Finderscope loose attachment

[marcusk]

Hi

I bought one of Altair Astros excellent 10x60mm finderscopes last month - it is very good but I find the fitment to my Starwatcher Evostar 120 to be very loose. The attachment on the finder scope is significantly smaller than on the telescope so its very loose. When I tighten the (single) screw it angles the finder quite a considerable amount and upon releasing and re-tighting I have to re-align every time. I'm not blaming the finder here I just want to see if anyone has any suggestions? Ideally I could rid myself of the Starwatcher attachment and use the one supplied with the finder but its am integral part of the telescope and has no-where else to fit a finder...
I can send pics when I'm not at work.

Any ideas?

Cheers

Marcus

[brantuk]

Yes I get the same thing when using the AA finder with SW shoes. I guess you can meddle around with a few matchstick wedges in the shoe to see if you can get it more in line with the scope. I don't know if your finder came with guide rings, but mine did and realigning the finder within them is the way I do it. Hth

[marcusk]

Thanks Brantuk... yeah, figured I could do a bodge to fix as you say, just wondered if there was a more secure/permeanant solution. Hmmm. I do align with the guide rings but because its single screw on the SW its not perfectly aligned each time it comes on and off.

Wondered if I could screw this - http://www.firstlightoptics.com/finders/baader-universal-quick-release-finder-base.html to one of the screws above the focuser (where the white metal meets the black tube)?

[bambuko]

You'd be definitely better off drilling and tapping two holes either side of the original central fixing screw, to replicate two screw fixing on the Altair mount.

[Pig]

Marcus post a picture that shows your set up, its easier to assist when you can see the concern in a picture.

I have the same finder and didn't use most of the bits it came with so you never know your luck

[bambuko]

I had the same question , so I quickly googled Starwatcher Evostar 120

and it looks like this:

hence my advice ( I am guessing that marcusk is trying to fit it into existing mount).

On a reflector you can use mount provided by Altair in the package which has two fixing screws instead of Skywatcher's one

[brantuk]

Thanks Brantuk... yeah, figured I could do a bodge to fix as you say, just wondered if there was a more secure/permeanant solution. Hmmm. I do align with the guide rings but because its single screw on the SW its not perfectly aligned each time it comes on and off.

Wondered if I could screw this - http://www.firstlightoptics.com/finders/baader-universal-quick-release-finder-base.html to one of the screws above the focuser (where the white metal meets the black tube)?

Actually Marcus - I have exactly the same finder set up as yourself (Altair finder/guider) and the same focus tube with the welded on shoe on my Tal100RS as in the pic above (don't ask why I have a SW focuser on a Tal ota - it's a long story lol). I just got them both out and tested the fit and there is about a 2mm gap between the finder base and the inside edge of the shoe where the screw tightens up.

The reason I never noticed this problem before is cos I also have an Orion Raci which fit's the SW perfectly and I've always used that on this particular scope. The solution I think would be to fashion an oblong steel spacer that you can slide inside the shoe to fill the 2mm gap on the screw side. Then when you tighten it up it will exert a uniform force along the spacer and hold the finder rigid.

How about one of those guy rope sliders that keep the poles up and tent taught..... That would be about the right size......

[ronl]

I used plastic cut to size, then glued them together to 

get the right thickness, it works ok for me. try different

things to cut them from to reach the right thickness

[marcusk]

thanks for all the advice folks - and yes Bambuko, well found on the pic

I will find a spacer as that seems the best solution. And I have an old tent in the garage so will try one of those guy rope sliders (good call If not I have plenty of odds and sods to make a shim.

Cheers all

Marcus

PS. The AA finder is *really* nice. Getting carried away looking at their 'scopes now as well...

[brantuk]

The AA finder itself is superb - like a small telescope in it's own right - just a shame about the guide rings which I don't get on too well with. Mine came as part of the AA115EDT package when they first came out. Very nice scopes indeed for the price imho.