Skip to main content

Feeling the Love and Joy

Comet Lovejoy has been gracing the night skies for several months. As it travels north-ish across the background of stars, it's been getting higher in the sky for us in the northern hemisphere. It also recently completed perihelion (the point in its orbit when it's closest to the Sun) and its closest approach to Earth. These have all come together to make a pretty impressive showing for this comet discovered just last year.

As comets get closer to rounding the Sun, they typically get brighter. That's because the Sun heats up the comet's body, causing material on the comet to sublimate, which produces gas vents and loosens debris. The gas and other material fly off the comet body, which is what makes a comet "fuzzy" and usually produces a noticeable tail.

It's often mistakenly believed that a comet's tail indicates its direction of travel. When airplanes leave contrails or rockets take off leaving a stream of exhaust, we naturally understand that the trailing tail indicates the direction the object is traveling. (If the rocket's exhaust is trailing in one direction, the rocket must be traveling in the opposite direction.) This is not necessarily the case with comets. There is no air in space to interact with a comet's tail. It streams away from the comet's head because of solar radiation, i.e., the solar wind, which is not really a "wind" as we know it. It's a stream of charged particles that constantly shoot off in all directions from the Sun. In this image, the comet (officially known as C2014/Q2 Lovejoy) is moving toward the 4 o'clock position, nearly perpendicular to the tail.

Comet C2014/Q2 Lovejoy
AGO 10" f/3.9 Newtonian and FLI ML11002-C
Single 2-minute exposure

This desaturated and inverted image shows the extent of the comet's tail. The star cluster is the Pleiades.

Canon EOS 6D, Rokinon 85mm f/1.4 lens at f/2.5. 30 seconds. ISO2000. Tracked using a Losmandy Starlapse.


Popular posts from this blog

The Great American Total Solar Eclipse of 2017

American eclipses are about to be made great again! It's been about 38 years since there's been a total solar eclipse over the American mainland. And that one just grazed the northwest and northern plains before turning traitor and curving up into Canada. This time around, the path of totality runs essentially through the middle of the entire width of the continental United States, from Oregon to South Carolina. It will be one of the most witnessed total solar eclipses in history.
When: Monday, August 21st (exact times vary based on your location... more below)Where: An approximately 70-mile wide path that cuts through Oregon, Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and South Carolina.Greatest Eclipse: Near Hopkinsville, KentuckyLongest Eclipse: Near Carbondale, IllinoisEclipse LengthShortest: West coast of Oregon at about 1 minute 58 secondsLongest: Southern Illinois at about 2 minutes 41 secondsHow is all the above in…

The Ambiguously Galactic Duo

M81 and M82 are two galaxies hanging out in the constellation Ursa Major, the Big Dipper. M81, on the right, is also referred to as Bode's Galaxy (for its discoverer, Johann Elert Bode). M82, on the left, is also know as the Cigar Galaxy.

Here are the wacky things about images like this one...

(1) Every single star you see in this image is in our own galaxy. It's easy to think you're seeing individual stars in M81 and M82 but that's simply not the case. At 12 million light years away, the galaxies are fairly close to us but they're still much too far to be able to resolve individual stars. Also, while there are such things as rogue stars that get flung out of their home galaxies due to gravitational disturbances, it would be quite rare for one to show up in an amateur astronomer's image.

(2) If your monitor is bright enough and calibrated well, you can see a lot of fuzzy patches, each of which is another galaxy!

Don't look at them too closely... M81 harbors…

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.

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).