Read and discuss Chapter 5

Read chapter five.

Pics

THere are some nice pics over at MSNBC. http://www.msnbc.msn.com/id/6955261/?GT1=7538

Notes

Vista is being more than poopy right now and we might be using this blog alone for awhile. ALso to get to all the blog notes just go to the archieves and hit the January 2006 link.

Moon Journal

The moon journal is a very simple thing.

Materials:

1 small notebook (3"x5" is fine)
1 piece large piece paper (constuction, butcher's paper, etc).

On the large paper sketch a panorama of the southern sky at the place you plan on viewing the moon. This diagram should just have the ground features (trees, houses, and other relatively perminent object). The ground features should take up no more that the bottom 10% of the paper. This is so you can put a mark where you saw the moon relative to the ground and put a date beside that mark. This is so you can look at the long term motion of the moon.

In the notebook you should record the weather (in terms of cloudyness), and if you see the moon sketch what the moon's shape. If you don't see the moon record that.

That's it. At the end of the observing period send me the notebook and panorama, nothing more.

David

Problem 7 Page 40

To give you an example (and introduce you to the back of the book) of the small angle formula I am going to do problem 7 from your book.

Now I notice that the size of the prominence is 5 minutes of arc. The book on page 40 says to use the small angle formula I need this angle in seconds. Well every minute has 60 Seconds, so 5 minutes would be 5 times 60 (5*60) seconds or 300 seconds.

Here and over at vista I am going to write the small angle formula as AD/206,265"=LD/D

with AD being angular diameter, etc.

I know what AD is; 300s
I go to the back of the book (the back of the book is our FRIEND, you can get all sorts of things from the Appendices). I find on page 617 Properties of the Planets. Under earth I find the distance to the sun (semimajor axis, we can't make this easy can we). It is 149.6E6. E6 means ten to the 6th, just like on your calculator. This is the Distance (D).

Let's put the numbers we know in the formula:

300/206,265=LD/149.5E6 Now we solve for LD---> LD=300*149.5E6/206,265 .

ON my computers calculator here is the bottom order: 300*149.5 Exp (One button)6/206265 =

I get (with rounding): LD= 217,000 km. This is my answer. By the way usually I would hit the F-E button on my calculator and get LD=2.17e+5 km. For most of our numbers this is a better way to report. By the way e+5 is hundred-thousands, e+6 is millions, e+9 is billions, e+3 is thousands, etc

By the way, let's say I need to put a negative exponent in say 9.11e-31 (the mass of an electron), here are the key strokes:

9.11 Exp 31 +/- (which is the button under the 2 button).

You are going to be doing just this thing with just this formula for most of your problems this semester. If you need just come in to see me.

David

Read Chapter 4

Read chapter 4

David

Reading Chpater 3

Read Chapter 3. Any questions can be posted as a comment to this post.

First Assignment

I have Seeds Eighth edition.

On page 28 there is a "Problems" Section starting on the lower right. Do problems 1-7 (out of 90.

Each of these problems can be solved by using the chart on page 14. Notice that for problem 5 and 6 the magnitude difference isn't on the chart. Either you guess at the answer use the nearby numbers or you can use the equation on page 14.

For example, I have two stars with a magnitude difference of 7.3. My intensity ratio Ia/Ib=2.512^(mb-ma). My mb-ma is the magnitude difference which in this case is 7.3.
S0 I take 2.512^7.3=832 (rounded). Try it.

David

This is due January 26 (a Thursday).
You may comment to this post if you have difficulties and I will answer your questions.

Syllibus

Astronomy 131 Spring
Instructor: David Emigh
Homework E-mail Address: physics@qvcc.commnet.edu
All homework that is being submitted online must be sent to this address or sent using the email function in Vista. I will not be responsible for homework sent to my regular e-mail address.
Time: Online
Room: 125 at QVCC
Office Hours: Monday and Wednesday 12:00-2:00 p.m. Wednesday 5:00-6:30 Tuesday and Thursday 3:30-4:30
Text: “Foundations of Astronomy”, by Michael Seeds
Catalog Description: This is an introductory course in astronomy that covers the origin and evolution of the sun, the universe, and the planets. In addition, methods of observing and analyzing astronomical events will be discussed. Students may also explore special topics of contemporary interest.

Moon or other Observing Journal: Every student will be required to complete a half semester long observing journal. The moon journal is a half semester long observation of the moon. Five times a week at a set time (10:00 pm for example) you will go outside and note the weather, where the moon is (or is not), and what phase it is in. You can either start the last week of January and observe until the time change in April, or start the Sunday after the Time Change until the end of the first week of May. See Webct Vista for more detail.
Other needs: If you are a student who has documented special needs please come talk to me privately so that I can tailor this class to help meet these needs. If you need documentation, you should see Chris Scarborough in the learning assistance center.

New to Blogs?

Since some of you are new to blogs I thought I would note a few features:

1. You cannot create post only post comments, this is the one real weakness for using blogs in a class setting. I will try to create posts for every eventuality so you can comment question, comments in general, and problems with the material.

2. On the right hand side of the blog page you will see Archieves. This allows you to get to much older material. If you visit http://qvccgeology.blogspot.com you will need to use the archieves to see all the pictures. By the way their are blogs on just about any topic you want. You can explore the blogs available at blogspot, typepad, etc to find your interests.

3. I have enabled the editor, so if you say something you wish you hadn't, or had a mispelling, or some such you can edit your post.

4. You can actually create your own blog for free. Just go to http://www.blogger.com and have at. As you play with blogs you will be able to upload pictures to yout blog using free software that places copies of your pictures on a free host.

I any case have fun.

Discussion of Chapter 1 and 2

Every week I will be putting up a post like this one so people can ask questons and discuss that weeks readings. I will have similar posts for homework and for labs.

Let the games begin.

David

PS. Be sure to respond to the first post of the blog.

Welcome to Astronomy at QVCC

Welcome to my Astronomy Blog. This blog will be used to give out assignments, labs, and answer any and all questions. I have chosen this venue rather than Vista as it's much easier for me to use. You might want to bookmark it.

When you want to comment you will be asked to enter a funkly little verfication code.

So I know you all have gotten here please respond to this note.

David