope
- finder bracket screws are bit small and slippery
- plastic tips of adjustment screws need to be glued with superglue

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