The Official Astronomy Thread

[mercurial]

Haha. Well let me know how well the refractor does. Which one is it?

 

[Crusader]

It's the Skywatcher 90mm f/10 Evostar Achro (909AZ3) on the AZ3 Alt-Az mount.

 

[mercurial]

Cool. Well let us know how it goes. My laser collimator arrived promptly yesterday, so I need to get the scope sorted soon.

 

[marine1]

what does the collimatir do?

 

[mercurial]

Every now and then, especially with a reflector telescope, the mirrors loses its allignment. If they are not properly alligned, the images you see are out of focus/blurry and doesn't have the right contrast. A collimator shows you where it needs to be properly alligned. You basically then just adjust some screws to adjust the tension of the mirrors.

 

[marine1]

Ok I suppose they are fairly expensive ?

 

[mercurial]

The laser one which is the best costed R650.

 

[Crusader]

A laser collimator isn't required but it makes it much easier. A collimation cap will be adequate in most cases. Pinpoint collimation is very important in fast scopes of f/5 or lower. Slower scopes can take quite a bit of miss-collimation while still showings excellent views. They also hold collimation much better only needing adjustment once a year or so.

 

[mercurial]

A laser collimator isn't required but it makes it much easier.

And it's also a lot more accurate.

 

[Kalvaer]

And it's also a lot more accurate.

Only if you are sure the laser is collimated as well If the laser is out you can set the mirrors up completely wrong.

Unless of course, if you Barlow Collimate

 

[Crusader]

Yes, provided that the laser is collimated itself or by using the barlowed laser method.

 

[mercurial]

My laser now also needs to be collimated?

 

[Kalvaer]

LOL technically yes.

Its easy to do though. Well, if you have a long passage. I do it by placing the laser on a L shaped block, where the laser sits in the corner. Turn it on and go to the other side of the passage and put a piece of paper on the wall. Then put a dot where the laser is. Go back to the laser and turn it (so that the laser light moves on the wall. If you can rotate the laser 360 degrees with out it moving off the dot, the laser is fine.

If not, then you need to adjust it.

But as mentioned. If you do the barlow way.. you dont have to bother.

 

[mercurial]

I don't get it - the part about rotating the laser without moving off the dot
If I'm going to move the laser, then it won't be pointing at the dot.

 

[Kalvaer]

You "roll" the laser around in the corner of the L block. If the laser is collimated, then as you roll the laser. It will always shine on the same spot. but if its not, the light will actually move around.

You can actually see this in your scope. Put it in and turn it while its in the focuser. If it moves around in circles on the mirror, then its out.

 

[mercurial]

I must be blonde today, but anyway, I'll try it out. Thanks

 

[Kalvaer]

Its actually hard to try explain.

I actually built my first collimator out of PVC pipe and a pocket laser. So I had to learn all about setting it up. I'll try see if I can find the link I used as it becomes clearer when you see the photo's

 

[mercurial]

I agree. Pics would be awesome I'll probably try and YouTube it later as well

 

[Kalvaer]

Here is a VERY detailed explaintion of it all by Nils Olof Carlin. He goes into a lot more detail than the PDF I posted above.

http://web.telia.com/~u41105032/kolli/kolli.html

And then also his link on how to make your own which I originally used.

http://web.telia.com/~u41105032/kolli/kolli2.htm#mklaser

 

[mercurial]

Sweet, thanks