Home Forums Meteors LCD Shutter Hi,

Bill Ward


The exposures were 27 secs at iso1600. 30mm f1.4. In short you can’t know. The chopping, in principle, is used to provide  accurate meteor duration and precision astrometry allowing meteor velocity and decelerations to be measured. This in turn is used with other observations to produce better orbits. The previous owner of the mechanical system I’m trying to re-instate, the late Steve Evans, wrote a very interesting paper in the BAA journal on precision observations. One of the reasons his shutter system was designed to chop at 60 breaks/sec.

I’m having some trouble with vibrations so will need to re-evaluate my design. The advantage of the mechanical shutter is that it is working at 100% efficiency. The shutter blades completely block or not. The LCD shutters have both polarisation issues and the fact that when open are still ~30% opaque (thats ~0.6 of a stop). Any meteor needs to be that much brighter with a LCD cf mechanical.

Like everything with meteor astronomy it’s all a trade off!