SEC: UNCLASSIFIED:-ATM Smidth-Newton dobson problems

[Andrew.Martyn@defence.gov.au]

As you say short tubes do not provide much leverage particularly in azimuth
when the scope is pointing close to vertical. An easy way to get more
leverage is to attach a lever to the rocker box (for azimuth leverage only)
or the scope itself for increased leverage on both axis.





Goran Hosinsky <ea8yu@arrl.net>@shore.net on 30/10/2003 07:44:24

Please respond to Goran Hosinsky <ea8yu@arrl.net>

Sent by:    owner-atm@shore.net


To:    atm@shore.net
cc:

Subject:    ATM Smidth-Newton dobson problems

Hello,
I have built a dobson mounting for my 10" Meade LXD55.
http://www.hierbabuena.com/stuga/dobson.jpg
but I am not really satisfied, to much "sticking" in elevation.

The telescope is short, 93 cm, and balanced nearly at the mid
point of the tube. This makes for a high rocker box, difficult
to transport in a small European car, and no real leverage
for pushing the telescope. This might be the main problem.
In fact, when I use it, I find myself gripping the mirror cell
with my right hand to move the telescope.

I could move the present tube clamping structure down to the
mirror end of the tube which would give me a 70 cm leverage,
but I would need 4-5 kg extra at the mirror end, and I do
not see a good way to attach this.

Any ideas what I could do to get a better dobson? Should I
use smaller elevation circles, I am using 34 cm dia after
reading somewhere that you should strive to get the same
diameter on the bearings in Az and El.

Grateful for any ideas.
Saludos
Goran   La Palma   28 deg 41' N   17deg 57' W