Collimation woes

[Crunchard]

I have been trying (and failing) to get my TAL150P collimated correctly - or so I think anyway.

This was where I started:

And I got it to this:

I then realised there was a smudge on the primary mirror (should have looked first), so out it came for a clean and now I can't get anywhere near the collimation I want!

It is currently sat at this:

I must be missing something ... so here's hoping that some other TAL1 / TAL2 / TAL150 owners can shed any light on some handy neat tricks - or anyone come to that ... I've got till the 15th to get it all sorted ... something about Jupiter and the moon

Cheers, Jeff

[mdstuart]

It does not look too bad to me..Is the secondry mirror centralised in the tube at the eyepiece end.....

As they will tell you on here go for Astro babies collimation tutorial...

Stage one get the secondry central in the tube and directly below the focuser and showing the main mirror central...THEN move to the secondry and get all the circles lining up..

Have you tried making an artificial star from an LED shining through a pin hole. This lets you work in the dry and take your time to get it all spot on...

Mark

[umadog]

This is a useful and under-rated guide: http://www.propermotion.com/jwreed/ATM/Collimate/Chesire.htm

[Crunchard]

Cheers for that.

I have looked at Astrobaby's page, and I think the 2ndary is central.

Liking the Cheshire page.

Things to try

[8kids]

Read Astro babys guide to collimation, I used this when I first collimated my 300pds. The important thing is don't panic or lose heart you can do it.

I did however at one point confuse the spider vanes with the cross hair on the collimator but once noticed it was then a doddle.

[Crunchard]

Ok, the secondary was out by about 1mm, enough to make it look like 2 inches through the focuser

Once that was right, it was about another 30 minutes of fiddling ... with the mirror adjustments ... tsk ... to get it to this point:

I think that is job done.

Cheers, Jeff

[mdstuart]

It still looks a bit odd to me as all the circles should be lined up but the cross is in the centre of the smallest circle so its pretty good in my humble amateur opinion ....only collimated about three scopes about ten times...!

Mark

[Freff]

This is a useful and under-rated guide: http://www.propermot...ate/Chesire.htm

I agree with umadog. This is an excellent guide.

Read it carefully and follow it to the letter, don't try jumping the gun by lining up anything ahead of the sequence.

Make sure the secondary is perfect before adjusting the primary.

[moriniboy]

I found centre spotting my TAL 1 with a paper ring reinforcer helped when using my laser collimator, I also use a cheshire as well.

Have you tried watching Astronomy Sheds videos?

[Crunchard]

2 hours of playing this evening and I now have this:

Sorry about the brightness, had my very own portable sun (ok spotlight) doing it's best to illuminate.

[umadog]

It still looks a bit odd to me as all the circles should be lined up but the cross is in the centre of the smallest circle so its pretty good in my humble amateur opinion

The circles should not all be concentric, if that's what you mean. See: http://www.cloudynights.com/ubbthreads/showflat.php?Cat=0&Board=reflectors&Number=3033065

[mdstuart]

Try a star test now to see if you get nice rings around a bright star on high power on both sides of focus..

Your circles are better than mine now!

If you do you are fine...

Good luck..

Mark

[Crunchard]

Stars ... remind me again ... are they the things that twinkle above the clouds?