Re: [ATM] plans to build an adjustable observing chair - cheap!

[Mark Holm <mdholm@telerama.com>]

James Crombie wrote:

> http://www.umce.ca/astroclubnb/chairjim.htm.     Also available in the 

It's a nice looking chair, but I have a few nits:

Where does one find wood that is actually 1 inch by 2 inches without
having to rip larger stock down?  For those of us without a suitable
power saw, it is a bit of a drawback.

It is a bit complex compared to some other designs I have seen.  I think
the parts count can be noticeably smaller.

It has four ground contact points.  That means it will always be tippy
(unless it has low enough torsional stiffness that it bends till all
four points make contact or you set up in mud).


Here is one version of the "Denver" observers chair:
http://www.schlatter.org/Dad/Astronomy/chair.htm

No long rip cuts on this one.  The long bits are all stock size.

I'd go with varnish rather than paint, because all the pigment in paint
adds noticeable weight.  I'd also choose the cheapest stud grade 2x4 for
the simple reason that they are less dense than better grades.  You can
definitely notice the weight difference.  Use southern yellow pine if
you need a workout.  Use fluffy fir if you'd rather skip the workout.
Unless your personal gravitational attraction is really high, the cheap
wood should be strong enough.  Even if you are "highly attractive", only
the front upright and perhaps the rails under the seat, need to be good
wood.  The rest of the structure won't be highly loaded unless two or
three of your "attractive" friends sit on your lap.

This page has two chairs, a Denver and another style commercially
available: http://mpgf.net/buildit8.htm

You can buy plans, or a kit for Jim Fly's "CatsPerch", or you can buy a
finished chair:  http://www.catseyecollimation.com/cperch1.html

If you are too cheap to buy the plans, the pictures on the web site are
good enough to draw up your own plans from.

Here is a modified Denver chair:
http://www.tulsawalk.com/projects/denverobserverchair/index.html

This page has pics of four different chairs:
http://www.sctscopes.net/SCT_Tips/Items_You_Can_Make/An_Observer_s_Seat/an_observer_s_seat.html

Another Denver chair modification:
http://www.augustana.edu/users/psvincent/Denver.htm

This one has the front "foot board" rotatable for more compact knock
down: http://dbpeckham.com/Telescope/Chair/Index.htm

This one slots the foot to make folding it simpler:
http://dgilbank.freeownhost.com/chair.html


-- 
Mark Holm
mdholm@telerama.com

_______________________________________________
ATM mailing list http://www.atmlist.net/