Purchasing Amateur Telescopes FAQ by Ronnie B. Kon
In Part II
7. Where Do I Buy My Telescope?
7.1 What About Buying Used?
7.2 What About Building A Telescope?
8. What Accessories Will I Need?
9. What are Digital Setting Circles?
10. Why Should I Start With Binoculars?
10.1 How Do I Hold Binoculars
11. What Books and Star Charts Are Recommended?
11.1 What About Computer Programs?
11.1.1 What Programs Can I Get For Free?
12. About this FAQ
7. OK, Where Do I Buy My Telescope?
Well, there are three basic places:
Yes, the obvious--you find a store (NOT a department
sells telescopes and write a check (or, if they
won't give you a
cash discount, use a credit card that offers buyer
gives you bonus miles, or some such).
The advantages of this method is that
you have someplace to
return the telescope to if
you have problems with it. Some
places even offer your money back if you change your
some grace period. The 'droids that
work in the store may even
attempt to offer some advice. My experience is
that this is usu-
ally 100% wrong, but that's actually as useful as
advice which is
always correct, but you have to know to invert the
The disadvantage is that you generally pay more for the
itself, and you pay sales tax.
There are two sorts of mail order: the discount stores
all sorts of stuff through the mail,
and telescope stores that
sell through the mail in addition to selling from their
The advantages and disadvantages of mail order are
cannot take the merchandise back easily if
something goes wrong,
but it's cheaper (and you probably pay no sales tax).
You can find some great deals in used telescopes.
buy expensive telescopes, use them two or three
times, get bored
and sell them. The advantage is strictly
monetary: you pay sig-
nificantly less (and, of course, no tax).
The disadvantage is that you are buying something "as
you may want to think
twice about doing if you are buying an
expensive telescope. Also, both Meade and
Celestron offer (lim-
ited) lifetime warranties on
their optics, which are not
All that having been said, here is a list of places you can buy tele-
scopes, with comments as applicable. Note that all will sell
or will ship.
P.O. Box 1158
Santa Cruz, CA 95061
(also San Francisco and Cupertino)
Orion Telescopes carries a wide selection of binoculars, telescopes,
and accessories (Celestron, Tele Vue, and their house brand; they do
not carry Meade). They have a 30 day "no
guaranteed" refund policy, which they do seem serious about. A
number of people (myself included) have bought at Orion and all
very satisfied with the way they were treated. This place is
expensive, and they have the unfortunate policy of charging a "stock-
ing fee" if you buy from the store, which always seems to be the same
as the postage and handling fee for mail ordering from their catalogue
(which they will send you for free if you call them).
(see S&T or Astronomy for Address)
This is where I ended up buying my telescope. No
there really was no opportunity for anything to go wrong: I drove up
knowing exactly what I wanted and what their price was, paid by credit
card, and drove my new telescope home. And it is not all that impres-
sive that they had it in stock--I bought one of the most popular tele-
scopes around at the time.
(see S&T or Astronomy for address)
Higher prices than Adorama and Focus (see below), but lower than Orion
and Lumicon. Enthusiastically recommended by a couple of
the net. As with all mail order, make sure the shipping
Pocono Mountain Optics
(formerly Wholesale Optics of Pennsylvania)
(see S&T or Astronomy for Address)
Not to be confused with Pauli's Wholesale Optical in Danbury, CT (see
below). Enthusiastically recommended by a
few people on the net.
Owned by Glenn Jacobs who goes to most of the astronomy get-togethers
in the NY-NJ-PA-CT area so you actually meet him if you live
area. Often willing to cut a package deal if you
are buying big
ticket items. No problems returning things with which you are dissa-
(see S&T or Astronomy for Address)
Enthusiastically recommended by a person on the net. Not the
expensive, but top-notch service. Roger unpacks, inspects and colli-
mates every 'scope he sells, and is very good about refunding
money if you are dissatisfied.
(see S&T or Astronomy for Address)
A few people have reported using University Optics, and all
receiving good service. I have heard no complaints.
Kenneth Novak & Co.
(see S&T or Astronomy for Address)
A couple of respondants have bought accessories from here, and
very happy with them.
(See S&T or Astronomy for Address)
A couple of people have mentioned that shipment can be pretty delayed,
but the quality of their equipment appears to be high, and improving.
Salespeople vary from knowledgeable to bubble headed.
42 West 18th Street
New York, NY 10011
orders: (800) 223-2500
info: (212) 741-0052
Along with Focus Camera (see below), the lowest prices you will find.
Expect no dealer support, and make sure you find out how
will charge for shipping before placing your order. And pray that the
optics arrive intact. I really would recommend that you not buy tele-
scopes from these guys. Eyepieces and other accessories, however, are
probably worth the risk if the price difference is significant.
4419-21 13th Avenue
Brooklyn, NY 11219
orders: (800) 221-0828
info: (718) 436-1518
Refer to Adorama. Same comments apply.
Pauli's Wholesale Optical
A fair number of people on the net reported having bad
with these people. The most common seemed to
be being lured into
driving 4 or 5 hours to the showroom and then being
rudely. Only one person seemed even moderately happy with them.
7.1. What About Buying Used?
Think long and hard before spending a lot of money on a used
scope. You will not have a warranty, and you have no assurance
the optics are in good shape. If you decide to buy used, get a
scription to The Starry Messenger and/or The Cosmic Exchange and look
at their ads. Also check your local paper for classified ads selling
telescopes--this is where you will find your best deals, as they are
selling to the smallest audience.
It appears that most people want to get about 75%
of list when
advertising in the astronomy rags (Starry Messenger, S&T, etc). This
is probably not enough of a discount to make it worthwhile. If
can find something at 50% of list, you might want to think about it.
You certainly want to see the telescope before you buy. A used tele-
scope is just as good as a new one if it's been properly stored, tran-
sported and used. A little dust on the optics is generally a sign of
a telescope which hasn't been cleaned frequently, which
better than one which has. Get the May 1990 issue of Astronomy maga-
zine which had an article on star testing a telescope (Test Drive Your
Telescope by Dick Suiter). If you don't live close to the seller, try
to get someone from the net to go inspect the telescope for you. (You
probably want to send them the money in this case and get them to ship
it for you. This is a major imposition,
please note, so you will
probably have to do some serious begging to talk anyone into it, but
it lessens the chance of fraud).
7.2. What About Building A Telescope?
This section was written by Andy Michael.
We just took a rather unusual approach to getting a beginning
scope: we took John Dobson's telescope building class and built an 8"
and a 12.5" reflector on Dobsonian mounts (of course). We went
way for a few reasons: to get large aperture
for seeing deep sky
objects and higher magnification with good resolution when compared to
small refractors in this price range, to keep the price down, and to
soak up John's wit and wisdom. The down side is that these telescopes
are not suited for astro-photography (at least not without building a
different mount) but that didn't bother us. Also they are large. The
8" tube we broke into two pieces for easy portability, but the 12.5"
one will probably go on the roof rack. These are about f/7 telescopes
so the tube lengths are 56" and 7' respectively. Of course, when you
build yours you can make whatever size you want. On the other
you can pack your clothes in them; try that with an SCT. The cost was
about $250 for the 8" telescope, $450 for the 12.5"er plus about 24 to
30 hours of work and 16 - 24 hours of class. It's a challenging pro-
ject but the first time you focus on something with a
ground is an incredible thrill. Another benefit is that we now know a
lot about telescope design and if we ever have problems with them we
know how to fix them.
If you don't have access to John's (or other peoples') classes
you can try building one by reading his book
and by watching the
video. Our class was the first to see parts of the video
great success at finishing the telescopes fast and without needing to
correct the mirrors very much. Coincidence? Class consensus was no.
The book (excerpted from the order form): "How and Why
to Make a
User-Friendly Sidewalk Telescope" by John Dobson with Norm Sperling.
To appreciate why Dobson makes each factor just so,
learn how he
thinks about it. His philosophy of star-gazing
perfuses his tele-
scopes and his book. The book includes the only detailed
wonderful vignettes from the Sidewalk Astronomers' many expeditions;
their own special way of describing celestial objects; and, of course,
complete details for making a Dobsonian.
169 pages; 154 clear,
friendly line drawings; 9 photos. Hardbound in
favorite material. Exclusive source. Send $39.95 + $5.00 shipping to
Everything in the Universe, 185 John Street, Oakland, CA 94611.
Rumor has it that there is a 90-minute video in which
shows how you can build your own low-cost Dobsonian Telescope.
video is a complete step-by-step guide, covering telescopes
inches to 16 inches in diameter. $39.95 + $3.50
shipping. This is
not available from the Everything in the Universe store.
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
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. It is also easier.
Which eyepieces should you start with? I'd suggest three
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
$150 telescope is pointless (it would also probably tip
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
verts 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
you which way to move and how much.
What makes DSCs so desirable is that they work on
scopes; and, even with equatorial mountings, it is not
polar align the mount. (However, it's desirable to have the mount at
least roughly polar-aligned so it follows an object.)
Additionally, most models have an internal catalog and a "guide" mode.
One selects an object (or, in some, a planet), and the DSCs tell which
way to move each axis.
They are marketed by Lumicon, Jim's Mobile, Inc., Celestron, and Orion
Telescope Centers. The various brands and models
differ mostly in
their internal catalogs of celestial objects.
All are actually
manufactured by the same company, Tangent Instruments of Palo
California, USA, who, however does not sell directly to individuals.
I own the NGC-MAX from JMI, so some of my statements may not apply to
9.2. Must the ground board be leveled?
No. An alt/az mount must have a fiduciary mark such that the tube can
be placed accurately at 90 degrees to the elevation axis. One way to
do this is to (one time only) level the ground board, then the tube.
Make the mark in such a manner that it can be adjusted when something
changes. Some models of DSCs allow an alt/az mount to be initialized
in a vertical position. When starting the DSCs, the tube must be set
horizontal (or vertical), and then two stars are used to align.
stars must be at least 20 degrees apart in the sky (90 is ideal), and
the first may not be Polaris.
9.3. How does one set up an equatorial mounting?
If the mount is known to be accurately polar aligned, you may
use two stars as mentioned above. Or you may set
the DSCs to take
advantage of the known alignment, and it will require only one object,
and no zero degree reference mark is needed.
If an equatorial mount is not polar aligned, it must have a reference
mark at zero degrees declination, and must use the
For a German mount, the mark may be on either side of the scope (tube
pointing east or west), and the DSCs set to correspond. The mount may
be driven or undriven. As for an alt/az mount, the stars must be
least 20 degrees apart, and the first may not be Polaris.
9.4. Do the DSCs support a Poncet platform?
Probably depends on the model. The NGC-MAX provides telescope type ET
(equatorial table). It assumes that the table is carrying an
scope, and that the scope is initialized with the tube horizontal. I
believe that an equatorial mount could be used, but have not tried to
9.5. How accurate is the device?
The position of the scope is displayed to one minute of RA
minutes of dec. Guide mode displays position error to 0.1
arc. The actual accuracy depends on the care with which the alignment
was done, the accuracy of the mounting, accuracy with which the shaft
encoders were installed, the resolution of the encoders, and a bit of
luck. If the level or zero was not set accurately, the
work poorly, and it should be re-started. If star settings were done
carelessly, one can simply re-do one or both of them.
The "luck" factor stems from the digital nature of the shaft encoders.
If the encoder is on the verge of a step, you
could be off by one
The absolute theoretical resolution is three encoder steps, assuming
everything else is perfect. In practice,
I get about 0.2 to 0.3
degrees, and closer near the alignment stars. If I move a long
across the sky, the error is perhaps 0.5, but then I
re-align on a
convenient nearby star. It's not too unusual to get 0.1 if all
gone especially well during alignment. This with 4000 step encoders.
Accuracy is best between the alignment stars, and the DSCs calculate a
"warp" so as to spread out the error. When re-aligning, only one star
sighting is needed. The DSCs retain only the two
settings, provided they are at least 20 degrees apart in the sky.
Some models allow alignment on ANY catalog object, which is helpful,
but I find that accuracy is best on stars or very round
find that planetary positions are especially suspect. The
carries only the date, not the hour. (Use UT date.) I have often had
poor alignments when using planets, and do so only for daylight set-
ups; I re-align on stars as soon as I can find any. Open clusters are
especially unreliable; galaxies are not much better.
9.6. What objects are in the internal catalog?
This is the major difference between models. All have a
named stars, used especially for initial alignment.
Some have the
planets. The Lumicon models have a catalog of
which is Dr. Jack Marling's specialty.
The NGC-MAX version 3.94 (July, 1992) has the planets; 28 user-defined
objects; the Messier catalog (including M40 and M110); the full NGC,
including the so-called "non-existent" objects; about half of the IC
catalog; a catalog of 951 interesting stars (multiple, red, variable);
and a list of 367 additional deep-sky objects, many of which are very
For each object, the catalog has the position, magnitude, size (diame-
ter or separation), constellation, name (if
any) and/or catalog
number, and the type of object. Some have a word or two of
tion. This probably varies with the brand and model.
9.7. May I add my own objects? Comets, for instance?
The NGC-MAX accepts user objects, and I presume most other
models do as well. I like to put in the Sun and Moon, so that
align during the day. This must be done carefully,
with the Sun
filter attached. THIS IS DANGEROUS, as the filter
must be removed
when sighting on the Moon, and if you come back to the Sun, you MUST
have first re-attached the filter! The
moon is a poor alignment
object because it has up to a degree of parallax, and it moves about
0.5 degrees per hour. But it provides a start, and it may be
to locate some bright stars, and re-align.
9.8. What is "identify" mode?
Identify mode is present in the NGC-MAX, and probably other
One specifies the class of object, and the faintest magnitude,
the DSC selects the nearest to the telescope's position. Very
but in the Realm of Galaxies, alignment is critical and then there are
too many to be certain. To check, read out the magnitude and descrip-
tion, and go to Guide mode and see how far away the object is.
It's especially useful in clouds, as one may point the scope into
clear spot, then ask what is nearby. One must separately
galaxies, clusters, etc.
Identify mode runs continuously, so that, as the scope is moved, the
DSCs will (after a few seconds), indicate the new (or nearest) object.
9.9. Can it replace star charts?
For comparatively easy objects, probably. In a crowded
Some models support the Tiron Atlas 2000 and the Uranometria 2000, by
indicating, for each object, the page on which it (the object) will be
found. These models also indicate the chart
corresponding to the
position of the scope, regardless of specific object.
9.10. What other functions are present?
This varies heavily with model. The NGC-MAX (here we go again)
two that have not already been discussed.
"Timer" counts up in hours, minutes, and seconds. It can be stopped,
reset, and re-started, but can't be restarted
without first being
"Encoder" shows the encoder positions in degrees. If an alt/az scope
was pointed north when the DSC was powered up, then encoder mode will
read elevation and azimuth, if the scope is also standing reasonably
9.11. How is it powered? How long does the battery last?
There is an internal 9-volt transistor battery. The load is 18 to 40
mA (NGC-MAX), depending on how bright the display is. I suppose this
might depend on the model, too. The maker claims 30 to 50 hours on an
alkaline battery. They do last a good long time.
There is a "low
battery" indicator which would turn on at about 4.5 volts,
practice, I get "encoder error" messages before that.
Some models have a second connector (serial port) by which external 9
- 15 volts DC may be supplied. This does not
require the internal
battery to be removed; the two supplies are in parallel with diodes to
prevent back-circuits. It does not recharge the internal battery.
9.12. How accurately SHOULD the mount be constructed?
The brief answer is, as accurately as you'd like the DSCs to operate.
For an equatorial mount, there must be little flexure;
the RA axis
must be perpendicular to the dec axis, which in turn must be perpen-
dicular to the optical axis of the tube.
For an alt/az mount, the ground board must be rigid, the azimuth bear-
ing surface must be flat, dent-free and stiff; and the side bearings
must be the identical height, that is, the elevation and azimuth axes
must be accurately perpendicular. In addition, the
optical axis of
the tube must be perpendicular to the elevation axis. There is a ter-
rible irony here: the Dobsonian mount works
precisely because its
kinematically stable design does NOT require that it be
9.13. How accurately should encoders be installed?
Again, the short answer is, as accurately as you'd like the DSCs
operate. One can't do the job with a hand-held drill. OTOH,
work with a modest lathe and drill press is quite sufficient,
cially if performed by a modest machinist. Most astronomy clubs have
such a person.
Best accuracy is obtained with high-resolution encoders.
encoders have 2048 steps per revolution, and high-res type has 4000.
One can also use gears to provide greater resolution, but see below.
If the encoder is connected directly to a shaft, the hole in the shaft
must not be oversize. It must be
straight, well centered, and
parallel to the axis. The body of the encoder must be held so that it
cannot rotate with the shaft. If it is connected by gears, the shafts
must be parallel, and there must be no backlash.
Encoders are not especially delicate, but they do not like to be bent.
They require very little torque, and rotate
setscrew should not deform the shaft. The 4-wire connector should be
looped so it does not pull on the encoder. They may be mounted
that the shaft is stationary, with the body moving, or the usual way;
the direction is set in the DSCs' setup option.
In an alt/az mount, the azimuth encoder is typically mounted atop the
center bolt. In this case, the bolt must be nicely
the ground board, and the comments about shaft mounting (above) apply.
If the rocker box has any side play, it will be nearly impossible to
avoid some runout. This can be reduced by using a very long lever arm
to hold the body of the encoder.
Both side bearings must be round (especially
the one with the
encoder), the center must be carefully located, and the encoder shaft
parallel to the elevation axis. Any runout here will cause
inaccuracies when moving across the sky.
9.14. How accurately MUST the mount be constructed?
Please don't feel that only a million dollar mount can be
with DSCs. My 1972 Optical Craftsman (German) mount works very well,
even with about 0.5 degrees of error if I shift the
return to an object. This was the economy model! A machinist
helped me drill the holes for the encoder shafts.
I used UGMA grade 10 precision gears to step up the dec shaft speed.
The designer of the DSCs was amazed at that, and admitted that he used
UGMA 4 with adequate results. I don't know how to calculate how much
more accuracy I might be getting from my expensive gears.
My alt/az mount, crafted of wood in my shop with only hand tools, car-
ries a 108mm f/4 scope, and *always* puts an object in a
field. OTOH, if I re-collimate the scope, I must also re-position the
vertical mark. I usually re-align after moving far across the sky.
If the mounting is less than perfect, it means that you will need to
re-align more often. But if the mount is *really* sloppy, it probably
will not be satisfactory.
9.15. Can I connect the DSCs to my own computer?
Yes, for some models. The NGC-MAX, and probably others, has a serial
port that may be used with an external computer, so that the
shows a dynamic star map, identifies objects, etc.
But the attached computer must take over ALL functions, including the
prompting for "level me," pointing at particular
guiding, calculating the conversions for RA and Dec, etc. I
stand The_Sky, from Software Bisque, does all this, but
I have not
seen it in use nor heard from a live user.
The port is a modular telephone connector (RJ11). It has four wires:
B+, data in, data out, and ground. External to the NGC-MAX, the cable
must route DTR back to the attached computer as DSR, CD, and/or CTS,
as needed by the attached computer. The 4th wire is +Battery, a 9 to
15 volt external power supply, which does not charge the internal bat-
tery. It is not necessary to remove the internal battery,
When the NGC-MAX is operating in "BBOX" mode, it
blanks its own
display, and does nothing but pass the shaft encoders' values over the
serial port. It multiplies them by the encoder ratios (the latter set
in the NGC-MAX setup function), and scales them such that 00000 is the
position at power-on, and 32767 is just under 1 rotation.
Communication is at 9600,8,N,1. When the NGC-MAX powers on, it sends
a hello message such as "V2.94". When the attached computer
character (the sample program uses "Q" but anything seems to
down the port; and the NGC-MAX replies with 13 characters of the for-
mat "+00000t+00000" where the "t" is ASCII 9, and the 00000s are the
two encoder values.
I don't use this facility, but I'm too curious not to have tried it.
I used my modem program to supply the computer side. I use the
MAX whenever I'm doing general observing, and I like it very
But I don't have a portable computer to use with it, and
much see the need. OTOH, if I fell into a laptop, I'd surely want to
try connecting them.
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 lenses.
If you wear eyeglasses, you may be able to find binoculars which can
focus without them (unless you have significant astigmatism).
sure the image is sharp at the center and edges at the same time.
"7x" is the magnification. Most people can hand hold these
needing to bother with tripods, etc. The "50" means 50mm
objectives (aperture). This gives light gathering ability similar to
many small telescopes. Many advanced star gazers regularly use bino-
culars 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
view. You also will not get a crick in your neck.
You might also use a plastic pad to lie on.
10.1. How Do I Hold Binoculars?
This section was written by Jay Freeman.
If you don't have a tripod (and tripods are sometimes a little clumsy,
and are often difficult to use when the binocular is pointing near the
zenith), it is important to know how to hold a binocular correctly to
achieve maximum steadiness.
The way most people tend to hold a binocular is with one hand on each
side of the middle of the body--roughly where the prisms are in a con-
ventional 7x50, say, so that the left hand is directly to the left of
the center of gravity of the instrument and the right hand is directly
opposite it, to the right of the center of gravity.
For most people, there is a better position. Imagine that
holding the binocular to your eyes, with your hands positioned as just
described. Now, slide your hands along the body of the
toward your face, until only your pinky and ring fingers are
around the back end of the binocular body. In this
binocular feels a little nose-heavy, because you are
behind its center of gravity.
Now curl each thumb up as if you were making a fist, and flex
hands so that the second bone in from the
tip of your thumbs are
pressed up against your cheekbones (counting the bone in the part of
your thumb where the thumbnail is, as the first bone). This
quite solid structural connection between the body of the binocular,
through your hands and thumbs, to your face, and markedly improves how
steadily you can hold the instrument. Similarly, curl the first
middle fingers of each hand around the corresponding binocular
piece, to provide a little more structural connection (and
also some protection from stray light). In this position, your hands
are not far from where they would be if you brought them to your face
to block out stray reflections while peering through a store window at
For most people, this position leads to markedly steadier viewing, but
if the binocular is especially long and heavy
(say, a 10x70 or an
11x80), the out-of-balance position can be quite tiring.
case, move *one* hand out to the objective end of
its side of the
binocular, so that you are supporting the instrument on opposite sides
of its center of gravity, but with some structural connection between
it and your face; namely, the other hand. When the hand way out there
gets tired--just switch hands.
For each person, there is a limit to how heavy and / or how powerful a
binocular can be, before there is no way for that person to
steady enough. I am an averaged-sized adult male in reasonable physi-
cal condition, and I find I can hold a 10x70 (Orion's) steadily enough
to use indefinitely on astronomical objects. But I have an old Celes-
tron 11x80, that doesn't look much bigger or heavier than the 10x70,
that I can only use for a few minutes before my arms get tired. As a
12-year old I am sure I could have used a 7x50 indefinitely
problem, but at a younger age I might have had difficulty using
continuously. Your experience may vary with your strength,
condition. Try before you buy, if at all possible.
10.2. What Are Some Eye Relief Figures?
If you need to wear eyeglasses while looking
(presumably you have astigmatism, but if you require many diopters of
correction you might need to as well) you need reasonably good
relief. Dana Bunner contributes the following table:
Advertised ER Measured ER
Bausch & Lomb 7x26 Custom
Celestron 10x50 Pro
Celestron 7x42 Ultima
Celestron 7x50 Ultima
Celestron 10x50 Ultima
Celestron 8x56 Ultima
Fujinon 8x40 BFL
Fujinon 7x50 FMT-SX
Fujinon 10x70 FMT-SX
Minolta 7x50 Standard
Minolta 10x50 Standard
Minolta 10x50 XL
Nikon 8x30E Criterion
Nikon 7x50 Windjammer
Optolyth 10x40 Touring
Pentax 8x24 UCF
Pentax 7x35 PCF
Pentax 7x50 PCF
Swift 8x25 Micron
Zeiss 7x42 B/GA T Dialyt
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
is The Stars, A New Way of Seeing Them by H. Rey, which
non-orthodox way of drawing the constellations so they are easier to
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
mended. It is very inexpensive ($13), small and handy to use
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
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
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
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
as "An Observer's Guide to the Universe Beyond the Solar
rather all-encompassing claim, which it manages to live up to. Infor-
mation on every item of interest you can think of: galaxies,
stars (optical and binary), variable stars, nebulae, etc. More infor-
mation than you could use in a lifetime. I consider this a necessity.
Sky and Telescope's 100 Best Deep Sky Objects. About $5,
kind of expensive for a list, but it sure makes it easier to
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 Corporation
P.O. Box 9111
Belmont, MA 02178-9918 USA
Their catalog is free. See also in our Shop
11.1. What About Computer Programs?
There are basically two types of astronomy programs: calculations of
astronomical things and computerized star charts. I
either of them worth buying as a tool to help an observer.
other hand, some of them (particularly the star charts) can be a lot
of fun to play with during the day or on cloudy nights. Before
buy any, you should probably check out the ones available on the net
(see next section).
For a good example of the variety of programs which will
things, look for Zephyr Software's ad in
Sky and Telescope (or,
presumably, Astronomy). They list two pages of programs, for
$60 each, which can calculate things like solar
eclipses, or lunar
phases, or ephemerides, etc. To my mind, your money would be
spent on eyepieces, or a bigger telescope to begin with.
As for computerized star charts (usually $100 - $250), these can
very nice. Most will draw in the constellation
lines if you like,
will let you click a mouse on an object to have it identified,
objects by name, and so forth. Also, the fact that they
the sky is much nicer than having to turn pages in a printed
The fact that they can show the stars as they are tonight, as opposed
to a fixed time (such as 2000.0) is so pointless as to be laughable.
The only problem is that you will probably never be able to use your
computer at your telescope, which means that this is something
will use indoors. This strikes me as a nice recreation,
you would be better served by spending the money on a better
As for recommendations for programs, both Dance of the Planets ($200),
and The Sky 4.1 ($75 - $175, depending on the size of the database of
objects) tend to get rave reviews in the magazines. Both are only for
IBM PCs and compatibles. The former is available from
A.R.C Science Simulation Software
P.O. Box 19558
Loveland, CO 80539
The latter is available from
912 12th St.
Golden, CO 80401
For the Macintosh, a program called Voyager is the dominant program.
David Nash comments that:
1) It has a lot of features for the planets.The accuracy of its posi-
tions probably isn't as great as some more
dedicated program like
Dance of the Planets, but it is more than sufficient for
observers. And it does a lot: in addition to the standard
planets against the stars" mode, you can get conjunction
(handy for finding eclipses), planets displayed with disk and
indicated, a "tracking" mode that plots planet positions at a
interval (say, steps of 2 days or 1 month), and a
bunch of little
features that come in handy, such as a program that produces
magnitude - vs - time and angular size - vs. time plots that you see
in the astronomy magazines.
2) NICE interface compared to most programs I've seen, including Mac
programs like MacAstro, but then again that is
shareware and less
fully-featured. Each starchart has Mac-style scrollbars on each side
-- one for RA (or Azimuth) and one for Dec (or altitude). This makes
navigating around the sky fast and simple -- grab the scroll bars and
you're off and running. Similar sorts of controls allow you to
in on a region (down to 1 deg. x 1 deg.). Much more
The_Sky for the PC (the DOS version anyway -- I haven't tried the Win-
dows version, so this may not be an entirely fair comparison).
3) Many options for plotting charts. You can get them in
(RA/Dec) or local horizon (alt/az) coordinates (or several others, but
these are the most useful). A little counter in one corner
screen tells you what the coordinates of
the cursor are in the
appropriate modes. You can add coordinate grid lines, mark important
points or areas (zenith, horizon, ecliptic, etc.).
4) Miscellaneous fun stuff: a 3-D map of the ~50 or so nearest stars
to the Sun (click on the axes to change the view), an "orrery"
that shows the Solar system from above, making it easy to see plane-
tary relationships (conjunctions, oppositions, etc)
It also has a fairly comprehensive deep-sky database.
The only really big drawbacks here are that the program is black and
white only, even on color Macs, and the star database is a bit limited
compared to many programs (esp. some for the PC). There is, however,
a new version which supports color, and adds more stars.
Brian Cuthbertson has a program HyperSKY, which he was kind enough to
send me to review. Unfortunately, the first disk was
corrupt, so I
could not load it onto my computer. However, from the brief instruc-
tion list he sent it appears to do what you would expect a computer-
ized star chart to--zoom, pan, identify objects, is mouse-based, and
so on. (Yes, I know that I don't have much here to base a review on,
but: 1) he is on the net, and I admit to a net.bias; and 2) he
nice things about my FAQ and sent me a free copy of his program).
HyperSKY is available from Willman-Bell publishers (see ad in any copy
of S&T or Astronomy).
A correspondent recommends the program Distant Suns as being a
computerized star chart, that was written by Mike Smithwick, who some-
times reads this group. If Mike would care to
contact me, I'll
include price and address here. If he wants to send me a review copy,
I'll even give my opinion.
11.1.1. What Programs Can I Get For Free?
Well, I use a program called ephem, for calculating a whole
stuff (like ephemerides, phase (of moon and planets), dawn, dusk, etc.
and like it a lot. There is a motif based upgrade, xephem,
have not yet used. You can pick it up from ftp.x.org or iraf.noao.edu
in contrib/xephem. Ephem and xephem were written by Elwood Downey.
I have heard good reports about a program called 'starchart'
another called 'observe', the former prints out star charts, and the
latter calculates where objects are, in a format accepted by
chart.' You definitely want to get these before paying for
For Macintoshen there is a free/shareware program MacAstro available
>from cs.dal.ca in
/pub/comp.archives/macastro and from
/.disk2/usenet/comp.archives/sci/astro/macastro. It will show the sky
at any time, including stars, sun, moon and planets. It
give the rising/setting times of the sun
and the moon. It is
shareware, $20, written by Nicolas Mercouroff (email@example.com).
12. About this FAQ
This FAQ is a copyright work. You have my permission to reproduce it
however you like, as long as you don't make any money off of
you leave all the attributions and the copyright notices.
All the opinions are mine, and not my employer's.
If you have any questions, I will be happy to try to answer them. But
be warned that I am not a very experienced observer. Many many people
on the net have much much more experience than I do.
Because the FAQ is kept as an nroff file, generating diffs is a hard
This FAQ does not appear on news.answers, because they didn't like the
No, I am not interested in having someone convert this to HTML for a
Mosaic World Wide Web Information Superhighway Wired
application. This is an article, and I want
people to read it
This FAQ is available via anonymous FTP from ftp.cisco.com, in /faq.
The files are astro1.txt and astro2.txt for printable text; astro1.ps
and astro2.ps for postscript files.
To the first FAQ