Expert: Paul Wagner - 3/24/2005

Question
hi
     I Have just got a newtonian telescope which is 76mm diameter and 900mm focal length.I have got 2 eyepieces,one is 20mm and the other is 12mm.This is my first telescope ever.I would like to know first:Is this telescope is a good choice and what are his limits.Second:I would like to know how to look at the sky.How to see mars and how to read the star maps and point my telescope on them.I am in egypt and by the way my holder dont have a scale degree on it,So how to point it exactly on stars.Thank u in advance and please answer me soon.....This was my childhood dream(apart from being an astronut..hehehe).

Answer
Dear Hassan:

Thank you for writing.  You have a nice telescope there, and you should have a lot of fun with it.  

I don't know what company made this scope, so I can't really comment on its quality, but I can say that some famous observers in the history of astronomy used a telescope very much like yours!

The first thing you can do to take full advantage of the telescope is to find some dark skies.  Go outside the city, ideally into the mountains, where you will be amazed at how many stars you can see.  And your telescope will show you much more!

Secondly, you must now learn to navigate the sky.  I would buy a star atlas, but you can also find much of this information on line. Here is a great site from Hawaii that gives you star maps, plus maps of important objects.  From a dark location, almost all of the objects on the Messier list should be visible through your telecope:

http://www.hawastsoc.org/deepsky/lists.html

And Sky & Telescope Magazines website has good information as well--look at this page:  http://skyandtelescope.com/observing/ataglance/article_110_1.asp

If you can learn the major stars and constellations, then you can find your way around the sky quite easily.  Start with your 20mm eyepiece--this is the one with lower power, so you can see more in the field.  Then, as you find an object, you can change to the 12mm for higher magnification.  

With this telescope you should be able to see objects as dim as 10 or 11th magnitude.  YOu should be able to see four moons and some detail on Jupiter, the rings and five of the moons of Saturn, lovely images of the moon, and many galaxies and nebulae.  They will not look as good as the best photographs from a professional observatory, but you would need a telescope about 10 times larger for that!

Paul Wagner