Page 4 of 4 FirstFirst 1234
Results 31 to 38 of 38

Thread: Writing in the Sky

  1. #31
    Join Date
    Nov 2007
    Location
    Bend Oregon USA
    Posts
    3,350

    Default

    well maybe photonbeam will chime in and tell us how far he was standing from the scanners. That might help. Well not much measurable angle were discussed in this thread. But I have done it live, in clouds, rain, snow, fog , indoor smoke and pyro and it looks great right at the scanners... get more than say...30 degrees and buh buy image...so its FREAKIN MAGIC!!!

    Paul R. did not have geometric correction that I am aware of, AFAIK he didnt even have blanking. (as you see in the AA logo there is no blanking) I would bet my left nut...he is standing right in front of his projector and the beam is shooting right over his right shoulder.


    anyway...carry on...
    Last edited by Laserman532; 10-15-2012 at 15:51.
    Pat B

    laserman532 on ebay

    Been there, done that, got the t-shirt & selling it in a garage sale.

  2. #32
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,248

    Default

    I can see a practical experiment coming on...
    Frikkin Lasers
    http://www.frikkinlasers.co.uk

    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

  3. #33
    Join Date
    Nov 2007
    Location
    SoCal / San Salvador / NY
    Posts
    4,018

    Default

    Quote Originally Posted by planters View Post
    ...why would the conditions be rare? A low altitude dense overcast...
    Compare these two projections.. One, with a fairly-high cloud-celing, I *estimated* 10K', based on local-weather reports that nite... but, this test was done at about 3-4 am, so.. not quite sure where the celing had ended-up, by the test-time.. http://www.youtube.com/watch?v=3bRUSP5YHXw

    ...not bad, especially to the 'naked eye', looked clean and clear.. but not nearly as-bright and 'visible', as-when we did projections for the actual Client in Guate.. http://www.youtube.com/watch?v=HBxRFek-qNs and http://www.youtube.com/watch?v=o9Lp2I4RVBc ..Because that night was a *much* lower ceiling... Based on this shot...

    Click image for larger version. 

Name:	LS40_Guate_1.jpg 
Views:	12 
Size:	76.1 KB 
ID:	35264....maybe 1100-1200', tops?? (..judging, based-on the height of the bldg, there, and approx. where it 'appears' the beam was first-intersecting with the clouds...) So, yes, the results vary-widely, and thus, while possible, are never really 'predictable', with certainty, and certainly not sellable...(...unless you're someone like the aforementioned spinner of reeealy tall-tales.. In-all, conditions I would second-being classified as 'rare' (..optimal, that-is..)

    Anyhoo, as-to the 'angle-question', compare the 'projection angle, vs the viewing / videoing angle', from the first vid (http://www.youtube.com/watch?v=3bRUSP5YHXw) and here's a still:

    Click image for larger version. 

Name:	LS40_CloudScan_2.jpg 
Views:	16 
Size:	24.6 KB 
ID:	35266 ..(btw, shows how-much time-exposure can boost 'visibility', in a still-shot, which, I-agree - is nearly-all of what we're lookin-at in that 'AA' shot.. just look at how lit-up that apt. complex is!! :P

    ...to this-shot, from out in the front-lot at the NY-shop, there..

    Click image for larger version. 

Name:	LS40_SkyScan_4.jpg 
Views:	15 
Size:	51.8 KB 
ID:	35265 ...not sure the exact-angle, but prolly more than 30˚.. plus, the ceiling had become more 'varigated' by then, and was not as smooth-looking, even from below...

    Quote Originally Posted by Laserman532 View Post
    I have projected in rain and snow and actually love the way that makes the beams sparkle.
    ..Deffo with-ya on that, Cap'n! http://www.youtube.com/watch?v=LuxL1pfUAI4

    j
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

  4. #34
    Join Date
    Apr 2007
    Location
    Costa Rica
    Posts
    523

    Default

    Those photos were July 4, 1988. I'm pretty sure I was right next to the laser with the camera. I built a joystick controlled pan/tilt mirror on a turret mounted above the scanners. The idea was to track the fireworks smoke puffs and project images and words (POW, BANG, etc.) on them. I know, kind of lame - but pretty cool back then. We used Apple IIe's. There was no geometric correction. In fact as the turret rotated, the images rotated. So the correct orientation of the photo is this-
    Click image for larger version. 

Name:	7488d.jpg 
Views:	17 
Size:	110.4 KB 
ID:	35271Click image for larger version. 

Name:	7488a.jpg 
Views:	20 
Size:	108.2 KB 
ID:	35272Click image for larger version. 

Name:	7488c.jpg 
Views:	19 
Size:	119.9 KB 
ID:	35273

  5. #35
    Join Date
    Nov 2007
    Location
    Bend Oregon USA
    Posts
    3,350

    Default

    photonbeam...what are your thoughts on angle of viewing. How far from the projector were you when you took the statue of liberty and "bob" photographs.
    Pat B

    laserman532 on ebay

    Been there, done that, got the t-shirt & selling it in a garage sale.

  6. #36
    Join Date
    Apr 2007
    Location
    Costa Rica
    Posts
    523

    Default

    I think I was next to the laser or no more than a short walk - less than 50-100ft away. The flatter the cloud cover, the farther off axis you could view it. Hard to remember - it was a long time ago. They tell me I had a good time though.
    Last edited by Photonbeam; 10-15-2012 at 18:36.

  7. #37
    Join Date
    Sep 2006
    Location
    Netherlands
    Posts
    1,435

    Default

    Has anybody ever tried fitting a 10Klumen projector with some extra small-angle optics, and point it at the sky?
    Even if you leave 90% of the pixels black, a stage videoprojector would be able to spit out much more photons than a laser could.

  8. #38
    Join Date
    Feb 2011
    Location
    New Hampshire
    Posts
    3,513

    Default

    Even if you leave 90% of the pixels black, a stage videoprojector would be able to spit out much more photons than a laser could.
    I disagree. I have been running a 4300 lumen projector at full brightness right next to a 9W RGB that is producing a "white" test pattern and the scattered light from the projection screen is significantly brighter through out the entire room when the laser is running. The laser is significantly hotter at the aperture when your hand is placed several cm in front of each projector. And finally, white light produces somewhere around 670 visible lumens/ watt.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •