Skywatcher Laser Collimator

[FLO]

The new Skywatcher laser collimator has arrived and is surprisingly well made for its price.

* Designed for the accurate collimation of Newtonian Reflectors, Dobsonians and Refractors.

* Large display window allows the user to clearly see the face of the device.

* Seven adjustable brightness levels.

* Supplied with a removable adapter for use in both 1.25" & 2" focusers.

Price : £45 inc delivery

[algol]

nice price steve, don't think mine needs collimating yet, but when it does, i know where i'll be coming

[FLO]

It does have a nice quality 'GSO' (I am only guessing) feel about it.

[GazOC]

I may be missing something obvious but I can't see how it can collimate refractors.....

[FLO]

It took me a while to get my head around that. When using a single-beam laser you cut a paper circle the same size as the front cell opening then punch a small hole in its center. Centre the paper circle in front of the lens cell then fit the laser into the focuser without the diagonal. Switch the laser on and check that the lasers beam passes through the hole. Alternatively you can also use a ruler held across the lens cell to check the beams position horizontally and vertically. This assumes of course that you have a refractor with a collimateable lens cell...

[GazOC]

Gotcha!

[jimlennie]

It took me a while to get my head around that. When using a single-beam laser you cut a paper circle the same size as the front cell opening then punch a small hole in its center. Centre the paper circle in front of the lens cell then fit the laser into the focuser without the diagonal. Switch the laser on and check that the lasers beam passes through the hole. Alternatively you can also use a ruler held across the lens cell to check the beams position horizontally and vertically. This assumes of course that you have a refractor with a collimateable lens cell...

Hi Steve,

What you are describing above is the method used to ensure mechanical alignment of the focusser to the optical axis centre using a laser, a thing I had to do when fitting a new moonlite focusser to my 6" refractor. The lens collimation is usually performed by using a cheshire eyepiece. With the lens cap on and in a dark room using a laser it is possible to see if lenses are aligned by looking at the reflected spot on the laser graticule ( similar to aligning a reflectors main mirror using a laser ) if the spot is off centre then you can use the screws on the lens cell, if fitted, but you have to make sure that you have focusser alignment set properly in the first place.

When I checked my Skywatcher ED80 with a cheshire I could see a figure of eight in the cheshire which meant that collimation was off slightly, as this scope does not have a collimatable lens cell I had to play around with the focusser ( building it up with tape to ensure a better fit to the main tube ) to get a single doughnut. I gather that this was a common problem with these scopes when they first came out.

Jim

[FLO]

Hi Jim,

Yes, you are right, what I described was only half of of the story :salute: 8)

The next step is to adjust the objective so that the laser's spot, reflected from the centre of the rear element surface, is returned to the collimator face and centred in the usual way. An accurately aligned objective with no wedge should form a single reflected spot. Multiple reflected spots suggest alignment problems within the objective.

I know you speak from experience Jim and that we are practically neighbours, my knowledge of this is theoretical so perhaps I could call in sometime for a demo

[jimlennie]

Hi Jim,

Yes, you are right, what I described was only half of of the story :salute: 8)

The next step is to adjust the objective so that the laser's spot, reflected from the centre of the rear element surface, is returned to the collimator face and centred in the usual way. An accurately aligned objective with no wedge should form a single reflected spot. Multiple reflected spots suggest alignment problems within the objective.

I know you speak from experience Jim and that we are practically neighbours, my knowledge of this is theoretical so perhaps I could call in sometime for a demo

Hi Steve,

You are welcome anytime and don't forget that I have some equipment of yours here ! Glad to get back into the hobby again as have been extremely busy with work and rocketry since last September so haven't used my scopes much. I've been using the Helios 20x90's for the odd quick fix and must say that I'm delighted with these binoculars.

Jim

[FLO]

Excellent