laser mount

[caleb]

how can i mount a laser to my telescope. where can i buy a mount, will anymound do, such as a usual one for a typical 2X finder.
where can i buy, how do i put mount on telescope without drilling etc.

[OneOfOne]

I use a Lumicon mount, but I had to drill holes in the tube when I had it on the 8" Newt. When I got the C11 I was able to use some existing mount screws on the tube (whew!). I think either Star or Sirius were making their own, check their site, but I don't know if it needs holes or is double sided tape like the TelRad.

[caleb]

do you have a pic. what laser are you using?

[Starkler]

I wish i could buy a laser, but living in Vic..... :(

[asterisk]

There are 2 at MyAstro - one you can use double sided adhesive :

http://www.myastroshop.com.au/products/details.asp?id=MAS-268b

http://www.myastroshop.com.au/products/details.asp?id=MAS-268

Cheers

[caleb]

astersik, that is exactly what i need. but $60 is alot of money. i woult have thought they were much cheaper than that. i am sure it is of excelent quality though.

[erick]

Yep, they have always been expensive to me. And when it is cold, the laser gets too cold to operate efficiently (it's not the batteries - its the laser itself).

When I get the time I'll put up an article on my extremely low cost, no frills, no moving parts laser pointing system in which you get to keep the laser warm.

[MrB]

Interesting, I had read somewhere that some research labs had been supercooling laser diodes to shift their wavelength down(shorter), no mention of reduced output power, not saying your wrong tho, just that it's an interesting observation.
Have you tried it at the same temp with an alternative power source?

Edit: Nevermind, I just thought of a possible explaination why reduced output might occur.

[erick]

This in an FAQ on a site selling green lasers:-

"I've heard that green lasers don't work well in the cold — does Jasper have this problem?
All green lasers are sensitive to cold temperatures for a couple of reasons. The laser circuit itself is not as efficient and batteries deliver lower voltage at cold temperatures. Jasper's lithium battery works better in cold temperatures than do standard alkaline batteries.
Jasper's APC further minimizes this problem by applying maximum electrical power when the laser output is dim or non-existent. As the laser warms and becomes more efficient, electrical power is reduced.
Lasers without APC deliver a constant amount of electrical power without regard to output power. While such a setting is sufficient at warm temperatures it isn't enough in a cold environment.
Even Jasper will not start in extremely cold temperatures. You can overcome that problem by warming Jasper in your hand for a minute or two before using it on cold nights. Once Jasper begins operation, it will usually generate enough heat to keep itself warm."



Looking at the quoted "working temperature" for the multitude of green handheld lasers some say lower limit of 20degC, some 10degC, some 0degC??

[madtuna]

That may be a problem for a mounted laser, but for hand held I just keep it in my pocket and never have a problem

[erick]

Indeed, that is the solution in cold weather. Now one then needs a quick install mount arrangement to facilitate the fact that the laser lives mostly in a nice warm pocket.

In fact, I think it's a good idea, in the new regime re lasers, to keep that laser secure in ones pocket most of the time.

[madtuna]

That's why god invented the bum crack and the pocket on the front of daddy undies

[Jeff]

Hi Caleb,

You can cheaply mount a laser in the using a small (useless) finder scope. I purchased a cheap 5x24mm finder/mount on eBay for under $10 delivered, then shoved the laser up my ..... finder tube with a bit of cloth tape added to make it a snug fit.

If unable to find a suitable finder bracket, I probably would have made something out of wood and well prepared chewing gum.

Hope this helps.

Cheers,
Jeff

[OneOfOne]

I cut my laser open with a hacksaw so I could connect directly to the battery terminals and then connected it to a voltage regulator circuit set to output 3.00V from 4xAA cells. If I put it in the freezer, it outputs 2.96V. The problem is the laser doesn't work even in the fridge, so yes, that confirms that it is the laser diode and not the batteries at all.

My next thought is to put a small resistor inside the laser tube and run a couple of watts directly from the batteries to keep it warm, with a switch to turn it on when needed...or maybe a dew strap wrapped around it!

But normally I only use the laser for alignment at setup time. At public viewings I use the one in my pocket.

[MrB]

Yes it's the laser, I made the comment above before I remembered you guys use green lasers.
I figured there may be a problem with the shift in wavelength of the diode being pushed outside the operating bandwidth of the frequency doubling optical crystals used in these.
While this is true, after doing a bit of research I found it's mainly a problem with just one component. While all other components would be quite happy at lower temps(including one of the crystals (Nd:YAG)) and likely to be more efficient, one crystal(the freq doubler (KTP)) is happier the warmer it is (40-50c).... room temp happens to be a handy compromise for all components.

If anyone is interested in learning more, check out Sam's Laser FAQ (http://www.repairfaq.org/sam/lasercds.htm#cdstoc) - a massive website, the link tho is directed to a page about a homemade green laser diode with mention about temperature wavelength tuning, KTP heaters etc.

Thread hijack over....(sorry!)

[erick]

Thanks for the info, MrB :thumbsup:

Surely there is a market for an astronomical version with a small heater on that KTP crystal. Would the battery drain be too great to get it up 10 deg C?

[MrB]

Maybe, maybe not - depends what size cells are used, if they're the little button cells, then yeah too much drain, but if AAA or larger there would be plenty 'nuff grunt for ?? hours of run time with a resistor or two as heaters.

[mabsj2]

try ebay. i am sure there are such stuff for sale..

[astronut]

Caleb,
This is how I mounted my laser. I've run a lead from my power supply to a heater wrapped around the laser.
This helps to keep the unit operating in cold conditions.
I also recommend that you use Lithium batteries to run the laser.:thumbsup:
I purchased the mount from Scopestuff.

[caleb]

if i have my laser on and walk outside it will dim. usualy diming to nothing. and it usualy takes a few mins to warm up and it sudenly goes bright green.

and.. i havn't found anything for a mount yet, still looking.

[OneOfOne]

Here are a couple of shots of my modified mount and laser. I cut the tube down with a hacksaw and soldered directly to the power connection on the circuit board. The power wires then go to a small regulator circuit which will maintain the voltage at 3.00V even when it is cold. Very simple circuit, LM317 regulator as I recall and a couple of resistors.

The mount is a lumicon.

[caleb]

i like!
kinda took ages to reply but yeh, still havnt got one.
and, do you think its beter for a laser to be able to stay on or just a button you have to hold down?