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Fornax Lightrack II: Alternative counterbalance arm?

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6 replies to this topic

#1 900SL

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Posted 22 June 2021 - 01:48 AM

I recently bought a Fornax LT II.

I also have a SWSA 2i with the counterbalance arm and L bracket Dec head.

 

Rather then shell out $400+ for the Fornax counterbalance, I've been thinking about adapting the Sky Watcher SA counterbalance to work with the Fornax. 

 

My initial thinking was to get a 3/8" mount slim panorama head to fit to the Fornax. This would allow rotation of the counterbalance. These all seem to come with an Arca Swiss type clamp however. 

 

The SWSA counterbalance has a Vixen style wedge so I would need a Vixen clamp to hold it. It seems relatively straightforward to use a Vixen clamp on an Arca plate to connect to the panorama head. 

 

Has anybody out there used a SW counterbalance arm with a Fornax LT II, and if so, how did you manage the interface?



#2 900SL

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Posted 23 June 2021 - 04:53 AM

OK think I might have a simple solution:

 

TS optics pano head to mount to Fornax LT thread:

 

panoramakopf-1000.jpg

 

 

 

 

And this large Vixen clamp with 1/4" mount to fit to the Panorama base:

 

prismenklemme-dx-gewinde-1000.jpg



#3 nyx

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Posted 23 June 2021 - 07:09 AM

Another option:

 

https://lacerta-optics.com/Avanthead#m

https://lacerta-optics.com/AvantLT#m

 

Yes, you do get the wedge (which you may not need) along with the head, but oh well. Keep in mind, maximum payload is 3kg.


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#4 900SL

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Posted 14 July 2021 - 06:02 AM

OK this works just fine. Can adjust RA and dec and its very solid. I modified the TS optics pano head and removed the top section to reduce the overall height (and therefore eccentric moment). Counterweight not shown. 

 

 

 

 

Attached Thumbnails

  • post-366739-0-19978200-1626259252_thumb.jpg

Edited by 900SL, 14 July 2021 - 06:03 AM.

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#5 Hesiod

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Posted 14 July 2021 - 06:20 AM

Nice!
Another option, in the case you would want higher payload, is to get a small alt/az head (e.g. TS AZT6, Berlebach Castor, Teleoptik MiniGiro) and the counterweight shaft
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#6 900SL

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Posted 23 July 2021 - 04:42 PM

Nice!
Another option, in the case you would want higher payload, is to get a small alt/az head (e.g. TS AZT6, Berlebach Castor, Teleoptik MiniGiro) and the counterweight shaft

I have the SWSA counterweight, so its good to go. Tried it last weekend, no issues.

 

I'm never one to leave something alone so I'm trying to figure out how to reduce the offset to the dec mount and get it closer to the central axis to reduce the weight offset 



#7 900SL

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Posted 27 July 2021 - 03:03 AM

Sorted out the 110 minute limit. Smallrig magic arm. Fully articulated rose jointed arm locks the counterbalance in position with a single wingnut at the center.

Release the panorama head clamp and reset the Fornax arm. Holds the camera on target and dithers a few pixels. 

 

Tighten the panoclamp, release the Magic Arm, start tracking again

Attached Thumbnails

  • 1627372817380.jpg

Edited by 900SL, 27 July 2021 - 03:08 AM.



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