Saturday 24 August 2013

Astronomy Observation Chair

As the nights get longer at my latitude (North West England) thoughts can now go back to observing the universe. Last year my wife bought me a brilliant present of a 8" reflecting telescope for a significant birthday.
I have been using it whenever there were clear skies last year and during the winter of this year.
One of the problems I found though was I just couldn't find a chair that was comfortable enough to cope with the varying angles possible with the telescope. When it was pointing upwards I had to stand, when it was pointing at around 45 degrees I had difficulty sitting or standing. When it was a low angles I just couldn't get a chair or stool down low enough.

I saw an article in last August's (2012) Sky At Night Magazine about building a suitable chair. Unfortunately the iPad version of the magazine didn't contain the plans. Undeterred I decided to google it. I mean everything is on the internet - right?
After lots and lots of searching I found some individuals who had setup an internet group for it.
So I joined this Yahoo group called telescope_observing_chair at this address http://tech.groups.yahoo.com/group/telescope_observing_chair/

Elly laughed when I told her about this group. "That's what I love about you - if you want to find something you'll research it until you find it." she said.

So I downloaded a set of plans called Shawn's Observing Chair based upon a commercial product called a Cats Perch Chair. There were a few mistakes in the plans but I decided to build a prototype from 3/4" plywood. I also had a snapped broom handle that would become the pivot points.

It took about 8 hours of work but joy of joys it actually works. I used biscuits and Titebond II glue to make the two verticals. These are called the back rest and rear leg.
It has adjustments to the seat every 2 1/2" all the way from the bottom to the top (58") so you can now get comfortable. When used on the higher settings there is also a footrest. It is surprising comfortable. I made the seat from some Western Red Cedar.

Here are a few photos.
Folded it hangs on a hook
on the wall in the shop

I modified it so any loose bits
could be secured to the body

The rear leg folds out and
I added a cross brace
secured with some hand bolts

I made the stabiliser foot
detachable. Again it is secured
with a single hand bolt

The seat is placed into position
and the rear dowel (ex-broom handle)
is pushed into place.
You can adjust the seat up or down without
removing the dowel by tilting the seat upwards from the
front and moving it to the desired position

Now I will be trying it out over the next few weeks to see what the pros and cons of it are. That way I can work out what modifications need doing before I build one (or two) in hardwood.

Happy woodworking or star gazing.


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