Astrophysics fall trimester  2011

 syllabus   &  course expectations
safety, tardy, classroom computer use, and honesty

 Astronomy Picture of the Day         what's up in the sky this week

August 29
August 30
August  31
September 1
September 2

JIT due in moodle by 9:30 am

JIT unlikely for friday, since it looks like we will be able to do the sun lab

possible jit due in moodle by  8 am tomorrow if the sky is not going to be clear tomorrow

if clear, we do the
solar luminosity lab:
we measure the luminosity and temperature and radius of the sun with a meter stick, a light bulb, and two pieces of wax, and aluminum foil

we do this in the first lab book (the one with image processing in it); maek sure you have it (I will be returning it probably on thursday)

don't wear your best clothes today, because you may end up sitting on the dirty observing platform.... but it is a lab, remember

(always done before class)


17(6) & Box 17-4

7(2, 3)

note the big reading assignment for tomorrow, too....perhaps start today?

for class today and  possible friday JIT:
8(1,2,4,5) particulalry section 8(4)


as you read this, be looking for possible energy sources that might explain the discrepancy between the calculated blackbody temperatures you presented in class on wednesday and the actually measured temperatures of the planets

in class yesterday, we heard one explanation for why the surface temperatures of planets might be hotter than predicted by the blackbody laws: the greenhouse effect!

which is well explained on pages 212-213, so please read that so that you are culturally literate

read the solar luminosity lab carefully -- up through data collection --  in advance; your data collection will be graded immediately after the collection phase ends.... so make sure that you know the lab guide expectations well

 read about the pinhole camera,
so that you know how one works

a useful pinhole camera diagram, which shows how you will get an image of the sun

for after we come back for labor-day break:
pick and choose chapters 7 -  14 sections relevant to planetary heating
(i.e., sources of energy that raise the temperature of planetary surfaces beyond that predicted by the blackbody laws)

questions you should know the answer to before coming to class

what are the main differences between the terrestrial and jovian planets?

what stellar properties do we now know exactly how to determine from observations?  what observations do we need to make and what laws do we use in combination with the observations to get these properties?
(i think the number of properties in this list is presently 3..... suppose someone gave you the distance to the star also.... how many additional star properties would you be able to determine?  which?

our best (to-date) theory of the origin of the planets is called the
condensation-accretion theory

what does condensation mean?

what does accretion mean?

which must happen first?


bring (to class) concrete examples!

remember Tuesday's assignment (differences between jovians and terrestrials)?.... be prepared to name some today in class (from the notes that you undoubtedly took!)

(written assignments
to be turned in)

do you have (several) show-and-tell problems to present at the beginning of class today?

BRING your planet's temperature (calculated -- with all numbers used and all work shown --  AND actual) to class today, on paper to hand in to me at the beginning of class:

distance to your planet is given in Appendix 1 and is called "semimajor axis".... note the units, and convert to proper SI units!!

albedo is in Appendix 2

solve for T (using the formula we derived in class today) and
check units first!
if your units aren't correct, don't bother with the number... it wont be correct either

the sun's luminosity  and sigma constant can be looked up in the later appendices....

check with your table partner BEFORE class (as in tonight)!

ALSO, on your homework paper, write down your planet's actual temperature
(you will have to go to the chapter on your planet.... at the beginning of the planet chapters is a table with that planet's table -- for example, the earth's table is on page 210 -- containing important info, e.g., temperature, etc. about that planet....

if your planet has more than 1 temp listed, write them ALL  down including where on the planet they were measured)

if your planet is Moon or Pluto:

Moon chapter has its own table as described above in the Moon chapter

Pluto information

coming attractions (after labor day):

your star homework due
next Friday after labor day
web stuff

red sky on Mars

red sky on Earth
(due to volcanic eruptions)....
and also responsible for the red sky in Edvard Munch's "The Scream"

Rayleigh scattering and blue sky, blue water, and  ...

relfection nebulas are blue but not due to rayleigh scattering

and the blue of blue jays was thought to be due to Rayleigh scattering until 4 years ago when someone checked....
full details from Journal of Experimental Biology

you can find % of your star's luminosity in the uv, visible, and ir using the

spectrum explorer
(launch the explorer; it requires java, so that must be enabled; 2 new windows should open in a minute or 2-- a useless one and one containing axes; on the latter, click on the "blackbody" button to add a blackbody, type in the temperature below the thermometer, and you'll find the %s in another new, tiny window that opens


this applet may not work for every version of windows or mac.... and it may also depend on whether you have the correct version of JAVA

but if it doesnt work, you can also use your calculator to find the %s (as described in class on tuesday)   .... this assignment will be part of homework to be turned in sometime after labor day.... it appears in friday's slot as coming attractions

as part of section 2 of the spectra lab, ADD the following:

look at the fluorescent light source in the SW corner of lab 1,
and deduce the state(s) of matter of a fluorescent light bulb

as part of section 2C of the spectra lab, ADD the following:

the MINI fluorescent light is now near the 4 gas discharge tubes in lab 1

also, as part of section 2, part C, you are supposed to identify the physical state(s) of matter producing the light (THIS IS NOT ON THE HANDOUT< SO MAKE SURE YOU ADD IT TO YOUR ANALYSIS !!!)

remember that i'm expecting you to show me your tentative identifications of the 4 discharge tube gases BEFORE TURNING THE LAB IN.... this way you are unlikely to lose point for getting this wrong

spectra lab due

solar luminosity lab

wear appropriate shoe, appropriate clothes for sitting on a dirty floor and for stretching, etc without revealing unnecessary body parts or undergarments
of the week

August 22
August 23
August 24
August 25
August 26

continuation of students teaching classmates about light

butchered class schedule

last chance to teach the class something (a property, a behavior) of light from Walker chapters
(this is the first big homework assignment and worth a bit more than the 10-properties assignment due yesterday

have you done YOUR contribution?
(otherwise you do have a zero on this first assignment)
I have tutorial tonight...
a great chance to get lab questions answered

we do the spectra lab.....
see lab slot

dress appropriately and bring your second lab book to class for this lab
(always done before class)
Universe 6(1 - 3)
Walker chapters  on light

Walker 28(1-3) plus other Walker sections

5(6 and 3, 4)

5(3,4) again,
particularly numerical examples in  box 5-2

also see reading from yesterday that we didnt get to

questions you should know the answer to before coming to class

we covered some properties (wavelength, speed, frequency) and some behaviors (reflection, refraction, dispersion, what? what is dispersion) last friday, but we have a few more properties and a lot more behaviors & laws to go....
BE PREPARED to "teach" the rest of the class, as your peers did friday, a few  today!

last day on light

be ready to talk about behaviors/laws of light discovered after 1805

there are still about 5 - 10 behaviors left (including some really simple ones) and few properties still left

know the laws of two-source interference

(at least) one person has explained how the polarizers did what they did in class today... have you?

know the different kinds of spectra (there aren't that many)


the physical states of matter that produce each type of spectrum

and what is a blackbody anyway

in what ways (maybe at least 3) does a hotter blackbody's spectral curve differ from a cooler blackbody's?

what two mathematical laws can be used to describe how the curves (hotter and cooler) are different?
know the laws!
study the associated examples!

how does flux differ from luminosity?

you should be able to tell the class at least 3 different ways

(written assignments
to be turned in)

list of 10 intrisnsic properties of stars we would like to know about
(can't use temperature or power/luminosity)

no jargon;
no redundancies;
  give intrinsic properties of stars (i.e., ones that are ONLY star-dependent and not star- AND observer-dependent; e.g., none of the 3 above are observer-dependent; they are entirely intrinsic to the star)

here's what we have done so far:

properties (wavelength, frequency, energy, momentum, speed, oscillation of E/B fields, amplitude of oscillation)

behaviors [reflection, refraction, dispersion, polarization, interference, why light can interact with matter (light carries E fields which accelerates charges, which matter is composed of) ]

make sure that you "know" all these (i.e., you could explain them quite well to your grandmother)

web stuff

the largest optical telescopes
in the world


parts a & b of image processing lab due in black box by 5 pm

what we saw in observatory last night:

the open cluster M6
which I said was 600 c-yrs, but I meant to say 600 parsecs, which is 2000 c-yrs away

M31 the Andromeda galaxy, 2 million light years away (1000x farther than the open cluster)

what can we conclude about their relative linear diameters (in, say, kilometers)
make sure you have a second lab book for today's spectra lab
of the week


August 16
August 17
August 18
August 19

astronomical light detectors
image processing
more about light detectors
& then lab

make sure that you have a lab book for today's class, with the lab guide taped into the interior front and back covers

bring your laptop to class today if you have installed the software (see yesterday's email or yesterday's lab slot)

image processing lab continues

bring your laptop to class today if you have installed the software

you'll need your calculator in class/lab today
TODAY we will do 20 - 30 minutes of lab and the use the rest of the time for you to tell me about light and its behaviors/properties

safety, tardy, classroom computer use, and honesty  to class today
(and you also have actually read it carefully, right?)
(always done before class)

1) all of the lab guide

text, 6(4)

2) at least the first couple pages of the CCD handout
that you got in class yesterday, enough so that you know how a CCD work, if you can.... I know we have convocation, etc tonight....

an electronic copy of the CCD reading

finish the CCD handout
that you got in class Tuesday

an electronic copy of the CCD reading

optional reading, but encouraged:

the invention of the CCD

on October 17, 1969
wins the Nobel Prize in Physics on October 6 , 2009
(the Nobel Lecture by Smith and the Scientific Background are the best)
Universe 5(1-2): what is light? and
6(1-2); how does it behave?

you should know/learn some  properties of light (e.g. wavelength, frequency)

also, Walker has 5 (!) chapters on light

and some behaviors of light (e.g., reflection, refraction)
see the Walker references on the syllabus


perhaps you will learn some laws that go with the behaviors as you read?

maybe two sides of a page of notes while you're reading?

questions you should know the answer to before coming to class

how does a CCD work?
what is the output?

(and what's the output of photographic film?)

what are the two BIG advantages of CCDs over retina/film?

how is a CCD image stored (on a computer)?

(the reading tells you everything!)

what is "pixel" a unit of?
or, phrased differently, what other units can pixels be converted to?

what quantity does a CCD (or retina, or film) respond to?
phrased differently, the greater the _______ of the incoming light,
the greater the output of the detector
(it's actually dependent on both the star and the observer)

(written assignments
to be turned in)

make sure that you have a lab book (with the lab guide on the inside front/back covers) for lab tomorrow

number the odd pages of your lab book....

finish the browser5 part of the lab
(i.e., just the one we started in class yesterday)

today or tomorrow, download a NEW image processor for part 2 of the lab before coming to class (if possible.... depends on how soon the electrical problems are solved).... see lab slot below

for monday, list of 10 INTRINSIC (i.e., NOT observer-dependent) properties of stars we would like to know about
(can't use temperature or power/luminosity because these came up in class).... and I wouldn't limit myself to 10, just in case some of yours are redundant or not intrinsic

no jargon;
no redundancies;
must be INTRISIC to the star, and not observer-dependent, such as distance
web stuff

stellar evolution summary
(to be used in lab);
not necessary to read beforehand

 electromagnetic radiation java applet

  for tomorrow's lab,

download & install
SalsaJ software version 2.2 (for windows) or version 2.1 (for max/unix)  ...  however, since I dont have access to a mac i actually dont know if the non-windows versions work....

the way to test SalsaJ is to download one of the browser images in the slot to the right (--->) and see if the image opens in your version

materials for today's lab:

image processing lab,
part a

(I will have hard copies of this in class today... no need to read this lab in advance, because it's mostly software instructions)

images for the image processing lab:
to open an image DO NOT left click on the link; instead, right click and then save it to your hard drive, then use the open command in the software

images for today's lab:

new browser 7
browser 2
browser 3
browser 4
browser 5
browser 6

lab guide
(that gets taped on your inner sides of your lab book covers)
it would nice if you finished up the browser 5 section of the lab before coming to class today.....

image processing lab
continues in blocks C/D today

directions for installing ds9

on your computer

however, both HOU and ds9 are installed on all physics-floor public computers

image processing lab,
part b
I'm thinking that the blue lab (ip part a, with HOU) is going to be due Tuesday and the orchid lab (ip part b, with ds9) is going to be due Friday on next week
of the week

graphene detected in interstellar space?

Moon not necessary for Life on Earth?

supernovae parents found

meteorites: tool kits for creating life on Earth
read it and weep:
US math proficiency at 32%...
rank in the world?  32
cost?  $1,000,000,000,000 per year

the unexpurgated results here 

Treason on Schools