Roof observatory

Hi all,

I'm planning a roof observatory. Made a post a couple of days ago but
have more info now. And questions.

The best bang for the buck seems to be the 16" Dob. for around $1200.
Probably a Meade.

Big questions a

Can go-to electronics be purchased for this scope?
Do they track very well?
Will there be vibration through the house?
Do I have to mount a concrete beam down 3 floors, through the basement,
and into the ground 4'.

Thanks for the help,

Lou

Most (I repeat, "most") GOTO electronics for big Dobs do not track... they
are more accurately described as "PUSH-TO."

You might want to invest in an equatorial tracking platform.

www.johnsonian.com

http://astronomy-mall.com/regular/pr.../eq_platforms/



"Lou" wrote in message
t...
Hi all,

I'm planning a roof observatory. Made a post a couple of days ago but
have more info now. And questions.

The best bang for the buck seems to be the 16" Dob. for around $1200.
Probably a Meade.

Big questions a

Can go-to electronics be purchased for this scope?
Do they track very well?
Will there be vibration through the house?
Do I have to mount a concrete beam down 3 floors, through the basement,
and into the ground 4'.

Thanks for the help,

Lou

Lou wrote in news:1lpIb.9124$Vv2.4041428
@news1.news.adelphia.net:

Hi all,

I'm planning a roof observatory. Made a post a couple of days ago but
have more info now. And questions.

The best bang for the buck seems to be the 16" Dob. for around $1200.
Probably a Meade.

Big questions a

Can go-to electronics be purchased for this scope?
Do they track very well?
Will there be vibration through the house?
Do I have to mount a concrete beam down 3 floors, through the basement,
and into the ground 4'.

Thanks for the help,

Lou


Another couple of options apart from what was suggested by Kilolani could
the the RXdesigns Servocat/Stellarcat, which works either ALT/AZ or
equatorial. It is designed to work with Obsession Dob's and similar
clones but might be able to be adapted to the Meade. It will cost more
than the scope though.

http://www.stellarcat.biz/

Another possibility is the DIY goto system described on Mel Bartel's web
site:

http://www.bbastrodesigns.com/cot/cot.html

Klazmon.

On Tue, 30 Dec 2003 19:09:17 -0600, Lou wrote
(in message ):

From: Lou
Newsgroups: alt.astronomy

Hi all,

I'm planning a roof observatory. Made a post a couple of days ago but have
more info now. And questions.

The best bang for the buck seems to be the 16" Dob. for around $1200.
Probably a Meade.

Big questions a

Can go-to electronics be purchased for this scope? Do they track very well?
Will there be vibration through the house? Do I have to mount a concrete
beam down 3 floors, through the basement, and into the ground 4'.

If you have a pier going through three floors you will have to have it more
than a mere 4 feet into the ground. Three floors are going to be close to 24
feet from basement to top floor plus at least another 3 to 4 feet above that
to mount on, so you have one heck of a lever above ground, and you have to
isolate it from the building or it will pick up vibrations from it. Even with
enough underground it will still hold vibrations from just moving the scope
unless you encase it in a lot of concrete.

My piers have always been as much underground as above, so if it has 4 feet
above it has at least 4 feet below, with the bottom 3 feet buried in several
hundred pounds of concrete.

To build a pier through a building as you are wanting to do I think it will
end up costing far too much and will still be too flexible. And it will
almost certainly leak rain.
--
Harry F. Leopold
aa #2076
AA/Vet #4
The Prints of Darkness

The Internet is full, we can not accept any more posts until further
notice. Thank you. - Kalinka Djnepropetrovska

"Lou" wrote in message
t...
Hi all,

I'm planning a roof observatory. Made a post a couple of days ago but
have more info now. And questions.

The best bang for the buck seems to be the 16" Dob. for around $1200.
Probably a Meade.

Big questions a

Can go-to electronics be purchased for this scope?
Do they track very well?
Will there be vibration through the house?
Do I have to mount a concrete beam down 3 floors, through the basement,
and into the ground 4'.

Thanks for the help,

Lou
I think you need to do a _lot_ more thinking.
The first thing, is "do you understand what a 'Dobsonian' is"?. A Dobsonian,
is a Newtonian telescope on a Dobson mount. The Dobson mount is designed to
be cheap, for 'point and look' observation, and easy to make without much
tooling, but is _not_ designed for electronics, or tracking. It is possible
to make a Dobsonian 'track', by standing the entire scope on a 'barn door'
tracking base, or to add DRO's to the axes, to give a 'readout' of the
current pointing position, but the result becomes a lot more expensive. A
Dob, does not 'track' at all, without such upgrades. Full 'goto', is not
really practical on such a mount.
If you want 'goto', then think again about your purchase options. Reckon on
spending as much on the mount, as on the OTA, if performance is going to be
reasonable.
If you want a rigid mounting, you need a lot more than a simple 'beam'.
Think in terms of how rigid a 3 foot length of 4" timer in, yet how easily
the top of a flagpole moves at the slightest touch. To get reasonable
rigidity, for the sort of height involved, you will be looking at putting
something like an 18" column, (for 3 stories), or something like a 24"
column if the basement is 'extra' (you say 3 stories + basement). These are
_minimum_ sizes. Then this column will have to be boxed, so that no part of
the buildings structure touches it, and have something like a foam rubber
'gasket' at the top. Below ground, the amount of foundation needed will
depend on the subsoil, but going down perhaps 6 feet, for an area three or
four yards square, would be 'typical'. If your soil is soft, you would need
to go wider or deeper. If you are lucky, and there is a solid layer of
something like alluvial gravel, you might be OK with a shallower base.
Realistically, if you are happy with 'point and look', then go with the Dob.
They are great value for money. However if you are trying to build an
observatory that can be used semi automatically, consider a GEM instead, and
a slightly smaller OTA (unless your budget is massive).

Best Wishes