These will be posted from time to time (about one per week on average), so keep watching.
The black book will become a journal of your observations over this semester. The books are in the bookstore and cost a couple of bucks..
They are green and labeled "QUADRILLE" on the front, which means that every page is ruled with squares.
This will make it very easy to sketch things accurately. There are also similar sized quadrille books with grey
covers, which are made of recycled material and cost a few pennies more. Either one is good; nothing else will be accepted.
For any particular project, one square may represent one degree or five degrees or ten degrees etc.
The only rule is that you cannot tear out any pages.
I expect you to make lots of mistakes and false starts; that is what a real lab-book looks like.
Well, another rule is that you do not copy from someone else, but I don't need to tell you that, do I?
Make your own observations. By all means go out in a group, or with someone you like spending time in the dark
with, and figure it out together, but the observations in your book must be your own.
What goes into the black book? You should do as many as possible of the projects suggested below. You should also take some initiative for doing
pieces of observing that I may not suggest explicitly. For instance, go to the
Sky Events Calendar
for each month. That may give you some ideas. Or you might take a crack at Mercury. If it is really
clear in the west at sunset, you might just get lucky. Either way, write up the attempt. Or there may be a gloriously clear night, and you go out
hunting for constellations for the sheer pleasure of it.
THE RULES
WHAT IS IT WORTH TO ME (i.e. YOU)?
So here is the first project R1: THE FACE OF THE MOON
The best time to sketch the moon is actually at dawn or dusk. That way, you can easily see what you are drawing, and you don't need a flash light. Also, your eyes are not dark adapted, so the light from the moon is not nearly so dazzling.
(In case anyone thought of copying a photograph from the book, that's a very bad idea. Among other things, because of some subtleties in the moon's motion, it's rather easy to tell that's what you did. Not that you would, anyway, would you?)
R2: HERE IS AN EXCELLENT WAY TO CALIBRATE YOUR HAND if you can find a tape measure, or (since you are all smart Brandeis students) improvise. Basically, you use the skinny triangle formula (A = 57.3 D/d degrees). So if you have something that is 1 foot in size, and stand 57.3 feet away,
it will subtend an angle of 1 degree. If it is 1 inch in size, and you stand 57.3 inches inches away (that is 4 ft 9.3 in), it will subtend 1 degree again. If you double the scale, so its 2 inches seen from 114.6 inches (which is 9 ft 6.6 in)
it will probably still fit in your room. So get a strip of paper and make markings on it every 2 inches. Stick it on the wall and stand back nine and a half feet. Now you can calibrate your hand in the warmth and comfort of you room. I will leave the details up to you,
but explain what you did, include a diagram, and finish with a table listing a bunch of useful angles. Something like 1,2,3,5,10,15 and 20 degrees. Or go the other way and list how many degrees in your little finger, index finger, thumb, various knuckles, fist, outstretched hand.
Doesn't have to be in your room either. The side of a brick building would be good. Measure the width of one brick, and walk away from the wall a distance equal to 57.3 bricks. That will be 1 degree, again. Side note: most of you probably had to write lab reports in high school. And there was probably a strict format of exactly how it should be done. Well, don't worry about all that. All the projects in the black book ARE informal lab reports, but about the only thing I care about is if they are
clear and convey information. The test of this is if you showed it to your roommate or to your parents at Thanksgiving, say, would they understand immediately what you did and why? (This is how I will grade them.) Draw the constellations not for me, but for an Australian friend who has never seen
the northern constellations (and sees Orion upside down compared to our view!). And everything should be really neat. That's not hard if you are using pencil (required). It is difficult working in the dark, but when you come in you can clean up the page and add annotations, explanations and comments. R3. THE SUMMER TRIANGLE and friends Now face Vega and look about one o'clock to your right and half way down to the southern horizon. You will find another star, almost as bright as Vega. This is Altair, in the constellation of Aquila the Eagle. Look up again, but a bit more to the east, and you find the third star of the summer triangle, Deneb,
in the constellation Cygnus the Swan. Deneb, Vega and Altair form an almost right-angled triangle. Cygnus is cross shaped (or swan shaped) and you should be able to see all of the cross. Its long arm is the long neck of the swan, and it's flying straight down the Milky Way between Vega and Altair. To see what that
part of the sky looks like, see the summer sky map at the beginning to chapter 2. (If it is really clear, and dark (i.e. you have gotten away from lights) you may just see the faint glow of the Milky Way. It runs along the cross of Cygnus, past Altair, sweeping down to the southern horizon. It may be easier to see if you follow Cygnus backwards to the north-east. About half way to the north
east horizon, you come to the great W (or M depending on how you are standing) of Cassiopeia. Cass, as we affectionately call her, is right in the Milky Way too, and the line from Cass to Cygnus is the brightest part of the Milky Way.)
Now find Vega again. Half way between Vega and the western horizon is another bright star. This is Arcturus in the constellation Bootes (pronounced Boo-oh-tees) the Herdsman. Arcturus is one of great red giant stars, and if you give your eyes enough time, it should appear distinctly pinkish compared to other stars. Now for the actual assignment. I want you to sketch as accurately as you can the summer triangle (Vega, Altair and Deneb) and include as much of the constellation Cygnus as you can see. Make sure you follow the instructions given above (called "THE RULES"). It is hard sketching in the dark, holding the book in
one hand, a flashlight in the other, and a pencil between your teeth, so I suggest doing it in two stages. (1) Once you have found the stars, make just a rough sketch. Measure the angle between each pair of stars using your hand, and write those numbers on the sketch. (2) When you get to your room, turn to the next page and reconstruct the sketch accurately and neatly, using the numbers you measured. This time do not write the angles on the sketch, but you can label the three stars of the triangle. Finally, tell me how many degrees you measured from Vega to Deneb, from Vega to Altair, and from Altair to Deneb. R4: AS THE WORLD TURNS. Make a large and accurate sketch that includes the Dipper, Cass and Polaris. Be sure to note the time, and include your horizon on the sketch. We want to get the orientation and relative positions of Polaris and the two constellations right. One way to do this is measure the distance of the pointer stars, say, above the horizon, and horizontally from Polaris. That gives you an up-down and a left right fix on them which is easy to plot on the squared paper. Then sketch the rest of the constellation. Do the same for Cassiopeia As late as possible BEFORE THE DIPPER GETS TOO LOW TO SEE, go to the same location, and sketch the Dipper. Cass and Polaris again ON THE SAME SKETCH. Keep the position of Polaris the same as before (it doesn't move, does it), and the stars of the Big Dipper and Cass will be in new positions. Note the exact time again. Now draw a line from Polaris to the Pointer stars in their first position. Draw another line Polaris to the Pointer stars in their second position. Draw corresponding lines to Cass. Measure the angle between the pairs of lines WITH A PROTRACTOR. Note added on October 5: The Big Dipper is so low on the horizon for much of the evening, that this is getting hard to do. (It is at its lowest point around 10 pm right now. That time will get earlier as we go through the semester. By the beginning of November it will be about 8 pm. By the beginning of December it will be 6 pm.) You have several options. R5: WHERE DOES THE MOSS GROW? Lots of people say that moss tends to grow on the north side of trees and that's a simple way of finding north. And lots of people say that's an urban myth, and you will never find your way out of the forest like that. Rather than argue about it, let's find out! So here's the assignment. Get a campus map (go to http://my.brandeis.edu/map/ and print out any of the three maps offered) and paste it into your blackbook. All three have a compass marked on them so that wherever you are on campus you can estimate where north is by the alignment of nearby buildings with the compass. Now you are going to spend a pleasant afternoon or two rambling over the campus in search of trees. When you come to a tree look for moss on the trunk. If there isn't any, move on. If there is, then mark its position as best you can on the map with a dot. Now estimate where north is (this will work a whole lot better if you can beg, borrow or purchase an actual compass, otherwise use the map). Figure out which side of the tree the moss is growing on. It is good enough for our purposes just to use the cardinal points North, South, East and West: which of these is closest to the mossy side? Then over the dot you made on the map, write N, S, E, or W (small and neat, or you won't have room for many trees. When you have enough trees (you decide) choose how to summarize the data -- a simple bar graph, perhaps. Tell me what you conclude. Is it true or is a myth? Is it just a weak tendency? Do you see any other patterns in the data? Are different parts of campus different? Are the clumps of trees where the moss is always on the east side, for instance? If there are, why might that be? What about trees on the north side of buildings whose trunks are always in the shade? etc. R6 THE PEGASUS PROJECT
Answer the following questions: R7: ORION and environs. By midnight (mid-October, or 10 pm by mid November, 8 pm in mid December), Orion is magnificant in the south-east. If you don't know what Orion looks like, Google it. Orion's belt is unmistakable; the stars in it are 1.4 degrees apart -- about a pinky finger at arms length. The shoulders of Orion are Betelgeuse and Bellatrix. His knees are Rigel and Saiph. Betelgeuse and Rigel give you one of the clearest naked eye color contrasts in the sky. Carrying on round Orion, near 1 oclock you get to a lovely golden star called Capella, which is the brightest star in a pentagon called Auriga, hanging above Orion's head. EC for telling me the story of Auriga and Capella. It's rather touching (first ten emails etc). A little farther and you are back to the Pleiades.
We are going to try sketching the surface markings on the moon. This turns out to be quite hard to do well, because you are looking at a pattern with no very distinct shape to it. The next full moon is on 9/15, but it is still close enough
to full for a few days eiter side of that. It may take several attempts to get good at it. Often when students do this, they just put a sort of impressionistic shading scribbled on the disk: they have LOOKED, but they haven't really SEEN. And its not what I'm after. See how well
you can get the actual shape of the darker regions. Everything you see corresponds to real physical features of the Moon's surface. Are there bright spots you can see? If you can lay your hands on a pair of binoculars, they will help lots (if you do, tell me what rating they were
e.g. 7 x 35). A good way of getting features in the right location on your sketch is to think of the moon as a clock face. Then some feature -- the edge of one of the big maria, say -- might be at 2 o'clock, half way from the center to the edge of the disk.
(You needn't actually restrict yourself to a full moon. Some markings get more distinct when the Sun's rays are more oblique, and the shadows are longer and more prominent. So you can sketch the moon as many times as you like over the semester, so long as you do it at least once.)
We are going to find some constellations, and some famous stars, and use our now calibrated hands to make a good sketch. (We will calibrate our hands carefully next week, but for now just read section 2.3 and use the angles given in Figure 2.12.) Find a good place to observe from (dark, low horizon). If you go out around 8 pm, look overhead, and slightly to the south-west, and you will see the brightest star in the fall sky,
This is Vega, in the constellation Lyra. Lyra is a tiny, no-account constellation, but it happens to contain the mighty yellow giant Vega, and a beautiful blown-off shell of a dying star called the Ring Nebula which we should be able to see through the telescope. By the way, who or what was Vega in
classical mythology (not General Motors mythology)? First 10 correct e-mails to me get an extra-credit (EC) point. (That's email to wardle@brandeis.edu. Do not post the answer on the bulletin board)
This one is really important because it helps you truly see how the stars move. Choose
a night when it is clear in the north and you can see the Big Dipper, Cassiopeia and Polaris clearly. Right now the Dipper sinks into the Waltham lights by 10 PM or so, so you want to start this as soon as it is dark enough to see the stars.
If you do not have a protractor, bring your book to class and use one of mine. It is essential that the angle is MEASURED, NOT ESTIMATED.
Write down this angle, and also the elapsed time between the two observations. Figure out at what rate (in degrees per hour) this line is rotating in the sky around Polaris. Now figure out how long it would take the Polaris-Pointers line and the Cass-Polaris line to turn through 360 degrees. Comment briefly on what you have just measured.
(1) Use only Casseiopeia. Not my favorite choice, but much better than not doing it at all.
(2) Get the Dipper (and Cass) around 8 pm, and then wait until it is rising again, around 12-1 am.
(3) Do it at 1 am and 3-4 am. These times will get earlier in Novenber and December.
(4) Wait till December, when you can get both observations in before midnight (but beware of the weather going bad on you, and it being colder).
(5) Sit on a hill or a mountain with a nice clear, dark horizon. Then you can do it any time. The Dipper never actually sets (it is "circumpolar"), the trouble is the lights of Waltham.
Time for another constellation. As the summer triangle sets earlier and earlier, the great fall constellation is Pegasus the horse. He is due south and high in the sky by 10 pm, and what you notice first is a large and nearly perfect square, with sides equal to about an outstretched hand. Cassiopeia, Cygnus, and Pegasus form roughly a large equilateral triangle. Some stars off the two righthand corners of the square are also part of Pegasus. The two lines of stars stretching from the top left corner look like they ought to be part of Pegasus too, but actually they form Andromeda.
The assignment is to find Pegasus and make a "big picture" sketch of its region. You should include the great square of Pegasus, and any nearby stars you can see. Also include Cassiopeia and Cygnus, so 1 square should probably be 2 dgrees for this one.
Which is the longest side of the square? (left, right, top, bottom)
Which is the shortest side of the square? (left, right, top, bottom)
Of the four stars that make the square (top-left, etc), which is the brightest?
Do you perceive any color difference between those 4 stars?
Measure the distance in degrees between the middle of Cassiopeia and the middle of the square of Pegasus.
Do the same for Cassiopeia to Cygnus and Pegasus to Cygnus.
Now, if it seems really clear, and your eyes are well dark adapted, look at the region betwee Cass and Cygnus. You may be able to see the Milky Way. This is the brightest part. It extends down to Altair to the right and Capella in Auriga to the left.
If you can see the Milky Way clearly, then have a go for the great Andromeda galaxy. Look at figure 2.28 in the textbook. The galaxy is located just below the second a in Andromeda. Look for a faint fuzzy patch, and good luck.
If you follow the belt up and to the right, you come to a distinctly pinkish star called Aldebaran. About as far again gets you to a fuzzy patch which is a cluster of very young stars called the Pleiades or the 7 sisters. If you have good eyes you can probably see 7. There are actually 100s there. They are lovely to look at through binoculars -- what color do you see?
If you follow the belt in the opposite direction you come to the brightest star in the northern sky -- Sirius. It will be very low in the sky, and you may want to wait an hour or so. (Right now Sirius is not visible till about 1 AM. By the end of the semester it will be up by 9 PM.) Circling around Orion in a clockwise direction from Sirius, you come to another pretty bright star, Procyon. If you think of Orion as a clock face, then Sirius is oriented at about 7 oclock, Procyon is at about 9 oclock. Around 11 oclock, you find a pair of very similar brightness stars. These are the twins Pollux and Castor of Gemini.
Procyon is the main star of the Little Dog constellation (Canis Minor). As far as I can tell there is only one other naked eye star in Canis Minor. It's really very minor indeed. A chihuahua, perhaps. Sirius is the main star of Canis Major. These are the hunting dogs of Orion. The "dog days of summer" are when .....why don't you figure it out and tell me (The first 10 emails get EC too). It's just a coincidence, but Sirius and Procyon both have white dwarf companion stars.
So, make a beautiful sketch, of all of this, with Orion, Aldebaran, Pleiades, Procyon, Saturn, Castor & Pollux, Sirius and Capella (with the pentagon of Auriga). And Mars. It's the best part of the sky for sky gazing, and you can watch it all winter. Procyon, Sirius and Betelgeuse are called the Winter Triangle, and in Mexico, the belt stars are called "the Three Kings" because Christmas is not far off. You will probably want to use both the left and right hand pages of your blackbook, and may need to make the scale 2 degrees to a square. Label neatly all the stars mentioned above.
Now answer the following questions: