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Re: (meteorobs) Re: rotating shutters
Marc,
Hello! We had a discussion about rotating shutters awhile back...somewhere in
the discussion I mentioned that my shutters RPM's varied greatly according to
my stroboscope. I reported that I usually have RPM's between 2100 and 2600
and that recently I had a rate of about 2500 in the early evening and during
the early morning hours I had an RPM measurement of about 1300. This seemed
like a very big fluctuation even to me although I took the measurements
carefully etc. I just want to say that during my Perseid campaign, I was
having stroboscopic determined rates of about 2500 RPM's again...but out of
curiosity, I turned down the stroboscopes flashing lights to match that of
1300 RPM's I mentioned in the past. To my surprise, I found that my rotating
shutter also appeared stationary at 1300 as well as near 2500 with no hint of
extra "ghost-like" images of the two blades. The blinking of the stroboscope
were obviously of different rates...The only thing I can conclude was that
one of these was a "harmonic" of the other of sorts. I now tend to think that
the 1300 is the harmonic based on nebulous reasons...have you ever
encountered this problem with a stroboscope? Is this normal? I personally
feel that the 1300 RPM is half that of the actual 2500(or could be near 2600
actually...or even that the 1300 is actually 1250). But I was never aware
that a stroboscope could do this.
George Z.