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What weights for rear heavy refractors?


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Due to the convoluted focusing setup I have on my TMP 105/650 it is very rear heavy and as things stand I cannot get the DEC balanced as I cannot get the scope far enough forward.  I do have an ADM saddle mount on the way which will help but are there any solutions for adding some weight around the dew shield say?

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Any thoughts of adding a longer dovetail bar under the existing one?
Preferably one with the slot for the mounting screws [assuming the existing dovetail has some threaded holes in it] then you could 'slide' the rig up and down accordingly. I do this with my 're-modded' ETX105 when it is rear-end heavy.
Apologies... I don't have an image of it to show at the present time.

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2 minutes ago, Philip R said:

Any thoughts of adding a longer dovetail bar under the existing one?
Preferably one with the slot for the mounting screws [assuming the existing dovetail has some threaded holes in it] then you could 'slide' the rig up and down accordingly. I do this with my 're-modded' ETX105 when it is rear-end heavy.
Apologies... I don't have an image of it to show at the present time.

Yes - funny you should say this as it just occurred to me after I posted I could look at a longer dove tail.  That said some form of weights would likely be cheaper!.  Good quality Losmandy bars are pricey :).  It is probably the correct solution though...

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I had similar problem and longer dovetail with rings at the end and in the middle solved it:

DSC06694.thumb.JPG.7dfcaf101788cd891e71a9885cdc0a28.JPG

Dovetail (yellow) is mounted in the saddle at the rear part, and rings (green arrows) in the front part of the dovetail. 

Edited by drjolo
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I use a cheap skywatcher tube ring with  weight suspended from it, and just move the ring up and down as needed. The weight in this case is a very strong taxi magnet that I picked up on Ebay, to which I can add more weight if needed....:smiley:

IMG_2374.JPG

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I have an 8" dovetail on my 72ED and a 14" dovetail on my 90mm APO triplet to get the CG far enough back to use heavy 2" eyepieces and binoviewers with both.  I do have to be careful with the focuser knob's orientation, or it will either touch the dovetail or be behind it, depending on the scope.  I suppose dovetail flex would be an issue for imaging, but it's not an issue for visual observing.

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So here we have my spangly new Geoptik Losmandy dovetail. Works a great and I can now get the DEC balanced :)

I have also requisitioned the shorter one and re-fashioned it as a natty mounting point for my mini PC and PPBA...

20220111_145640.jpg

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