NetNews Usenet Archive 1992 #16/NN_1992_16.iso/spool/sci/astro/8515

Internet Message Format | 1992-07-30 | 5.6 KB

Path: sparky!uunet!usc!rpi!bu.edu!dartvax!Frederick.A.Ringwald
From: [e-mail] (Frederick A. Ringwald)
Newsgroups: sci.astro
Subject: Re: Help on first scope
Message-ID: <[e-mail]>
Date: 31 Jul 92 04:47:31 GMT
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Organization: Dartmouth College, Hanover, NH
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I've gotten some e-mail on my previous post, so let me make some
clarifications:

a) I do not in any case advocate buying junk. Although it is possible,
with skill and knowledge, to put even junk to good use, you should
*NOT* prefer junk. It will be much easier and more enjoyable for you to
acquire your skill and knowledge with good equipment.

b) I didn't say enough about finding things. This can be a source of
undue frustration for the beginner, and a major reason for too many
otherwise fine telescopes to be gathering dust and not starlight. A
small, low-power (5x or 8x) finding telescope, mounted securely onto
your main telescope's tube, can be a big help. (This is not the same
thing as a guide scope, which is an accessory for photography.) Cross
hairs can help; the height of luxury, battery-powered ones, are called
illuminated reticles. Make sure there's some way of realigning it after
someone cracks his/her head on it, which will inevitably happen. (Note
that modern astronomy is a very practical science.) For a first
telescope, stick with a straight-through model; ones with right-angle
bends can take some getting used to. Get some star charts, too:
Norton's Star Atlas and Telescopic Handbook, by A. P. Norton, is a
must. The Peterson Field Guide to the Stars and Planets, by Donald
Menzel and posthumously updated by Jay Pasachoff, is very useful, too.
You can't just point a telescope in an arbitrary direction and expect
immediately to see something interesting: it's a big Universe, after
all, so it really helps to know your way around. I still like the
Stars, by H.A. Rey, the same book I learned the constellations from
when I was in 3rd grade. A planisphere, sort of moving star map where
you dial up the date and time and a sky map is shown through a window,
can be handy, and can be found in most fine bookstores or planetarium
shops. I like the ones made of plastic, such as the Phillips, as they
can be dropped into wet grass many times. Don't sweat it if you can't
get one for exactly your latitude; what if you go on vacation?

c) Other accessories include a good flashlight, preferably with a red
lamp so as not to ruin your night vision. You can buy these specially,
at exorbitant prices; or you can get a piece of red plastic to put in
front of the bulb, for negligible cost; or you can paint the bulb with
red nail polish, although obtaining this can be embarrassing, for a
man. Another accessory is an easily-transported folding chair for you
and your friends to sit in and be comfortable while observing.
Contorting into bizarre positions in order to get to your eyepiece is
silly: you observe best when your mind is on your observing, not how
uncomfortable you are.

d) Tracking stars across the sky as the Earth moves, with a clock
drive, is a nice luxury which requires an equatorial mount. On the
other hand, some amateur astronomers will wonder why you don't just
give the telescope a little push with your finger now and then. It's a
lot cheaper. The clock drive will need electricity to run, which can be
a hassle requiring a long outdoor extension cord. An equatorial mount
has to be polar-aligned, too, a simple operation once you learn how to
do it. Yet again, the question comes up - what's it worth to you?

e) As regards moving your telescope, I wasn't clear enough about coarse
motion ("slewing") and fine motion (often called setting). All you
really need is the ability to do both, smoothly: you don't need much
sophistication. The difference between slewing and setting with a
well-made Dobsonian is how fast you're pushing it around with your
hands. A top-of-the-line equatorial mount with drive motors will have
special buttons to push which say "slew" and "set", but is of little
use if they are just for show and do not work well, in something not
quite at the top of the line. For small telescopes, slewing is usually
not much of a problem (with Hubble Space Telescope, it is: it slews
about as fast as the minute hand on a clock moves); usually, you just
undo a screw or something, and the thing crashes to the ground, if
you're not careful. So what this all boils down to is: make sure there
is some way to move your telescope smoothly, just a little bit.

f) The Sky & Telescope for September just arrived, with the annual
directory. It lists several clubs in Minnesota, where I presume you
are. I can't say too much about this magazine, although some people
prefer its less-technical cousin, Astronomy. I also can't say too much
about going to your local astronomy club, even if only once, to check
out what instruments they have. These magazines also have articles
about buying a first telescope, but they are of course inferior to
mine.

g) Take it light. It will take some patience to get the hang of things,
but keep in mind it takes about 6 years to get a Ph.D. in astronomy
(and the job market is currently stinky). Do what you like. I hope you
have lots of fun observing. For $750, you can fix yourself up with a
very nice instrument, although your money will go farther if you get
the instrument best suited for what you enjoy observing - and that can
only be decided by you.

Fred Ringwald
Department of Physics & Astronomy
Dartmouth College
Hanover, NH 03755-3528