(meteorobs) Rotating shutter RPM's

• To: meteorobs@latradedot com, jrendtel@aipdot de
• Subject: (meteorobs) Rotating shutter RPM's
• From: GeoZay@aoldot com
• Date: Tue, 27 Aug 1996 23:45:58 -0400
• Reply-To: meteorobs@latradedot com
• Sender: owner-meteorobs

Okay, today I brought home my rotating shutter and stroboscope and did a
series of tests.  I marked one blade as suggested by Wayne Hally.
  Apparently this suggestion will enable some interpretations.  The
stroboscope results with RPM's and how the marked blade appeared on a 2
bladed shutter are as follows:

450  RPM's = Showed only 1 blade marked.
650 RPM's = Showed the marked blade appearing on both blades.
1150 RPM's = Showed only 1 blade marked.
2300 RPM's = Showed the marked blade appearing on both blades.
4400 RPM's = Can't freeze shutter to show only 2 blades, but does freeze 4
appearing blades that shows the marked blade on all 4 blades.

In light of this test, my hunch that the shutters correct RPM's is either 450
or 1150 RPM's...I'm leaning in favor of the 1150 RPM. The 450 seems to be a
too slow of a number for the fan motor.  If the 1150 RPM figure is right,
then at my observatory, the apparent correct RPM's must be near the 1250
figure and that my 2500 RPM is the incorrect harmonic.  Any help in
confirming my hunches here will be appreciated.
George Zay

• Re: (meteorobs) Rotating shutter RPM's
• From: Lew Gramer <dedalus>

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