Tuesday, August 9, 2016

Perseid Meteor Shower 2016 - Bang or Bust?

The Perseid meteor shower is coming up SOON! Here are some facts about how to view the shower.

  • What? Like all meteor showers, the Perseids occur annually. Also like all meteor showers, the Perseids are caused by the Earth making its way through the debris field of a comet that passed years prior. Those little specks of dust and rock (about 1 to 10mm in size) that the comet left behind smack into the Earth's atmosphere at about 35 miles per second and burn up in an instant, emitting a bright streak of light in the process. Different meteor showers are attributed to different comets. The comet in question for the Perseids is Comet Swift-Tuttle (109P/Swift-Tuttle), which made its way through the inner solar system most recently in 1992.
  • How? Get away from city lights! That's the most important bit of advice for viewing a meteor shower (other than open your eyes and look up). City lights create light pollution and wash out the fainter stars and meteors of the night sky. Go to the desert or the mountains at least 90 minutes from LA. Sit back in a comfortable reclining chair or lay on the ground with a blanket and/or air mattress. Aim yourself so you're looking northeast, but look up. Meteor showers are named for the constellation from which they appear to radiate. The Perseids are named for Perseus, which rises in the north east. But that doesn't mean you'll only see meteors in the vicinity of Perseus. They can appear anywhere in the sky, but they will always appear to radiate from Perseus, an effect of linear perspective. You don't need (or want) a telescope or binoculars to view a meteor shower, just your dark-adapted eyes.
  • When? Thursday night (8/11) into Friday morning (8/12). It'll actually be early Friday morning, about 1:00AM, by the time best viewing begins.

A Perseid meteor from the 2012 display shoots through the field of view in this image of the Heart Nebula.
100-minute exposure using a Takahashi FSQ-106EDX telescope and FLI ML11002-C camera.

  • What constitutes "best viewing"? Perseids appear to emanate from Perseus. Perseus rises relatively late in the evening this time of year and climbs higher throughout the early morning hours. The higher in the sky the radiant is, the clearer view we'll have of the meteors. Also, for the sky to be at its darkest, there must be no Moon. During this year's Perseid peak, the Moon sets at about 1:00AM (PDT) on Friday morning. When those two conditions are met (Perseus is high in the sky and the Moon has set), prime viewing will begin. This occurs between 1:00AM and dawn on Friday, 8/12. That's not to say you won't see any meteors on Thursday evening. You will. But you'll likely see more after midnight and after the Moon sets.
  • Will the sky be full of meteors? While the event is indeed called a "meteor shower," keep in mind that any source that claims there will be a "shower of meteors raining down" or something similar, is full of it. They probably also have photos of sharks attacking helicopters and warn of impending doom by a previously undiscovered sister star of the Sun. Except for very rare occasions, meteor showers typically consist of 1 or 2 streaks per minute, and that's considered a really good display! The Leonid meteor shower is known to have periodic "outbursts" — the 1966 and 1998 Leonids were considered meteor storms!
  • But I heard this year's Perseids are going to be crazy active. Is that true? This year's Perseids are predicted (by some) to be more active than most years — The theory is that Jupiter has perturbed the debris field left by Comet Swift-Tuttle, and placed a denser portion of it in Earth's orbital path. The problem is that no one knows for sure the density of the debris field, how squarely the Earth will hit it, what part of the Earth will hit it and when exactly, etc. The predictions rely on models that use a lot of assumed data. Remember Comet ISON? Yeah.

Get more information about the source of the Perseid meteors, Comet Swift-Tuttle. And find out more about meteor showers.

Enjoy the "shower!"

Sunday, June 5, 2016

Dusk in the Desert

Dusk in the desert can be a magical time. The sun has just set, temperatures continue to cool and pink and orange hues take over the landscape.

Star parties are a great way to experience that time of day. Here are a couple aerial shots as star party guests at GMARS gather and get ready for an evening of observing and imaging.

Star party-goers gather and set up at GMARS

Bird's eye view of GMARS along with the row of observatories and the telescope field
And, of course, here's an aerial video of the Landers area. It features the area at dusk, a 1-mile flight from GMARS to CS3 and back, flyovers of star party-goers, and a flight over Kate's Lazy Desert (at the end of the video).

Sunday, May 29, 2016

Summer is Approaching

In the northern hemisphere, when you start seeing the Milky Way crawl over the eastern horizon in the middle of the night, you know summer is approaching.

Below are a couple images of the Milky Way rising over GMARS. The first is an 8-panel mosaic taken at GMARS around 12:30AM on May 28th. The far left end of the image is looking northeast, and the far right end is looking southeast. From left to right, the light pollution domes are Las Vegas, Joshua Tree & Twentynine Palms, and the Coachella Valley (Palm Springs, et al) on the far right. Also on the far right is Mars, nearing opposition.

The second image is similar, but taken the following night from a different part of GMARS and uses 15 individual frames to create the mosaic. Notice the difference in green airglow from the first night to the second night.

Images like these aren't terribly difficult to take. You just need a tripod, a decent DSLR and a good editing program like Photoshop. Rather than trying to describe the equipment and steps here, I'll simply point you to one of the best websites out there for tripod-based astrophotography, lonelyspeck.com. In particular, check out this article on stitching individual images into one larger image for nice wide views.

The Milky Way over Goat Mountain and GMARS
A Canon EOS 6D and Rokinon ED 14mm lens were used to capture 8 frames for this mosaic.
Each frame: 20-seconds, ISO6400, f/4.0
Another view: Milky Way over GMARS
This image is from the telescope field at GMARS. Same image details as above but with 15 frames.
The southern portion of the Milky Way is full of nebulae and star clusters. Below is one of the many nebulae in the Sagittarius and Scorpius region, the Swan Nebula.

M17, the Swan or Omega Nebula
AGO 10" f/3.9 Newtonian Telescope, FLI ML11002-C camera, single 10-minute exposure.