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Pictured is a Delta IV rocket launch from Cape Canaveral on November 21st, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.
Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New. A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.
The Sun is our nearest star, and goes through an 11-year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 2013-14.
Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.
Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a near-weekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.
Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.
A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth’s shadow is apparent in the image.
The Algonquin Indians had names for each of the seasonal Full Moons, many of which survive today. The Full Snow Moon pictured occurs in the month of December, when the first large winter storms coat the ground with snow. This Full Moon also tends to fall near the Winter Solstice, and thus rides high in the nightly sky opposite to the Sun on long winter nights.
Every rocket launch is unique, but twilight shuttle launches where by far the most impressive. The image pictured was of the April 5th, 2010 launch of Space Shuttle Discovery from the Kennedy Space Center at dawn. The exhaust plume caught the rising Sun overhead just right, and numerous noctilucent clouds persisted right up until sunrise. Unfortunately, space shuttle launches are now relegated to the pages of history.
Astro-Challenge: Haunting the “Ghost Double.”
The “Ghost of Gamma…” (Created by the Author in Starry Night).
Sometimes, the new and the unexpected lies just inside the field of view of the familiar. This week, we’d like to turn your attention to a hidden double star in the field of a star party favorite. Halloween means sidewalk astronomy season, as we show off the delights of the universe to high-fructose corn syrup-filled suburbanites. Hey, it’s wonderful that a pagan Cross Quarter tie-in holiday (as in a celebration approximately midway between the equinox and the solstice) gets some play in this day and age.
The trouble is, what do you show ‘em when city lights are burning bright and planetary detail is nowhere to be seen in prime time skies, such as Halloween 2012?
We give em’ double stars, and one of the finest examples is Gamma Delphini in the constellation Delphinus the Dolphin. The pair is an easy find on Fall evenings, being located at the eastern “tip” of the “diamond” asterism. If thoughts of happy frolicking dolphins aren’t ghoulish enough for Halloween viewing, the asterism also sometimes goes by the obscure name of “Job’s Coffin.”
The constellation of Delphinus the Dolphin… or do you say “Job’s Coffin?” (Photo by Author).
Gamma Delphinus is an easy split with a small telescope of about 9” arc seconds. The pair is within one magnitude brightness at +5.0 & +4.4, and has a physical separation of about 300 astronomical units and an estimated orbital period of about 3,249 years. First recorded by F.G.W. Struve in 1830, colors at the eyepiece range from white to yellow to violet. A pretty pair, to be sure… but did you know a visual twin lurks nearby?
James Mullaney notes in the October 2011 issue of Sky & Telescope that a “Ghost Double” in the form of Struve 2725 is apparent in the same 30’ arc minute field as Gamma Delphinus. At magnitudes +8.2 and +7.5 respectively, the pair is an easy grab, once you know to look for them. Struve 2725 is only a slight bit closer in visual separation at 6.1” arc seconds and about 256° degrees out of position angle alignment with Gamma Delphini.
Though the pair lies in the same direction, that’s only a happy circumstance of our vantage point in space and time. Both systems have different proper motions and are moving apart from one another. Struve 2725 is 125 light years distant, versus Gamma Delphini’s slightly closer 102 light years. Struve 2725 lies 15’ arc minutes south-southwest of Gamma Delphinus.
There has also been some controversy over the 1999 claim of an exoplanet for Gamma Delphini B; estimates from a study carried out by the McDonald Observatory place a lower limit on the unseen planet at 0.7x Jupiter masses and a distance of 1.5 A.U.s. The total mass for the Gamma Delphini system weighs in at 3.3x Sols. Together, Gamma Delphini and Struve 2725 are also sometimes referred to as “the Dolphin’s Double-Double” in reference to Epsilon Lyrae, but I like the Halloween meme of “The Ghost Double” as a system that seems to be stalking the famous pair.
The current positions are as follows;
Gamma Delphini:
R.A.: 20 Hours 47’
Declination: +16° 8’
Struve 2725:
R.A.: 20 Hours 46’
Declination: +15° 54’
Happy Halloween!