Laser pens.

[Merlin]

Can anyone recommend a UK supplier of laser pens that are not temperature sensitive?

I use my pens as finders on both 'scopes and high-power binoculars. Below about 5C the beam wilts to nothing. Pity the pens don't take Viagra.

I've asked this same query a few days ago on the Forum, but, alas, I've forgotten which thread I inserted it in.

[AstroTux]

It may not be the pens that are temperature sensitive, but the batteries. Normal alkaline batteries do not like low temperatures and therefore lose power when you go outside on a cold night. I use lithium batteries in my laser pen as they have a specified minimum operating temperature of -40° (C or F, doesn't matter) and have not had a problem with it yet.

Most companies now offer AA lithium batteries and whilst they are slightly more expensive they last a lot longer than alkaline and have a far greater shelf life (maybe this is the Viagra you were looking for !!).

[johninderby]

Lasers that have a regulated output perform a lot better in the cold. Unfortunately most of the so called astro lasers don't have a regulated output so as the batteries weaken they get dimmer instead of being about to automatically adjust the laser output to compensate for this.

The Wicked Core Laser was a very good regulated one, and only about £35.00, but is now very hard to find in the UK. You could try asking an astro dealer but most don't have a clue as to the full tech specs of the lasers they're selling. You might have to ask at a specialist laser retailer.

John

[Merlin]

I tried lithium batteries a while ago, but it didn't make any difference. One trick I try is to hold my fingertip over the end of the pen to warm up the diode, but it only works very briefly.

Thanks all the same.

[CowHampshire]

I've been using the Orion green pointer and it appears to do extreamly well with temperature (even when I leave it on WAY too long). Last night at ~0C I used it for several hours on and off with no change what so ever. Sad part is that I haven't used my Starbeam since I got it....!