Jump to content

collimating mirrors

S1m0n

Recommended Posts

S1m0n

S1m0n

Posted
Posted

Hi guys hope you can help

I purchased a laser collimator and it arrived today : ) I checked it to make sure the collimator was collimated by using a V block and I had a perfect dot while rotating.

Anyways I slotted the laser into the eye socket and tightened the screws so that it was steady and straight away I noticed the mirrors were way off, we are talking atleast 1cm maybe more away from the centre of mirror.

I started with the secondary mirror using the small screws at the end of the mirror to centre the dot but had a little trouble and had to physically put my hand in (gently) to slightly move the secondary mirror as just moving the screws would not align :( but I got it eventually .

I then started the second part to align the primary mirror to the collimator :) I adjusted the screws so the mirror matched the centre of the collimator and though walla done !!! and adjusted the finder scope so everything was centre etc ... then I put the collimator back in to check and it was misaligned again !!!! I thought what !!!! so I had another look and hit my head I forgot to tighten the other screws on the primary to keep it stable :o anyways I redone it all again and eventually everything is aligned.

Im a little concerned at the secondary mirror as I didn't think I would need to touch it so I have too a few pics and was wondering if you guys can have a quick look to see if I have done everything correct. :)

much appreciated.

dave

Link to comment
Share on other sites
gazza63

gazza63

Posted
Posted

If the laser is on the primary mirror sweet spot, and the secondary mirror is showing centred on the collimator, everything should be fine. You don't mention what scope you are using. If It's a long focal length F8 or thereabouts, collimation isn't that critical.

Link to comment
Share on other sites
S1m0n

S1m0n

Posted
  • Author
Posted

If the laser is on the primary mirror sweet spot, and the secondary mirror is showing centred on the collimator, everything should be fine. You don't mention what scope you are using. If It's a long focal length F8 or thereabouts, collimation isn't that critical.

using a dob 200p , I knew it probably would critical but thought I would just do it so I could get the best out of the scope.

I got the laser dot into the circle centre dot that is on the mirror , my only concern was I has to touch the secondary mirror housing a little as the screws would not align the mirror correctly :( so had to slightly nudge it with finger on either side (didn't touch the actual mirror surface).

If I get some clear sky tonight I can test it on the moon or Jupiter. Would love to get Saturn but I am not in a place where I can get a good spot plus Im in north of England and not sure if I can.

Link to comment
Share on other sites
Charic

Charic

Posted
Posted

S1m0n......... not a problem touching the assembly.  The centre screw (secondary mirror) just moves the mirror to / away from the primary mirror. It will probably rotate if you undo the screw(hold the whole assembly if unscrewing, to prevent any twisting to the assembly, my screw was VERY tight) So if the mirror is out of alignment in any way, you`d centre the mirror   by adjusting the screw, so mirror effectively moves left/right as viewed though the focus assembly. Then possible rotation is required, which is hands on( without getting sweaty fingers on mirror) to see  the circle, rather than  any eliptical shape of the mirror,  then finally the three allen bolts will set the tilt of the mirror.  Im waiting to get my collimator laser, but your images look fine. I used a 35mm film cap to check mine out, and the Star test was perfect, as mentioned in one of my threads,  but you already know, having the laser allows adjustments to be made without faffing about between main mirror to eyepiece to mirro,r over and over again. Check my pics in my gallery for  the gap in my scope? Thats why I  loosed my spider off to start again.

Link to comment
Share on other sites
S1m0n

S1m0n

Posted
  • Author
Posted

Many thanks for the replies guys , after collimating I took the scope out for a spin and got some nice views of the moon but cloud came over so didn't get to try any planets. Etc

Just some advice for anyone who's not used a laser before on the scope , make sure you put it in a v block and roll it and if you get a constant dot you are fine and also don't forget to tighten those eye slot screws :)

Link to comment
Share on other sites
NIGHTBOY

NIGHTBOY

Posted
Posted

Got one i use both now.

I can absolutely see how a laser would be most hand when doing the primary. Earlier on I had my mrs sat on a chair looking down the Cheshire saying  'closer... closer.... away....closer' etc as I turned the screws hahaha. :grin:  :grin: :grin:  

Link to comment
Share on other sites
wookie1965

wookie1965

Posted
Posted

I can absolutely see how a laser would be most hand when doing the primary. Earlier on I had my mrs sat on a chair looking down the Cheshire saying  'closer... closer.... away....closer' etc as I turned the screws hahaha. :grin:  :grin: :grin:  

Yes or just tweak the mirror and keep checking even when i have got the laser right i still check with Cheshire and then i use my torch on the Cheshire to light it up so i can get the dot dead centre.

Link to comment
Share on other sites
S1m0n

S1m0n

Posted
  • Author
Posted

Yea biggest problem with cheap laser collimator is you need to collimate the collimator lol!

This was my first time doing this and was nervous but I think everything went ok and was quite surprised how far off the mirrors were .

Link to comment
Share on other sites
wookie1965

wookie1965

Posted
Posted

I was then i checked with my Cheshire and that was out so i knew there was something wrong all OK now but like i said was nightmare collimating the laser did it over the length of my room made it the tightest circle i could rooms 24 feet long so when its in scope does not move when turned.

Link to comment
Share on other sites
jason.p

jason.p

Posted
Posted

Having cleaned the primary and re assembled I got it as close as I could with a Cheshire, then gave it a final tweak with a Barlowed laser. To be honest, it wasn't far out, but I felt better for doing it. I suppose the acid test will be a star test once I can get out under a clear sky.

Sent from my GT-P5110 using Tapatalk 2

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.