ASTRONOMY CLUB ....

ASTRONOMY Q & R

(Question and Response)

DISCLAIMER: Explorit is not an established source of information or expertise on things astronomical but answers below are accurate to the best of our knowledge. The questions are ones sent to us by visitors to this website and the responses are by a leader of our Astronomy Club. Currently we are not seeking questions but we hope you enjoy learning from the ones on this page.


Questions:
1. Riccioli
2. Herschel
3. A first telescope
4. Saturn Septenary?
5. Stars and supernovas.
6. The Milky Way

Question 1.: In terms of astronomy does the surname name Riccioli ring a bell?
Response 1.: Well, according to the "Astronomical Scrapbook" (1984) by the late Joseph Ashbrook, Giovanni Battista Riccioli (1598-1671), a Jesuit, was the first person (c. 1650) to use a telescope to discover a double star (Mizar in the handle of the big dipper). R.H. Allen's "Star Names" (1899) has a footnote stating that Riccioli also published the second decent map of the Moon in his book "Almagest" and it was pretty good for the time. It is notable for having named many of the features from "Jesuitical" sources and not being overmodest, his own name appeared first in the list of named features! He so wanted his name to be remembered!
Question 2.: I enjoyed your web site. I have been challenged to find out information on a planet called Herschel. To date, the only info I've found is that Uranus was once considered to be called that. Could this planet (if there is one) only be viewed through infared light? Is it a double star? Any suggestions on where I can find any info this. Thanks.
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Response 2.: Uranus is the seventh planet from the Sun and was the first to be discovered since ancient times. Sir William Herschel first observed the planet through a telescope on Mar. 13, 1781, seeing a featureless bluish green disk that he nevertheless recognized as a highly unusual object. Although Herschel wished to call the newly discovered planet Georgium Sidus (Georgian Star) for King George III of England, and although many French astronomers referred to it as HERSCHEL, Johann Bode's proposal of the name Uranus--the mythological father of Saturn--was over the years accepted more and more widely and finally became universal in the mid-19th century.

Infrared measurements from Voyager 2 indicate that Uranus has an effective temperature of -214 degrees C (-353 degrees F). Unlike the other giant planets, there is no evidence of any significant internal heat source. A very extended corona of atomic and molecular hydrogen encompasses all the known rings of the planet, perhaps heated by low-energy electrons. Sunlight falling on this corona causes it to radiate ultraviolet light, a phenomenon that scientists have termed electroglow.

The above two paragraphs are copied from the article "Uranus" by Ellis D. Miner (of the Jet Propulsion Laboratory in Pasadena) writing in "The 1997 Grolier Multimedia Encyclopedia" CD-ROM.

Note that Uranus is a planet, not a star, it does not make its own light, but reflects the light from the sun.
Question 3.: I am new to the computer and star gazing and wanted to know if you could tell me what type of telescope and what size would be good for looking at the stars. I bought a Bushnell 430 and it doesn't impress me as being a good one. I would appreciate any info that you could give me. Thank you, J. I.
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Response 3.: The best first telescope is a pair of binoculars. A "real" telescope or pair of binoculars should be purchased with the advice of a local member of an astronomy club. Contact your local club, find out if they have an appropriate meeting or activity you can attend, and take a look through telescopes and binoculars for yourself and find out from other amateur astronomers what they think is appropriate. I guarantee you will be suprised at what you can see and NOT see through telescopes and binoculars and you will be suprised by how expensive this hobby CAN become if you let it.

After the obligatory purchase of a cheap pair of binoculars or telescope, get acquainted with the stars and constellations. Again, there is just no substitute to having someone familiar with the night sky point out where the stars and constellations are and where appropriate objects are in the sky that can be viewed with binoculars or small telescopes. A local club or science center is your best resource. That is how I started. Many people are surprised that there are MANY interesting and beautiful objects that can not be enjoyed through telescopes because telescopes do not view a large enough area of the sky to capture the complete object, such as a star cluster.

If you need help locating a club in your vicinity, drop me an e-mail.

I wish you many clear, dark skies and happy discoveries ahead.

Dennis Smith, Davis Astronomy Club, Explorit Science Center

Question 4.:
I am reading a history book and mention the saturn's triple septenary. I look for information, and I could not find anything. Do you have any idea what it is? Thanks, O.S.
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Response 4.:
Dennis Smith responds:
The only scientific aspect of Saturn's appearance that I associate with a "septenary" that is, a cycle of 7, is the visibility of the rings of Saturn, which move from the apprent "edge-on" position to the utmost opening of the rings visible in our sky, in a cycle that requires approximately 7.5 years. But this is not a "triple septenary."

Perhaps your reference is from a religious or occult source, since the number 7 is often an important number in those obsure studies. The number 7 is important to Bible scholars, since the universe was "created" in 6 days and on the seventh day was a day of rest. One of many sites associating the planet Saturn with a "triple septenary" is this site: http://www.netnews.org/bk/astrology/astr1252.html There you will see: "Occultism must win the day before the present era reaches... Saturn's triple septenary of the western cycle of Europe - before the end of the 21st century A.D. (S.D. Vol. III, 23)." SD here refers to "The Secret Doctrine" by Madame Blavatsky (1831-91) founder of "Theosophy" -- a mixture of various eastern and western religious and occult thought. You can learn more about theosophy at the same site.

I'm sorry I couldn't find something more scientific for you, but this "triple septenary" sounds to me like another of those "end of the world" predictions.

Sincerely,
Dennis Smith
Davis Astronomy Club
Question 5.:
Describe the state of matter that stars are made from. Describe a supernova. What elements came from a supernova?
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Response 5.:
Here are three very short answers to your questions:

1. Describe the state of matter that stars are made from.
Stars are made from hydrogen gas, mostly. Our sun is approximately 98 percent hydrogen, and most of the remainder is helium gas. Of course there is just about every other chemical element in a star as well, but hydrogen outnumbers all of them.

2. Describe a supernova.
A supernova is an explosion that occurs when a very large star -- larger than our sun -- is unable to continue thermonuclear reactions at its core, and the force of gravity causes most of the outer shell of the star to explode.The explosion boosts the stars brightness by about 10 billion times (for a few days).

3.What elements came from a supernova?
The supernova explosion creates most of the atomic elements that have an atomic weight greater than iron -- plus much debris consisting of all other stable elements. The star's core often becomes a neutron star with a diameter less than 10 miles and a density of 1014 (that's a 1 with 15 zeroes) times that of water.
Question 6.:
How do we know the Milky Way is a spiral galaxy?

If we had a picture of our galaxy on a letter size paper, what would be the radius of our naked eye visibility on a clear moonless night?
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Response 6.:
Thank you for your e-mail. You asked two questions:
My authority for most of the questions asked is Dr. Sten Odenwald. If you have general questions about astronomy, and can read adult level books, I very much recommend his book "The Astronomy Cafe: 365 Questions and Answers from "Ask the Astronomer''" (1998). It is in paperback and costs about $15.00

1: In the book he states (page 117): " In the past 10 years, new infrared observations by astronomers at the University of Maryland and the 'COBE' satellite project seem to convincingly show that the Milky Way has a barlike central region extending many kiloparsecs into the disk, so we live in a barred-spiral galaxy, not a regular spiral-type galaxy, like the Andromeda galaxy, which is our closest neighbor." In my readings, I believe this is still the most accepted structural type among astronomers.

2: The farthest object "easily" visible with the naked eye is the great galaxy in the constellation Andromeda, also known as M31. In fact, I glimpsed it last Wednesday night during a break in the clouds here in Davis. Its distance is approximately 2.3 million light years. If you want to make a scale model of the distance between them using the size of the Milky Way as a comparison, we can approximate the size of the diameter of the Milky Way at 0.1 million light years across. So, draw a line of any length to represent the width of the Milky Way, measure it and then multiply its length by 23 to find out approximately how far from that line you'd need to put the Andromeda Galaxy. That also represents the farthest object "easily visible" to the naked eye on a clear moonless night.
(You'll need to experiment with the length of the line representing the Milky Way so that when you multiply it by 23 the result will fit on your piece of paper.)

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