OPTEC Libra Dovetail system

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menardre
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OPTEC Libra Dovetail system

Unread post by menardre »

I have a Celestron CPC1100 SCT. I mount a Stellarvue SV90 on the CPC1100 as a finder scope, guider, and imager. I originally mounted the SV90 to the CPC1100 using rings, but I found that there is just too much 'play' in the rings. I really wanted something that would be more solid, stable, and easy to adjust. I use the SV90 for imaging when I need a wide field of view, so I really wanted the SV90 attachment to be very solid. I also use the SV90 as a guide scope when I am imaging with the CPC1100 so, again, I do not want any 'play' in the system.

I have bought focusers from OPTEC and talked to Jeff Dickerman at OPTEC several times so I am comfortable with their products. I bought their Libra Dovetail System. This is an Alt-Az dovetail adjusting system which allows easy adjustment for any Losmandy D- plate dovetail. All you do is attach the Libra to your telescope (CPC1100 in my case) using a Losmandy dovetail, and then mount the 'finder' scope (in my case the SV90) to the other side of the Libra also using a Losmandy dovetail. The Stellarvue SV90 came with clamshell rings that can easily be attached to the dovetail. The clamshell rings are very stable. Very easy, precise and secure. I find this gives me a very stable connection and is extremely easy to align.

You can see the 90mm refractor mounted to the CPC1100. The two silver knobs are used to adjust RA and DEC so that the SV90 is aligned perfectly with the CPC1100.
Roger
libra_alt-az_002_med.jpg
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CPC1100-SV90.jpg
CPC1100-SV90.jpg (1.89 MiB) Viewed 2721 times
Roger M.
Celestron CPC1100 EDGE, Stellarvue 130T refractor dual mounted on iOptron CEM120 on permanent pier mounted in Observatory. Imaging camera ZWO ASI2600 OSC, guide camera Lodestar or ZWO ASI290MM.
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Pete
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Re: OPTEC Libra Dovetail system

Unread post by Pete »

That's the most rigid piggyback setup I've seen Roger. My 80mm long tube is almost the length of the 14" tube. Extra weight is a huge concern. So I've 2 lightweight rings screwed directly to the telescope rear casting and front casting, with the 3# scope in the rings. Fit isn't the best and neither is rigidity. What does your mounting system weight?
Pete P.
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menardre
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Re: OPTEC Libra Dovetail system

Unread post by menardre »

Here are some of the mechanical specs for the Libra mounting system.

The overall length of the Libra is 12.25", with a dovetail width of 4". Overall height (when level) is 2.75" . Clamp width is 2.5", and the Clamp knobs are 3/4" stainless steel and knurled. The Alt/Az knurled knobs are 1.5" stainless steel.

Altitude adjustment range is 4 degrees (height delta of 0.75"), and Azimuth adjustment is 9 degrees (lateral movement of 1.15").

Weighing in at 3.5Kg (7.7 pounds), the Libra is specified as having a payload of 25 pounds, with the (nominal) top plate being 4" male Losmandy "D" style, and (nominal) bottom plate being 4" female Losmandy "D" style.

There is a good review of the Libra system on Cloudy Nights.

The Libra is not light. Another alternative is the ADM ALT/AZ aiming device (MAX Guider ALT/AZ) . I actually have one of these (I replaced it with the Libra). It does the same function and weighs only 3.7 pounds. It is capable of supporting 15 pounds. Adjustment of the ADM aiming device is slightly more difficult, but works fine.

Roger
Roger M.
Celestron CPC1100 EDGE, Stellarvue 130T refractor dual mounted on iOptron CEM120 on permanent pier mounted in Observatory. Imaging camera ZWO ASI2600 OSC, guide camera Lodestar or ZWO ASI290MM.
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