Labeled Moon Diagram

APOD 3.3

26 Jan 2013 Alaskan Moondogs

    

    This image was taken in Miller Creek, Alaska, on January 17th.  This moon is in its first quarter phase and clearly has a halo around it in the sky.  This halo was created by ice crystals which are falling in the atmosphere and create a giant lens reflecting the light from the moon. On the left and right, moondogs can be seen. They are similar to sundogs but are created by the moon reflecting light on icy crystals in the atmosphere.  The scientific name for this apparition is paraselenae.  The moon must be observed from an angle equal to or greater than 22 degrees and the ice crystals must be of hexagonal shape for moondogs to be visible.  

APOD 3.2

24 Jan 2013: ISS and the Summer Milky Way

    This image was taken in Buenos Aires, Argentina in early January.  In addition to the usual clouds on Earth, this image documents the Milky Way Arc on the left side.  Also, starry clouds and nebulae can be seen.  The Carina Nebulae is the slightly pink area in the photo.  Some other galaxies can be seen at the top of the image, even though they are over 200,000 light years away.  Canopus is the second brightest star in the night sky from Earth and is in the Carina Nebulae.  It is the alpha star.  This image was exposed for five minutes at the same time that the International Space Station was passing by, creating the bright white streak in the sky.

APOD 3.1

Jan 15 2013, A Solar Ballet

    The video attached to this APOD shows a prominence erupting from the sun.  Solar Prominences are made up of gas and are very bright.  This one was observed by NASA's Solar Dynamic Observatory.  This video shows the prominence in the Ultraviolet spectrum.  Prominences are supported by the complicated magnetic fields of the Sun.  The plasma seen in this video falls back to the Sun's surface because it does not have enough energy to escape the Sun's powerful gravitational force.  Some prominences can last more than a month and the Earth could comfortably fit inside of one.  This year, the Sun will reach a solar maximum this year, meaning that events such as this one will become common on the Sun's active surface.  The solar cycle lasts 22 years in total.  

APOD 2.8 The Elusive Jellyfish Nebula

9 Jan 2013:  The Elusive Jellyfish Nebula

    Left of center in this image is the jellyfish nebula which is very hard to view.  The tentacles which gave it its name were created about 3000 years ago by a supernova explosion.  The bright star on the right is Eta Geminorum, part of what is often called the "celestial twin."  The first light from this nebula probably reached Earth about 30,000 years ago which means it is at least that old.  Similar to the crab nebula, which I wrote an APOD about a while back, this nebula has a neutron star which is a remnant of a collapsed stellar core.

Biography: Nevil Maskelyne

    

    Nevil Maskelyne was born in London on the 6^th of October, 1732. He came from a well off family although his father died when he was twelve and his mother died as well not long after. He was nonetheless able to study at the Westminster School, receiving a strong education both during the academic year and during breaks when he studied writing and math under a tutor. Since the eclipse of 1748, he was fascinated with astronomy and optics and studied math extensively in order to further his understanding of these fields. His next level of education was at Trinity College, Cambridge where he studied natural philosophy, pneumatics, and hydrostatics. In addition to this schooling, Maskelyne was ordained in 1755 and moved back to London to work.

In 1785, Maskelyne married Sophia Rose of Cotterstock and had his only child, Margaret, the same year.

In London, Maskelyne became the unofficial assistant to a Royal Astronomer, James Bradley, and helped him to compute tables of refraction. In 1761, Maskelyne was sent by Bradley to observe the transit of Venus on St. Helena. His trip was unfortunately unsuccessful due to clouds and malfunctioning instruments. Some sources say that he was able to salvage some observational data from the trip and later used it to calculate the Sun's distance with only 1% error. Although it is disputable whether or not he recorded Venus' transit, which is among the rarest of astronomical events, Maskelyne did perfect the lunar distance measuring method created by Tobias Mayer and wrote a book titled The British Mariner's Guide.

Maskelyne's second voyage was to Barbados with the intention of discovering the accuracy of a certain method of longitude measurement. He was entrusted with this mission by the Board of Longitude who also asked him to test a new chair aimed at making astronomical observations at sea easier. At this point in his life, Maskelyne was already a royal astronomer as he replaced Nathaniel Bliss as the 5^th Astronomer Royal after Bliss' death in 1765. From his voyage focused on longitude, Maskelyne gathered enough information to not only present his findings to the board, but also to write a book two years later, Nautical Almanac.

One innovation Maskelyne receives credit for is the creation of “Requisite Tables” which eliminate parallax, used for calculations. Today, Maskelyne's navigational aides are still used, proving his brilliance and phenomenal work in the field of astronomy.

In 1774, Maskelyne attempted to calculate the density of the Earth using the plumb line produced by a mountain in Scotland. His results were close to the accepted standard today, a remarkable feat for those times.

In addition to his work regarding longitude, Maskelyne studied the latitude measurements made by Mason and Dixon in Maryland and Pennsylvania and the latitude line in Greenwich. He used triangulation to calculate these values himself and was included in the book Elements of Astronomy by Samuel Vince for his work.

Some of Maskelyne's lesser known works include A Proposal for Discovering the Annual Parallax of Sirius and his work involving time. The proposal was his first published work and he was able to divide the measurement of time into tenths pf a second for the first time. He has been portrayed in a television episode based on a book about him titled Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time. Also, he has had a lunar crater and an island in Malekule named after him to commemorate his advancements.

Maskelyne died at the age of 79 in 1811. This was quite a long life for someone of this time and his daughter only outlived him by six years. His colleagues said he was always friendly and like a brother to all. Although he did not leave behind any instruments to the Royal Observatory, he still left a legacy of detailed calculations and very important publications which would be used for many years to come.

APOD 2.7 Orion Over El Castillo

21 Dec 2012: Orion Over El Castillo

    This image was taken in front of a temple at Chichén Itzá the day that the world was rumored to end according to the Mayan Calendar.  NASA posted a question and answer blog on their website, assuring people that the world would in fact continue.  December 21 was also the Winter Solstice.  The structure featured can be used as a calendar and also for astronomical alignments.  Orion the Hunter, the constellation in the background, is one of the most recognizable constellations in the night sky.  This image clearly features his belt and sword.