Expert: Paul Wagner - 3/11/2007

Question
I guess i am a dummy, I have a galileo FS-102Nt and I have attempted to line it up with the red dot, etc...i have read the instruction booklet which is poor, the dvd they sent with it is poor.  I am so disgusted, I cannot be this STUPID, or can I? I have tried finding other sites on how to work the telescope, etc... maybe it is a poor brand, I probably should have gotten a better one, but i am stuck with this one.


Answer
Hi Kay

This is a tough question.  I will try to talk you through it--but the best solution is to find a local astronomy club and ask one of the members to do this with you a few times.  Then it will seem easier.

1.  Start with the eyepiece tube.  Look into the tube, and make sure that when your eye is exactly in the center of the tube,  the image of the primary mirror is perfectly centered on the diagonal mirror.  You do this my moving only the diagonal mirror.  The easiest way to see this is to back your eye up a bit, until the image of the primary is almost filling the diagonal mirror's face.  Then look at the edges to make sure that it isn't shifted to one side or the other.  

(If you are using a laser collimator, just make sure that the dot that is reflected from the diagonal onto the primary is in the center of the primary mirror--keep adjusting the diagonal until it is.)

Got that?  That's really important.  Once that is done, you will find the next step easier with a helpful assistant.  

2.  Now that you have the diagonal straight, the next step is to adjust the primary.  This time you want to make sure that the image of the primary shows you the diagonal mirror exactly in the center of the primary mirror. You will need to fiddle with the screws in the back of the primary mirror, and see which one moves the mirror the right direction.  This is where your assistant can help.  Have him or her turn one of the screws, and see which way things move.  Then start giving directions.  It will take a bit of time...but you will get it centered.  

(If you are using a laser collimator, This is where you adjust the primary mirror so that the dot appears right on top of its outgoing image in the diagonal mirror)

Sometimes, one of the primary screws is moved all the way to the end of its range.  If you are moving one of those screws, and the mirror isn't moving, it's time to forget that screw, and either tighten or loosen on of the others.  There are always three screws, so you have to use them in combination to get the image centered.

You're done.  Does that help?  If not, I really would check with a local stargazer.  They are usually delighted to help, and you will learn a lot more than just how to collimate your telescope!

Paul Wagner