The strobe wheel technique was used at Lick Observatory to produce the first
pictures showing the pulsar pulsing and thus also confirming which star it was in
the field. However the first, days earlier, identification of that star was done
at Kitt Peak National Observatory by using a small pinhole aperture to isolate
the star at the focus of the 84-inch telescope. The detection of the pulses for
that was by a photomultiplier with its output being signal averaged synchronous
with the pulsar repetition rate. This same technique was used with a 36-inch
telescope for the very first detection of the optical pulses from the Crab
pulsar by Steward Obs. of the Univ. of Arizona..

Don

"William C. Keel" wrote:

In sci.astro.amateur Robin Leadbeater wrote:

"Eric" wrote in message
...
Nice job, Robin. I wonder if a BW TV camera would be able
to pick this up on a 16" telescope...

Eric.

Hi Eric,

You would still need some sort of strobe technique as the frame rate would
not be fast enough to catch the 30/sec double pulse. I suspect it would not
be sensitive enough either. I have a very sensitive camera and it needs a
few seconds exposure to catch the mag 16 pulsar. To catch it in a 1/60sec
frame I estimate would have needed at least 100x more light ie an 80 inch
scope. I would not mind having a try though if you know where I can borrow
one ;-)

This may be a case for the long-forgotten art of the mechanical strobe
disk, eliminating the need for rapid readout or 100% efficiency.
That's how the pulsar was first identified with a particularly
optical object, using an intensified TV camera. Getting the timing
and phasing right are left as exercises for folks who (unlike me)
know how to do it.

Bill Keel