Re: [ARSCLIST] NASA

[Don Cox <doncox@xxxxxxxxxxxxxx>]

On 16/08/06, Richard L. Hess wrote:
> At 05:45 PM 8/15/2006, David Breneman wrote:
> 
>> The moon walk was broadcast live.  The signal from the moon
>> was 320 lines, progressive scan, 10 frames per second. *Not*
>> high resolution by any standard (newer than 1934) but a
>> higher resolution than was seen by anybody except the
>> technicians at the three Deep Space Tracking Network
>> stations.  The conversion process (shooting a long-
>> persistence monitor with an NTSC video camera) produced
>> a lot of smearing and reduced the contrast range
>> significantly, so the already low-res picture was
>> even lower-res by the time anyone (except those few
>> engineers) saw it.  The reason it was sent as a slow
>> scan signal was because there wasn't enough bandwidth
>> to reliably transmit the necessary instrument
>> telemetry and an NTSC television signal on the
>> bandwidth available.
>> 
> 
> Apparently this is getting wide coverage. My wife saw it on our local 
> Toronto news channel as we got home from vacation tonight.
> 
> The challenge will be WHEN the tapes are found what can be done with 
> them. NASA has to close the lab that can still play the tapes. People 
> within the Gov't have their hands out to hold onto this gear.
> 
> Lots of people can play 14-track IRIG tapes (which these are). I 
> think these ran at 120 or 240 in/s - the PDF says, IIRC.
> 
> So, if the tapes are at all playable -- and I suspect they are -- the
> signals can be recovered. The next step is demodulating them in such a
> way that we can get them reliably into rasters. Then the rasters have
> to be replicated and played out. So 10 fps, would be actually played
> at 9.99 or something like that to get up to the 29.97 rate of NTSC.
> 
> The easiest (but not the best) thing would be to triple each frame. 
> The best thing would be to do motion interpolation between "key" 
> frames as broadcast and then create the intermediate frames based on 
> linear (if nothing better) interpolation of moving objects' positions.
> 
> The 320 line detail is all we'll get, but it should be much better 
> than the CRT standards conversion done in 1969.
> 
> The still photos are much higher resolution (Hassleblad and Nikon 
> cameras were used in that era of NASA, IIRC).

A good selection of the still photos, in excellent reproductions from
first-generation copies, is in the book "Full Moon" by Michael Light
(1999)
 
> I am in no rush to set up for 14-track 1" IRIG but it is on my radar 
> screen. I successfully completed my first FM 7-track 1/2-inch IRIG 
> transfer of seismic data. It was a real learning experience. The 
> client had searched for months for someone to do this and he was very 
> complimentary in telling others of my work.
> 
> I think the big problem here is FINDING the tapes. I think many 
> people could handle them. I would love to, but I suspect that someone 
> in the DC area could probably do it.
> 
> One concern is the jitter. The Ampex machines had a very interesting 
> low-jitter tape path while most instrumentation recorders look more 
> like audio tape players and don't have the time base accuracy of the 
> Ampex machines originally used for the recording. On the other hand, 
> I suspect that the slow-scan video doesn't need something like 10 ps 
> time base accuracy.

Regards
-- 
Don Cox
doncox@xxxxxxxxxxxxxx