# [ExI] help please, from you creative types

spike spike66 at att.net
Wed Sep 22 23:09:21 UTC 2010

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...On Behalf Of Tim Halterman
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>...If the location of the work is not in question, and you can
determine GPS coordinates of the camera shot you could take a picture of
celestial bodies, the sun the moon perhaps...

You got it Tim!  It would work if the skies are clear, which they often are
at the time of year this task needs to be done.  Take a photo of the rising
sun on the eastern horizon sighting along the back of the barn.  That fixes
both the location and the direction of sight.  From the position of the
sunrise, the time of year can be easily determined to plus or minus a week.

On the same day, take a picure of the moonrise, which can be at any time of
the day.  This will show the phase of the moon, from which a resolution to
plus or minus a day can be easily determined.

As a backup, I could take a picture of the corn, which grows quickly, so
that would give a date to plus or minus a couple weeks, along with the moon
phase.  Some weeds bloom with an uncertainty of plus or minus a week.

Wait, better still, pole of known length that would cast a shadow a specific
way depending on the time of year and time of day.  I need to work on that
one.

Good thinking!

>...I'll be the first to say that I don't think that it'll be easy
to do.  -Tim

On the contrary, if the skies are clear that day, it is the easiest thing to
do, by far.  It is just a matter of getting up at sunrise and calculating
the time of moonrise that day.  As an extension, one could do the same trick
with sunset and moonset.  If I wanted to go to the trouble, I could get my
telescope out and get a photo of Jupiter-rise with the work going on in the
foreground.  This notion gets me most of the way there.

Another thing I thought of is to buy a steak a few days before the work is
to be done, then take a photo of it each day.  It has a packaged-on date.
In the fridge, a steak turns from red to brown-ish in about 5 days, so it
could serve as a low-res clock of sorts.  On the other hand I suppose one
could freeze the thing after three or four days, then later thaw it and set
the camera clock back.

The sun-moon trick is clever though.  Depends on having clear skies.

spike

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