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jg
Saturday, March 21, 2015
Volcanic Mayhem
My latest science illustration project is this diagram of death blows from a volcanic phenomenon known as a Large Igneous Province. The diagram is a contribution to a two-part post on the subject by John Mason, writing for Skeptical Science.
Thursday, March 19, 2015
Nova in Sagittarius
A nova has appeared this week in Sagittarius. This time of year, Sagittarius is in low in the south between 5:00 and 6:00 am. I made a video comparing Sagittarius as seen on March 18 with Sagittarius seen last year.
Two years ago I photographed a nova in Delphinius. My regret is not following up over the year to observe the fading of the nova. Therefore, I have no personal estimate of how long a nova will last. I know it's not hard to research, but I prefer to observe first, a bit like reading a book before watching the movie.
Sagittarius is a summer constellation, so I will have a good six months to observe the nova's decline.
jg
Two years ago I photographed a nova in Delphinius. My regret is not following up over the year to observe the fading of the nova. Therefore, I have no personal estimate of how long a nova will last. I know it's not hard to research, but I prefer to observe first, a bit like reading a book before watching the movie.
Sagittarius is a summer constellation, so I will have a good six months to observe the nova's decline.
jg
Monday, March 2, 2015
An unusual fascination with pinhole projections and other optical analogies from my time in prism
I created a new astronomy presentation last weekend. I'll be presenting it to my club, the Temecula Valley Astronomers, tonight at 7:00 at the Temecula Library on Pauba Road -- nothing like the last minute, as working on it this weekend suggests, but it's based on observations of pinhole projections, also called the camera obscura, that I've been interested in for many years.
I believe the pinhole projection provides all the information to intuitively understand how telescopes work and how focal ratio affects depth of field:
To complete the analogy, I add prisms, which lead me to contemplating William Herschel's discovery of infrared. To resolve a discrepancy, I examine black body radiation curves, which leads me to understanding the green house effect, and for the first time I think I can explain why nearly every illustration of the greenhouse effect is wrong by over simplification.
I'd write more, but it's, as I said, last minute and I have preparation to do.
My presentation (which severely lacks annotations) can be found at this location:
http://www.brightstarstemeculavalley.org/pages/presentations.html
jg
I believe the pinhole projection provides all the information to intuitively understand how telescopes work and how focal ratio affects depth of field:
To complete the analogy, I add prisms, which lead me to contemplating William Herschel's discovery of infrared. To resolve a discrepancy, I examine black body radiation curves, which leads me to understanding the green house effect, and for the first time I think I can explain why nearly every illustration of the greenhouse effect is wrong by over simplification.
I'd write more, but it's, as I said, last minute and I have preparation to do.
My presentation (which severely lacks annotations) can be found at this location:
http://www.brightstarstemeculavalley.org/pages/presentations.html
jg
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