when to do collimation ??

[jenksie]

I have a astromaster 130md and was wondering when or what are the signs that it needs to be adjusted. Its a new scope only used about twice due to cloud.

[ronin]

Two choices really.

Do it soon after getting it as although not used you have no guarantee of it being in collimation when you unpacked it.

Wait until the view has obviously deteriorated so that it obviously requires collimation.

If you are happy enough with collimating it then perhaps do it to be sure that it is collimated. At least then you will know if collimated and what the image is like when collimated and can use that for future reference.

[Nova]

point the scope at a bright star making sure it is center of your fov and start to take it out of focus. the image of the star you see should change into a larger bright circle with a black spot in the center. if the black spot is not central then its probably worth going through the collimation steps. just remember that the star must be center of your fov. try not to get hung up to much worrying about wether your scope is out of collimation. if the images your seeing are ok for you then i personally wouldnt worry. I dont think 100% perfection is totally nessecery

[swamp thing]

Most scopes are collimated at the factory and should arrive correctly aligned, but obviously any bad handling during shipping and transport may affect it.

Therefore it is always wise to check the collimation before you use the scope.

After initial set up a small scope with a light mirror rarely becomes misaligned.

Regards Steve

[assasincz]

I did not feel any need to collimate my scope when I bought it second hand - partly because I did not know how to do it. The image seemed fine but I had nothing to compare it to. Then I fiddled around with it and the image significantly improved. Eventually, star collimation brought the image to perfection. Now I do the star test every time I am out before observing.

[jenksie]

thanks guys, one of the reasons i was prompted to ask was when i put my 3x barlow with my 10mm eyepiece i could not get it to focus on jupiter the other night. it was ok with 20mm, also scope was only outside for about 10 mins prior to viewing.

[RikM]

A 10mm Eyepiece with a 3x barlow is probably too high a magnification for a 130mm reflector. It could also be that the seeing was rubbish. If your scope is a 650mm focal length then you would have been close to 200x magnification and I think something like 120 - 150x would be a more typical maximum for your scope. I rarely get good views at much above 150x with my 150P.