Laser directing my scope(s)

[erick (Eric)]

I've found it useful to use a green laser to point scopes at targets. I just want it sufficiently accurate to get the object into a 30-35mm eyepiece and then take it from there. I usually observe from places where the temperature drops to where a green laser in the open soon decides to have a sleep, so my laser lives in my shirt pocket to keep it warm. I only need it out for some seconds - enough to find the target (and make all the imagers exclaim in anger!)

I have used various approaches - hold it on the scope against the focusser, made a little v-block to support it a little higher so the bean clears the end of the scope.

Finally I bit the bullet and decided it was time to improve on this. I put the call out and Occulta (Chris) came up with a cute little mount for me. Many thanks Chris.

http://www.iceinspace.com.au/forum/s...ad.php?t=41379

The mount will fit in GSO dovetail mounts, which I have on both my scopes. I have, however, fitted its own mount to my 12" reflector.

My current approach is to leave the two top screws out, "thread" the laser into place through the rings and hold it in place with a finger that also presses the "on" button. I have previously adjusted the four support screws so that the end of the beam is close to centred in my wide-field eyepiece. So simply move the scope until the end of beam is on the object of interest (or where I figure it to be from starcharts), remove the laser back into my warm pocket and commence observing.

I attach a couple of pics of the operation. I replaced the existing screws with "home-made" ones on which I could get better grip. A few turns of teflon tape on each to tighten the thread as well.

I'm debating whether to take the non-reversible step which I have planned all along which is to cut the top off each of the rings so I can easily place the laser on the ends of the screws and remove it again. I think I will soon.

[Robh (Rob)]

Eric,

I too use a laser for quick finding. Consider ...
The laser holder I use can be adapted to any mount which fixes the laser with 3 screws (120 degrees apart) front and back.
To secure the holder, you will therefore need the third top screw front and back to hold it in place. The holder is made from 15mm (internal diameter) irrigation riser for watering systems and a couple of irrigation plugs; it's just cheap black plastic tubing from the hardware shop. This is what you do if you're interested in the idea ...

Look at the two pictures and using a hacksaw, cut the tube length to suite your laser pointer. In the diagrams, I have put some white tape over the black tubing to give some parts more contrast. Cut a slot from the front to about one or two centimetres from the rear to slide the laser with pocket clip through. If you use a Stanley knife and steel ruler as an edge, make two parallel shallow cuts first to get the line then cut a little deeper each time. When through, cut the end of the narrow strip off. It's a bit tricky and you have to watch you don't cut yourself. Make sure the the laser and its clip slides in and out freely. If its not wide enough for the clip, slice more off.

At the front end you will need two 25mm (external diameter) irrigation plugs; also cheap to buy. Cut the plugged ends off with a hack-saw. For one of them, drill a hole through the centre of its side and screw a short allen key (socket) bolt through (or any short bolt will do). Make sure the bolt will turn freely. Adjust the position of the cut plug so the bolt is over the laser switch. I used a small piece, cut longways, off a nylon tube to take up the slack between the plug and the main plastic tube. It fits best near bottom.
The bolt will turn the laser off and on. You can use a small section of rubber tubing over the end of the bolt to turn it more easily.
The laser slides in and out from the front. Just remember to undo the bolt enough for the clip to slide past.

You will need the other cut plug behind the front one to adjust the width between the front and back screw mounts. To mount the holder, the rear trio of screws go around the end of the irrigation tube. The front trio of screws will go around the adjustible plug. Another piece of nylon at bottom will fix it. The object is to have the bolt (switch) in front of your mount for easy access.

Advantages. You can leave the laser in the holder. If it's a cold night, it's still easy to remove and keep it warm in your pocket. You can collimate the "on" laser in the holder without having to hold it. You don't need to hold the "on" laser as you move the telescope to the desired object. There is less chance you will drop the laser while moving the telescope.
Disadvantage. You have to remember never to leave it in the telescope unattended. Someone might unintentionally turn it on and damage their eyes. Although it is safer than just having the laser fixed between the 6 screws without the holder, as you have to actually turn the bolt to switch it on.
Regards, Rob.

[erick (Eric)]

Thanks Rob, I haven't taken the hacksaw to it yet, so I'll happily have a look at your approach.