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Re: (meteorobs) Video system compatibility

> Compatibility issues between US and European video INTENSIFIERS should not
> be a problem is my best guess.  The intensifier I 've got runs off 12 VDC,
> and the output of an intensifier is a light image, NOT an electronic
> signal.

Correct, the intensifiers do not differ. By the way, the Stano 
intensifiers we use are operated with 3V DC, the tube contains already 
the high voltage transformer.

> The issue is how good an intensifier do you want.  You can pay
> $3000 for a scientific grade intensifier with LOW NOISE, good linearity
> across the face, no dead pixels, better sensitivity into the near-IR. 

By the way, you can spend even more. :-)
We got an offer from a Japanese enterprise. They sell the MCP which you 
can get second hand from Stano at $380 for $8.000!!
We got also an offer from a German dealer for another proximity focus 
intensifier for almost $15.000. In fact, those are really professional 
devices, since you can choose the material of the photo cathode and the 
screen to fit best your needs (i.e. spectral response), but who has so 
much money...
Concerning near-IR sensitivity: Since meteors radiate most energy in blue 
light, those intensifiers are of little use. In fact, since most lenses are 
corrected for visible wave lengths only, IR-sensitive intensifier give a 
much worse image quality. 

> Mike
> Palermiti in Florida is still of the opinion that the Russian made
> intensifiers are just not that good (very noisy) if you want to push the
> limiting magnitude of meteor detection. 

Unfortunately, we have no experiences with Russian image intensifiers 
so far (i.e. Zenith an brands).

> My
> personal opinion is that if you want to contribute to good science you
> configure the best system you can with current technology.  That may
> translate into higher cost.  The European's have put together a system for
> less than $1000.  Maybe they have found some good quality components that
> we are not aware of in the US.  Sirko, can you provide any info on this
> thought?

As mentioned earlier, we use American image intensifiers. The quality 
varies, some of them show more signs of their former usage, others have less 
gain, etc. However, the quality is definitely good enough for our 
purpouses. If you want to spend more money - fine - but you really don't 
have to. If we want to, we are currently able to record far more meteors 
than we will ever be able to analyse...

> 1) You need a CCD at the back end, a low light sensitive frame rate CCD
> camera is a few hundred bucks
> 2) You need to couple the intensifier to the CCD, Mike P. uses a f/1.1
> transfer lens configuration, others fiber couple these which doesn't work
> well under extreme temperature changes.

Pete, I do not completely agree with those statements.
Directly coupled MCP/CCD systems do have the best efficiency there is, 
approximately 50 times higher than lens coupled devices. That was shown at 
the last IMC by Felix Bettonvil. However, from our knowledge it is almost 
impossible to obtain those intensifiers, since they are *really* high end.
The coupling lens need not to be extremely fast, neither need the CCD 
camera to be extremely sensitive. The background glow of the intensifier 
is usually quite bright, and you cannot do more than record the sky 
background.

> 4) You need to record the video signal (are you gonna lug a VCR around in
> the field that runs off AC) I did this with an automotive DC/AC converter
> but I now use a 8mm camcorder that accepts external video inputs for
> recording (far more portable and less power hungry). 

One advantage is that you can probably superimpose the time. The major 
disadvantage of that setup, however, is the short record time for each video 
tape. Is that right, that you can record at maximum 90 minutes per tape 
in standard mode?

> The other alternative
> is to run a detection program directly on the video as its produced
> real-time (need AC, computer and frame grabber board, (a few thousand) and
> software for automated detection (which I am currently working on).

From my experiences so far I would guess, that such completely computer 
based systems will not be available at reasonable prices within the next 3 
years.
By the way, Pete: What is the current status of your project? Any news?
At the IMC I had some interesting discussions with Chris Trainer from 
Leeds/UK on that topic. He is also dealing with that topic. His main idea 
is to use hough transforms for meteor detection.
Cheers, Sirko
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