Laser pointer to help align scope?

[jamieren]

Interestingly enough these are useful for more than just looking professional in a meeting and burning out your retinas now. I was reading that when mounted to a tele they can be a nice addition to help one know where it's pointed. Green colored ones were recommended in the book (anyone know why that would be?) but red would work well too, no? Just asking if anyone's tried this and how they went about mounting them. The ability to adjust will be a must, of course.

This would be so much handier than crawling along on the ground sighting up the tube ( :scratch: retailer didn't tell me about that part when he expounded the virtues of a right angle finder scope!).

[Psychobilly]

theres a lot happening with laser pointers at them moment and its not looking good for their continued use... too many idiots shining them at aircraft and police helicopters...you can buy mounts that allow them to be co-aligned with the scope...

[dogfish]

I used to use my green laser pointer to help with polar alignment. I'd stick it up the hold where the polar scope goes and if it pointed to Polaris I'd know I wasn't far out. It's also useful for finding alignment stars when you're out with other observers. "Which ones Capella?" [points laser] "That one". "ta mate!". Simple!

Obviously, not when you're under a flight path though.

Cheers, Martin

[themos]

I fitted an AC722 laser pointer mounting onto my Dob. I have a quite bright green laser and I will probably try a lower rated device, for added safety. You don't need any stars to align the "finderscope", it can be done very quickly in under a minute. I will use 10x50 binoculars, handheld, to guide the laser spot onto the target. M33 will be a good test, since it's more visible in the binoculars than the main scope.

[jamieren]

Just to test the theory I pointed my laser collimator up at the sky. Nothing. I couldn't see the beam of light at all. Mind you, it was the day before full moon (so you can imagine how bright the sky was) and it is a red laser (possibly less conspicuous?). I did however have lots of fun pointing it at faraway trees and saying 'wheee'!

[iancandler]

Just a note here, red wont work when pointed at the night sky, but green ones will as our eyes are much more sensitive to green light.

[jamieren]

Thanks, Ian. I had suspected as much. So what one would see is the beam being reflected off dust or water vapor in the air, in effect making a spotty "line" pointing towards where the beam is aimed? Man did that ever seem redundant!

[Keagle]

It's not really spotty. Mine just goes as a straight beam, as have the others I've seen.

I can see mine inside too, as a straight beam.

Of course, it is reflecting off dust and water vapour otherwise you wouldn't see it

Kurt

[jamieren]

Oy, I know the reply to this is probably going to end with "first light optics", but are there any particularly suited for the above prescribed purpose, or could you get one just anywhere? Being from Canada (eh?®) can have its disadvantages when posting on this site...

*edit* ebay looks like it could be useful after all! Someone should tell the guys @ first light to get a whack of 'em from Hong Kong with combined shipping... what a deal that could be!

[Merlin]

I have a green laser pointer attached to my 200mm Newtonian. It makes a great finder, but these laser pointers are temperature sensitive and don't work in near-frosty conditions, unless heated.

[robindurant]

I have found that Laser Pointers do not like cold weather. I need to warm mine up with my hand before it works.

Robin

[Psychobilly]

mines got its own heater plugged into one of the channels on the dew heater controller....

[jamieren]

Any ideas on what the difference is when it comes to output? I see by far the most common are 5 mw (milliwatt?). But there are also others in larger denominations (10mw, 40mw etc.). I'm hoping you don't need a high output unit to see the trail (since I'm in the process of purchasing a 5mw!), and that higher output mostly means "higher battery consumption".

[astro_dt]

Any ideas on what the difference is when it comes to output? I see by far the most common are 5 mw (milliwatt?). But there are also others in larger denominations (10mw, 40mw etc.). I'm hoping you don't need a high output unit to see the trail (since I'm in the process of purchasing a 5mw!), and that higher output mostly means "higher battery consumption".

Hi

5mW should be fine. There are regulations on the wattage and I believe that 5mW is permitted for scientific and educational work but 10 and above are not for public use. Make sure the pointer you buy is CE marked as well.

I use mine by pointing it into the finder scope...the beam shows you exactly where the scope is pointed.

Cheers

Danny

[jamieren]

Great idea Danny! I'll make a point of trying that if it ever arrives...

[jamieren]

It's also useful for finding alignment stars when you're out with other observers. "Which ones Capella?" [points laser] "That one". "ta mate!". Simple!

Obviously, not when you're under a flight path though.

Cheers, Martin

Although I've been off the astronomy warpath lately (winter is cold at latitude 55°N!) this is one thing I did try one night when it was not too frosty. With my son in tow we took out our newly acquired 5mw (green) laser pointer and set forth to identify some new constellations. Worked exactly like you explained Martin. It's so much simpler than trying to describe which star I'm talking about whilst pointing aimlessly upwards. These things are like having a mile long pointer, and if you've got someone along to point things out to, I can't recommend one enough! Also at the price tag of around $20-$50 it's a pretty minor investment for astronomy, and if we're all responsible (by not pointing them at planes etc.) we might even be able to continue enjoying their benefits.