While we were at Joshua Tree National Park in California last weekend, Margaret and I went to the monthly Dark Sky Program at the nearby Sky's The Limit (STL) Observatory and Nature Center in Twenty Nine Palms
We had a bit of cloud cover that evening but Ann Congdon, President of STL, kindly shared with me couple of photos of spectacular skies other guests have captured above their dome.
Nonetheless, it was a thrill to get a tour of the skies by Allen Schiano, who has a doctorate in Astronomy and Astrophysics and teaches at Irvine Valley College in Irvine. He previously worked at UC Irvine as a Director of Instructional and Research Computing. He was on stage with John Hill who is the Technical Director at the Large Binocular Telescope operated by the Steward Observatory of U of Arizona.
With their laser pointer as guide, us amateurs got to see
- Sirius, the brightest star in the sky
- The three stars in a straight line in Orion’s Belt
- The Big Dipper and the North Star
- The open star cluster, Pleiades, also known as The Seven Sisters
They answered a bunch of questions including how the recently launched James Webb Space telescope will be able to look farther back in time than previous telescopes using infrared light and will allow scientists to look through dust to see stars forming inside.
But the highlight was an experiment they ran as the clouds cleared. Allen describes it:
“It's a long story but the video at the end is worth the time it takes to read what it's all about.
My buddies John Hill and John Hoey and I had a crazy idea to try to see something with a 14 inch telescope that had only been seen with telescopes larger that twice that size. And we didn't use the method usually employed - a spinning disk in the focal plane - since it requires more equipment and expertise than most people could achieve. That was our goal- something simple others with amateur telescopes could do.
What were we trying to do, you say? We wanted to see the Crab Nebula pulsar 'pulse' on its close to 30 Hz frequency by taking 30 second images at the scope. Those could easily be shown to people watching with current amateur level equipment.
We rigged my Celestron C14HD SCT telescope with 'woofer' speakers and pumped nearly 30 Hz signals into speakers we had taped to its side (Data from the Jodrell Bank, UK ephemeris of the Crab were used to calculate the exact frequency which is critical). We aimed the scope at the Crab Nebula, specifically at the pulsar in the nebula which is the remnants of the star that exploded in a supernova which people saw on Earth in 1054 AD. The neutron star is 1.4 times the mass of the Sun and is about 10 km in diameter. It spins at a dizzying 30 times per second. Like a lighthouse, with every rotation it sweeps a beam of light past us. We see it as a 30 Hz pulse. That's too fast to detect visually for most people.
This video consists of four frames captured while aimed at the pulsar and with the speakers vibrating the scope just below 30Hz. You can see the stars bouncing around while the pulsar remains stationary. The pulsar does bounce around in the same direction as the stars since the location of the pulse is defined by the exact timing of each frame which we did not control.
As far as we know, this is a brand new technique for capturing the pulses of the pulsar and requires only a modest investment in equipment that almost any amateur astronomer could afford.
Instead of seeing it blink on and off this video captures its image as it vibrates 30 times per second. All the stars and background bounce back and forth as does the pulsar. But the pulsar is only lit for a brief moment every 1/30 of a second so it seems to stand still.
The images aren't perfect. This was our first attempt. But this definitely proves this concept works. And that is totally cool!
Tech Specs: Celestron C14HD at f11/Mallincam DS10cTEC camera/30 sec exposures at gain=110/160 and bin=1/image processing by GIMP (cropping, rotation), Topaz Labs DeNoise AI (noise reduction), and PixInsight (animation)
The video is here.”
In preparation for the trip, Margaret had tried out several monocular lenses to attach to her iPhone. Assembly turned out to be a bridge too far in the dark. So it is a bit embarrassing to see how deftly Allen assembles his 250 lb. telescope.
Talking about the dark, Margaret did bring along a tactical flashlight with red/green/blue lights. We used the red light to walk around and not spoil the viewing for others. Red light has a wavelength of around 650 nm. That can be detected by cone cells, but not rod cells in our eyes. Cone cells dark adapt much quicker than rod cells.
BTW, even a day trip to STL is worthwhile. It has an Orrery – walkable model of the solar system at 20 billion-to-1 scale, trails with desert flora and a variety of sculptures. It is off the grid thanks to eight solar panels plus a bank of reclaimed batteries donated by the USMC which has a large base in town. This system provides the power for computers, projectors, a weather station, and more.
Quite a memorable visit.
Photo Credit - STL and guests who signed them.
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