Starship Asterisk*

by **astrolabe** » Fri May 02, 2008 1:10 am

P.S. "Dimming of the Sun" aired on the PBS program "NOVA" April 18, 2006 and in March 2007 won the Earthwatch Institute's "Earthwatch Film Award". You can google the program title for more info.

by **astrolabe** » Fri May 02, 2008 12:52 am

Hello apodman,

Yes the numbers ARE huge! I was stunned when I first heard them. As far as instruments affected I wouldn't know, but with regard to regional climate changes the evidence points to particles in our atmosphere allowing more water vapor to collect on them, reflecting away sunlight in the process. An extremely interesting subject to be sure- and verifiable to boot. With that said...........Back to one of my all-time favorite thought-provoking subjects. Astronomy.

by **apodman** » Thu May 01, 2008 10:33 pm

Astrolabe, those numbers (10-30%) are huge.

Regarding limiting factors and observing conditions for earthbound astronomers, what instuments are affected most adversely by atmospheric jet residue? Put another way, what wavelengths are attenuated most by the particular materials and altitudes? (Like the ozone layer absorbing UV wavelengths, etc.)

Of course, I would think the environmental impact would be of more clear and present importance than deep space observations.

by **astrolabe** » Thu May 01, 2008 1:18 am

Hello All,

This APOD may not be about astronomy but it did serve to remind me of a program I saw a while back about a guy who had a theory that jet contrails were affecting the amount of sunlight reaching the Earth. It was difficult to determine until 9/11 when air traffic essentially was halted for what? Three days? The sky during this time became this most beautiful blue, however, the temperature also increased 1 degree C! Also, at different olaces around the globe since the 40's, it was discovered that evaporation rates had been declining and as a result of 9/11 it was determined that the amount of sunlight reaching the Earth's surface pre-9/11 had been reduced 10-30% depending on location. The gist of it was that contrails were the culprit and that COULD be masking just how bad global might already be.

This post probably should appear on a global-warming forum but I thought it would be of interest to APOD people too.

by **adrianxw** » Wed Apr 30, 2008 5:04 pm

However, computer simulations are not at all unprecedented. In fact, the very first APOD was computer generated:

Yes, I know, but at least that was astronomy related, and it would be difficult to see how a real picture of such a situation could be presented.

My point is, and has always been in the many discussions like this we've had, I agree, the picture/film was interesting - but that is not what I come to APOD for.

I have a whole list of "interesting pictures and films" sites in my favourites list. I would prefer that each did "what it said on the can". The argument that "we like to show broader range"..., (better worded but hey), is like saying "you people are unable to find other intresting sites yourself". It's patronising.

If the editors want to show off their favourite "other" pictures, set up a blog and put a link to it at the bottom of the APOD main.

by **henk21cm** » Wed Apr 30, 2008 10:24 am

apodman wrote:I like to see the *sky* in my astronomy pictures.

It took me some time as well to figure out what the connection between the air traffic map and astronomy might be. The best thing i come up with is the assumption or inference that in those area's with a lot of air traffic you cannot see the sky, due to condensation trails. These trails create a fuzzy kind of clouds, resembling to cirrus densus, which make the air too opaque to see nebulae. The sun and moon are generally sufficiently bright to penetrate these clouds and are visible.

A more far fetched inference might be that it is not a good idea to take photograhs of the sky in the neighbourhood of the dense air traffic nodules, since these photogrpahs will be spoiled by blinking lights.

by **apodman** » Wed Apr 30, 2008 5:40 am

I'm still calculating square fermi per pixel.

And can Einstein help me here? I don't know what this quantum stuff has to do with astronomy either.

by **BMAONE23** » Wed Apr 30, 2008 5:26 am

Amazing image APODMAN...And very little atmospheric distortion...Did you forget to mention that your "Little Automatic Digital Camera" was equipped with adaptive optics to eliminate that tricky distortion caused by the atmospheric density inherent in such a vast Plank Length distance from your subject.

by **apodman** » Wed Apr 30, 2008 2:38 am

Not an alien as it appears. The common Mourning Dove (Zenaida macroura) of which there are reportedly 130,000,000 all over North America. These nested too close to my front door to avoid photographing with my little automatic digital camera (which unfortunately leaves me far short of astrophotography - all I have is trees anyway). The pictorial is at http://j3000.com/doves2008 but remember it has NOTHING TO DO WITH ASTRONOMY.

by **astrolabe** » Wed Apr 30, 2008 12:03 am

Hello apodman,

I had no idea! What kind is it?

by **apodman** » Tue Apr 29, 2008 9:10 pm

So there.

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by **apodman** » Tue Apr 29, 2008 9:04 pm

I like to see the *sky* in my astronomy pictures.

Occasionally, maybe I'd like to see a picture of some fancy *equipment* used for observing the *sky*.

The folks at some magazine stumbled on the same formula long ago with "Sky" and "Telescope". Maybe I'd better check a recent issue to see if they've added "and Air Traffic Demonstrations".

I took some beautiful pictures of *birds* recently that I like for people to see. But THIS IS NOT THE FORUM for bird pictures. Yes, birds sometimes (like air traffic) are in the sky, but the *sky* I like to see in my astronomy pictures is not Earth's lower atmosphere but the *celestial sphere*, the *firmament*.

by **BMAONE23** » Tue Apr 29, 2008 7:27 pm

Thanks ... IamLucky to have you around. That Flightaware site shows me what I needed to see to make the correlation

by **iamlucky13** » Tue Apr 29, 2008 6:46 pm

This image might help place the coasts:

http://flightaware.com/live/

This is realtime minus about 5 minutes. The link right below the animation shows the last 24 hours in similar time lapse to the APOD. It's pretty cool how you can see the common routes and even pick out a few hubs with radiating spokes.

Adrianxw, this time I'm tending to sympathize more with your criticism. I still think it's really cool and enjoyed seeing it, but the link to astronomy is extremely tenuous at best. However, computer simulations are not at all unprecedented. In fact, the very first APOD was computer generated:
http://antwrp.gsfc.nasa.gov/apod/ap950616.html

by **BMAONE23** » Tue Apr 29, 2008 5:10 pm

If you were to presume that the brightest region to the right side is the eastern coast of the US then the air traffic is centered in New York and the far lower left region might be Los Angeles. But that places some of the flights terminating in the middle of the atlantic. If you were to presume that the brightest region is the central US with the Chicago area to the north, Florida to the south, and Hawaii to the bottom left, then the upper left would be Alaska and there would be relatively few flights originating or terminating in New York (those that appear to end in the Atlantic)

by **adrianxw** » Tue Apr 29, 2008 3:59 pm

I will add my usual "what has this to do with astronomy" comment. It is not even a picture, rather, a computer simulation.

by **orin stepanek** » Tue Apr 29, 2008 2:52 pm

BMAONE23 wrote:Todays APOD would be more interesting if there were an outline of the USA imposed over the movie so that you could see where all the air traffic is going
http://antwrp.gsfc.nasa.gov/apod/ap080429.html

I had to watch the movie from here http://youtube.com/watch?v=dPv8psZsvIU and there were a couple of times when you could tell where the USA was; otherwise you are pretty much left with your imagination.
Orin

by **BMAONE23** » Tue Apr 29, 2008 2:01 pm

Todays APOD would be more interesting if there were an outline of the USA imposed over the movie so that you could see where all the air traffic is going
http://antwrp.gsfc.nasa.gov/apod/ap080429.html

Starship Asterisk*

Airplane Flight Patterns over the USA (APOD 29 Apr 2008)

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Airplane Flight Patterns over the USA (APOD 29 Apr 2008)