[Prev][Next][Index][Thread]

(meteorobs) rotating shutter



In a message dated 96-07-16 18:47:43 EDT, you write:

<< what would you say the source of those big 
 variations in rpm for your shutter was, George? Changes in humidity, or some

 uncorrected voltage changes from your power source, or what? We've been
testing 
 with that little tape-recorder motor I  >>
--------
Lew,

It just happened to have been a dewless night the other night...dry as a
bone...but humidity is a possibility on other nights...but I don't know. No
doubt the power fluctuations has something to do with being at a very rural
location...kinda like the tail end of things on the power grid...any
significant usage will no doubt be noticed...big use of air conditioners,
fans...or no usage at all (like in the middle of the night...unless everyone
decides to turn off fans around 3 am because it's getting cool). Any trends
in power usage would most likely affect it. I'm not an electrician, but do
know enough about it to know that usage tends to change things a little at my
end. I do have a long extension cord (100ft) which creates low voltage in
itself.  Possible that ole Rambo(the Ram that I share the field with) naws on
the cord...he did once, but I would notice it if done more frequently...Just
one look at Rambo's lips would tell the story there.  Without the rotating
shutter and calibrating with the stroboscope, I most likely wouldn't have
noticed them....maybe sunspots? Whatever the cause, it definitely can't be
healthy to the shutters motor...but if it burns out, I already have another
one to take it's place. But whatever the cause, if I check the RPM's after
each significant meteor that crosses the camera's field of view, I see no
problem with it's use. 1400 RPM's was the lowest I've seen it dip down to and
2800 is the highest..dot it's rather seasonal too.  More frequently though it
hangs around 2200.  I'll tell you in the morning what tonights RPM's were.
George Z.

Follow-Ups: