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Newcomer -question about astronomy bluray use

svdr

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Jan 8, 2009
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Hi all!

I am from Belgium, Europe.

I am new here, but not new to lasers. I've built myself a 200mW red with aixiz components and before that I modded a 5mW DPSS greenie to about 30mW. Both work fine, but my question goes about a Blu Ray.

I am not about burning things. Me and some friends are into astronomy and we use 5mW greenies for aiming our telescopes. Our beams must not be too strong as otherwise it influences the dark adaptation of our eyes. A barely visible 5mW green beam is just fine. I use my 30mW green only for showing targets in the sky to larger groups. The problem we experience is that our greenies die at freezing temperatures. Bottom line : when it's to cold, we can't aim our telescopes...

We know it happens because the DPSS train shrinks out of allignating due cold.

My 200mW has no problems with cold since it is a direct pumped single unit laser, and I could build us all 200mW reds, but we don't feel very comfortable to the idea of using 200mW lasers where several people gather, including kids sometimes. it's like waiting for an accident to happen.

We could electronically heat our greenies, but it's like too much of a hassle to us : it involves extra cabling, batteries, a regulation systen, whatever more. We like to keep it as simple as possible. We 've got plenty of other materials to handle in the dark... Guess you understand.

Since a while I 've been thinking about the possibilities of a blu ray single unit laser for astronomy use, but I've never seen a blu ray beam. What mW of bluray would be about equally bright as a 5mW green to the naked eye in open air at night?

As to what I've read, I know the 150mW bluray beam is visible, but again, 150mW is far to much for us.

I was thinking about 20-25mW. The beam doesn't need to be bright. Barely visible is just fine. What is more important is that it doesn't die from cold.

Any experience?
 

lasersbee

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Sep 20, 2008
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Welcome to the Forum................

A Blu-Ray LD is in the 405nm wavelength range and is at the low end of the
visible spectrum for the human eye...
The Green 532nm wavelength is more near the optimal maximum visibilty of
the eye and looks brighter for the same Photonic energy (mW).

If the cold is a problem for the green lasers.... have you thought of temporarily
wrapping the Laser Pointer with those Chemical Packs they sell to put into your
gloves... That might keep your lasers warmer in the cold weather...
I'm not sure if it will work.... I have never tried it.... :)

Jerry
 

pseudonyms

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Jan 1, 2009
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lasersbee said:
Welcome to the Forum................

A Blu-Ray LD is in the 405nm wavelength range and is at the low end of the
visible spectrum for the human eye...
The Green 532nm wavelength is more near the optimal maximum visibilty of
the eye and looks brighter for the same Photonic energy (mW).

If the cold is a problem for the green lasers.... have you thought of temporarily
wrapping the Laser Pointer with those Chemical Packs they sell to put into your
gloves... That might keep your lasers warmer in the cold weather...
I'm not sure if it will work.... I have never tried it.... :)

Jerry
That sounds like a good Idea. I've used that for iPods when cold weather camping/ cell phones or other things of the sort.
 

JLSE

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Another idea you may wish to try, is a high power red. They dont mind the cold, green would be much brighter for sure but the cold can be a big pain. Im in Canada, and when my living room gets a bit chilly, a 50mW green pen will start at 2-3mW and takes forever to hit even 30mW.

Laserbees idea for the packs is a good one, as im sure a green would suit your pupose much better with regard to visibility. But if your eyes are adapted to the dark anyway, id try an open can red with an Axiz glass AR coated lens. They give a nice sharp beam, and can be run nice and long when the ambient temperature is good and low.


BluRay wont seem to travel as far and will appear distorted to the eyes. But then again, we all see the violet beam differently ;)
 

DayOfShadows

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wannaburn said:
Another idea you may wish to try, is a high power red. They dont mind the cold, green would be much brighter for sure but the cold can be a big pain. Im in Canada, and when my living room gets a bit chilly, a 50mW green pen will start at 2-3mW and takes forever to hit even 30mW.

Laserbees idea for the packs is a good one, as im sure a green would suit your pupose much better with regard to visibility. But if your eyes are adapted to the dark anyway, id try an open can red with an Axiz glass AR coated lens. They give a nice sharp beam, and can be run nice and long when the ambient temperature is good and low.


BluRay wont seem to travel as far and will appear distorted to the eyes. But then again, we all see the violet beam differently ;)
Not trying to correct you or anything but he said he already has a high power red and wants something lower powered with a visible beam. I would go with wrapping you green in heat packs. Simple and you get to keep your greenies busy
 

svdr

Member
Joined
Jan 8, 2009
Messages
89
Points
8
Yeah, we've tried the hot pads, but it's not that comfortable. Attaching the heating pad introduces vibrations that can either disturb the telescope's view, or it can even make that pointer and telescope are out of alignment.

Kinda fuzzy. There must be a better way.
 




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