APOD 2.1

I Zwicky 18, galaxy on the left which spans over 3,000 light-years, was thought to be one of the youngest galaxies that we know because its bright stars only seem to be 500 million years old. Astronomers were very intrigued by this galaxy because it resembles other early forming galaxies. The galaxy is only 59 million light-years away, relatively close, but is surrounded by other galaxies that are much older. Recent images by Hubble Space Telescope, reveal a population of old, bright stars intermixed with the bright stars within the I Zwicky 18 galaxy. So now, I Zwicky 18 is thought to be about 10 billion years old like its neighboring galaxies, but seemed to have an episode of new star formation. The possible reason for this new star development may be related to the changing gravtitational influence of I Zwicky 18's smaller companion galaxy, visible on the upper right. This is really interesting, especially because for so long, astronomers thought this galaxy was so young, but is actually relatively old. It is also interesting that it experienced this burst of new star formation, which makes the galaxy appear to be much younger than it really is.

Astronomer Biography

Danielle McCoy
Mr. Percival
Astronomy Honors
10 Oct. 2007
Johannes Hevelius

"The founder of lunar topography," Johannes Hevelius was born on the 28th of January 1611 in Danzig, Germany. In 1630, Hevelius studied jurisprudence at Leiden. Later, he traveled in England, France, and Switzerland. During his travels, he met many leading astronomers, including Pierre Gassendi. By 1634 he returned to and settled in his native town of Danzig. He worked as a brewer in the family business and later became town councillor. He married his first wife Katharina Rebeschke, who later died, and in 1663 he married Catherina Elisabetha Koopman, who could be considered one of the earliest recorded female astronomers.
By 1639, astronomy became his principle interest. In 1641, he built an observatory above his house, which included several excellent instruments. Included in his instruments was a tubeless telescope with 150 ft. focal length, which Hevelius constructed himself. His telescopes were described in detail in Machina coelestis, pars prior (1673), and was followed by Machina coelestis, para posterior (1679). On the 29th of January 1660, the King and Queen of Poland, John II and Maria Gonzaga, visited the observatory.

Hevelius dedicated many years of his life to making many observations of different aspects of astronomy. He spent 3 years making detailed observations of sunspots, devoted over 4 years of his life to charting the lunar surface, and discovered the moon’s libration in longitude. Many of his results were published in Selenographia (1647); due to this work, Johannes Hevelius is often called the founder of lunar topography. The work he did in Selenographia became known for its accurate illustrations of the lunar surface. Although, his system for naming the moon’s features did not last, but were replaced by Riccioli’s system (which used the names of famous astronomers and mathematicians). The only surviving term was mare (meaning sea), which is given to large dark plains. In the years 1652, 1661, 1672, and 1677, he discovered four comets and from this, suggested the theory of the revolution of these bodies in parabolic patterns around the sun. This idea was published in Cometographia in 1668. He also introduced the use of the vernier scale.

In a malicious fire on the 26th of September 1679, all of his instruments, books, and his observatory were destroyed. Though, he quickly repaired the damages, and was able to view the great comet of December 1680. His health deteriorated, and he later died from the shock of the fire on the 28th of January 1687, the day of his 76th birthday. After his death in 1687, his wife continued to publish many of his works.

Other works published by Hevelius include his 1690 publication of Prodromus Astronomiae, a catalogue of 1564 stars which contains Firmamentum sobiescianum, sive Uranographia, a famous collection of 50 excellent pictures of constellations. Hevelius gave names to eleven constellations, seven of which are still in use. He measured atmospheric refraction and compiled important observations of the planets, the penumbra of sunspots, and the bright regions of the Sun’s surface, for which he gave the name faculae, which is still used today.

Works Cited
"Johannes Hevelius." Adler Planetarium. 08 Oct. 2007 .
Van Helden, Al. "Johannes Hevelius." The Galileo Project. 1995. Rice University. 08 Oct. 2007 .

APOD 1.7

Venus is now being enjoyed by early risers as the morning star near the eastern horizon. Venus can be seen in the upper right hand corner in this predawn skyview photograph. The moon, in the middle, is seen as a crescent, and in the bottom left hand corner is Saturn. If you were to hold your fist at arms length, both planets and the moon would easily be covered in this 5 degree wide field. Sunlight reflected from Earth's dayside, Earthshine, shows many features on the lunar nightside. If you were to look closely, Titan, Saturn's largest moon, can be seen as a pinpoint near Saturn. The tight triangle between Venus, Saturn, and Regulus (the alpha star in the constellation Leo (top)) look very impressive. This picture is truely impressive, especially because you can see so much. The moon itself also looked very incredible, with the Earthshine.

Observation 1.3

Date: October 11, 2007
Time: 7:30 to 9:00
Place: Church off Clark RD
Sky Conditions: Clear skies
Instruments: Binoculars, Telescope

Planets: Jupiter, Venus

Noted Stars: Deneb, Vega, Altair, Antares, Arcturus, and Fomalhaut

Noted Constellations: Sagittarius, Ophiuchus, Serpens Cauda, Serpens Caput, Aquila, Lyra, Capricornus, Cygnus, Cassiopeia, Cepheus, Pegasus, Scutum, Corona Borealis, Scorpius, Sagitta, Delphinus, Andromeda, and Hercules

Binary Stars: Epsilon Lyrae (noted 2 different colors of 2 stars), Albireo

Deep Sky Objects/ M-objects: M8, M57, M27, M11, M13

Other: Four moon's of Jupiter (noted differnet colors of 2 moons)

I found this observation period very helpful and interesting. I enjoyed being able to see some of the M objects that we have been learning about in class. Also, seeing the different colors of Jupiters moons, and the apparent different colorings of 2 stars of the binary star Epsilon Lyrae(?). It helped to see all of these objects because I feel like they mean more by seeing them with my own eyes rather than just on paper and I can better commit them to memory.

APOD 1.6

About 20,000 light-years away from the sun lies NGC 3603, part of the nearby Carina spiral arm of the Milky Way Galaxy. To many astronomers, NGC 3603 is known as one of the Milky Way's largest star-forming regions. The open star cluster in the center contains thousands of stars, which likely formed only one or two million years ago, and are much more massive than our Sun. It is believed that NGC 3603 contains a good example of massive star clusters that may populate very distant starburst galaxies. Natal clouds, sculpted by energetic stellar radiation and winds, of glowing interstellar gas and obscuring dust surround the cluster. The image, which spans 17 light-years, was recorded by Hubble's Advanced Camera for Surveys. This picture is very amazing, the intensity and the color are incredible. Its hard to believe that this picture spans over 17 light-years, and that this picture of NGC 3603 is over 20,000 away from the sun.

Observation 1.2

The whole week of August 22nd thru 28th, the moon was clearly visible in the mornings and at night. Also, the first magnitude star Antares was visible. Jupiter was visible, low on the sky and close to the horizon. The moon was also visible; throughout the week, the moon seemed to progress from waning gibbous to full moon.

APOD 1.5

The dark area below the equator of the sun is a coronal hole- areas in the corona that are less dense and cooler than the surrounding areas, the solar magnetic field opens into interplanetary space. The picture, shown in false color, was taken on September 19th in ultravioletlight by the EIT instrument on board the space-based SOHO observatory. Coronal holes, studied in ultarviolet and x-ray light, are the source of high-speed solar winds. The solar winds streaming from this coronal hole caused colorful auroras on our planet, as seen by spaceweather watchers and astronomers from high altitudes.