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laser pointed through a telescope?

shockwave88

shockwave88

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Hey guys i have a telescope and i was wondering once i get my laser if i shine it through that telescope to an object would it burn the object a couple times more? depending what it is? like for example would it be able to burn a hole in my dry wall? the telescope has like 4 or something mirrors inside it. Could be magnifying glasses but im not sure. Any 1 try this b4? Cause it wud be pretty cool lol

This laser im getting is 200mw FLX green from rayfoss.
 
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photonaholic

photonaholic

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no, the optics in a telescope would not focus your laser correctly to burn anything, most likely make a dot the size of a basketball....

shining it in from the front, the focal point is right on top of the eyepiece, shining it the other way, the focal point will be like so far away it won't matter anymore.

If you want to burn a hole in the wall, you need a LOT of power, like a C02 laser puts out.
 
scopeguy20

scopeguy20

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I am not so sure the focus can not be made to be several dozen meters, with racking the eyepiece out some, as this makes the telescope focus at less than 40 yards, but although I have sent my under 90mW laser through the eyepiece to the sky to see the beam and know where the 'scope is pointed. I think the total light loss of typical telescopes is under 5%, but still if losing 5% and then being able to focus the remaining power to a dot typically about 20 times more condensed at a distance of many meters would give you more "burn' at your output power, then, it could well extend your burn distance by about 9.8 times what you had before. Sadly I did not ever try to burn things in this way, as I don't want to pipe my more powerful lasers through my equally treasured telescopes to pop a balloon or light a match. AMB! -Glenn
 
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shockwave88

shockwave88

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I c. Interesting im going to try this out once i get my laser :p ill tell u guys what the results are
 
KiLLrB

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Im not sure but if you have a newtonian style you may damage the aluminum coating on the mirrors not sure but i wouldnt try it with a higher powered laser.

I use a <5mW laser collimator all the time to collimate my scopes but when it come out of the aperature it gets bigger .
 
scopeguy20

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I seriously doubt the coatings would be damaged by <500 mW but still, I haven't piped my Spyder I through my Meade 10 in. Schmidt-Newt. -Glenn
 
KiLLrB

KiLLrB

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scopeguy20 said:
I seriously doubt the coatings would be damaged by <500 mW but still, I haven't piped my Spyder I through my Meade 10 in. Schmidt-Newt. -Glenn
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would you chance it? the coatings on those scopes especially yours if it has the acf coatings are hella sensative and i know you can burn through aluminum with a >500mW laser. and besides the corrective lens on the frontof yours will prolly be affected dont ya think? I dunno Im super paranoid about my optics on my scopes It prolly wouldnt do any harm since they are made to be super reflective but who knows.
 
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Bowtie41

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I'd look around on ebay,craigslist,fleamarket,etc,and get the cheapest if not free scope and give it a whirl!
 
Greenmechanic

Greenmechanic

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Bowtie41 said:
I'd look around on ebay,craigslist,fleamarket,etc,and get the cheapest if not free scope and give it a whirl!
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The cheapest scope you can get is a world away from a quality telescope.
You would probably get 50% loss (and lots of artifacts) with anything under $200. Just a guess, but I own a cheapie and I can not even see the moon clearly, it's a fuzzball.
 
KiLLrB

KiLLrB

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Greenmechanic said:
The cheapest scope you can get is a world away from a quality telescope.
You would probably get 50% loss (and lots of artifacts) with anything under $200. Just a guess, but I own a cheapie and I can not even see the moon clearly, it's a fuzzball.
Click to expand...

Exactly. But try at least 400 (IMO) for a scope worthy of any self respecting amateur astronomer. But be careful aperature fever is worse than laser addiction lol.
 
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B

BKarim

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no.
telescopes are designed to collect large area of light emitted from source at infinity, not laser beams.
also the focus point is limited by self-diffraction so size of optics doesn't matter.
the best way to focus a laser is to buy a focusable laser
 
G

Grokken

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Your laser will be focusable so you can already focus it down to a tiny dot. You don't need any additional optics for burning.
 
scopeguy20

scopeguy20

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I do want people to use caution, but it is also true that a beginner can make a laser beam expander and effectively do longer range burning and such with one. Also the laser beam expander is nearly the same optical set up as the early Galilean telescope, the main deference's are that the lenses should be very good quality or even "laser grade" and the coatings on the lenses would best be optimum for your laser wavelength. However even a small telescope or binocular, although not as good, can be used to get a smaller dot at a greater distance and in essence is then being used as a "laser beam expander" surplusshed.com sells lots of "laser grade achromatic lenses" at really low cost. I would advise a negative short fl input lens, maybe well less than -60 mm fl and a output lens of about 40+ mm dia. and about 85 - 135 mm fl to keep the assembly reasonably compact. AMB! -Glenn
 
Bowtie41

Bowtie41

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BobH said:
A couple hundred mW of any color laser beam isn't going to do anything to any telescope mirror or lens coating. If you hit a piece of black plastic inside the tube of a cheap telescope, like a baffle or cheap mounting part, you might burn a hole in that and get plastic smoke on the coatings. Wouldn't want that! Same with the black painted inside of the (possibly) cardboard tube. Send a beam into the eyepiece end of a telescope and you'll see the beam come out as a beam, if it's not stopped by a central obstruction, regardless of the presence of an eyepiece.

You obviously need to be very careful with your lasers. Without knowledge about the simplest optics (telescopes), you're in high danger of getting the beam into your eye or somebody else's. You are a prime example of why lasers will eventually be licensed. A laser "pointer" is only a few mW in power. Enough to point things out but not enough to cause damage. A laser that's higher in power than that but still small enough to be hand held is not a "laser pointer". It's a directed energy weapon. You play with fire, you WILL get burned. Or worse, burn somebody else.
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I definately didn't want anyone to get hurt,just give options for where to find one.I have one of those free telescopes that came from Marlboro a few years back(Now I know why they were free,blurry as heck,at least mine was)That I may just take apart to change the focal length to see what happens.Caution and goggles should of course be used if your gonna pump up the power/intensity,but like when I was a kid with mag. glass burning bugs,learn by trying.A friend I used to work with's Dad worked years ago at McDonnell-Douglas working with lasers.The first time they pulsed a laser was by mistake and blew out a cinder block wall,but they learned by trial/error.
I'm new here.I hope I don't offend anyone with this reply.
 
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