First night with mounted laser

[citivolus (Ric)]

Last night was the first night for some new equipment. I figured I'd try some trial and error work with the moon giving me a bit of light. One of the items I was using for the first time was my new mounted green laser pointer. I never thought I would use it as much as I did! I think I looked through my finder scope once, the rest of the time I just popped the laser on for a few seconds.

I did hear a couple of "what's that?" coming from my neighbours who were out at their pool, but other than that it was uneventful. There were no aircraft plummeting from the sky in flames, and no police knocking on my door

Re-aligning the scope after equipment changes and balancing was also much easier when not needing to look through the finder while moving the OTA. I was playing around in Orion, so I would just slew to Rigel, do my changes, and then, using the laser, return the scope to its proper position.

Eric

[dannat (Daniel)]

which mount are you using fr the laser pointer? at the moment I just butt mine against the scope but would like a permanent one

[citivolus (Ric)]

I bought a mount that fits into my finder scope dovetail on my ED80. I got it at Sirius Optics for $49.

It includes a screw that engages the switch on the pointer for extended operation. I also protected the pointer body with some small lengths of vinyl tubing, so that the screws that hold it in place don't actually touch it. I did this over the switch as well. I got the idea after seeing what my daughter's fingernails did to one of my old red pointers.

[erick (Eric)]

Something to note, come next winter. My understanding is that green lasers have a lower working temperature (I see some 30mW+ ones advertised as 15 deg C minimum operating temperature). On a cold night, your light output may drop away. Though it may be the batteries, it's more likely too cold for the laser to operate. I keep mine in my top pocket between uses. Yes, true that is not much help if you have it accurately lined up in a mount - taking it out may lose your alignment.

[citivolus (Ric)]

Hmm, I may have to mount a dew zapper on it

[OneOfOne (Trevor)]

Originally Posted by erick

Something to note, come next winter. My understanding is that green lasers have a lower working temperature (I see some 30mW+ ones advertised as 15 deg C minimum operating temperature). On a cold night, your light output may drop away. Though it may be the batteries, it's more likely too cold for the laser to operate. I keep mine in my top pocket between uses. Yes, true that is not much help if you have it accurately lined up in a mount - taking it out may lose your alignment.

I did a bit of work on experimenting with lasers and batteries at low temperatures. During the winter months, I tried several times to use my 30mW laser for aligning the GoTo but the laser was barely visible even on the palm of my hand. Not knowing what the problem was I got some bits from a local electronics store and created a 6V regulated power supply which I connected directly to the laser (I hacksawed the end off the tube and soldered directly to the circuit board connecting to the laser itself). I trimmed the output voltage to 3.00Volts and room temperature. If I put the whole assembly in the freezer for an hours or so, the voltage drops to 3.98V but the laser is totally OFF, not a peep out of it. As it warmed up again it came back to life. Putting it in the fridge at 4 degress gave an output of 3.99V, and the laser is still OFF.

Since then I have had the scope out on nights of around 10 degrees and the laser takes a minute or so to warm up, and I know the voltage should be within a wisker of 3V so the critical thing appears to be to keep the laser warm, although who knows what the batteries will do when they are cold too. At least now I know if I leave the laser on for a while it will come to life, eventually. The power supply has 4xAA batteries rather than just 2xAAAs so it has enough kick to warm the laser up. If you are interested in such a project, I can send you details.

BTW, I use a lumicon bracket which fits on it's own mount, that way I still have the finder. However, having done all this work on it, I now find I usually use the TelRad to align the scope now and rarely use the laser anyway (the only reason I mounted it was for initial alignment).

[astronut (John)]

Eric,
I was having the same problem with my 20mw laser.
So I added two things, firstly I'm now using Lithium batteries, these handle the cold a lot better than anything else.
Secondly I've placed a heater over the laser end of the tube, this helps keep the area warmer than usual.
So far it works well. Here are a few images of my setup.

[ballaratdragons (Ken)]

The few times my laser died in the cold made me think I should build a heater for it. I use my laser every time I set up, so it is well needed. But the heater only has to stay on for about 2 mins while I do my Polar Alignment. After that I don't need it.

I currently warm it up with the Hair Dryer and it works fine.