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I'm going to smash the ..... thing!


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Trying to Collimate hte dob, and all I'm doing is seriouly losing my temper with it.

I finally got the secondrey mirror and the spider centres.

However I twiddled the knobs for the primary mirror and now I can do sod all to get it right again

image.jpg

I dunno which ones to move or whatever, I want to smash the sodding thing.

Anyway I'm going into town to cool off before I really loose my rag with it.

Kain

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Hang in there mate!

I had the same problem with my 200mm Newt a couple of years ago.

I sat down had a beer and trawled the net to find out all I could. Then bought a Cheshire Eyepiece played around with it and way hay one collimated Newt :D

Cheers

Alan D

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As you look down the focuser - hang your fingers over the edge of the tube.

Then move you fingers round till they reach the place where the mirror needs adjusting - which in this case is just to the left of 12oclock. Then follow that position down to the mirror end.

Now if that position lines up with a collimation screw, then in this case it needs to be tightened (or if it won't tighten, the other two need to be loosened).

This may seem an odd way of doing it, but it should get you back somewhere you need to be. Once rough aligned then a startest is in order...

Hope that helps.

Ant

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In what way are they next to useless? I use one and it seems to work well. With the open frame of the Skelescope I can see where the red dot is from the primary mirror end which makes adjustment a doddle. At the other end I can see the red dot and the polo mint in the primary mirror while I adjust the secondary. The laser has got to be the easiest way to do a frame type Newt.

Captain Chaos

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Cheapie ones are, as I said, wobbly. Also, not too bright. I use a 5mw red laser on the beast and i=once I have centred the beam on the secondary I can do all the collimation from the primary end because the beam is so bright. (Can see when it comes back onto itself)

arthur

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In what way are they next to useless?

Cheap ones rarely keep collimation and the spot is often too wide to use accurately.

My opinion is based on a mix of experience and feedback from a couple of astronomers I know who bought cheap lasers off ebay.

Perhaps I am wrong?

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Ah yes - as you say some of the cheapie ones have odd shapes... I had one looked like Jupiter, darka t the top, light in the middle and dark at the bottom!

Nonetheless, just because there are cheapie lasers out there doesn't mean that laser collimating is a bad idea though. There are cheapie scopes out there but Astronomy is still a good idea, no?

arthur

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Just come back from town, read the advice here and had another little play, seem to have gotten somehwere

image.jpg

Hows that looking?

Still looks a little out?

According to the Cheshire, it's on in the centre of the crosshairs on the CEP...But looks ok down the tube?!

I'm mega confused lol.

Kain

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Nonetheless, just because there are cheapie lasers out there doesn't mean that laser collimating is a bad idea though. There are cheapie scopes out there but Astronomy is still a good idea, no?

Agreed :thumbright:

I just don't rate cheap lasers :D

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I think it's done!

Though the view in the EP is not bang in the centre of the secondary mirror don't think.

Looks better than what it was anyway.

Hopefully at some point I will meet up with some of you guys at a star party or something, then one of you could show me *hint hint* :D

Kain

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To be honest Kain, I get confused sometimes when collimating.

What I do now is start by putting some card in the OTA after the

secondary to block out the primary.

That way I find I can concentrate on getting the secondary set up with the focuser

with less confusing images to look at.

Once that's done, I find tweaking the primary the easy bit. :D

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