Author Topic: Apollo 11 video feed delay?  (Read 2804 times)

Offline David Ridlen

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Apollo 11 video feed delay?
« on: March 18, 2024, 12:21:33 AM »
Does anyone know where specifics are about how long the Apollo 11 video frame conversion process took?  An Apollo denier with some video experience is insisting it would have taken hours to process, preventing a live feed.  Offhand, I dont find precise info about how long the scan rate conversion (10 fps to NTSC) took to record and send.  The best I can find is this- https://www.parkes.atnf.csiro.au/news_events/apollo11/The_Apollo11_SSTV_Tapes_Search.pdf  but it does not say how long the conversion process took.

The denier's most recent claim is:

"...The TV signal had to have a significant delay in relation to the communication because the speed of recording on the hard disk and on the tape is limited by the speed of reading, writing and the speed of rotation of the disk and tape. Considering that the hard disk was returning the signal for rebroadcasting and scanning, it is clear that the minimum delay of the TV signal is 3 hours in relation to communication. Even if they managed to spin the hard drive at the speed of light and execute the whole process at the speed of light, the delay would be at least 20 frames every second. So definitely someone had to synchronize the communication and the video recording, and given that the communication was already in the live program of many televisions, it is logical that the televisions had to do that work. Assuming they knew exactly how long the delay was, they could do it in two ways. The first is to slow down the tone until the TV image reaches the communication and the second is to speed up the image. Since it is not visible in the live broadcast that they slowed down the tone, it remains that they could only slow down the image. All televisions that broadcast live broadcasts had to synchronize at the same time. Now there is another problem, and that is that they had to record all the video material first, and only then synchronize it, again all at the same time. So NASA and the TV stations that broadcast the live broadcast lied."

Thanks!

Offline Zakalwe

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Re: Apollo 11 video feed delay?
« Reply #1 on: March 18, 2024, 05:06:36 AM »
So he's not questioning that the events took place as seen, just that it took a bit longer to process?
"The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.' " - Isaac Asimov

Offline David Ridlen

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Re: Apollo 11 video feed delay?
« Reply #2 on: March 18, 2024, 05:51:00 AM »
Sorta.  He replies as if open to admitting to being wrong about fakery, remains civil, and at least partly admits when debunked. 

I am defending the impossibility of faking artificial lighting in the Apollo visual record.  He is mostly arguing how all photographic evidence can be faked one way or another.

He finds the video and 16mm footage more compelling to argue with, than any still images, since the camera and things move around, conceding that they cannot be post-composited.  For the moment, he is ignoring what I consider the most compelling visual recording- 16mm Apollo 15 footage of EVA 2 (also EVA 3), between Station 6 and 6a-   It cannot be miniature since uncut footage has astronauts walk in front of camera, and shows miles of evenly lit terrain with sharp, unidirectional shadows, where it is impossible to use or hide lights.  I will return to that.

But after days of debate on this frame-rate point (among others), he has retreated to claiming NASA is at least lying about a live feed, but not that it proves anything one way or the other.  But I know that if you dont debunk a particular detail they gather all wagons around that last hill.  So I was looking for a bit more definitive info on the A11 feed delay.
« Last Edit: March 18, 2024, 05:54:00 AM by David Ridlen »

Offline Mag40

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Offline bknight

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Re: Apollo 11 video feed delay?
« Reply #4 on: March 23, 2024, 10:49:05 AM »
I'm a bit confused.  The 16mm footage you refer is not transmitted live, it is film that was processed after the mission concluded.  The rest of the transmissions were "live" with roughly a 2 second delay. The only delayed video from was from A17 when the Cernan was driving to the parking place the antenna was positioned properly to have the DSN pick up that signal.  A11 video was processed to a format that could be presented to the TVs around the world.  I don't remember if there was an additional delay other than the transmission delay.  That may be addresses in Jay's Clavius site.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
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Offline Allan F

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Re: Apollo 11 video feed delay?
« Reply #5 on: March 23, 2024, 11:07:11 PM »
As the SSTV feed was routed to a monitor, and from there picked up by a TV camera and retransmitted across the world, it was practically instantaneus.
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline Bryanpoprobson

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Re: Apollo 11 video feed delay?
« Reply #6 on: March 27, 2024, 11:10:36 AM »
Sorta.  He replies as if open to admitting to being wrong about fakery, remains civil, and at least partly admits when debunked. 

I am defending the impossibility of faking artificial lighting in the Apollo visual record.  He is mostly arguing how all photographic evidence can be faked one way or another.

He finds the video and 16mm footage more compelling to argue with, than any still images, since the camera and things move around, conceding that they cannot be post-composited.  For the moment, he is ignoring what I consider the most compelling visual recording- 16mm Apollo 15 footage of EVA 2 (also EVA 3), between Station 6 and 6a-   It cannot be miniature since uncut footage has astronauts walk in front of camera, and shows miles of evenly lit terrain with sharp, unidirectional shadows, where it is impossible to use or hide lights.  I will return to that.

But after days of debate on this frame-rate point (among others), he has retreated to claiming NASA is at least lying about a live feed, but not that it proves anything one way or the other.  But I know that if you dont debunk a particular detail they gather all wagons around that last hill.  So I was looking for a bit more definitive info on the A11 feed delay.

This is 16mm footage and therefore any astronaut coms was added and sync’d as best possible.
« Last Edit: March 27, 2024, 11:12:20 AM by Bryanpoprobson »
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Offline Obviousman

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Re: Apollo 11 video feed delay?
« Reply #7 on: March 27, 2024, 04:53:05 PM »
Dwight will have all the answers you need.

Offline jfb

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Re: Apollo 11 video feed delay?
« Reply #8 on: April 12, 2024, 06:55:54 PM »
Here's a pretty authoritative document describing the conversion process. 

Short version: the signal from the Moon was displayed to a slow-scan, high-persistence-phosphor monitor.  A second TV camera photographed the image on the screen, that signal was doubled with a delay to emulate a 525-line NTSC frame, repeat 3 times per frame. 

I have no clue were he gets the "3 hours" from. 

Offline raven

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Re: Apollo 11 video feed delay?
« Reply #9 on: April 16, 2024, 05:52:30 AM »
I think it's an ingeniously quick and dirty solution for something at the time would be much harder to do  purely electronically at the time, to my limited understanding.