Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

Greenwich Meridian Laser

Joined
Jan 21, 2010
Messages
935
Points
0
Raise your hand if you recognise the following view:
100_1204-Copy.jpg

It's the view from the top of the hill in Greenwich park. It looks slightly different at night:
292789025_e83c84b0c8_b.jpg

(Not my picture)
See that almighty green line? That's a five Watt laserscope, coming from the Royal Observatory.

Well, guess what? My sister plays guitar with someone who works in the observatory and he knows the technician who operates the laser and... anyway, I asked whether I could take a closer look at it and it turns out it is switched on manually every day at 4:00 PM (presumably to avoid setting some unsuspecting birds on fire). So the technician offered me the opportunity to switch it on!

After me & Chez got in free, he took us into a little crevice underneath the main telescope and handed me a set of controls:
100_1179.jpg

(At this point picture-taking became a little awkward because the light was a bit strange and there wasn't a huge amount of room - if you can't tell, that's me from behind holding the control panel. If you look closely, you can see the "5.00" signifying the output in Watts :whistle: )

I was told which button to hit to start the diode warming up and then he spoke to me about the laser for a bit. After a while I hit another button to switch it on. He also pointed out buttons which allowed me to put a shutter up and down, which I had fun with.
Here is where the laser beam exits:
100_1181.jpg

I was expecting something far more fancy and high-tech but why complicate things when a hole-in-the-wall works fine? :D
The camera couldn't pick it up (although we did try) but there was a perfectly visible beam in the room lit by broad daylight. Very impressive! There's a sign just below the hole which says "Prime Meridian Of The World" because this laser was originally placed to mark the Meridian line. I'll leave someone else to explain exactly what that means because I sort-of understand but don't want to explain badly and lead to others getting it wrong. :thinking: I quit Geography at 14.

The view from the outside:
100_1198-Copy.jpg

This photo demonstrates the fact that you are completely unable to estimate the power of a laserbeam based on a photograph. I'll be doing it again in winter, when it'll hopefully be darker so I'll be able to watch an ungodly bright column of green rip through a night sky.
To top it all off, they gave me a certificate to confirm that I'd done it :D

Here's the best part... I'm still in contact with the technician. If anyone is planning a visit to London, send me a PM and if I'm at home I'll see if we can arrange something.

And now, unrelatedly, me & Chez looking nerdy outside the laser room:
100_1190.jpg

(Yes, those are my laser safety goggles. I brought them along just for a laugh.)
100_1192.jpg

(Chez is probably going to be angry because I stuck a picture of her up without asking, but oh well. See how it goes :p)

Happy lasering!
 





ARG

0
Joined
Feb 27, 2011
Messages
6,772
Points
113
I need one of those "LASER ON" signs :crackup:
 
Joined
Jan 21, 2010
Messages
935
Points
0
I need one of those "LASER ON" signs :crackup:
It's pretty cool, it lights up. Personally, i'd prefer to have a 10cm x 10cm hole in my bedroom wall so I could fire lasers out of it. The laser unit itsself is on a platform attached to the ceiling. It could hold a whole collection of handheld lasers and send beams flying everywhere.
 

Jez006

0
Joined
Sep 9, 2011
Messages
78
Points
0
Awsome. I live in London and didn't know about that...

Obviously +1 :p

Btw why would the birds not be set on fire at 4pm? Surely 5 watts would smoke 'em no matter what time it is!
 
Last edited:
Joined
Jan 21, 2010
Messages
935
Points
0
Oh, sorry. That sentence was hard to word. It's turned on manually to avoid smoking 'em. Not sure why it's turned on at 4:00, but the park closes at dusk so if they want to set a regular time for switching it on then they need to do it quite early.
 
Joined
Dec 29, 2009
Messages
3,136
Points
63
I've heard that the World Trade Center memorial in NYC (you know, the two big pillars of well-collimated white light) messes with migrating flocks of birds. They instinctively fly towards/into the light and can't fight their instincts and escape. They turn off the lights for a few minutes every hour or so to let the birds be on their way.

9/11 Memorial Lights Trap Thousands of Birds | Wired Science | Wired.com
 
Joined
Jan 21, 2010
Messages
935
Points
0
Oh, Jez, you're in London. Are you near enough to Greenwich to want to stop by sometime and flick on that laser?
 

Jez006

0
Joined
Sep 9, 2011
Messages
78
Points
0
hehe...thanks for the offer ;)

It's not too far to travel - I'm in Hendon. I'm pretty busy at the moment though..

I'll definately let you know when I've got some time though - would be amazing to see a 5 watt green in action...But then I might be bored of my 175mw when I get home!

Btw it's crazy that you can't see the beam in pic 4!
 
Last edited:

Benm

0
Joined
Aug 16, 2007
Messages
7,896
Points
113
Thats pretty cool! Does the beam terminate onto a building somewhere?

Given all the news about airplanes and lasers i'd thing shining a 5 watt into the sky in a city surrounded by airports may not be the best of plans...
 
Joined
Dec 29, 2009
Messages
3,136
Points
63
The beam terminates on a hot air balloon. They're currently doing an experiment to find out how long it takes to pop a balloon with a 5W laser.

:)eg:)
 




Top