Expert: Tom Whiting - 4/2/2009

Question
I'm about to buy my first telescope (for general viewing).
It seems that there are a number of reasonably priced 3.5cm Maksutov-Cassegrains on the market, but most of them seem to have altazimuth mounts.  I have always thought that equatorial mounts were much better, but various aids have appeared since my telescope book was published and some of them claim that modern altazimuth mounts make following an image very easy. Is this true?  Or should I insist on equatorial?
Thanks

Answer
Hi Michael,
In reality, there really is no such thing as an "excellent"
general viewing....telescope.  You always sacrifice something for
something else.  For instance, us that are into DSO's (deep sky
objects like galaxies, nebulae, star clusters, etc) want as large
a mirror (aperture) as possible with a short focal length to maximize
the FOV (field of view). Others who are more into lunar/planetary
details want a different type scope (generally a 4 or 5 inch
refractor with a front multi-coated lense up front) and with a very
long focal length for super-high magnification of a very small
spot in the sky (the planet they are viewing).  They care less about
how big the FOV is.
Then there are comet hunters that want still a different system,
generally a very low power scope with an ultra-wide FOV, say a full
3 degrees, for successful comet hunting.  Variable star observers
don't require much of any of these, so they can get by very well
with a standard 6 or 8 inch reflector telescope of just average
focal length, generally f8 or f10 scope.
Then there is the fellow who has a very small car, so for traveling
around, he needs very portable equipment as his primary factor,
so he'll purchase a Mak (like you are thinking of) or a Schmidt-
Cassegrain...with a sacrifice of both focal length, and that 30%
secondary mirror obstruction which drops contrast and amount
of available incoming light (a horrible sacrifice on quality of
image)....so he gets screwed all around, just for the convenience
of what he wants,.... easy portability.
Scopes are like airplanes....all airplanes fly but you don't send  a
bomber to do a fighter's job...scopes are exactly the same way.
(Otherwise, all us amateurs would have the same type of scope,
wouldn't we?  But we don't...there are different scopes for different
folks, depending on your main interest.)

As far as the mount, the only reason one wants equatorial mount is
for photography (and that in itself is an advanced subject in itself).  I have never owned a bulky, heavy equatorial mount..they
are time consuming on set up, and a lot of extra work, just to have
one motion track the sky. Ain't worth it, compared to the ease of
the alt-azimuth mount...in fact, I prefer the Dobsonian mount,
un-driven and no go-to equipment.  I am not lazy. I am my own drive
and my own "GO-TO"....saves a lot of money that way which you can
then invest into a bigger mirror and bigger scope.  Only reason one
needs clock drive to stay on an object is if again, you are doing
photography. As far as goto's, why not just spend 3-6 months and
learn the night sky yourself....and save a pile of money.  It really
isn't that difficult; If you can learn and memorize say 4 adjoining
counties....Hampshire, West Sussex, East Sussex, Kent...then you
can also learn and memorize in the night sky Gemini, Cancer, Leo,
and Virgo. They are simply fixed areas of the sky (since 1930).
No more picturing men or animals, but simple area's which are easy
to learn. There are about 40 Northern hemisphere area's or
constellations, and that's it. Simple.  All you need is a good map
(good star chart)...just like a sailor... a dark sky location, and
a red flashlight to maintain your night vision.  Sailors of the
seas need good charts, and so does a sailor of the stars.
For further advice, punch on our club website at
http://www.velocity.net/~bwhiting
and read "Tom Whiting's Sound Advice for the Novice Observer"
and read over what I have to say about the subject to a Newbie.
It will (or may) help you get started into our great hobby on the....right footing.  As it applies to the UK just as much as does
for the USA.
Plus, learning the night sky yourself is very rewarding activity....
and you'll never be the guy whose internal telescope computer goes
out on him on a beautiful night at a star party, and he's out of
luck because he never took the time to learn the night sky himself,
but depended on his GOTO...happens more often than you think.
Clear Skies,
Tom Whiting
Erie, PA USA

PS...yes, the newer alt-azimuth tracking equipment is just as good
as an equatorial tracking device. But, do you really want to layout
the money for that convenience, carry all those extra batteries to
power it, all those motors and servers and wires to connect,
then you got to take the time (away from observing) to calibrate it, align it, level it (not necessarily in that order)....sounds
like a horrible price to pay when all you really have to do for
visual observing is....move the scope a little to the west, every few minutes?  So, it takes two motions, up a little and to the right...So what?   To me, the electrical/mechanical clock drives ain't worth it. You aren't a lazy person,.... and put those extra "pounds" into a bigger mirror and better scope!
Just give me a DOB mounted manual scope, and I'm doing just fine. That's what all 5 of my scopes are, manual DOB alt-az mounted. Even
at my highest powers, I only nudge the scope every 30 seconds or so
to keep the object in the eyepiece. Unless you plan on astrto-photography someday, but that's an advanced topic which I don't do...besides, who can beat the Hubble or the twin 10 meter Keck's on Hawaii?  No one. Just download their pictures from the internet.
That's my feelings on it.
Tom