Saturday, April 14, 2012

The Telescope in the Store: Is It Good Enough?

Before you buy, can you:

A. Get a specific visible object in view? (Bright star, planet...anything harder to find than the Moon.)

B. Keep it in view for fifteen minutes or more without heroic efforts?

c. View it for that long or longer without an aching back, neck, or other physical discomfort?

D. View comfortably both standing and sitting?

What's needed:

A. Good low power or Telrad or red dot/ring finder, stable mount, working mount movement locks.

B. Good drive or slow motion controls.

C. Eyepiece at a good height and angle, good eye relief. May require an eyepiece diagonal, tube rotator rings, or other ways of bringing the view to where your body puts your eyes.

D. Suitably adjustable tripod, stand, and other accommodations as for C.

Note: Don't go by what store clerks or product literature tell you should work or should be possible. I have had many scopes with locking screws that don't lock, slow motion controls that are too coarse or sticky or difficult to adjust to be useful. Finders that don't let you see enough of the sky to find anything, wobbly mounts, diagonals that you can't use because the focuser won't adjust enough to focus with them in--all delivered with the telescope!

Don't blame yourself! If it's not working, it's not your fault!

Any properly designed product should do what it claims with the ability of an ordinary person of average ability. Contact the manufacturer or seller to make sure you're not just misunderstanding something, but if you're using the product as intended and not getting results--it's not a good product. Don't fall into the trap of thinking it's you.

Sunday, April 8, 2012

Telescope Portability: Questions to Ask

When considering a telescope, chances are your early telescopes will have to be moved around to be used. In other words, you're probably not going to start right out with a telescope that's installed in an observatory that never gets moved someplace else to be moved.

Here are some questions to consider:

Can I move this telescope or its parts by myself, or only at times when I can expect to have the necessary help both before and after observing?

Where will I store my telescope between observing sessions? Is it a safe place, with at least enough temperature control and protection from the elements that I won't end up with a damaged telescope?

How will I actually move it? All as a piece, or taken apart?

Can I move each of the pieces safely and comfortably?

If planning to transport it by car, will it fit in the car? Will the people and other things I want to take along fit with it? Will it be secured safely for the passengers and to be moved without damaging it?

Can I take it apart and put it back together in poor light or at night? What if I drop a screw or other part? Can I safely handle it while tired?

What do I do if the weather suddenly turns bad while it's out?

How many trips between car and observing site will it take to get everything I need out or back?

How will I store the accessories, tools, and other items I need during transport? And during the observing session?

You probably won't be able to or need to answer all these questions specifically, but they need to be considered when buying a telescope.

Here are a couple of pictures to consider:
Two Dobson Telescopes, six inch and eight inch,

This shows two telescopes I regularly pack in my car for star parties. In fact, I usually have one additional telescope in the back of my "compact station wagon" with them.

These two telescopes are Dobsonians, both have tubes about 56" long. One is an 8" scope with a 10" diameter tube, the other is a 6" with an 8" diameter tube. The bases are about 20" wide and deep and about 26" tall. The opening in the base is wide enough to accept the end of one or both telescope tubes.

They pack in the car on top of a cardboard box that has had semicircular cutouts taken out of each end. This forms a cradle for the bottom tube (the larger one). Then a piece of Sonotube is inserted into the "ear" of that tube (the bearing ring), and the smaller tube goes on top of that. They are slid into the car, with one half the seat back at the rear of the car folded down to make room. In the front a bungie cord holds the tube ends from moving side to side and secures them to the car. They fronts of the tubes go up against a footstool in back of the driver's seat. One of the rocker boxes (the wooden base) goes around the back end of the two tubes in the back of the car. The other is placed against the passenger side read seat back, and the accessory boxes are placed inside it.

Moving these scopes is really easy. There is the rocker box, the tube assembly, and an accessory case. When we're doing public star parties (showing the sky to people through our scopes) we bring two folding stepladders. That's four parts per telescope, usually haulable in two or three loads. Each tube has a garage door handle inside one of the bearing rings so that it can be carried one-handed. The rocker boxes have a handle cutout in the top so that they can be carried in one hand. So rocker box and tube go in one load, the accessory case and stepladder in another. Very easy, even when we park the car up to half a mile from where we're putting the scopes.

car packed for astroimaging

This has the car packed for an astro-imaging session. In this case we normally expect to drive right in to where we set up the scopes next to the car. There are two telescopes here, the one for imaging and a visual scope to keep us from messing with the imaging scope when it's taking pictures. The imaging scope is a Newtonian with a German Equatorial mount. The mount breaks into two pieces, the head and the stand. The head can have the counterweights removed to lighten it up, but I seldom bother.

The telescope tube is the third part, the accessories case the fourth. The tracking computer is in a separate case, as is the camera itself. That would be too many pieces if I wasn't working right out of the back of the car. I also have a red light I can mount inside the dome of my car to provide some "safe" light when rooting around among things, packing, or unpacking. That way I don't disturb other astronomers at the site.

The tubes on all these scopes are too long to fit in my car crossways. I can carry four passengers even if I fold down part of the back seat, but the two in the back need to be friendly. It's too tight for drives longer than an hour or so.

I am working on a new scope that will fit crossways into the back of my car, and making its rocker box act as a cradle for holding it in the car. It will take much less space than my present scopes, and allow more room for passengers. Or more scopes.