Observing chair mod to prevent slipping

[Graman]

Hi all,

I recently acquired a used astro observing chair (Skywatcher brand?). It is infinitely adjustable and works on a friction-based system. While it is sturdy enough when you are actually sitting on it, there is a risk that it can slip and fall to the bottom when you lift it up to adjust it or accidently bang against it. This seems to be a common issue with all such friction-based chairs (incl. Starbound, Omegon etc.) and this issue is extensively discussed in forums on CN, SGL etc.

In order to address this safety issue, I have come up with a cheap and easy mod/hack that seems to work reasonably well.

I purchased a pair of cheap 4x4/ATV headlight brackets on Amazon (~$15).
https://www.amazon.com.au/SUZCO-Mounting-Brackets-Horizontal-Heavy-duty/dp/B07ZHZ1VMP/ref=sr_1_2?crid=3UESX54FP0N8P&keywords=atv+utv+light+bar+mounts+m ounting+bracket+mini+bar+clamp+kits&qid=1660885268&sprefix=atv+bracket%2Caps%2C854&sr=8-2

I then got a couple of extension springs from Bunnings (approx. 12 cm long). I screwed the springs to the underside of the seat and connected to them to the headlight brackets using some bolts & washers and viola – job done!

The tension in the spring brings the seat-down to prevent slipping. For smaller adjustments (moving the seat ~20 cm) you can leave the spring stretched and it works just fine. For larger adjustments, i.e. where you are moving the seat from the top to the bottom, you will need to consciously move the brackets along with the seat. But this is easily done. Be sure to use a slightly larger than necessary rubber shim so the headlight bracket can move freely up and down the tube (Note: I used the 1.5 inch shim for the 1 inch wide tube on my seat and it works great)

I am attaching some pictures to illustrate what I have done. Hopefully this mod/hack is useful and prevents future injuries from seat slippage in the astronomy community!

Any questions/clarifications, pls feel free to ask.

Clear skies and stay safe,
GR

[BadWolf]

I have the same SW astro chair and the same problem. Thanks for the info. I will try the same modification over the next few days.

[Graman]

Cool, let me know how you go! I am thinking of swapping to slightly shorter springs to increase the tension further. Haven't had the time to swing by Bunnings yet given work commitments.

Perhaps get a couple of different lengths to test what works best. It is a matter of trial and error...

All the best!

[BadWolf]

Will do. Probably be later next week before I start, but will let you know. I will begin with shorter springs to increase tension.

[BadWolf]

Posting the following in case there is anybody else out there with a Skywatcher observing chair. Graman started this thread and devised a clever solution to modify the chair and make it less “lethal”. I have done the modification on my chair.
This type of observing chair seems to have a design fault, and relies on a seat that uses a pair of friction rollers to adjust and hold the sitting height. The problem is that the seat can suddenly perform a “posterior vertical displacement flip” resulting in one’s rear end hitting ground zero – possibly painful.


To work properly and safely, the sliding seat requires a force to be continually applied to the front edge. That force then prevents the seat from losing traction and dropping down the support tubes, hitting a dead stop at nearly ground level. The chair originally had a long spring attached to the front of the seat and to the foot of the chair. When the chair height was adjusted, spring tension kept a force on the front of the seat holding it in place. The original spring setup was pretty poorly designed and eventually became too stretched and inadequate to do the job.



I have modified my chair, and the attached photo shows the modification that Graman devised and it works well. Two vehicle spotlight clamps with heavy rubber bushings are secured to the outside tubes, and then two extension springs are attached from the front edge of the seat to the clamps. The seat and clamps are then moved up or down the tubes with the springs providing tension to hold the seat friction rollers in place. Probably not too many of these chairs out there, but thought I would post this in case anyone else has one.



The springs are from Bunnings and have the designation C-219 size – about $4.50 each. The clamps are via Amazon (search for SUZCO Spotlight clamps) and cost $15.95 for the pair which includes assorted rubber bushings and four clamp bolts.


Pics herewith


https://i.imgur.com/jeQT9Ejl.jpg

https://i.imgur.com/8QgDWS4l.jpg

[Graman]

Glad the mod worked for you too Stewart:thumbsup:

Thanks for the detailed post and pics…

GR