Baader LaserColi - collimate or not

[GazK]

So my bargain Moonlite focuser has arrived - thanks to FLO - so now it's time to fit it. I want to start with a well-collimated scope so I thought it was about time I checked my Baader collimator.

Having rigged up a vee-jig with one end on the drawtube end and the other on one of the circular housing sections, I pointed it at the garage door about 2.5 metres away. Rotation gives a circle of about 2" diameter described by the red dot.

On the other hand, astro friends always commend me on good collimation when we're out, and I generally only use the laser, with a cheshire only used once in a blue moon when its light enough to do so.

So, do I give in to my tinkering side and let my allen key loose on those oh-so-tempting bolts, or leave things as they are and avoid collimation-madness?

[John]

The "spot" needs to be more or less stationary at around 15 feet - thats what I aim for. A 2" circle at half of that distance is not really accurate enough, unfortunately.

[8kids]

I'm not an expert but technically speaking that's miles out.

[Saleratus]

Hi Garry,

Collimation madness is the way to go, definitely! You'll feel so good after it's over. Besides, there's nothing else to do right now.

[Saleratus]

Let me know if you'd like to borrow a set of Catseye tools--you can go deliriously mad with them.

BTW, Congratulations on the Moonlite focuser. They are wonderful.

[Steve Ward]

As the LaserColl you are using is not parallel you will never check it like that ,

assuming you are collimating the dob , put the laser in the ep holder and rotate in there and watch the dot on the primary, if it makes a circle there then you'll know it it's out.

Try these tutes

http://www.astronomy...php?f=19&t=2597

http://www.astronomyshed.co.uk/forum/viewtopic.php?f=19&t=7788

[Capricorn]

Sounds like you are fairly confident with the whole procedure so redo it with a well set up collimator.

[alan potts]

On the sumject of collimation. I wanted to coolimate my SC scope and wrongly read you could do it with the Baader Collimation Laser. The scope was fairly new and I didn't thing anything was wrong with it. It was a new toy, you know the feeling.

Now those of you that know how a SC is collimated will laugh. The sales pitch on the laser from Baader when you look a bit closer was, you collimate you SC scope using the normal method, with a star and then the Laser is for a check to see if it is still in the same place on the target so to speak . In short it didn't collimate a thing for me. I sent it back!

Lesson to be leant, read the small print!

Alan.

[GazK]

As the LaserColl you are using is not parallel you will never check it like that ,

assuming you are collimating the dob , put the laser in the ep holder and rotate in there and watch the dot on the primary, if it makes a circle there then you'll know it it's out.

Try these tutes

http://www.astronomy...php?f=19&t=2597

http://www.astronomy...php?f=19&t=7788

Thanks Steve, but surely if I rotate it in this jig:

The angle the colli is pointing at doesn't change and therefore I'll get an accurate measure of its paralellism?

[GazK]

John, Skids, thanks for the advice. mMMMmmm, bolts......

[GazK]

Let me know if you'd like to borrow a set of Catseye tools--you can go deliriously mad with them.

BTW, Congratulations on the Moonlite focuser. They are wonderful.

Will do Will (see what I did there?) I bet I could get really obsessive with kit like that....

[John]

Thanks Steve, but surely if I rotate it in this jig:

The angle the colli is pointing at doesn't change and therefore I'll get an accurate measure of its paralellism?

You are assuming that the casting of the upper body of the collimator is totally accurate and true / square with the axis of the chrome barrel. That might not be the case. There only has to be a very small deviation to throw things well off at 3m or so.

The Baaders are awkward to collimate because of their asymmetrical body shape, unfortunately.

[Steve Ward]

Ditto.

[GazK]

You are assuming that the casting of the upper body of the collimator is totally accurate and true / square with the axis of the chrome barrel. That might not be the case. There only has to be a very small deviation to throw things well off at 3m or so.

The Baaders are awkward to collimate because of their asymmetrical body shape, unfortunately.

I see what you mean - I just did the maths and the eccentricity required to produce a 2" circle at 2.5m is only 0.8mm.

I think I'll leave the collimator as is, and stick to barlowed laser collimation backed up with a cheshire. Thanks all...

[cs1cjc]

The way I would test for alignment is with your closest fitting 2" to 1.25" adapter gipped firmly but not tight enough to distort in a vice with the adapter screw tightened to the point where the collimator will just rotate. Or test it in the telescope by rotating it.

[alan potts]

I bought one of these and I really think they are jerry built, for the money I thought is was poor to say the least. I truely believe mine was not set up right from the day I bought it. When I put it into the scope it was telling me it was miles out and it was not.

I would be happy to spend money on something that works well, is made well and will tell me if a SC scope is correctly collimated. It might be nice if it worked on RC scopes and Mac/ Newt's. I guess that a refractor will not need doing.

Alan.

[Tinker1947]

For those with a Lathe, placing the end of the collimator in a 3 jaw chuck with the laser pointing into the chuck, rotating the chuck will show the red dot as it comes out of the end as this is hollow, it does require 1, a lathe, and 2 the lathe needs some space behind the chuck end, in my case 20' to the end wall, all i need a is a laser collimator now...

[John]

...I would be happy to spend money on something that works well, is made well and will tell me if a SC scope is correctly collimated. It might be nice if it worked on RC scopes and Mac/ Newt's. I guess that a refractor will not need doing.....

The Howie Glatter tools are reputed to be excellent and I think the ones with the holographic grid will work with SCT's, Maks etc:

http://www.collimator.com/coltext.htm

I use a laser collimator with my refractors to check that the focuser is square with the optical axis. For the tilt of the objective lens a standard cheshire does the job.

Star testing is good and free of course. Needs a lack of cloud though, which is hard to come by in the UK at the moment