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Balance a very light refractor in declination?

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7 replies to this topic

#1 Blueox4

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Posted 28 February 2020 - 01:29 PM

Here’s a pic of my FL70-S on a Vixen SXD2. It’s extremely light and even with the finder scope and bracket off though on in the photo, is still focuser end heavy. I can’t move it up anymore in the saddle even if the rings were closer together because the focuser knobs hit the saddle. I was thinking of adding a single ring close to the dew shield to get the weight needed to balance in declination. Is there a better alternative?

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#2 Hesiod

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Posted 28 February 2020 - 01:38 PM

A longer dovetail bar.

With the FL55 the provided dovetail bars extends almost 15cm behind the focuser's knobs


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#3 WadeH237

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Posted 28 February 2020 - 01:53 PM

If it's that light, do you even need to worry about a slight imbalance?  It looks like you are set up for visual, so I suspect that everything would work find just as it sits.


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#4 Blueox4

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Posted 28 February 2020 - 01:57 PM

With a eyepiece added it’s more than a slight imbalance. It is light enough where this mount would overcome it I’m sure but I would rather try and balance it a bit better. Also, a longer dovetail still results in the focuser knobs hitting the saddle at the same point unless I elevate the rings with a spacer or new dovetail that is higher. 



#5 Jim R

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Posted 28 February 2020 - 02:26 PM

I like your idea of putting a ring near the dew shield.



#6 SkipW

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Posted 28 February 2020 - 02:30 PM

With a eyepiece added it’s more than a slight imbalance. It is light enough where this mount would overcome it I’m sure but I would rather try and balance it a bit better. Also, a longer dovetail still results in the focuser knobs hitting the saddle at the same point unless I elevate the rings with a spacer or new dovetail that is higher. 

Does it balance if you remove the finder? If that helps, replace it with something lighter.

 

You realistically have three choices:

  1. Reduce weight at the tail end.
  2. Add weight at the objective end.
  3. Live with it.


#7 rlillard

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Posted 28 February 2020 - 02:44 PM

I feel your pain.  I am less than a year into the hobby and my biggest frustration by a wide margin has been the what should be a simple act of bolting things together.  To be in this hobby you need to own a machine shop and a hardware store.

 

I offer two solutions. I've used both.  See pix.

 

1) a second dovetail plate and saddle

 

saddle_and_plate.jpg

 

mntd.jpg

 

2) Riser blocks.

 

risers.jpg

 

Regards,

Ray

 

Fixed images.

 


Edited by rlillard, 28 February 2020 - 03:16 PM.

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#8 Tom3

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Posted 28 February 2020 - 06:44 PM

I used this for a similar problem:"Amazon.com : Bullet Weights SCL14 1-Pound Roll Solid Core Lead Wire Fishing Line, 1/4-Inch : Lead Core And Wire Fishing Line : S"

 

Tom


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