Friday, August 14, 2015
Comet Swift-Tuttle only passes the earth and circles the sun once every 133 years, but the earth passes through its trail of dust every year. The debris field is large, so Perseid meteors may be seen on nights from July 17 through August 24. The earth passes through the most dense portion of the comet's dust trail on the night of August 12-13, so that is when the peak, or maximum hourly rate of meteors, is seen.
On any given night, the sun sets as your position on the earth rotates away from the sun, then around midnight you rotate to a point directly opposite the sun. As the earth also moves in its orbit around the sun, your position on the earth is just starting to rotate to the side of the earth leading its movement through space, which collides with more debris. So meteor rates go up starting at midnight. At dawn you're approximately in the middle of the face of the earth as it flies through space, so meteor rates continue to climb slightly towards dawn. So the best bet in the evening is after midnight, in the last hours of darkness before the dawn's oncoming light brightens the sky.
This year I pursued the Perseids on the mornings of August 9, 11, 12 and 13. The best viewing was on the peak morning of the 13th, as expected. The composite photo above shows many of the meteors that my camera picked up over the course of nearly four hours.
I also assembled a time-lapse video that condenses several hours of meteor activity into seconds of video. You can see it on Vimeo here:
Perseid Meteor Shower 2015 from Jeff Sullivan on Vimeo.
Not everything that moves in the video are meteors; the meteors are the brief streaks of light, the slower ones are airplanes. As you see the Milky Way and stars move, that is from the rotation of the earth. You can also see smoke from forest fires.
According to Wikipedia, Comet Swift–Tuttle has been described as "the single most dangerous object known to humanity". But don't worry, its next close encounter with the earth isn't expected until the year 4479. With a nucleus 26 kilometers across, if there were an impact, the force is estimated to be 27 times larger than the one which formed the Chicxulub crater beneath the Yucatán Peninsula in Mexico, which is believed to have caused the extinction the dinosaurs.
Doomsday preppers take note, you only have 2464 years to get ready!
Monday, August 10, 2015
Comet Swift-Tuttle only passes the earth and circles the sun once every 133 years, but the earth passes through its trail of dust every year. The debris field is large, so Perseid meteors may be seen on nights from July 17 through August 24. The earth passes through the most dense portion of the comet's dust trail on the night of August 12-13, so that is when the peak, or maximum hourly rate of meteors, will be seen. The rates will also be high throughout the August 11 - 14 period, so you can look for Perseid meteors any or all nights this week.
Below is a video that I assembled in 2009 from several nights photographing the Perseid meteor shower. It is a time-lapse video that condenses several hours of meteor activity into seconds of video:
Not everything that moves in the video are meteors; the meteors are the brief streaks of light, the slower ones are airplanes. As you see the Milky Way and stars move, that is from the rotation of the earth.
You can also see haze that is smoke from forest fires that year. I may have similar challenges this year due to the fires currently raging during California's drought. Already the photo I captured above from last Saturday night is darker than usual, due to smoke from a wildfire.
Sunday, August 09, 2015
If you are on the photo sharing site +500px , they have put out a call for licensing bathroom pictures on behalf of +Lonely Planet. Their example is an outhouse photo, so your favorite outhouse photos from Bodie should be fair game!
For the photographers joining me in Bodie this Saturday, look for opportunities in golden hour light, without the daytime crowds as we access the park before it opens and after it closes.
The contest is much broader than just outhouses, so see what other ideas you can come up with as well. You can find more details on the "Find the World's Coolest Toilets for Lonely Planet" opportunity here.
Monday, August 03, 2015
|Sunrise at Topaz Lake on the California / Nevada Border|
In recent years the availability of maps and satellite imagery online in programs like +Google Maps made the location planning easier. The availability of fairly detailed weather forecasts days in advance through the National Weather Service made the choice of where to go in a region a little easier. Apps like +The Photographer's Ephemeris added lines to show the direction of the sun and moon at any time of day or night, so you could anticipate the exact sun rise and set time, general sunlight illumination during the "golden hour" before sunset and after sunrise, as well as anticipate the location of the moon.
|Forecast for August 2, 2015|
Another handy feature of SkyFire is to compare forecasts for a list of favorite locations that you've saved, so you can decide between locations to drive to, in order to have the best odds of a nice sunset.
I've tested these features a number of times now, and they do well at predicting when there will or won't be sunset color. Weather forecasting is notoriously imprecise, so of course you can't predict the direction or extent of the color, but so far the correlation between the SkyFire forecast and the outcome is impressive.
Here's the sunset that actually occurred with the forecast shown to the right for August 2:
|Multi-day SkyFire forecast on TPE|
The SkyFire service is an optional in-app purchase for TPE, with prices as follows:
Top In-App Purchases
- Location Synch (1 year)$0.99
- Skyfire Plus (3-months)$14.99
- Skyfire (3-months)$9.99
There is also a new location synchronization feature, which finally enabled me to sync my iPhone TPE with my Windows TPE. There was a procedure to do it before that I had not been able to complete. With this new method it was quick and simple.
If you don't already have TPE, here's a link that you can use to find it in the Apple iStore:
The Photographer's Ephemeris - Crookneck Consulting LLC
Crookneck Consulting also offers a Photo Transit app which enables you to anticipate what focal length you'll need to capture a certain field of view to get the shot that you want:
The Photographer's Transit - Crookneck Consulting LLC
I'm also testing TPE 3.4, so I'll probably have some details on that for you shortly!
|Another sunset accurately predicted by SunFire|