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(meteorobs) Re: what image intensifier should be used

Hi Jeff,

> One quick question for those active in Video Meteor observing, forgive
> me if this has been asked before, but what sort of gain do you recommend
> for the intensifier, and would a 1st or 2nd generation tube be best?

generally I would comment a second generation intensifier. The image has a
higher quality which makes the analysis easier. There are some cases were
first generation devices should be prefered (i.e. if you want to use wide
angle lenses and therefore need very high gain), but this is not the
usual case.
Generally the MCP should have a gain of >10.000. However, also
intensifiers with a gain of 5.000 may work well.

> I have tested my video camera with a 2nd generation tube of unknown gain
> (but I think it is low) and from a good site it can reach about
> magnitude 6 for stars. However single frames are usualy very rough when
> captured on my simple frame grabber.

Do not underestimate the role of the lens. Our currently used optics are
that fast, that we have to turn down the intensifier's gain (which results
in less noise) as long as we are not at a very dark site. A fast lens
in cnnection with a low gain intensifier may give good results, too.
Magnitude 6 stars means nothing as long as you do not relate it to the
field of view you obtain. It is very good for wide angle systems, but
rather poor for standard video systems.
Sirko

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*           Sirko Molau             *                    __              *  
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