Suntanning

Summary

In this lab you and your lab partner will be assigned a month of the year. You're going for a virtual all-expense-paid, one-weekend trip (Friday evening to Sunday evening) to get a great suntan in your appointed month. Where will you go? How do you select the perfect place?

Assignment

The heart of this lab is sorting through your options, which are many and complex. This is where your discussions with your lab partner are of central importance.

Be sure to write up and submit your recommendation independently. There is no right answer, only a reasonable one. We want to see how you added structure to an ambiguous problem in formulating a decision.

In a few short paragraphs, state where you would go and why you selected that location. The quality of your answer is much more important than the quantity. Your grade depends on the strength, clarity and conciseness of your arguments. Insofar as your grade is concerned, we're looking for a strong astronomical rationale. This is an astronomy class after all. So state very clearly all of the astronomical criteria you considered, and whether you treated them as primary or secondary in importance.

But that isn't all there is to this problem. The non-astronomical considerations are also germane. Mention three issues which you considered. How did these issues affect your decision? (Please be specific as well as brief.)

There are many challenges in identifying the best place to suntan. So before you proceed much further think carefully about what they are. Consider the relevance of such things as the duration of daylight, the height of the Sun, etc. Weather is another issue. And don't forget about skin cancer. Finally, if you select a very remote beach, keep in mind that you'll have to squander a lot of time getting to and from it by helicopter.

To make your job a lot easier, here are some average temperatures for cities along the west coast of the Americas at various latitudes.

Mean Monthly Temperatures at Five Locations
Avg Daily Temps (oF) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Valparaiso (33oS) 72727067646062 6364666871
Quito (0oS) 59*59*59*58*58*58* 58*59*59*59*59*59*
San Diego (33oN) 55565759626468 6967646157
Seattle (48oN) 41434651566163 6460534642
Barrow (71oN) -16-18-150193440 4131171-10
* Quito is cool owing to its altitude of 12,000 feet. Add 30 degrees for the temperatures at sea level at this latitude.

Below, you'll find a table with some useful astronomical data for these same cities. If you need it, there's quite a bit of additional data on these cities in various atlases in Suzallo or public libraries. Feel free to use Redshift in Suzallo or the Computer Lab in A214 (first check with your T.A. for access).


SOLAR DATA FOR VARIOUS CITIES (from Voyager)

Location: Barrow Latitude: 71o N
Date    Rise Time   Set Time         Noon Altitude          Rise Azimuth           Set Azimuth          Day Length
1/22       --         --         nevero above hor'zn             --                     --              00:00 hr:m
2/22     9:37 AM     5:47 PM       9o above S hor'zn    120o=30o S of E(ESE)   240o=30o S of W (WSW)
3/22     6:18 AM     6:24 PM      20o above S hor'zn     85o             (E)   275o              (W)
4/22     4:34 AM    10:22 PM      31o above S hor'zn     45o=45o N of E (NE)   315o=45o N of W  (NW)
5/22       --         --          39o above S hor'zn             --                     --              24:00
6/22       --         --          42o above S hor'zn             --                     --              24:00
7/22       --         --          39o above S hor'zn             --                     --              24:00
8/22     4:44 AM    10:12 PM      30o above S hor'zn     47o=43o N of E  (NE)  312o=42o N of W  (NW)
9/22     7:06 AM     7:32 PM      19o above S hor'zn     87o= 3o N of E   (E)  273o= 3o N of W   (W)
10/22    9:20 AM     5:02 PM       8o above S hor'zn    124o=34o S of E (ESE)  236o=34o S of W (WSW)
11/22      --          --        nevero above hor'zn             --                     --              00:00
12/22      --          --        nevero above hor'zn             --                     --              00:00


Location: Seattle Latitude: 48o N
Date    Rise Time   Set Time         Noon Altitude          Rise Azimuth           Set Azimuth          Day Length
1/22     7:48 AM     4:55 PM      23o above S hor'zn    119o=29o S of E(ESE)   241o=29o S of W (WSW)       hr:m
2/22     7:03 AM     5:43 PM      32o above S hor'zn    104o=14o S of E  (E)   256o=14o S of W   (W)
3/22     6:09 AM     6:25 PM      43o above S hor'zn     88o         (due E)   272o          (due W)
4/22     5:08 AM     7:09 PM      54o above S hor'zn     71o=19o N of E  (E)   289o=19o N of W   (W)
5/22     4:24 AM     7:48 PM      63o above S hor'zn     57o=33o N of E(ENE)   302o=32o N of W (WNW)
6/22     4:11 AM     8:11 PM      66o above S hor'zn     52o=38o N of E(ENE)   307o=37o N of W (WNW)
7/22     4:34 AM     7:57 PM      63o above S hor'zn     58o=32o N of E(ENE)   302o=32o N of W (WNW)
8/22     5:14 AM     7:10 PM      54o above S hor'zn     71o=19o N of E  (E)   288o=18o N of W   (W)
9/22     5:56 AM     6:08 PM      43o above S hor'zn     88o         (due E)   271o          (due W)
10/22    6:38 AM     5:09 PM      31o above S hor'zn    105o=15o S of E  (E)   254o=16o S of W   (W)
11/22    7:24 AM     4:26 PM      22o above S hor'zn    120o=30o S of E(ESE)   240o=30o S of W (WSW)
12/22    7:55 AM     4:20 PM      19o above S hor'zn    125o=35o S of E(ESE)   235o=35o S of W (WSW)


Location: San Diego Latitude: 33o N
Date    Rise Time   Set Time         Noon Altitude          Rise Azimuth           Set Azimuth          Day Length
1/22     6:49 AM     5:11 PM      38o above S hor'zn    113o=23o S of E(ESE)   247o=23o S of W (WSW)       hr:m
2/22     6:24 AM     5:40 PM      47o above S hor'zn    102o=12o S of E  (E)   259o=11o S of W   (W)
3/22     5:50 AM     6:01 PM      58o above S hor'zn     89o         (due E)   271o          (due W)
4/22     5:11 AM     6:23 PM      69o above S hor'zn     75o=15o N of E  (E)   285o=15o N of W   (W)
5/22     4:45 AM     6:45 PM      78o above S hor'zn     65o=25o N of E(ENE)   295o=25o N of W (WNW)
6/22     4:41 AM     7:00 PM      81o above S hor'zn     61o=29o N of E(ENE)   299o=29o N of W (WNW)
7/22     4:55 AM     6:54 PM      77o above S hor'zn     65o=25o N of E(ENE)   295o=25o N of W (WNW)
8/22     5:16 AM     6:26 PM      69o above S hor'zn     75o=15o N of E  (E)   284o=14o N of W   (W)
9/22     5:36 AM     5:45 PM      57o above S hor'zn     89o         (due E)   271o          (due W)
10/22    5:58 AM     5:08 PM      46o above S hor'zn    103o=13o S of E  (E)   257o=13o S of W   (W)
11/22    6:25 AM     4:44 PM      37o above S hor'zn    114o=24o S of E(ESE)   246o=24o S of W (WSW)
12/22    6:47 AM     4:47 PM      34o above S hor'zn    118o=28o S of E(ESE)   242o=28o S of W (WSW)


Location: Quito Latitude: 0o S (note: alt=12,000 feet)
Date    Rise Time   Set Time         Noon Altitude          Rise Azimuth           Set Azimuth          Day Length
1/22     6:22 AM     6:29 PM      71o above S hor'zn    110o=20o S of E(ESE)   250o=20o S of W (WSW)    12:07 hr:m
2/22     6:24 AM     6:31 PM      80o above S hor'zn    100o=10o S of E  (E)   260o=10o S of W   (W)    12:07
3/22     6:18 AM     6:24 PM      90o=overhead           89o         (due E)   271o          (due W)    12:06
4/22     6:09 AM     6:16 PM      78o above N hor'zn     78o=12o N of E  (E)   282o=12o N of W   (W)    12:07
5/22     6:07 AM     6:14 PM      69o above N hor'zn     70o=20o N of E(ENE)   290o=20o N of W (WNW)    12:07
6/22     6:13 AM     6:19 PM      66o above N hor'zn     66o=24o N of E(ENE)   294o=24o N of W (WNW)    12:06
7/22     6:17 AM     6:24 PM      69o above N hor'zn     70o=20o N of E(ENE)   290o=20o N of W (WNW)
8/22     6:14 AM     6:20 PM      78o above N hor'zn     78o=12o N of E  (E)   282o=12o N of W   (W)
9/22     6:04 AM     6:10 PM      90o=overhead           89o         (due E)   270o          (due W)
10/22    5:55 AM     6:02 PM      79o above S hor'zn    101o=11o S of E  (E)   259o=11o S of W   (W)
11/22    5:56 AM     6:04 PM      70o above S hor'zn    110o=20o S of E(ESE)   250o=20o S of W (WSW)
12/22    6:08 AM     6:17 PM      67o above S hor'zn    113o=23o S of E(ESE)   247o=23o S of W (WSW)


Location: Valparaiso Latitude: 33o S (note: on Pacific Coast due West of Santiago)
Date    Rise Time   Set Time         Noon Altitude          Rise Azimuth           Set Azimuth          Day Length
1/22     6:01 AM     7:59 PM      76o above N hor'zn    114o=24o S of E(ESE)   246o=24o S of W (WSW)      hr:m
2/22     6:31 AM     7:53 PM      67o above N hor'zn    103o=13o S of E  (E)   257o=13o S of W   (W)
3/22     6:53 AM     6:58 PM      56o above N hor'zn     90o         (due E)   270o          (due W)
4/22     7:16 AM     6:18 PM      44o above N hor'zn     76o=14o N of E  (E)   284o=14o N of W   (W)
5/22     7:37 AM     5:53 PM      36o above N hor'zn     66o=24o N of E(ENE)   294o=24o N of W (WNW)
6/22     7:52 AM     5:49 PM      33o above N hor'zn     62o=28o N of E(ENE)   298o=28o N of W (WNW)
7/22     7:47 AM     6:03 PM      36o above N hor'zn     66o=24o N of E(ENE)   294o=24o N of W (WNW)
8/22     7:19 AM     6:24 PM      45o above N hor'zn     76o=14o N of E  (E)   284o=14o N of W   (W)
9/22     6:39 AM     6:45 PM      56o above N hor'zn     90o         (due E)   270o          (due W)
10/22    6:00 AM     7:07 PM      68o above N hor'zn    104o=14o S of E  (E)   256o=14o S of W   (W)
11/22    5:34 AM     7:35 PM      76o above N hor'zn    115o=25o S of E(ESE)   256o=26o S of W (WSW)
12/22    5:36 AM     7:58 PM      80o above N hor'zn    119o=29o S of E(ESE)   241o=29o S of W (WSW)


Notes: