Re: ATM 10" Flex Mirror

["Jim Miller" <jim@jtmiller.com>]

Some of my observations of other peoples scope setups which led to my
design:

Setup time must realistically include cooldown to useful stable temp which
for tubes exceeds trusses, sometimes significantly.

Paired truss tubes are much easier to assemble than individual truss tubes,
1/2 the wavy things to wrestle into sockets.

Collimation can occur within the cooldown time and why wouldn't you take a
quick check anyway if you're serious about what you're trying to see?

Portability in an ordinary car is important to me.

have fun!

jtm

----- Original Message -----
From: "mike coslo" <mjc5@psu.edu>
To: <atm@shore.net>
Sent: Friday, October 19, 2001 5:36 AM
Subject: Re: ATM 10" Flex Mirror




Dennis Woos wrote:

> couple of issues.  1)  Should we build with sonotube, or move to a new
> (for us) truss-tube design?

Oh,no, this is going to be a religious war! ;^)

My rule of thumb is less than 12 inches, a tube scope is probably better
over 12, trusses become the better option. That being said, I have a 12
inch tube scope, and a 6.5 inch truss scope. Go figure! 8^)

Tube scopes usually need less colliimation, and usually take less time
to set up. If you are using a EQ mount, the tube is easier to attach to
the tube than to trusses. In fact, truss OTA's on EQ mounts (horseshoe
excepted) are more tube than truss.

Truss's tear down and ship in smaller space than tubes. So you gan get a
huge scope in a Yugo. Also they have a sort of panache that tubes don't.

Now for my personal experience with the two designs:

My 12.5 tube is a joy to set up. In fact, if I have a second person with
me, I an pull it off my pickup truck fully assembled. So setup time is
0.00 seconds. Otherwise I have to take it in two stages, and it takes 5
seconds.

My 6.5 inch two tube truss. This one takes a bit longer to set up,
although sometimes I'll put it in the pickup assembled. For a complete
setup, it takes around 10 minutes or so. This is without trying to prove
how fast I can set it up.

The truss obviously needs collimated, but in practice, they both do.

So my final thoughts are that unless you want the "cool"" factor of the
truss, a ten inch scope is a bit more practical in t tube configuration


> say more.  Shadow transits on Jupiter are easy, and the GRS is visible
> but washed out.  In fact, all color on Jupiter is kind of washed out. at
> least compared to what we expected.  However, we recently looked at a
> CCD image taken through a Zeiss 6" f/15, and it was very similar to what
> we see.  Anyway, we are happy with the scope, and are looking forward to
> pulling the 10"!

Welcome to the world of unenhanced images! Jupiter is mostly a silvery
sort of color. On a good night, you can see some pink in the GRS, but it
has been pretty pale the past few years.