Telescope Info/Buying FAQ for Beginners - Part 2

This is where you can read up the answers to some FAQs on astronomy and star-gazing in Singapore. Members' contributions are welcomed.
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Airconvent
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Telescope Info/Buying FAQ for Beginners - Part 2

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/CONT from part 1

--Equatorial Disadvantages--:

1. Good Equatorial mountings tend to be bulky and heavy, making them less
portable than some altazimuth designs (often have to be broken down
into many smaller components for transport).
2. German Equatorial mount requires heavy counterweight on a long shaft
to make the scope balance. This can be a problem in the dark with
people running into them. German Equatorial mounts can also have
problems with the scope running into the pedestal for some objects
near the zenith, requiring a "roll over" reversal for continued
tracking.
3. Moment arms of equatorial mounts tend to allow flexure and vibration
to become problems unless the mount is heavily overbuilt. Fork mount
tines tend to flex, making for mild tracking errors and periodic
lower-frequency "pogo" oscillation vibration problems with heavy
scopes and longer tine length.
4. Good Equatorial mounts usually have four bearings, and can often be
more expensive than altazimuth mountings (they can still be home
built, however).
5. Proper polar alignment is necessary for accurate tracking.
6. Less intuitive for beginning amateurs, although once the amateur gets
used to them, the amateur can often find and track objects faster and
more easily than with altazimuth mountings.

NOTE: none of these disadvantages will eliminate a mount design from use by
the amateur. For strictly visual use (especially for the beginner), the
altazimuth can easily be recommended, while for long-exposure photography,
the equatorial is often the mount of choice. For very large apertures
intended for easy portability, the altazimuth almost has to be used.
However, the compact split-ring equatorial design can also remain fairly
portable even with telescopes as large as 18 inches. Computers and
computerized driving systems have narrowed the choice between the two
mounting systems (and driven up their prices), but their basic
characteristics have not changed. In any case, both the altazimuth and the
equatorial have a firm place in amateur astronomy.

David Knisely

7.4 Binocular Telescopes

There have been some people who have built their own Binocular Telescope,
this is two telescopes who are the same in every way that are mounted
together and are used more or less like a pair of binoculars but are much
more powerful. During the last few years a bino viewer has been made that
turns a normal scope into a bino-scope.

Now there is at lest one company that is making and selling their own
Binocular Telescope. While I have not been able to use such a scope (I
don't have that kind of money!), I would think that the images from it
would be awesome!

SanJO Instruments
1157A&nbspBucke&nbspSt.
London,&nbspOntario
Canada&nbspN5Y&nbsp3S2

8. What Accessories Will I Need?

In addition to a telescope, you absolutely must have a mounting and a
tripod. You will also need a few eyepieces, a telescope with only one
eyepiece is like a piano with one key.

These accessories don't come cheap, expect to pay as much for the mounting
and tripod as you paid for the optical tube. For a first telescope, you
probably will want to buy an entire system it tends to be less expensive
that way.

Which eyepieces should you start with? I'd suggest three or four, maybe a
30mm, 25mm, 20mm, 8mm and a 2x Barlow (which will give you coverage of
30,25, 20, 15, 12.5, 10, 8, and 4 mm). Buy eyepieces of like quality to
your telescope. Putting a $300 Nagler eyepiece on a $150 telescope is
pointless (it would also probably tip over the entire telescope).

9. What Are Digital Setting Circles
This section was written by Jim Van Nuland

9.1. What Are They?

Digital Setting Circles (DSCs) are a small special purpose computer,
mounted on or near a telescope. The scope has shaft encoders attached to
sense the motion of the scope's axes, and the computer then converts these
motions to the position of the telescope, and displays it (for instance) in
Right Ascension (RA) and Declination. An 8-conductor cable runs from the
computer to the encoders, with 4 wires to each encoder. RJ-45 telephone
connectors are used at the computer.

They do NOT move the scope. You push it by hand, and the DSCs tell you
which way to move and how much.

10. Why Should I Start With Binoculars?

The quick answer is because you already have them, so you do not have to
spend any money. Certainly going right out and buying the Fujinon 25x150
Astronomical Binocular ($11,000 list price) would be a pretty stupid thing
to do, no matter how good the binoculars are.

You should also avoid the quick-focus binoculars, as they are easy to
de-focus as well.

The remainder of this section was written by Paul Zander.

Based on my experience, I suggest that you start with a pair of 7x50
binoculars. This is the most popular size and hence good ones are available
from many stores, even some of the discounters. Be sure to get ones that
have anti-reflection coatings on the mirrors and lens. If you wear
eyeglasses, you may be able to find binoculars which can focus without them
(unless you have significant astigmatism). Make sure the image is sharp at
the center and edges at the same time.

"7x" is the magnification. Most people can hand hold these without needing
to bother with tripods, etc. The "50" means 50mm (~2 inch) objectives
(aperture). This gives light gathering ability similar to many small
telescopes. Many advanced star gazers regularly use binoculars to either
locate items to focus telescopes on, or just for the wider field of view.

When trying to view near the zenith, use a reclining lawn lounger: you can
lie back and support your arms on the chair, giving a steadier view. You
also will not get a crick in your neck.

You might also use a plastic pad to lie on.

11. What Books and Star Charts Are Recommended?

If you don't know the constellations, you might want a book that will help
you learn them. A "fun" book for those just learning the stars is The
Stars, A New Way of Seeing Them by H. A. Rey, which presents a non-orthodox
way of drawing the constellations so they are easier to visualize.

You will probably want a beginner's guide, such as the book by Sherrod
mentioned above. Sky Publishing has some introductory materials which would
probably be as useful, which you get for free when you subscribe to Sky and
Telescope.

Petersen's Field Guide to the Stars and Planets comes highly recommended.
It is very inexpensive ($13), small and handy to use at the telescope. It
has a good discussion about stars, planets, nebulae, and galaxies; and has
a very complete albeit small-scale star chart, along with a the usual
tables. It has long lists of deep-sky objects for each area of the sky.

You will need a bigger star chart than is included in Petersen's. Try Sky
Atlas 2000.0, by Wil Tirion. The field edition, which has white stars on a
black field, is probably more useful than the desk guide. It is also
printed on heavier paper, so is more resistant to dew and the rigors of the
night. For beginners, buying Uranometria 2000.0 is probably a mistake. Yes,
it is the "best" star chart, but the scale is impossibly small- when the
Orion constellation takes up four separate pages it is really hard to use
for beginners.

Burnham's Celestial Handbook ($36). This three volume set is billed as "An
Observer's Guide to the Universe Beyond the Solar System" rather
all-encompassing claim, which it manages to live up too. Information on
every item of interest you can think of: galaxies, double stars (optical
and binary), variable stars, nebulae, etc. More information than you could
use in a lifetime. I consider this a necessity.

Sky and Telescope's 100 Best Deep Sky Objects. About $5, which is kind of
expensive for a list, but it sure makes it easier to figure out what to
look at when you are just beginning. The items are sorted by Right
Ascension, which makes it real easy to figure out which ones are currently
up.

All the materials listed are available from:

Sky Publishing Corp
P.O.&nbspBox&nbsp9111
Belmont,&nbspMA&nbsp02178-9918

Their catalog is free.

11.1. What About Computer Programs?

There are too many types of computer programs that I can NOT review, as
they do not run on my machine. I think there should be a FAQ just for all
the computer programs.

11.2. There is another world where a lot of info can be gotten, that is the
world of Cyberspace. Not only web sites, but the world of E-Mail lists too.
Here are a few:

For Astronomy:
http://iridium.cedura.net/mailman/listi ... uskrat.com

For Telescopes:
http://groups.yahoo.com/group/Dobsonian

For ATMers:
http://groups.yahoo.com/group/ATM-L

12. About this FAQ

This FAQ is a copyright work. You have my permission to reproduce it
however you like, as long as you leave all the attributions and the
copyright notices. If you find this FAQ useful a small Donation sent to the
address below would help.

Slc.Dennis Bishop This FAQ now is Home
470 20th West #23 on an Atari Falcon030
Rosamond,Ca.93560 and Atari TT/030.

Wanted: 8in F4.8 mirror

Created on ... June 29, 2002
The Boldly Go Where No Meade Has Gone Before
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United Federation of the Planets
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