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Adjustable Astronomy Observation Chair

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Project by Smay posted 06-04-2011 08:15 PM 5077 views 19 times favorited 10 comments Add to Favorites Watch

This is one of my first woodworking projects, so there are a few mistakes and I definitely learned many ways to not do things. Overall I’m pretty happy with how it came out.

Background
I love going out at night and looking through my Dobsonian telescope, but depending on where I’ve got it pointed, the height of the eyepiece can be anywhere from ~2-4 feet off the ground. It gets pretty uncomfortable stooping down or kneeling to look through it, so I decided to build an adjustable observation chair.

Functionality
The seat height is adjustable from 10” at its lowest setting to 3’ at the highest setting. The seat fits around the frame, and is held in place by a 1” oak dowel which fits into round grooves in the backrest. To adjust the height, I just tip the front of the chair up and slide it along the backrest.

To keep the back support leg from slipping, I added an adjustable bracer which is held in place by a 1/2” dowel. The back support and bracer pivot on dowels, and the chair frame collapses (almost) flat for storage/transport. I haven’t tested the max weight limit, but I often invite friends out to observe and the heaviest person who has used it so far weighs about 225lbs—the chair seems to have held up fine.

Construction/Materials
The chair is made from 3/4” red oak, and everything is held together with glue and (red oak) dowels. The only place I used screws was to hold the wide foot to the main chair frame (2 screws). The finish is a 3 coats of clear polyurethane.





10 comments so far

View lew's profile

lew

11343 posts in 3221 days


#1 posted 06-04-2011 08:49 PM

Cool!

I know nothing about astronomy so this may be a stupid question, but do you sit facing the up-right or with your back against it?

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Smay's profile

Smay

8 posts in 2016 days


#2 posted 06-04-2011 08:57 PM

You sit with your back against it. Generally I don’t actually use the back at all, since I’m leaning forward to look into the eyepiece. I found this picture on another website which gives a good idea of how it works

View lew's profile

lew

11343 posts in 3221 days


#3 posted 06-04-2011 09:56 PM

Thanks!!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View BritBoxmaker's profile

BritBoxmaker

4607 posts in 2502 days


#4 posted 06-04-2011 11:13 PM

I am a (very) amateur astronomer, using a pair of 7×50mm binoculars but even I can appreciate just how useful this can be to my better equipped comrades. Great post, beautifully made, thanks. Oh and welcome to LJ’s, have fun.

-- Martyn -- Boxologist, Pattern Juggler and Candyman of the visually challenging. http://www.theartofboxes.com

View Dennisgrosen's profile

Dennisgrosen

10850 posts in 2581 days


#5 posted 06-04-2011 11:40 PM

smart , well done and welcome to L J , enjoy and have fun :-)
thankĀ“s for sharing

Dennis

View yrob's profile

yrob

340 posts in 3118 days


#6 posted 06-05-2011 12:20 AM

Great Chair, nice design. How heavy is it ? It looks like it would be nicely portable and easy to carry to the observation site.

-- Yves

View Smay's profile

Smay

8 posts in 2016 days


#7 posted 06-05-2011 12:44 AM

yrob, it weighs about 18 pounds (8kg). It could be made a lot lighter by having less wood support between the back legs or by cutting out some of the seat back, since neither of those pieces is a major structural component. I prefer the ‘more wood’ look myself though :)

View Bluepine38's profile

Bluepine38

3341 posts in 2551 days


#8 posted 06-05-2011 06:04 PM

Welcome to Lumberjocks. Excellent first project, I also like the more wood look and extra strength it gives
the project, not that I have ever broken anything I made too weak, LOL. Thank you for sharing and I hope
you enjoy your woodworking and stargazing for many years.

-- As ever, Gus-the 77 yr young apprentice carpenter

View yrob's profile

yrob

340 posts in 3118 days


#9 posted 06-05-2011 06:59 PM

You know, that chair would sell at stargazing conventions. People are always looking for good comfortable ways to observe.

-- Yves

View RexMcKinnon's profile

RexMcKinnon

2593 posts in 2661 days


#10 posted 06-07-2011 08:36 PM

Great chair. I don’t think you need to ba an astronomer to use it though. 3 or 4 of these could easily fit in a small space and be taken out when needed. I am sure they would be a great conversation piece.

-- If all you have is a hammer, everything looks like a nail!

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