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Dovetail bar or tube rings?


Derry

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Hi All,


Here is my first question as a newcomer to EMS (but nt a newcomer to astronomy).


 


I have a Meade LX10 8" SCT and have just purchased a Sky Watcher HEQ5 Pro mount and tripod, with a view to deforking the OTA and putting it on the new mount.  I also bought a dovetail bar to fit the Meade OTA (the supplied one is far too short).  So far so good.


 


The ADM dovetail bar is made of high grade aluminium and has two shiny steel bolts which, I'm told, will happily hold my OTA and any accessories I care to hang on it.  Now, whilst I'm sure they will hold the weight, I'm worried that the tube will flex as I point it at different parts of the sky.  I've seen plenty of articles about deforking a Meade OTA, but very few talk about remounting it on the new mount.


 


Note: I don't know how much the OTA weighs but, while I was in a spending mood, I also bought a Crayford Moonlite focuser and f/r flange which weigh 1.4 Kg on their own.  Camera and eyepiece could bring this to over 2 Kg.


 


So, my question is: will the dovetail bar alone do the trick, or do I need to purchase tube rings.  (And, if so, can anybody recommend a type and/or or supplier?)


 


Derry


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I think that adding tube rings would just add weight and raise the the centre of gravity of the ota slightly higher than on the dovetail bar alone. The ADM bars are excellent and made for the job, and should not cause any flexure. The 8" ota only weighs 7kg without accessories, which is less than many 5" refractors. I'd say that the dovetail alone would have advantages over tube rings and would probably look neater.

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Yep I agree only use a dovetail.


 


They make special dovetail bars with radius blocks to mount SCT's. 


 


I would get one of them.


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Thanks for the swift replies.  That's given me the confidence I needed to go ahead and defork the OTA.  I didn't want to leave myself with a non-working scope for too long.  Give me a day or two and I'll let you know how I get on.


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I fitted the Meade OTA to the HEQ5 mount last night.  It seems firm enough, even with the heavy focuser and flange.  However, mounting the thing is quite fiddly and it would be frighteningly easy to drop the tube in the process.  I plan to practice a few times before attempting this in the dark and cold.  With the weather forecast as it is, I don't think I'll miss much.


 


Thanks again for advice.


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Hi Derry, an Sct with full length dovetail is fine, Ive used an 11" that way with no problems. Tube rings are a little more versatile but will add weight. I know what you mean about handling, i find the handles celestron fit to their sct cells a great help. If you went the tube ring way you could always fit a handle to the rings, thats what Ive done with my mak180.

Edited by philjay
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