Re: ATM [Fwd: RCA: Astro Class wrapup (LONG)] (fwd)

[Fred Floberg <atm@cyphyn.nai.net>]

Nils Olof Carlin <nilsolof.carlin@swipnet.se> on best placement of focuser
around circumferance of OTA:

>    I am "right-eyed" (and right-handed) and like to have my scopes to my
> right. However, I have tried both but I wouldn´t put the focuser either on
> top or side of the tube (in the horizontal position). For comfortable
> viewing I want it at 45 degrees, then I can sit comfortably when observing
> at any altitude. With 13.1 in. I use an adjustable height seat, with 6 or
> 10 in. I can use a stool or chair of fixed height.
> 
> With a really huge Dob, focuser at the side may make sense, but how do you
> people with medium-size dobs and focuser at the side manage to view at low
> altitude???

Because my OTA is made of 3/8" plywood, and because the tube extends 12"
beyond the focuser axis, the balance of the scope is such that the altitude
bearings are fairly close to halfway up the tube. This necessitates having
a very tall rocker box (about 2' 6" or so). That height, along with the
height of the azimuth boards (3/4" each) and leveling feet (2"), the focuser
when the OTA is horizontal is nearly 3' off the ground. Viewing at that height
is pretty easy.

Don't know what I'll do when I rearrange things to have the balance point
closer to the primary mirror end of the tube and thus have a more squat
rocker box.

As to which side, left or right, the focuser is best placed, I can lift the
OTA out of the rocker and roll it over to put the focuser on either side.
I've used it both ways without any problems. My "master eye" is my left
eye, but I generally use my right eye when viewing because of poor eyesight
in my left eye, and I'm left handed.

Fred

-- 
F.C. Floberg - N1GVA
Latitude 41.4498
Longitude -72.8194