Collimating Laser Collimators...

[Guest]

I was wanting to get a decent Cheshire but Auntie @FLOis out of stock of the one I wanted.  Another option would be to buy a laser collimator, but these can be problematic due to the fact that they can be out-of-collimation!  That being said, there are several YouTube videos on how to do this...

https://www.youtube.com/watch?v=5ZsgNlgIrqQ

https://www.youtube.com/watch?v=bE09_X43UUQ

This should be relatively easy for me to do.  That being said, are there some laser collimators that I should avoid like the plague?🤔

[Rustang]

I have a baader laser colli, cant remember the model but its a half decent one, its slightly out itself but if you feel you could sort that i would happily sell it to you cheaper than normal as im moving away from reflectors. Or just get a premium Cheshire eyepiece, but yeah stock is crazy at the moment, my dovetail is going to be really late now! 

[johninderby]

Something like the Hotech will be spot on as it comes but of course it isn’t cheap but you get what you pay for. 🙂

Had  a Baader Laser Colli but it ended up in the bin as it broke but it did need collimating to get it spot on. One thing I really like about the Hotech is that it projects a crosshair not a dot which is really useful. One thing to watch out for with the really cheap ones is that many project an irregular blob not a dot. 

However if you buy one of the cheaper lasers test it for the quality of the dot projected and send it back if not right. If the dot is a proper dot then you should be able to collimate it and end up with a usable laser.

One other thing to consider with a laser collimator is how good is your focuser? If your focuser shifts as you focus the laser isn’t going to do a good job and a Cheshire  may be better.

 

Edited August 18, 2020 by johninderby

[Guest]

49 minutes ago, johninderby said:

Something like the Hotech will be spot on as it comes but of course it isn’t cheap but you get what you pay for. 🙂

Had  a Baader Laser Colli but it ended up in the bin as it broke but it did need collimating to get it spot on. One thing I really like about the Hotech is that it projects a crosshair not a dot which is really useful. One thing to watch out for with the really cheap ones is that many project an irregular blob not a dot. 

However if you buy one of the cheaper lasers test it for the quality of the dot projected and send it back if not right. If the dot is a proper dot then you should be able to collimate it and end up with a usable laser.

One other thing to consider with a laser collimator is how good is your focuser? If your focuser shifts as you focus the laser isn’t going to do a good job and a Cheshire  may be better.

 

I've lived this long without a collimator, so waiting a little while longer for Auntie @FLOto get the premium Cheshire ones back in won't be a problem...

[Jiggy 67]

+1 for the HoTech...it is a quality laser that doesn’t need collimating and uses a compression ring in the focuser so you know it’s centered in the focuser. It is expensive but quality costs 

[Pixies]

I got a Starguider laser collimator off of ebay (Skys the Limit) for £20. It can be collimated - but didn't need to be. My collimating tool is quite basic:

The laser image at 10m:

I find it fits OK in the Bresser focuser without any obvious movement when I rotate it or tighten it. I wouldn't use it for adjusting the secondary, but it's very useful for adjusting the primary - so you can adjust in the dark and watch the progress as you work. I do double-check with the Cheshire afterwards, and it is spot on most of the time. Takes about 1 minute.

I tried the barlowed laser method but my cheap x2 Barlow had such a high level of reflectino back from the lens, that I couldn't use it. I now have a Baader Hyperion zoom barlow, so I'll have to try again.

So in all, I find it useful. Mind you, if I had to give up the laser collimator, I wouldn't be lost without it.

[Jiggy 67]

.......bizarre battery though....😀 the HoTech that is

Edited August 18, 2020 by Jiggy 67

[johninderby]

12 minutes ago, Jiggy 67 said:

.......bizarre battery though....😀 the HoTech that is

CR123 3v battery

https://www.amazon.co.uk/Duracell-Lithium-CR123-Designed-Flashlights-black/dp/B00N3VH7DG/ref=sr_1_4?dchild=1&keywords=cr123+battery&qid=1597754076&sr=8-4

[almcl]

As far as laser collimators to avoid like the plague, I bought a cheap (~£20) Seben Laser collimator a few years ago and it rates as possibly my worst astro purchase to date.

As delivered, 

• The on/off switch didn't work properly and it would randomly switch itself on in the box resulting in a flat battery every time it was taken out for use.
• The index mark for the intensity settings and the off position was way out of alignment.
• The laser dot is a spread out, diffuse kidney bean rather than a dot.
• It was miles out of collimation and the collimation grub screws (minute 2 mm allen headed bolts) were buried under black mastic which was awkward to remove.
• I did eventually get the switch to work, but only if used on the two settings either side of 0, but I have never managed to get it collimated satisfactorily.

However, I know other users have had good experiences with them so perhaps mine was just a bad example?

Edited August 18, 2020 by almcl

[Jiggy 67]

4 hours ago, johninderby said:

CR123 3v battery

https://www.amazon.co.uk/Duracell-Lithium-CR123-Designed-Flashlights-black/dp/B00N3VH7DG/ref=sr_1_4?dchild=1&keywords=cr123+battery&qid=1597754076&sr=8-4

Thanks John, saved to my Amazon wish list for future reference 

[johnturley]

4 hours ago, Jiggy 67 said:

.......bizarre battery though....😀 the HoTech that is

Its a lot better than those little hearing aid type batteries which can be and fiddly to fit, and difficult to obtain the right size.

John