How are laser pointers used in astronomy?

Ladewig · 30th January 2008, 11:35 AM

On a website that sells powerful pocket lasers (5 - 125mW), I found some comments that the lasers were useful in amateur astronomy. How are they used?

Ziggurat · 30th January 2008, 11:57 AM

Originally Posted by Ladewig

On a website that sells powerful pocket lasers (5 - 125mW), I found some comments that the lasers were useful in amateur astronomy. How are they used?

My understanding is that since the beam itself is moderately visible on a dark night, people use them as very long pointers to indicate to other people what they're talking about or looking at, since just pointing with your finger at the sky only gets the other person in the general neighborhood of what you're pointing at.

Madalch · 30th January 2008, 11:58 AM

I would assume that you can see the beam, which makes it like a very big stick to point things out with.

Not good for much if you're stargazing by yourself, I guess.

ETA: What ziggy said.

Alric · 30th January 2008, 12:08 PM

I use one to point out features in the sky. The beam is easily seen from the grouund at its point of origin.

genesplicer · 30th January 2008, 12:11 PM

Green works best. Gotta have green...

Ladewig · 30th January 2008, 03:05 PM

I had always thought that if there was enough dust in the air to see the beam, then viewing conditions were less than favorable. Is it the color or the extreme power that makes the beams more visible?

EHLO · 30th January 2008, 04:36 PM

Mmmm.. I've been eying off a 100mW green laser from WickedLasers for some time now. The high power/intensity means that the beam is visible even in relatively clean air for some distance and from any viewing angle (some reports say in daylight but I'm not convinced).

Having said that, my old 5mW red pointer was still visible for several meters on clear nights when looking along the beam, which is generally how you use it in astronomy - very useful for pointing to stars/satellites etc. (not aircraft!)

MG1962 · 30th January 2008, 06:24 PM

They are also used on telesecopes for working out exactly where the scope is pointed

Ladewig · 30th January 2008, 08:32 PM

Originally Posted by MG1962

They are also used on telesecopes for working out exactly where the scope is pointed

Ah, yes. In googling, I found a website that sowed how to make a laser-pointer mount that would take the place of an eyepiece.

Thanks for all the explanations.

Terry · 30th January 2008, 08:34 PM

Note that some sites request that laser pointers not be used, because the green ones in particular can be bright enough to affect dark-adaption even when you are just seeing the scattered light.

fishbait · 30th January 2008, 08:54 PM

Originally Posted by Ladewig

Ah, yes. In googling, I found a website that sowed how to make a laser-pointer mount that would take the place of an eyepiece.

Thanks for all the explanations.

Not quite. It is used to take the place of or used along with a spotter scope. The spotter scope is just a small telescope with a low powered eyepiece mounted on top of the main scope and is used to point the main telescope tube to the proper spot. The main scope has it's own interchangable eyepieces of various powers.

Another type of spotting device is the Telrad spotter.

lionking · 30th January 2008, 09:31 PM

There were reports in the newspaper today that laser pointers were aimed at cockpits of passenger jets coming into Melbourne Airport twice in the past week and one pilot was momentarily dazed. Perhaps people should have to give a bona fide reason before purchasing one.

EHLO · 30th January 2008, 09:41 PM

Originally Posted by lionking

There were reports in the newspaper today that laser pointers were aimed at cockpits of passenger jets coming into Melbourne Airport twice in the past week and one pilot was momentarily dazed. Perhaps people should have to give a bona fide reason before purchasing one.

I think they meant "dazzled". With the large increase in power of these devices I tend to agree (unless it stops me getting one!)

I remember carting a home made HeNe laser down to the beach as a teenager and zapping planes as they took off. The collimation was so bad I doubt that it looked like anything other than a bright light.

lionking · 30th January 2008, 09:44 PM

Originally Posted by EHLO

I think they meant "dazzled". With the large increase in power of these devices I tend to agree (unless it stops me getting one!)

I remember carting a home made HeNe laser down to the beach as a teenager and zapping planes as they took off. The collimation was so bad I doubt that it looked like anything other than a bright light.

Dazzled is what I meant. Are all you people from Adelaide so anti-social?

EHLO · 30th January 2008, 09:46 PM

**** off.

EHLO · 30th January 2008, 09:47 PM

Doh! They filtered my swearing. Where's the fun in that!

UnrepentantSinner · 30th January 2008, 10:43 PM

I found that a flashlight with a tight beam and decent candlepower is just as good and you don't run the risk of blinding pilots.

JoeTheJuggler · 31st January 2008, 08:30 AM

Originally Posted by fishbait

Another type of spotting device is the Telrad spotter.

I've got a Telrad on my telescope. I really like it a lot. It looks like concentric circles out in the sky. (This is an illusion--unlike the green laser pointers which really do make a visible beam out in the air.)

30th January 2008, 11:35 AM	#1
Ladewig Hipster alien Join Date: Dec 2001 Location: not measurable Posts: 16,786	How are laser pointers used in astronomy? On a website that sells powerful pocket lasers (5 - 125mW), I found some comments that the lasers were useful in amateur astronomy. How are they used?
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30th January 2008, 11:57 AM	#2
Ziggurat Penultimate Amazing Join Date: Jun 2003 Posts: 26,176	Originally Posted by Ladewig On a website that sells powerful pocket lasers (5 - 125mW), I found some comments that the lasers were useful in amateur astronomy. How are they used? My understanding is that since the beam itself is moderately visible on a dark night, people use them as very long pointers to indicate to other people what they're talking about or looking at, since just pointing with your finger at the sky only gets the other person in the general neighborhood of what you're pointing at.
	__________________ "As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law

30th January 2008, 11:58 AM	#3
Madalch The Jester Join Date: Nov 2006 Location: The wet coast. Posts: 8,697	I would assume that you can see the beam, which makes it like a very big stick to point things out with. Not good for much if you're stargazing by yourself, I guess. ETA: What ziggy said.
	__________________ As the size of an explosion increases, the number of social situations it is incapable of resolving approaches zero. -Vaarsuvius It's a rum state of affairs when you feel like punching a jar of mayonnaise in the face. -Charlie Brooker Last edited by Madalch; 30th January 2008 at 11:59 AM. Reason: Ninjad.

30th January 2008, 12:08 PM	#4
Alric Muse Join Date: Apr 2007 Posts: 554	I use one to point out features in the sky. The beam is easily seen from the grouund at its point of origin.
Alric Muse Join Date: Apr 2007 Posts: 554	Last edited by Alric; 30th January 2008 at 12:08 PM.

30th January 2008, 03:05 PM	#6
Ladewig Hipster alien Join Date: Dec 2001 Location: not measurable Posts: 16,786	I had always thought that if there was enough dust in the air to see the beam, then viewing conditions were less than favorable. Is it the color or the extreme power that makes the beams more visible?
	__________________ Is the JREF message board training wheels for people who hope to one day troll other message boards? It is not that hard to get us to believe you. We are not the major leagues or even the minor leagues. We are Pee-Wee baseball. If you love striking out 10-year-olds, then you'll love trolling our board.

30th January 2008, 12:11 PM	#5
genesplicer Critical Thinker Join Date: Sep 2007 Location: Riverside county, CA Posts: 321	Green works best. Gotta have green...

30th January 2008, 04:36 PM	#7
EHLO Critical Thinker Join Date: Mar 2007 Location: Adelaide, AUS Posts: 283	Mmmm.. I've been eying off a 100mW green laser from WickedLasers for some time now. The high power/intensity means that the beam is visible even in relatively clean air for some distance and from any viewing angle (some reports say in daylight but I'm not convinced). Having said that, my old 5mW red pointer was still visible for several meters on clear nights when looking along the beam, which is generally how you use it in astronomy - very useful for pointing to stars/satellites etc. (not aircraft!)
	__________________ Give a skeptic an inch and they'll measure it

30th January 2008, 06:24 PM	#8
MG1962 Guest Join Date: Sep 2006 Location: Kansas (Australia) Posts: 14,750	They are also used on telesecopes for working out exactly where the scope is pointed

30th January 2008, 08:32 PM	#9
Ladewig Hipster alien Join Date: Dec 2001 Location: not measurable Posts: 16,786	Originally Posted by MG1962 They are also used on telesecopes for working out exactly where the scope is pointed Ah, yes. In googling, I found a website that sowed how to make a laser-pointer mount that would take the place of an eyepiece. Thanks for all the explanations.
	__________________ Is the JREF message board training wheels for people who hope to one day troll other message boards? It is not that hard to get us to believe you. We are not the major leagues or even the minor leagues. We are Pee-Wee baseball. If you love striking out 10-year-olds, then you'll love trolling our board. Last edited by Ladewig; 30th January 2008 at 08:32 PM.

30th January 2008, 08:34 PM	#10
Terry Zeitgeist-impaired Technical Moderator Join Date: Jun 2003 Location: logged in to the server Posts: 6,450	Note that some sites request that laser pointers not be used, because the green ones in particular can be bright enough to affect dark-adaption even when you are just seeing the scattered light.

30th January 2008, 08:54 PM	#11
fishbait Raggin' the Blues Join Date: Jun 2003 Location: New York Posts: 1,013	Originally Posted by Ladewig Ah, yes. In googling, I found a website that sowed how to make a laser-pointer mount that would take the place of an eyepiece. Thanks for all the explanations. Not quite. It is used to take the place of or used along with a spotter scope. The spotter scope is just a small telescope with a low powered eyepiece mounted on top of the main scope and is used to point the main telescope tube to the proper spot. The main scope has it's own interchangable eyepieces of various powers. Another type of spotting device is the Telrad spotter.
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30th January 2008, 09:31 PM	#12
lionking In the Peanut Gallery Join Date: Jan 2007 Location: Melbourne Posts: 29,644	There were reports in the newspaper today that laser pointers were aimed at cockpits of passenger jets coming into Melbourne Airport twice in the past week and one pilot was momentarily dazed. Perhaps people should have to give a bona fide reason before purchasing one.
	__________________ A fanatic is one who can't change his mind and won't change the subject. Sir Winston Churchill

30th January 2008, 09:41 PM	#13
EHLO Critical Thinker Join Date: Mar 2007 Location: Adelaide, AUS Posts: 283	Originally Posted by lionking There were reports in the newspaper today that laser pointers were aimed at cockpits of passenger jets coming into Melbourne Airport twice in the past week and one pilot was momentarily dazed. Perhaps people should have to give a bona fide reason before purchasing one. I think they meant "dazzled". With the large increase in power of these devices I tend to agree (unless it stops me getting one!) I remember carting a home made HeNe laser down to the beach as a teenager and zapping planes as they took off. The collimation was so bad I doubt that it looked like anything other than a bright light.
	__________________ Give a skeptic an inch and they'll measure it

30th January 2008, 09:44 PM	#14
lionking In the Peanut Gallery Join Date: Jan 2007 Location: Melbourne Posts: 29,644	Originally Posted by EHLO I think they meant "dazzled". With the large increase in power of these devices I tend to agree (unless it stops me getting one!) I remember carting a home made HeNe laser down to the beach as a teenager and zapping planes as they took off. The collimation was so bad I doubt that it looked like anything other than a bright light. Dazzled is what I meant. Are all you people from Adelaide so anti-social?
	__________________ A fanatic is one who can't change his mind and won't change the subject. Sir Winston Churchill

30th January 2008, 09:46 PM	#15
EHLO Critical Thinker Join Date: Mar 2007 Location: Adelaide, AUS Posts: 283	**** off.
	__________________ Give a skeptic an inch and they'll measure it

30th January 2008, 09:47 PM	#16
EHLO Critical Thinker Join Date: Mar 2007 Location: Adelaide, AUS Posts: 283	Doh! They filtered my swearing. Where's the fun in that!
	__________________ Give a skeptic an inch and they'll measure it

30th January 2008, 10:43 PM	#17
UnrepentantSinner A post by Alan Smithee Join Date: Aug 2001 Location: USAian is not a word Posts: 26,351	I found that a flashlight with a tight beam and decent candlepower is just as good and you don't run the risk of blinding pilots.
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31st January 2008, 08:30 AM	#18
JoeTheJuggler Penultimate Amazing Join Date: Jun 2006 Location: St. Louis Posts: 26,667	Originally Posted by fishbait Another type of spotting device is the Telrad spotter. I've got a Telrad on my telescope. I really like it a lot. It looks like concentric circles out in the sky. (This is an illusion--unlike the green laser pointers which really do make a visible beam out in the air.)
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