Expert: Tom Whiting - 4/4/2004

Question
Hi!

I live in a light polluted area with a 5.4 magnitude limit.

A few months ago, I bought a 4.5 inch reflector telescope (900 mm focal length). I looked at a lot of planets, the moon and at stars so far. A few days ago, I decided to look for nebulas, galaxies and star clusters. Howhever, I couldn't even find one single thing from the Messier catalog or in general...

So I would like to ask you 3 questions:

1) What diameter (mm or inch) of telescope is required for a light polluted area in order to see galaxies, nebulas, etc.?

2) Do GOTO telescopes really work and is it worth the money?

3) Is a refractor more appropriate in this situation?

Overall, what can I do to see something EXCEPT to move to a non-light polluted area?

Thank you very much!

Answer
Deeb M,
in Reverse order, (3) yes, a refractor is more appropriate
in this situation, since you will not be observing DSO's
(Deep Sky Objects) but only planets and bright double
stars anyway.  For example, our club in Erie, PA is mostly
large reflectors as we have the moderate dark skies for the Messier objects, but when we travel to Pittsburgh, those members own mostly refractors in the 4-7 inch catagory as their sky is so heavily light polluted.

(2) Yes GOTO's really work...are they worth the money?
That is a matter of opinion...to me NO, because I already
know the night sky and don't need it.  A better question
is, are you too buzy to learn the naked-eye night sky? (Takes about 2-3 months). If Yes, then you'd better get the GOTO, in all honesty.  If no, then save yourself a few
hundred bucks (get a better scope?) and learn the night sky.....it isn't that hard...
constellations, as you probably know, are just areas...
if you can learn and memorize PA, OHIO, IND, ILL, 4 adjoining areas, then you can also learn Gemini, Cancer,
Leo, Virgo....also 4 adjoining areas.
This ain't rocket science, you know.

(1) Under heavy light pollution, no amount of large aperture will show the DSO's....You can always substitute a smaller aperturefor a larger aperture if you want a bigger image,
but there is NO *substitute* for clear, dark skies.
(Travel is your only option there...which is what we do).

There is one "cheating" device called a Nebula filter, but
it only works on nebulosities by allowing only certain
wavelengths of light to enter the eyepiece...but again,
you have to know the night sky and know exactly where the
nebulosity is to begin with in order to find it.  They also
make a "light pollution filter" too, but you lose almost
a full magnitude of light thru your scope, so they are only
good in moderately light polluted skies.

I have found the key to enjoying good astronomy today is
to stay mobile and portable...many of us travel on the new
moon weekend, hundreds of miles and camp out at our favorite
dark sky site all weekend. In Pennsylvania, there is even
a special State Park set up for mainly astronomers in a
dark sky, called Cherry Springs State Park...people drive
for up to 8 hours, especially from the NYCity, Washington
DC area, for a weekend of zero light polluted skies.
That park is located about 15 miles southeast of Coudersport, PA, and is free camping to all astronomers.
You can check it out on the internet.

BTW, several of the Messier objects are in fact, naked eye,
even in moderate light pollution....the Pleiades in Taurus
(M-45), the Beehive star cluster (M-44) in Cancer, the
Great Neb. in Orion (M-42), and the Andromeda Galaxy (M-31)
and perhaps the Lagoon Neb (M-8) in Sagittarius...I have
seen them naked-eye in moderate light pollution using
averted vision. But that's about it....OH, the double open
cluster in Perseus is also naked-eye (NGC 884 and 869).

Just as an example of aperture, I own a 30 inch portable
truss-type DOB scope, and I even have to travel, as even
a 30 inch is worthless in heavy light pollution....you
can see this scope on our club website at
http://www.velocity.net/~bwhiting/
Good Luck, and hope all this helps, and in the future, if
you need any observing help, feel free to E-mail me directly at bwhiting@velocity.net

Clear Skies,
Tom Whiting
Erie, PA