Archive for the ‘Night Sky’ Category

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Jupiter / Moon Conjunction

Sunday, January 9th, 2011

Tonight and tomorrow night (January 9 and 10,) the waxing crescent Moon will rise and set with our solar system’s largest planet, Jupiter.  You’ll find the pair high above your SW horizon at sunset and setting into the west by about 10:30 pm.  If you’re up to a fun challenge, grab a pair of binoculars to see if you can spot Jupiter’s four brightest moons to either side of Jupiter, and the planet Uranus to the very near lower-right of Jupiter.

While these two may appear close together, they are actually 365-million to more than 500-million miles apart.  As you look at them together, consider their many differences.  Jupiter is a gas-giant planet measuring nearly 90,000-miles at its diameter; Luna is a rocky “satellite” roughly 1/4 the radius of Earth.  Jupiter completes one solar orbit in twelve years; the Moon completes an Earth orbit in just over twenty-seven days.  Surprisingly, though Jupiter dwarfs the Moon, it completes one axial rotation in just over nine hours, while one full day on the Moon, from one sunrise to the next, is equal to 29.5 days.

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Posted in Moon, Night Sky, Planets | No Comments »

An Image Mystery

Tuesday, January 4th, 2011

Tonight, I discovered a mysterious object in two of my “Jupiter with Uranus” images.  Perhaps, someone can help me to determine what it is.

Some points to consider:

1) Both images are 30-sec exposures.  The first was taken at 18:49; the second was acquired at 18:50.  (Thirty seconds elapsed between the end of the first exposure and the start of the second exposure.)

2) Although the mystery object appears as a mere dot against the extended trails of the background stars, a close-crop reveals that the mystery object is also trailed, as would be expected with a long exposure and as would not be expected with typical image noise.

3) The stars’ trails extend from upper-left to lower-right, in the direction that the stars are actually moving, but the mystery object’s trail extends in a direction perpendicular to the stars, yet it appears to move (from one image to the next) in a direction exactly opposite that of the stars (from lower right to upper left.)

4) As luck would have it, my dog bumped the tripod during one of the exposures.  Oddly enough, it was actually “good luck”, because the mysterious object reveals the same “bump” seen in all of the stars – something one would not expect to see with typical image noise.

5) A satellite would show a much longer trail with a 30-sec exposure and it would have traveled much further between the two exposures.

6) A satellites check in Stellarium shows one craft, AO7, at 15-degrees beneath Jupiter and Uranus three-minutes after the second exposure.  Less than one-degree separates Jupiter and Uranus.

The images: (These can be enlarged by clicking on the images. Images 2 and 3 are especially large, to show more detail, and should be closed using the “close” tag in the bottom right corner of the image.  If you click the “X” in the top right corner of your browser, you will close the web page.)

This first image is an animated gif of four frames: original image, labeled, crop insert, and apparent movement.

Animation - 4 frames

This second image is the first of the two original images. This is the dog-bumped image, acquired at 18:49.

Original Image #1 - EST 18:49

This third image is the second of the two original images.  This image was acquired at 18:50.

Original Image #2 - EST 18:50


Posted in Astrophotography, Night Sky, Uncategorized | 4 Comments »

Round-the-World ISS Wave!

Thursday, December 23rd, 2010
ISSwave

http://isswave.org

In “celebration of human solidarity,” the grassroots effort, ISS Wave, is encouraging everyone to look up and wave at those fellow humans orbiting our beautiful blue planet!  The group is focusing particular attention on this next week – a holiday season for many cultures – so, head on over to their site and get involved!

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Posted in ISS, Night Sky, Outreach, Twitter | No Comments »

Total Lunar Eclipse – Dec 21

Sunday, December 19th, 2010

WHAT: Total Lunar Eclipse
WHEN: Evening of December 20 / Morning of December 21
WHERE: The Night Sky!
OBSERVING and SHARING:

Although the eclipse will officially start when the Moon makes first contact with Earth’s outer shadow, at 05:29 UT /12:29 am ET / 9:29 pm PT, totality will not begin until Luna begins its 72-minute passage through Earth’s inner shadow, at 07:40 UT / 02:40 ET / 11:40 PT.

Lunar eclipses are best observed with the unaided-eye, but a standard pair of binoculars will help to intensify totality’s coppery red color.  Photographs are also very effective in bringing-out an eclipse’s dramatic colors.  If you’re new to night sky or eclipse photography, these Basic Photography Tips explain the three technical elements of an image and this Lunar Eclipse Exposure Guide suggests basic settings for eclipse photography.  You might also like to try a multi-exposure image, to illustrate the progression of the eclipse.

Add some evaluation fun to your evening, by using the Danjon Scale to determine the Moon’s appearance and brightness during totality, or engage in more in-depth analyses as described in Daniel Fischer’s “What They Don’t Tell You About Tonight’s Total Lunar Eclipse.”

Share your observations with others!  Spaceweather.com is encouraging observers to submit their Danjon Scale ratings, to assist climate scientist Richard Keen with his Lunar Aerosol Climate Experiment.  JPL has a Lunar Eclipse Flickr group, where you can share your eclipse images.  You can also share your observations on Twitter, by including hashtags like #LunarEclipse, #skywatch, and #moonwatch with your tweets.

As the Moon becomes immersed in shadow, try identifying various craters and Apollo landing sites, as well as neighboring celestial objects.  Luna will spend the evening in Taurus, near the borders with Gemini and Orion.  This region includes such deepsky favorites as Orion’s Nebula; Messier clusters M35, M36, M37, and M38; Monoceros’ Cone Nebula; and Taurus’ Pleaides and Hyades clusters.  Some brighter stars in the area include Betelgeuse, Aldebaran, Procyon, Pollux and Castor, Capella, and Alnath and Alhena.  There’s also the Ursid Meteor Shower, which may be more apparent in the darkness of Totality!

While December’s Full “Long Night” Moon doesn’t officially occur until December 21st, Luna will be “full” when it rises Monday evening (else we couldn’t have a lunar eclipse!)  A rising full Moon is always a pretty thing to see, so watch for it on your ENE horizon around 4:30pm, or about 30-minutes before sunset.

If your skies are too cloudy, you can observe the eclipse via live image streams and webcasts:

Astroguyz’s Flickr PhotoStream

ChrisAstro on JustinTV

Columbus State University’s Coca-Cola Space Science Center

NASA-hosted live chat and video feed!

Night Sky Network (an Astronomers Without Borders list of nine different broadcasters)

SLOOH Online Observatory (registered members only)

AFM*Radio will be discussing the eclipse tonight!  You can tune in by clicking the “Listen Now” button on their home page, or via iTunes, where you’ll find them as the sixth station listed in the News/Talk Radio section.

FUN FACTS:

This month’s Total Lunar Eclipse is the first in nearly three years – our last total event was in February 2008.

This year’s Total Lunar Eclipse nearly coincides with the Solstice, which will occur on December 21 at 23:38 UT / 6:38pm ET / 3:38pm PT.  While a “solstice eclipse” is not rare, it is an infrequent enough occurrence to warrant special mention.

There will be two Total Lunar Eclipses next year, in June and December, the latter of which will be visible in parts of the U.S.

The outer and inner shadows, through which the Moon passes, are known as the penumbra and umbra.

A Total Lunar Eclipse, or totality, occurs when Luna is completely immersed in Earth’s inner shadow.

There are other types of lunar eclipses, including a penumbral eclipse, when the Moon passes through Earth’s outer shadow, and a partial eclipse, when Luna passes through only a portion of Earth’s inner shadow.  The most dramatic, and more elusive, of eclipses is a selenelion, or horizontal eclipse, when any lunar eclipse can be viewed opposite the Sun, such as during sunrise or sunset.

The duration of an eclipse varies according to Luna’s path through Earth’s shadow.  The maximum time an eclipse can last, from penumbra entrance to penumbra exit, is 3-hours, 40-minutes.  The longest totality, when Luna passes through the very center of Earth’s shadow, is 1-hour, 40-minutes.  Partial eclipses are much shorter, particularly when only a small portion of the Moon slips through the top or bottom of Earth’s outer shadow.

Lunar eclipses occur 2 to 3 times a year and are visible over an entire hemisphere. (Solar eclipses occur 2 to 5 times a year, but are visible along a path not more than 167-miles wide.)

Total Lunar Eclipses are always preceded or followed by a Solar Eclipse, with exactly two weeks between the two.  This month’s Lunar Eclipse will be followed by a Partial Solar Eclipse on January 4, 2011.

Lunar eclipses follow a long-term rhythm, wherein each eclipse’s characteristics are repeated every 18 years, 11 days, 8 hours (223 synodic months.)  This month’s eclipse is #48 of Saros 125, a series of 72 eclipses, beginning on July 17, 1163 and ending on September 9, 2443.

*SOURCES:

Astroguyz – Breaking News for Sky Aficionados - Dan Durda’s Exploring the Apollo Landing Sites - David Bradley’s Science Base - Digital Cameras Help – Ewan Bryce - Farmer’s Almanac - Keith’s Moon Page - Mr. Eclipse – MSNBC - NASA/GSFC - Night Sky Hunter - Shadow and Substance - Sky and Telescope - Space.com - Spaceweather.com

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The 2010 Geminids!

Monday, December 13th, 2010

Credit: Wally Pacholka TWAN


WHAT: Geminid Meteor Shower

WHEN: December 13 / 14

WHERE: The Night Sky!

OBSERVING and SHARING:

While Gemini currently rises from the east horizon around 9pm, tonight’s first-quarter moon sets around 1am local time, when Gemini is higher overhead, so best observations will likely be in the hours between 2am and dawn, local time.

Don’t overlook tonight’s first-quarter Moon with Jupiter, earlier in the evening, and all those celestial goodies surrounding Gemini, throughout the night!

If your skies are too cloudy to see the Geminids, you can listen to their radar echoes on Spaceweather Radio!

NASA is hosting an all-night Geminids webchat, from 11pm – 5am EST, where you can have your questions answered by  NASA astronomer Bill Cooke!

Twitter-users are including the #Geminid hashtag to share their observations from around the world.

Photograph tonight’s meteor shower with helpful hints from this article, by Dennis Bodzash.

Collect tonight’s meteor shower with this micrometeorites how-to from Brian Carusella.

Contribute to meteor science with the International Meteor Organization’s electronic visual report form, here, and the American Meteor Society’s fireball reporting form, here.

FUN FACTS:

Meteor showers occur when our planet encounters the debris fields of passing comets.  Much of the debris is dust-sized particles, but some streams can contain larger objects ranging from gravel to small rocks.  Individually, these particles are known as meteoroids.

Most debris fields are ancient, having been left tens and hundreds of years ago, by comets as they near the Sun.  As the material leaves a comet, it falls into orbit as a collective stream or elongated patch.  Some streams can extend for millions of miles.

As Earth moves through a comet’s debris field, those particles (meteoroids) passing through our atmosphere are vaporized, resulting in the bright streaks that we call meteors.

Meteoroids that survive their encounter with our atmosphere, and actually impact the Earth’s surface as a small rock, are known as meteorites.

Meteor showers are named for the constellation from which the meteors appear to emanate, rather than for their physical origins.  That apparent, or visual, origin point is known as the “radiant.”

Observed nearly every December since the late 1800s, the Geminids are named for the constellation Gemini, with their radiant appearing to be just north of Gemini’s two brightest stars, Castor and Pollux.

Although Geminid meteors are slower and exhibit less trails than most other meteors, Geminids put on a fantastic display as one of the more prolific and consistent meteor showers of the year.

Geminids activity has steadily increased through the decades, with plateau peak rates reaching as high as +/-120 in more recent years.  A 2005 analysis of sixty years of observation data suggests the Geminid stream to be about 6,000 years old.

A meteor shower’s physical origin is known as the “parent body” or “progenitor.”  Geminid meteors originate in Earth’s encounter with the debris field of the near-Earth-object, 3200 Phaethon.

The Geminids’ progenitor, 3200 Phaethon, became the first asteroid discovered by a spacecraft, when scientists spotted it in images from the multi-national Infrared Astronomical Satellite (IRAS.)  Those scientists were Simon F Green and John K Davies, and the year was 1983.

3200 Phaethon is categorized as an Apollo class near-Earth-object, as well as a potentially hazardous asteroid (PHA,) with its closest pass missing Earth’s orbit by a mere 2-million miles.

Although most meteor showers do originate from comets, 3200 Phaethon is not a typical comet, nor does it appear to be a usual asteroid.  While some scientists originally thought that Phaethon may be a “dormant” comet, a more recent study proposes an entirely new kind of object – a “rock comet” possibly even born of an impact event with the large main belt asteroid, Pallas.

A better understanding of Phaethon’s peculiar comet/asteroid characteristics and possible Pallas relationship might also help scientists make more learned determinations about other similar peculiar events, such as the recent comet-like coma detected around the asteroid (596) Sheila.

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Posted in asteroids, Citizen Science, Comets, Meteor Showers, Meteorites, NEO, Night Sky, Uncategorized | 1 Comment »

Sharing the night sky, one book at a time!

Friday, December 3rd, 2010

Together, we can help lift Indonesia’s eyes to the night sky!

Imagine one of your own astronomy books in the hands of a young Indonesian exploring the Universe for the very first time.  While astronomy materials are commonplace in many countries, they are expensive and limited in developing countries, like Indonesia.  In fact, many Indonesians have never even seen a picture of a nebula or read about the fantastic history of people like Galileo, Brahe, and Carrington.

A Sky Full of Stars is a proud participant in AstroBookDrive‘s latest project, seeking to stock Indonesia’s future Langitselatan (LS – Southern Skies) library.  With donated materials from people like you and me, the LS group will have a powerful tool to enable greater astronomy learning for the local students and encourage larger astronomy participation amongst the general community.

Contributing to this celestial endeavor is as simple as packing a box and delivering it to your local post office.  New and gently-used astronomy books and magazines, including back-issues, are needed.  Whether you’ve one or many items to donate, every bit will make a positive difference, and that includes shipping your donated items directly to the LS group.

To help with those shipping costs, consider enlisting others, such as friends, family, and local astronomy clubs.  When shared amongst a group, international shipping rates become much more affordable, and contributing to those costs enables everyone to “share the sky” even if they’ve no items to donate.  This drive runs through the end of January, so there’s plenty of time to organize a group effort!

If you aren’t able to donate any items, you can still participate in the Langitselatan AstroBookDrive by sharing it with your friends, family, and local astronomy club, or by promoting it on your own website.  (For website promotion details, contact Thilina Heenatigala at thilina.heenatigala (at) yahoo.com.)  If you do get involved, whether through sharing this information or donating books, we’d love to hear from you with a comment to this post or a shout-out on Twitter!  (AstroBookDrive / Langitselatan / A Sky Full of Stars)

Below is a list of needed items and the Langitselatan shipping address.  Be sure that you clearly print the shipping address to avoid any misdirected shipments, and note “AstroBookDrive-ASFOS” somewhere on the box to help with participant tracking.

NEEDED ITEMS: General Astronomy books * Children’s Astronomy books * Teachers’ Astronomy guides * College-level Astronomy textbooks * Various Astronomy magazines, including new subscriptions and back issues (five years and newer)

*All materials must be English version

SHIPPING ADDRESS:

Avivah Yamani
langitselatan

Jl. Budi Luhur I no. 23 c
Bandung – 40153
Jawa Barat – Indonesia

Together, we can help lift Indonesia’s eyes to the night sky, one book at a time!


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Posted in Night Sky, Outreach, Uncategorized | 1 Comment »

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