HOW TO TELL TIME ON THE PLAYA
There seems to be no consistent recollection of the relationship between the hands of a clock and the numbers on its face while living in Black Rock City. Try as you may to remember to check the time, most of us are rendered powerless by PLAYA TIME. It can be a welcome submission except when you really want to be somewhere at the same time the event is happening. To circumvent this timeless reality, we in the AEZ revert to a pre-clock method of social gathering. It is based on the sun's distance from the horizon.
Quite often, come late July and early August, one might read a Burning Man invitation similar to this:
*~*~*~*~*
Thursday Night at the base of the Man
Jolie and I wish your presence at the holiest of unions, our FIFTH Burning Man wedding!
At 4 fingers my wife and Jolie's husband will officiate this gayest of gatherings.
Come CELEBRATE as we embark on the new lives we again will live together separately!
*~*~*~*~*
Of all that you might wonder about in this announcement - 5th wedding, other wife and other husband celebrating, live together separately - what the heck is 4 fingers?!? It is the estimation of local sun time with your outstretched hand placed between the sun and the horizon. The estimate is that each finger represents roughly 15 minutes. So the aforementioned wedding between "Jolie and I" would be about 60 minutes before nightfall.
The truth is that the event would happen at sundown. The organizers knew it would take awhile for you to realize it was getting dark, find your flashlight, and locate your goggles, el wire parasol, and wig. It is the playa for Pete's sake! And you're on Playa Time...
This topic is not about Alternative Energy but important to our Community all the same. A question was posed to our list asking the measure of time at Black Rock City without the use of a clock. Dig in here folks, reading this will give you an idea of our list's broad spectrum ranging from humorous quips to sage advice, gentleness to rage and from simple curiosity to seemingly indecipherable calculations of energy.
The question was asked:
Can someone (or everyone) please explain to me how many fingers mean how much time when the sun is setting? I don't even know how to ask this question but you jokers know what I mean. Those of you who have no idea what I'm referring to will soon find out - you're probably just a little new to the list.
These are the responses:
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The old 4 fingers?
I always thought that it was the height of the sun over the mountain as you hold your hand extended with your fingers in, palms facing you, oriented horizontally.
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yes - it is one of those wonderful relative subjective hand waving (If you'll pardon the expression) units of measure. One persons measure of 4 fingers is not going to match anothers, it probably won't even be the same as your own if you don't hold your hand a constant distance from yur face.
All you can tell is 3 fingers is one finger closer to sunset than 4 fingers but for rough calibration you can use the following : 3 hands = tell your friend to get their hands out our of your face 2 hands = it's afternoon, time for cocktails 1 hand = it's later in the afternoon, you're 1 hand closer to sunset time for an another cocktail
4 fingers = yes, the sun is still setting, time to have another cocktail
2 fingers = no, it is not sunset yet, why are you so obsessed with knowing what time it is? go have another drink
for the scientists, you can 'approximate' 1 hand == 1 hour, but it really depends on how fat your fingers are.
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Using these calculations, 2 fingers = one cocktail.
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I got one finger while on the way to work this morning. I guess that means I'm still in L.A.
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Experiment:
I just did a test. It was a bit more than 4 fingers from the sun
to the horizon at 3:52PM with my arm outstretched and fingers at 90 degrees.
Sunset is about 5:06 today but will come earlier at my house because the
sun sets over a ridge near our house not at the horizon. That suggests
about 1 hour for 4 fingers or 15 minutes per finger.
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4 fingers gives roughly twice the time before sunset as 2 fingers
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I propose that the interrelationship between the length of your arm and the width of your fingers creates a consistent ratio from one person to the next. Does anyone have any theories on that?
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Experiment update:
Local sunset occurred at 4:52 so as close as I can read fingers my four
equal 1 hour exactly.
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I'll come out of lurk mode and pass along the info in my "Bushcraft" survival book (it's really good). In the 35 pages devoted to time and direction by sun and stars it says the following about estimating "local sun time": Paraphrasing...Every 15 degrees of sun travel is equivalent to 1 hour, so each degree is approximately 4 minutes. The "finger" estimates given with hands at full arm's length are:
1. Fingers widely spread (little finger to thumb)...22 degrees
2. Fingers widely spread (thumb tucked in)........15 degrees
3. Closed fist.....................................................8 degrees
4. From second knuckle to edge of fist...............3 degrees
5. Between two center knuckles.........................2 degrees
There doesn't seem to be a measure for the four fingers that we would commonly measure with, but this suggests that one fist at 8 degrees would be roughly equivalent to 32 minutes. To try to convert this "relative sun time" to clock time would require corrections for longitude and earth tilt (there's a table of corrections for this).
Obviously, your mileage would vary depending on how big your hands are (as well as arm length). Might be interesting, tho, to see if these estimates work at all.
I'm very interested in the AEZ group and have been following the threads with great interest. I was with the OBOP group (we had the phone booth to God and some great live music) this year. Returning to lurk mode.
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Amateur astronomers sometimes use hand and finger measurements for estimating angular distances across the sky. I'm told that this works well for both children and adults, because arms and hands stay proportional as we grow. Of course, there are individual variations.
We can start from the following nearly exact relationships between clock time and angular distance through which the sun moves in a clock time interval:
* 24 hr = 360 degrees
* 1 hr = 15 degrees
* 4 min = 1 degree
and then continue with the amateur astronomers' rules of thumb or "rules of arm." All of these assume that you have your arm *fully* stretched out in front of you and that your hand is in your line of sight.
* Width of a fist, with thumb wrapped over the top of the index finger = 10 degrees = 40 minutes
* Width of a hand outstretched as far as it will open, from the tip of the thumb to the tip of the little finger = 20 degrees = 80 minutes
So "four fingers" amounts to about a 1/2 hour's worth of sun movement.
If you want to calibrate your hand and fingers against the night sky, use the following standards:
* Diameter of full moon = 1/2 degree
* Big dipper from end to end = about 25 degrees
How many full moons fit into your own four fingers measurement? To convert to your "four fingers" time, count 2 minutes of clock time per full moon.
Or how many "four fingers" fit into the Big Dipper from end to end? To convert to your "fingers time", divide 100 minutes by the number of "four fingers" that fit.
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I was going to stay out of this one, but when Carlos mentioned
"Of course, there are individual variations."
Well, I just had to butt in. I chopped off the end of my finger and so I believe my mileage will differ.
Our use of 4 fingers was an attempt to remind people that something was happening "soon" (30-75 minutes from now.) And the only "time" that people would notice is when the sun was noticeably going down (not at 2pm or 4Pm) Setting an event at "just before it gets too dark to find your flashlight" seemed good because when it got a little darker or when they saw the sun nearing eye-level, then they started to get ready. (And so were only 20 minutes late)
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Wayne and I independently came up with the estimate that the sun travels "four fingers" in about a half hour. That's four fingers aimed perpendicular to the path of the sun, not vertically above the mountain. As Wayne mentioned, if you put four fingers parallel to the ground, so that you are measuring elevation rather than sun travel, the time is always longer than a half hour, as long as your latitude is above 23 degrees (i.e., North of Havana, Cuba). At any given location, four fingers of elevation will correspond to the shortest clock time interval on the summer solstice and to the longest clock time interval on the winter solstice.
If Bruce flew out to visit me tomorrow, his "four fingers" above the mountain would be longer here in the SF Bay Area than in New Mexico. If he flew to Reno and drove to the Black Rock desert, he'd get an even longer time interval than here.
Does anyone have the table that shows how long it takes for the sun to move 8 degrees in elevation near sundown at Black Rock City around September 1?
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According to my trusty GeoClock V8.4 data, the sun's elevation was 8d on 1 Sep 2003 at 18:42:03 and 0d at 19:24:43. Since the latitude there is 40.9d, the sun sets at 40.9d clockwise from vertical, and travels 6.92d to the right/north during those 8 "vertical" degrees (setting at 280.76). The trig (c=sqrt(a^2+b^2)) works out to a net 10.58d hypotenuse, and the 42:40 time divided by four minutes per degree also equals 10.58! Joy! c.f. 1 March (@Black Rock) sunset takes 43:32 to traverse the final 8 degrees of elevation, and 7.28d of azimuth. (setting at 260.55) 1 Sep 2003's 8 degree elevation drop at sunset in San Jose takes 40:30 since the angle is only 37.3 degrees from vertical.
At the equator, those 8 elevation degrees must take close to 32 minutes, since the sun sets close to vertically thereabouts!?
Hmmmm...
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I'm not sure we can use these measurements at sunset though. the sun appears to change speed (and size) as it's light has to pass through more of the atmosphere as it approaches the horizon... or is it just me?
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for many years, I have been using my fingers to estimate how long till sunset, useful information while hiking in the woods. i.e.: can I make it back to the car/campsite before the sun sets? I have tested it many times, in real life, and found four fingers equals about an hour. and, no, my fingers are *not* that fat.
I say 15 minutes per finger...yes, times will vary *a little* with finger size. enough with the fancy math...go out in the backyard and check it tomorrow evening. :-)
loves ya, lurkers and all,
jolly 'don't give me the finger' jill
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Well, there you have it. Any questions?
Jan out.
