Search found 12 matches

by wbeaty
Sun Nov 13, 2011 7:11 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)
Replies: 47
Views: 11043

Re: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)

> No, iridescent clouds don't jump around that way. They are stable for minutes or longer. Read the main entry again, I believe you've missed the entire point: the cloud in the videos aren't jumping. The sudden motions in all the various different videos are obviously not motions of clouds. (Especia...
by wbeaty
Thu Nov 10, 2011 8:39 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)
Replies: 47
Views: 11043

Re: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)

What the heck is it my computer blocks youtube CAN ANYONE TELL ME WHAT IT LOOKS LIKE BECAUSE I LIKE TO SEE THE ASTRONOMY PICTURE OF THE DAY EVERYDAY HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :cry: :cry: :cry: :cry: :cry: The video shows bright bands ?cirrus? next to a thunderhead, and the bright...
by wbeaty
Wed Nov 09, 2011 1:56 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)
Replies: 47
Views: 11043

Re: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)

IMHO, and in concordance with seasoned atmospheric optics observers, I must say the jumping sensation CANNOT be a sundog, Again, "sundog" refers to the first video in the list of six in the first link. as there is no color at all. My question would be, whether the vid has been taken throu...
by wbeaty
Tue Nov 08, 2011 11:42 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)
Replies: 47
Views: 11043

Re: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)

The NWS is in the process of developing some products from this system that compares vertical polarization with horizontal polarization of both ice crystals and precipitation. So far, NWS research has found sharp bands of contrasting values where dual-polarized radar beams intersect ice crystals ar...
by wbeaty
Tue Nov 08, 2011 11:17 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)
Replies: 47
Views: 11043

Re: APOD: Jumping Sundogs Over Thunderclouds (2011 Nov 08)

Is the bright spot in the video actually a sundog Nope, it seems to be a Pileus cloud above a thunderhead. "Sundog" refers to one of the videos listed on http://amasci.com/amateur/sundog.html, specifically this one: http://www.youtube.com/watch?v=fEiQKOLXU8Y I'd think that in general, if ...
by wbeaty
Wed Dec 08, 2004 8:57 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Strange streak discussion: 2004 Dec 7 APOD
Replies: 2124
Views: 537803

And about planar contrail shadows: they arise and vanish in a space of minutes. The duration of the apparent contrail shadow would depend on the apparent drift speed of the contrail. If the contrail was fairly low, and the wind at that altitude was fairly strong, then the dark stripe might be visib...
by wbeaty
Wed Dec 08, 2004 8:47 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Strange streak discussion: 2004 Dec 7 APOD
Replies: 2124
Views: 537803

And about planar contrail shadows: they arise and vanish in a space of minutes. They become visible when the observer is inside the plane of darkness (the planar region where there is a lack of scattered sunlight from the air.) They vanish again when the observer is no longer inside the shadow regio...
by wbeaty
Wed Dec 08, 2004 8:44 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Strange streak discussion: 2004 Dec 7 APOD
Replies: 2124
Views: 537803

> Yes, of course it can be faked. But if you read the APOD description, > > "The photographer insists that the streak and flash on the above image > has not been created digitally." As with any photo of a controversial phenomenon, the reputability of the photographer becomes paramount. If ...
by wbeaty
Wed Dec 08, 2004 8:36 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Strange streak discussion: 2004 Dec 7 APOD
Replies: 2124
Views: 537803

If the shadow was sourced at the lamp, then the shadow would not appear as a line with parallel edges. Depending on the distance between the light source and the opaque object, the shadow would spread out more or less. Also, if the distant lamp caused that shadow, it would be caused by a lack of sca...
by wbeaty
Wed Sep 29, 2004 10:52 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Lewin's Challenge Image
Replies: 332
Views: 147075

another photo

Another photo of glass-bead rainbow
http://www.geocities.com/CapeCanaveral/ ... t.html#TLP
by wbeaty
Wed Sep 29, 2004 7:54 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Lewin's Challenge Image
Replies: 332
Views: 147075

The "underground sidewalk-rainbows" effect also works great at night under a single streetlight. When I develop enough ambition, I go and sprinkle a bit of the stuff on the sidewalk surrounding the bronze Jimi Hendrix statue on Seattle's Broadway Avenue: http://www.vrseattle.com/html/vrvie...
by wbeaty
Wed Sep 29, 2004 7:51 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Lewin's Challenge Image
Replies: 332
Views: 147075

DOES ANYONE WANT A COUPLE OF POUNDS OF GLASS MICRO-BEADS? With a bag of beads, you can reproduce Dr. Lewin's photo at any time. A sunny day is required though. I still have about 100LBS of the stuff out in my garage; bought for distribution at the monthly meeting of the Seattle Weird Science Salon. ...