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Will this dovetail work?

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#1 Cheap Scope Jeff

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Posted 26 January 2010 - 09:36 PM

I have recently gotten a Stellarvue AT1010N and a CG-5 mount :jump: The mount has no dovetail bar and I am ready to buy one but I have no way of measuring the dstance between the holes on the scope's mounting ring :confused: This very nice photo from Agena AstroProducts shows the exact distance between the holes as: 35mm/1.38in.
link to image
If I had a ruler, I would know... I would really appreciate it if someone could give me an answer before I buy it.

Clear skies,
Jeff

#2 Billydee

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Posted 26 January 2010 - 11:17 PM

Jeff,

Suggest that you go down to:

Harbor Freight Tools
Roanoke Salem Shopping Center
4142 Melrose Ave STE7
Roanoke VA 24017

Purchase a 6 inch Digital Caliper (list price $29.95, usually on sale for $9.95 with flier ticket, item number 47257). It reads out in inches and with the push of a button it reads out in metric mms. You can measure inside or outside holes, bolts, screws or anything your heart desires. Comes with an extra battery and a great LCD readout. Reason for this suggestion, this will not be the last measurement you will need to take on your scope/mount. By the way, Harbor Freight Tools is an adult candy shop and you will really enjoy all the junk they carry (and I mean that in a nice way). Plan to be there at least one hour the first time.

Luck, Bill

#3 gnowellsct

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Posted 26 January 2010 - 11:35 PM

Vixen style dovetail fits the CG5 hence the use of the term "clone." Greg N

#4 Eddgie

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Posted 27 January 2010 - 08:33 AM

Be careful. This dovetail may not work without modification.

If your mount is a CG5 ASGT, the plastic housing for the DEC motor comes VERY close to the base of the saddle. Notice how the Vixen dovetail has tabs that are actually lower than the bottom of the "V" part of the dovetail. The plastic motor housing can intefere with the tabs when you put it into the saddle.

Now this inteference can vary some becasue these housings somtimes sit a little higher or lower depending on the individual mount, but I have owned two of these mounts and in both cases, the Vixen style dovetail like you show in the picture hit the Dec motor housing when it was installed on the mount. You can make it work by pressing it into the saddle causing the housing to deflect, but I worried about cracking the housing.

I was able to modify one dovetail by taking a heavy metal rasp and filing off the corner of the bottom of the tab where it intefered with the dec motor cover. It only took about 10 minutes. The places where you need to file or grind are where the vertical lines at the end of the 89mm dimension line at the bottom of the dovetail are.

Otherwise, I am afraid that I can't answer your question if the dovetail will fit the scope. It seems like I had a Stellarvue 80 Achromst once with this clamshell and used a standard Vixen dovtail on it, but that was 5 years ago, and honestly I cannot remember exactly. I am pretty sure it worked though. Often these things are kind of standardized.

Or course Stellarvue may be able to tell you too.

#5 mclewis1

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Posted 27 January 2010 - 10:02 AM

I have recently gotten a Stellarvue AT1010N and a CG-5 mount :jump: The mount has no dovetail bar and I am ready to buy one but I have no way of measuring the dstance between the holes on the scope's mounting ring :confused: This very nice photo from Agena AstroProducts shows the exact distance between the holes as: 35mm/1.38in.
link to image
If I had a ruler, I would know... I would really appreciate it if someone could give me an answer before I buy it.Clear skies,Jeff

Jeff,

First of all while the spacing of the bolt holes is 35mm on that particular dovetail bar you don't mount your rings in that orientation (length ways). Your rings would mount using the center bolt to the holes in the bar.

That particular bar is not one of my favourites, sure it's inexpensive but it's not very robust and has some other peculiarities like Eddgie mentioned. Just about any Vixen/CG-5 dovetail will work for you, all you really need to be concerned about is having room for the bolt heads. Countersunk holes or a bar that has a groove or gap in it is what you're looking for. The spacing between the bolt holes isn't that important as you can slide the rings around a bit on your scope. If you don't want to deal with all this I'd have a chat with Stellarvue who offer a variety of bars about one that will bolt right up for your particular setup.






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