collimater

[patch58]

hi all, which collimater would i need for a dobsonian 200p,doe's it have to be specialy for a dosonian or will any do,thanks

[Uplooker]

Hi Patch,

Collimaters work for all types of newtonian's whether its a 150, 200, 250 or 300. There are two main types Laser and Chesire. People use both. The downside about the laser ones is that they do not always come with the laser itself collimated properly. That means that as you rotate the barrel of the laser the light beam traces a circle or an ellipse. It is not that difficult to collimate them, its just a bit of flaff you could do without.

As it happens i have just bought myself one of these: http://www.firstlightoptics.com/other-collimation-tools/cheshire-collimating-eyepiece.html

If you have a look at Astrobaby's collimation guide it will see you right on how to go about collimation, just google "astrobaby" to get to her very informative site or look herehttp://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm

Ian

[Scott]

No, either a cheshire or laser will do the job....If you want this thread to go on for 5-6 pages ask which is best . 

I've got both but tend to use the cheshire most. No batteries required

[patch58]

thanks for the replies i appreciate it ,thankyou.

[Scott]

no worries....200p dob hey...thats a scope to put a smile on your face if ever there was one. enjoy it and don't get too hung up on collimation. yes it's good to get it right and with a bit of practice it will become a two minute job at the start of a session but it's all to easy to get collimation ocd. don't let it spoil your fun

Scott

[ScottS]

I use a laser that has collimation bolts to adjust it and a Barlow lens that helps with collimation. You still need to be careful that the secondary mirror is set up correctly though.

[Charic]

patch58............welcome. Astro Baby has been mentioned. Check  her site out and  try the film cap method if you have one ( remember, its the base of the canister that gets sawn off, Iv`e seen it done the other way ?)or drill a small 1mm hole through the focuser dust cap( at no expense at all ~ can be taped over later ) its a reliable method to collimate. Just take your time, and keep the telescope tilted so if you drop a screwdriver or alan key it only slides to the mirror, rather than smashing into it. All becomes clear when you follow Astro`s advice. I have a laser  too (that needed adjustments before I could use it?)  I simply  use  it in the field, as I cant look through the eyepiece and adjust  M1 (M1=primary mirror, M2 being the secondary mirror) at the same time. Everyone has  their likes / dislikes for the tools required, but I think everyone  who has them,  prefes r the Cheshire, then maybe a Laser (or combination) but the cap is free, cheap, effective. Try it out. Some Cheshires come with cross hair alignment, which is why people like them. The 1mm hole in the eyepiece cap is there to aid /  align your eye to  M2, prior to final adjustments of M1. 

[Gomtuu]

I use a cheshire for the main task, then a barlowed laser to fine tune the primary.

I can recommend this cheshire : http://www.firstlightoptics.com/other-collimation-tools/premium-cheshire-collimating-eyepiece.html

[Rapallokid]

Hi Patch 58

I have a 12" dob and have found using a Cheshire an issue. maybe it is down to personal preference but for me the laser is easier to use and more accurate.

Just make sure that everything else is set up properly and you should be ok.

Give yourself plenty of time.

[patch58]

thanks again all,just ordered a laser just been watching on youtube how to collimate the collimater, thanks again all great forum and great members.

[TenBears]

I just had a replacement laser come in the mail today (the one that shipped with my zhumell has problems).

I had to collimate the laser before I could use it.  Wasn't hard though, only took like 5 minutes.

As for lasers though, some are better than others.  The base Zhumell lasers, are not that great IMO.  Light is too intense and makes a large splatter.  Hard to tell the center, as it is not a fine pinpoint.