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middy
02-05-2007, 08:53 AM
Hi all,

I received my Orion collimation tool the other day and I gave it a try the day I got it. I managed to tilt the secondary so I could see the full reflection of the primary. However, when I tried to adjust the primary to centre the spot I found that if the spot was aligned the reflection of the secondary in the primary (the doughnut) was off centre and vice versa.

Last night I had another go at it and decided the secondary wasn't centred under the focusing tube correctly (it needed some side movement). So I adjusted the spider vanes to fix that problem. I then adjusted the secondary again to get the full primary reflection, and adjusted the primary to align the centre spot. This time it all seemed lined up a lot better. My problem now is the centre spot is so damn small and faint it is hard to see where it is under the big fat shiny cross hairs of the collimation tool. It actually looked as though there were four centre spots under there (no I hadn't been drinking :P ). Maybe it was some funky difraction effect :shrug: Any hints or tips?

I took it outside to give it a check. The moon was full but it looked quite crisp around the edges. I thought I could see more detail on Jupiter but the seeing is atrocious at the moment. Overall I guess it wasn't the "Holy smokes look how much better everything is now" experience I had hoped for, given all the adjustments I had made.

When I looked at Jupiter I could see a shadow transit in progress with the GRS so I quickly grabbed the Toucam and snapped some videos. The seeing was really bad though and it was nothing fantastic after I gave it a quick process.

Enough waffle from me. I guess I'll wait until new moon to give it a proper test.

Edit: Yay my 300th post.

Geoff45
02-05-2007, 01:41 PM
Things should look like this thumbnail. Note the off centre image of the diagonal.
Geoff

rmcpb
02-05-2007, 02:06 PM
Andrew,

If you are aligning for the first time you will have to adjust the secondary, then the primary, then back to the secondary, etc a few times till it is just right. By adjusting one you alter the other but the changes get progressively smaller till they are right. Also, give yourself a break and do it in the daylight so everything is fully illuminated, its much easier.

Cheers

astro_nutt
02-05-2007, 05:53 PM
And don't forget a cuppa or two while you're doing that!! Do it in small steps!

RAJAH235
03-05-2007, 04:22 AM
Andrew, as has been said, take your time n do in daylight.
See link for explanation of 'why offset' is necessary.
HTH. L.
http://skytonight.com/howto/diy/3306996.html