Expert: Paul Wagner - 12/24/2006

Question
ok i have been having some really really bad problems with the new telescope that i have just bought.. it is a meade etx-80 with autostar..the problem is that the compass is a piece of junk that they sent me and it is crucial to the autostar feature to find north....now im no expert so i dont think that counting degrees will work very well and i was hoping i could just find north instead of going out and buying a compass...but the other thing that i am confused about is the barlow lens.... i have no idea what it does or how to operate it...if you could give me some tips on how to use my telescope manually that would be great too because this autostar thing just ruined my planned out night of viewing...thanks for the help Paul

~Nick

Answer
HI Nick;

Let's start with the easy one---every astronomer should know how to find North.  And if you don't know where North is, look on a map to see.  Another way is to simply go outside at noon. The sun will be due South, so if you look directly away from the sun, you will be looking North.  And North doesn't change.  It's always the same direction.  It would probably make sense for you to even set up a marker in your backyard, or find a landmark, that will always show you where North is.  

If you can ever find the Big Dipper ( Ursa Major ) in the sky, the two "pointer stars" of the end of the bowl also point to Polaris, the North Star.  It is due North, as well.  

I would suggest that you find a book called "Turn Left at Orion."  It is a great guide to naked eye astronomy, and will really help you find your way around the sky.

Now as for that Barlow lens.  The Barlow lens is a system that acts as if it is lengthening the focal length of the telescope.  You have to take your eyepiece out of the tube, insert the Barlow lens, and then put your eyepiece into the end of the Barlow.  That's where it goes, now let's talk about how to use it.

The Barlow lens really magnifies the image--sometimes way too much to do you any good.  So start with something easy.  Point your telescope at the moon, and using your LOWEST power eyepiece ( probably 25mm) find the moon and look at it through your telescope.  Got it?  Good.

Now, without moving the telescope at all ( and that will be hard ) take out the eyepiece, and put it into the larger end of the Barlow lens.  Then insert the Barlow lens into the telescope focuser.  Play with the focus until it is as clear as you can get it.  That's it.

Too many people try to use the Barlow lens with a very short focal length eyepiece.  While this gives you higher power, it also makes the telescope almost impossible to manage.  Work with the 25mm eyepiece first, then try some of the shorter ones, that will give you even higher power.

And let me know how you get on.

Paul Wagner