Laser Pointer

[Dennis G]

Laser Pointer
Can a kind person who uses a laser pen as a telescope pointer, provide me with the average operating power limitations of a 10 or 20 watt laser pen used as a laser pointer on a scope?
The questions I’m seeking answer to are:
· How many minutes or seconds can the laser be left switched on?
· What would be the expected life of the two AAA quality batteries?

[Ingo]

10 or 20 Watts?

Miss and you'll burn a hole in your scope.

I think you mean Milliwatts. 10 to 20 milliwatt is only going to be visible in the sky if it's a 532nm Green Pointer.

All pen pointers shouldn't be left on more than 100 seconds, then turned off for 10 seconds and back on for 100 seconds. It's a duty cycle.

It all depends on the batteries. If you can get your hands on some Energizer E2 Lithiums, they should last you an extremly long time, probably wont have to change the batteries for months.

[DJVege]

Yep. I doubt there'd be an occasion when you'd need the laser on for more than a 100 seconds.

[RB (Andrew)]

Longest I leave mine on is approx 15-20 sec at a time.
I don't find the need to leave it on longer than that.
Doesn't take long to line up the chosen object.

Get good quality Energizers/Duracells and they'll last a long time like Ingo said.

I haven't tried NiMH rechargeables with mine yet.

[ballaratdragons (Ken)]

Isn't it funny how we get contradicting reports!

I occasionally put a clothes peg on mine to hold the switch down (mine is mounted on the scope) and use it for pointing out objects to which the people can look in the scope and see what its pointing at. I leave it switched on by clothes peg for up to 5 mins or more with no dramas. I am still using the same energisers I put in it about 12 months ago. And I use it a lot! Just ask the folks from Camp!

Last month I used it handheld at the SVAA club night to show members and visitors all over the sky and it was on for long periods. Later in the night I used it for Eric to point his scope where it was pointing to find the Leo Galaxies, and it was on for long periods then too.

[Ingo]

Originally Posted by ballaratdragons

Isn't it funny how we get contradicting reports!

I occasionally put a clothes peg on mine to hold the switch down (mine is mounted on the scope) and use it for pointing out objects to which the people can look in the scope and see what its pointing at. I leave it switched on by clothes peg for up to 5 mins or more with no dramas. I am still using the same energisers I put in it about 12 months ago. And I use it a lot! Just ask the folks from Camp!

Last month I used it handheld at the SVAA club night to show members and visitors all over the sky and it was on for long periods. Later in the night I used it for Eric to point his scope where it was pointing to find the Leo Galaxies, and it was on for long periods then too.

Leaving a green pointer on for that long can damage the pump diode and decrease the life of the diode. It can also damage the crystals. I guess it'd be okay outside on a not to warm night though.

[ballaratdragons (Ken)]

I've been using it like that for a year already, Ingo. And it still works as good as new.

But yep, it gets awful cold here.

[Ingo]

Originally Posted by ballaratdragons

I've been using it like that for a year already, Ingo. And it still works as good as new.

But yep, it gets awful cold here.

It might be because of the low power and that the diode is turned down under spec. There's probably a potentiometer underneath the button you can turn to crank your laser up another 10-20mW.

I know my 130mW fluctuates at startup because it's not the right temperature, and after about 10 minutes, the power will start to drop. Even though there is no duty cycle on mine, the diode will heat up.

[Dennis G]

Many thanks to those members who answered my request for information re laser pointer. Dennis G

[Terry B]

Curiously I find my 5mw one gets brighter after about 30 sec of operating so I usually hold it down for that long.

[starstruck]

Originally Posted by Dennis G

Laser Pointer
Can a kind person who uses a laser pen as a telescope pointer, provide me with the average operating power limitations of a 10 or 20 watt laser pen used as a laser pointer on a scope?
The questions I’m seeking answer to are:
· How many minutes or seconds can the laser be left switched on?
· What would be the expected life of the two AAA quality batteries?

You don't want to put a laser pointer on a scope because even the low powered ones have a duty cycle. You can't leave them on indefinitely. recommended max is 60 seconds. After that you'll have power loss and possible diode damage.

Hulk lasers from Dragonlasers (http://dragonlasers.com/hulk) do not have a duty cycle and are ideal for mounting on a telescope. They take 2 C size batteries. No idea how long theyd last for. Haha C size are plenty big so long enough.

For more info, there is another thread here some where on lasers.