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R: (meteorobs) Performance of PC164C

Friends, our (small!) group of meteor observers is very interested to buy
the PC164C camera for Meteor images getting.
But we have (at least up to now) a big problem: we don't know where we can
find it in European PAL version.
Someone can help us, please?
Thank you a lot.
Roberto Haver


-----Messaggio originale-----
Da: Chris Crawford <chriscrawford@wavedot net>
A: meteorobs@atmob.org <meteorobs@atmob.org>
Data: venerd́ 1 febbraio 2002 5.12
Oggetto: (meteorobs) Performance of PC164C


>I received my PC164C camera last week and have had poor skies, but Monday I
>did get some good images. The moon was near full, so these images are
>representative of performance during the upcoming Leonids. I used a 9mm
f1.4
>lens. The total cost of the setup ran to USD170.00.
>
>My conclusions are as follows: the PC164C is exceptionally strong at the
red
>end of the spectrum; star fields don't match the maps. The camera
>under-represents blue stars and exaggerates red stars. Overall, the camera
>seems capable of recording down to magnitude 4.2 -- averaging blue stars
>with red stars. Thus, it easily saw some red stars of magnitude 4.5, but
one
>magnitude 3.8 blue star was barely visible. There is also, of course, the
>fact that its response from frame to frame is quite variable. This can be
>averaged out with stars, but not with meteors. The field of view is 32
>degrees by 24 degrees.
>
>So, is the PC164C cost-competitive with a system using an image
intensifier?
>I don't know, because I don't have solid specs on such systems. Moreover, a
>proper cost comparison requires full system comparison. With that in mind,
I
>shall present two preliminary sets of numbers, both highly speculative.
>Moreover, I have slapped together a figure of merit based on the assumption
>that the number of meteors recorded is directly proportional to the light
>sensitivity of the camera. Thus, a camera that can record one magnitude
>fainter will see 2.54 times more meteors. I'm sure that someone will
correct
>that assumption.
>
>I assume that other members of this list will correct these numbers:
>
>PC164C System:
>   PC164C       $139
>   Lens          $50
>   Power Supply  $15
>   Computer    $1000
>
>Total Cost:    $1204
>Coverage:       768 square degrees to magnitude 4
>Figure of Merit: $1.57 per square degree - meteor
>
>
>Image Intensifier system:
>   Intensifier $1000
>   Lens          $50
>   Camera       $100
>   camera lens   $50
>   Computer    $1000
>
>Total cost:    $2200
>Coverage:       1000 square degrees to magnitude 7
>Figure of Merit: $0.13 per square degree - meteor
>
>Again, I remind everybody that I am pulling these numbers out of thin air;
I
>hope that they are so wrong that somebody will be motivated to post better
>numbers.
>
>The primary cost of the PC164C system is the computer. I assume a computer
>that can take regular video in and process it -- that's fairly expensive.
It
>seems to me that there are two interesting possibilities here. First, what
>if the video output of the PC164C were recorded using a regular video
camera
>(not a digital one), and the tapes were fed into the computer? This would
>require more busywork, but it would also greatly reduce the cost of a large
>system.
>
>The second possibility would be to build special hardware to process the
>data. If we could get our hands on the data stream coming out of the CCD,
>before it goes into the video converter, then we would have direct digital
>video ready for fast processing. I don't think that's possible, as Sony has
>designed their chipset to function in an integrated fashion; it's not
likely
>that we could get our hands on the raw data stream.
>
>I confess that I am not competent to handle true video processing. I can
put
>together some simple digital systems, but this might be over my head --
>unless somebody knows about some handy-dandy chip out there that would make
>this task much simpler. It seems to me that the most time-consuming
>processing is very simple: just moving brightness bytes around, taking
>averages. It might be possible to do this at the board level, which would
>allow us to use much cheaper data-recording computers.
>
>Chris Crawford
>
>
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