Centre Spotting and Laser Collimation

Muppet Man

Hi folks, I'm pretty certain that my new scope needs to be collimated. Its a Newtonian Reflector shipped from Germany and then half way around every bumpy road in Ireland in the back of van and then a car, so no surprise I suppose that it would need to be adjusted. Symptoms are:

* I am unable to focus crisply on stars,
* The "fully defocused" trick shows the black centre is not in the centre of the defocused image (its off centre at a 10 o'clock position),
* The moon edge (the "Horizon" of the moon as such) looks like it has an atmosphere (a blur),
* "Parts" of Jupiter / Saturn at 100x magnification are quite visible and clean, but again, but at the same time some parts of the same image seem defocused.

This isnt helped by the fact that I didnt have a centre spot on the primary mirror. I followed the steps here - http://www.garyseronik.com/?q=node/168 for centre spotting the primary mirror and thankfully this has largely been uneventful. It took about an hour to get the primary mirror off - only 3 screws held the mirror in, but it just wouldnt pop out - it needed to be "encouraged" by leveraging gently with a stanley blade. Once off, it only took about 10 minutes to center spot it, and 1 minute to the mirror back on. While out, I also lifted a tiny black piece of dirt off the mirror with a q-tip, which had been annoying the bejaysus out of me...

The only issue now is that I dont have a Laser Collimator. I know I need to buy one as part of my ongoing maintenance of the scope, but I was wondering in the meantime if I could borrow a Laser Collimator from anyone in the Dublin area. I guess I want to make sure that the scope does need to be collimated before I go an buy one (and to ensure that there isnt anything else more serious wrong with the scope). I can do the collimation myself, just need to borrow the laser collimator. Anyone willing to help out? Please PM me.

Thanks, Muppet Man.

ZeRoY

Take a look at this recent thread.

http://www.boards.ie/vbulletin/showthread.php?p=82609665

And yes it looks like your newt needs collimation!

Was rightfully advise against laser collimator - they often need collimating themselves! Lookup Cheshire collimator, cheaper and better!

Muppet Man

Thanks Zeroy... funnily enough, while looking today, it seems many prefer a Cheshire over a Laser collimator... and I had seen Astrobaby's guide. There is a Celestron Cheshire (94182) available in Astronomy Ireland for 54 euro, which seems kinda pricey, but I'll probably just bite the bullet on it cos it seems like something I must have with a Newtonian.

Thanks for replying...
Muppet Man.

nanook5

Look here much cheaper !

Kersh

Whereabouts are you?

Ill give you a loan of one tomorrow if it suits.

I can loan you a laser, cheshire and a collimation cap that I use myself.

Muppet Man

Kersh - you're a legend, I will PM you.