Author Topic: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous  (Read 2463 times)

Offline bknight

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #60 on: May 02, 2019, 01:12:09 PM »
<snip> Passive aggressive commentary.

First, BKnight, the distance is more than 3600 feet between the LM and CSM. The communication you quote is the first dialogue when they come around from the far side of the moon. The A11 clip is 20 minutes in real time. It took 55 minutes for the LM to transition from its lunar orbit to the CSM's lunar orbit approximately 12-14 miles higher. Clearly that points to a greater separation between the LM and CSM at the start of the clip than you are suggesting.

<snip>
No the distance is not greater did you read the PAO commentary the filming started at that point.  Yes the LM was much further away when the LM engine cut off.
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124:29:17 LM Crew: Shutdown. [Pause.]
124:29:23 Aldrin: We got 5,337.3 [feet per second horizontal velocity, 1,626.8 m/s], 32.8 feet per second [vertical velocity, 10.0 m/s], 60,666 [feet, 1849.1 metres altitude].
There is no measurement comment until:

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126:03:20 Collins: [Very weak.] Eagle, are you ready to copy [garble].
126:03:30 Collins: [Very weak.] Okay, your CDH [garble] 45 [garble] 0.2. [Long Pause.]
This is Apollo Control. Columbia's now in an orbit measuring 56.6 nautical miles [104.8 km] by 62.5 nautical miles [115.8 km], and the displays here in Mission Control show the range from Eagle to Columbia a tad over 100 nautical miles [185 km] and about 99 feet per second [30.2 m/s] closure rate.

This is nearly plus hours after shut down, one orbit, and several burns with the RCS system to get the orbits matching, but no filming until
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127:43:43 Collins (onboard): I have 0.7 mile [1.3 km] and I got you at 31 feet per second [9.5 m/s], [garble] look good.
127:43:50 Aldrin (onboard): Okay, [garble].
About now, Mike begins to film the approaching ascent stage as they orbit above the Moon. At the start of the shot, the LM is almost impossible to see except for a flashing light lower left of centre.

Prove that the film was started 20 minutes from acquisition to rendezvous.  The clips you have proved and on AFJ are a little more than 4 minutes.
Do you comprehension issues with the English language?
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Offline bknight

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #61 on: May 02, 2019, 01:16:07 PM »

Another question:  are we sure the DAC was filming at 6 fps, as opposed to 12?


I was able to sneak home for lunch and can have a peek at the Apollo 11 Flight Journal now.  So, to reconcile distances: 


At 127:43:43, they're going 9.5 m/s.
I had forgotten they were breaking during this time rather than just coasting (I was thinking a bit too Kerbal for my own good).  By 127:46:13 they're already down to 3.4 m/s.  And by 127:52:05 they were already stationkeeping.  So even ignoring Collins' comments, the distances covered would be even less.

So 2:30 at an average speed of ~5.6 m/s ~840m.  And another 400 seconds at an average speed of 1.7m/s would cover 680m.  1.52 km, plus whatever their separation was at that point.  Compared to 1.7 km Collins called out.  So it checks out!

ETA:  Collins gave the distance as 1.3 km, not 1.7.  Still a close enough agreement.

The AFJ gave .7 miles and my post of 1.7 miles was incorrect, thanks for the correction.

You see jr Knowing how easy it is to admit an error?  Why not try it?
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Offline jfb

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #62 on: May 02, 2019, 01:51:21 PM »
JFB and Jason Thompson, your suppositions actually help my case. Jason, even if one agrees to your plotting of the LM relative to the CSM and the range of view from the CM window (both which I take exception to), you (and JFB) seem to ignore the fact of how this was filmed. It was was filmed into a mirror. More specifically a right angle mirror. First off the use of a 1.5 inch mirror will greatly curtail the scope of view. Even if you can overcome this, if the CSM is pointed nose down as you suggest how is it possible to film the entire sequence using a right angle mirror. I have attached an Apollo photo of the Command Module and how the DAC camera was deployed with a right angle mirror. As you can see (when you re-orient the photo so the Astronaut's head is at the top of photo) if the CSM is nose down (astronauts head is at the top of the CM cone) the right angle mirror would be shooting off into space away from the moon's surface.

I've attached an annotated version of the image showing what's going on. 

The right-angle mirror gives the DAC the view outside of the rendezvous window (the same direction the astronaut is looking); IOW, the direction the LM is approaching from.  The mirror is mounted close enough to the lens that it fills the lens' field of view.  The whole assembly is mounted a couple of inches from the rendezvous window, so it has a mostly unobstructed view. 

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Futhermore, if you look at the photo, the question arises why would you want to use a mirror anyways? If you just remove the right angle mirror from the DAC, the camera is pointed in the direction you suggest in your hypothesis .

No, it isn't.  Think of how the astronauts sit - "forward" is towards the pointy end, "up" is toward the main hatch. The camera is mounted so that it's pointing "up", aiming at the part of the hull where the hatch is. 

The camera is a bit bulky to mount such that it's pointing out the window, and would obstruct the astronaut's view.  So it's mounted "sideways" against the window and the mirror is used to give it the same view as the astronaut. 

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Of course, as you can see the window is too small and on angle to get a clear view in that direction. So any shot of LM in a CM nose down position will undoubtedly have part of its view obscured by the window frame.

Again, the camera is mounted a couple of inches from the rendezvous window - there's nothing to obstruct its view. 

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The question then is if your supposition is correct why is A12 rendezvous clip not obscured by the window frame at all.

Because the camera is mounted a couple of inches from the window.
« Last Edit: May 02, 2019, 02:30:29 PM by jfb »

Offline Zakalwe

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #63 on: May 02, 2019, 04:34:50 PM »
First off the use of a 1.5 inch mirror will greatly curtail the scope of view.

Huh? How do you figure that? You clearly know very little about how cameras, lenses and optics work.

Have you ever used a telescope? Ever notice that virtually all telescope designs (except the huge refractors in older observatories) all use a diagonal to turn the lightpath through 90 degrees? The "standard" size of these are either 1.25" or 2" (this refers to the barrel size of the eyepiece that the diagonal can accommodate. The larger 2" designs are used when using heavy lenses as the body of the diagonal is physically able to accommodate heavier loads (strictly speaking, especially with dielectric mirror coatings a 2" diagonal has less aberrations near the edge than a 1.25").

The field-of-view available to the DAC will all depend on the focal length of the system. The depth of the focal field will depend on the aperture of the camera. The size of the mirror is virtually irrelevant
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Offline molesworth

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #64 on: May 02, 2019, 05:11:55 PM »
I appreciate your responses to my claims (and Jay, I do believe I am attempting to reciprocate, albeit I don't have enough time in the day to respond to everyone.
Then pick one topic to discuss and concentrate on that, rather than multiple unrelated issues.  Perhaps then you'll have the time to respond.  Many of us have full time jobs and other interests as well, so it would make our lives easier too.

It was was filmed into a mirror. More specifically a right angle mirror. First off the use of a 1.5 inch mirror will greatly curtail the scope of view.
How will the field of view (I presume you mean) be affected by a planar mirror at 45 degrees to the optical path?  What can you conclude from observing that he edges of the mirror aren't visible?

Rather than going by what you might "feel" or "expect", perhaps you should find out the diameter of the camera lens, its field of view, and the distance from the lens to the mirror.  Then please show us what effect this arrangement would have on the overall field of view.

Also no one has taken a shot on why the A11 footage of the LM's movements and rotations appear to be mechanical in nature and not natural. To the point, some of the rotations appear to show the LM 'bouncing back' in the opposite direction after a rotation ends. Does anyone have any ideas?
I did cover this on page 1 of the thread, but you skipped over it.  Again, it's time to move beyond guessing and expectations, and do some real analysis.  What was the mass of the LM during ascent?  How are the RCS thrusters positioned?  How much force do they apply when operated to rotate the craft?  Now work out the angular accelerations and resulting angular velocities, and tell us whether this matches what we see.

These are truly amazing films.
Yes, they are.  However, you seem unable to appreciate just how remarkable.
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Offline jfb

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #65 on: May 02, 2019, 06:59:09 PM »
Also no one has taken a shot on why the A11 footage of the LM's movements and rotations appear to be mechanical in nature and not natural.

It's a machine - by definition, its motions are mechanical.

And remember, the camera was undercranked, so the motions are sped up, adding to the "unnatural" feel.

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To the point, some of the rotations appear to show the LM 'bouncing back' in the opposite direction after a rotation ends. Does anyone have any ideas? 

Think of it as the space equivalent of parallel parking.  The astronauts move the LM around by applying the thrusters.  Since they're human, they sometimes thrust for too long and move too far in a particular direction, so they have to thrust the other way to correct.  It takes a couple of tries to get the LM in the position they want.   

This is basic stuff.  It's Newton's Third Law in its purest form (you don't have to take friction or air resistance into account). 

Offline raven

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #66 on: May 02, 2019, 10:54:29 PM »
To the point, some of the rotations appear to show the LM 'bouncing back' in the opposite direction after a rotation ends. Does anyone have any ideas? 

Think of it as the space equivalent of parallel parking.  The astronauts move the LM around by applying the thrusters.  Since they're human, they sometimes thrust for too long and move too far in a particular direction, so they have to thrust the other way to correct.  It takes a couple of tries to get the LM in the position they want.   

This is basic stuff.  It's Newton's Third Law in its purest form (you don't have to take friction or air resistance into account).
A two dimensional example would be  the 40 year old video game, Asteroids (or for an older still example, Spacewar!.) For a three dimensional example, Kerbal Space Program and Orbiter are two good examples, the latter being free. Seriously, I claim no special expertise,  especially compared to others here, but if you are making basic, simple, elementary mistakes like this, you may wish to rethink your position, jr Knowing.
« Last Edit: May 02, 2019, 10:56:47 PM by raven »

Offline JayUtah

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #67 on: May 02, 2019, 11:53:17 PM »
...and Jay, I do believe I am attempting to reciprocate, albeit I don't have enough time in the day to respond to everyone.

That excuse wore out a long time ago.  Just man up and admit you were wrong.  You had plenty of chances to try to rehabilitate those arguments.  But you know you can't.  You don't know what you're talking about, and the honest thing to do would be to admit that.  That would be the friendly thing to do, too.
"Facts are stubborn things." --John Adams

Offline gillianren

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #68 on: May 03, 2019, 02:16:03 AM »
I don't think it would take that much digging to find examples of everyone in this discussion being corrected and acknowledging said correction.  Except for one person . . . .
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Offline Jason Thompson

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #69 on: May 03, 2019, 04:09:13 AM »
I don't have enough time in the day to respond to everyone.

This excuse comes up so often from hoax believers, and always apparently un-ironically without realising why this situation arises in the first place.

JR, if you stuck to a topic, addressed the comments on that topic, and conceded your mistakes, we wouldn't still be responding to old topics when you bring up new ones. The reason you 'don't have time' is because you keep bringing new elements to the discussion. What exactly do you expect to happen in that case?

I still want an answer to my question about the mathematics of LM stability from the memo you brought up as evidence to support your claims in your earlier thread. If you want me to stop bringing it up then actually respond, whether it's to challenge my interpretation of the mathematics or to concede you were wrong. Frankly I don't care which. But don't sit there trying to present yourself as the victim of an avalanche of responses you don't have time to deal with when you're the one poking the cornices and triggering the avalanches in the first place. Clean up one before moving on to the next.  It's simple enough, no?
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Offline JayUtah

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #70 on: May 03, 2019, 09:49:38 AM »
The reason you 'don't have time' is because you keep bringing new elements to the discussion.

Arguably to distract from having been backed into a corner on the point at hand.  Changing the subject, or "pivoting," as the politicians call it, is a time-dishonored way of avoiding uncomfortable questions or evading responsibility for failure.  Jr's critics respond the way they do here because they're well aware of the tactic and are properly not letting him get away with it without consequence.

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I still want an answer to my question about the mathematics of LM stability from the memo you brought up as evidence to support your claims in your earlier thread. If you want me to stop bringing it up then actually respond, whether it's to challenge my interpretation of the mathematics or to concede you were wrong. Frankly I don't care which.

This is my vote too.  I have no desire to pursue Jr on some other damn fool idealistic crusade until I know whether there's a destination.  I will keep bringing up LM stability until there's a resolution.  The notion that Jr will let things be "resolved" only in his favor -- or failing that, some pretended impasse that he can walk away from -- is antithetical to any sort of reasoned exercise.
« Last Edit: May 03, 2019, 10:16:32 AM by JayUtah »
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Offline Bop

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #71 on: May 04, 2019, 03:13:27 AM »
It's not uncommon for a hoaxer to keep posting until everyone 'gives up' on that thread as they go to the multitude of 'newer' threads, then they claim (either there or elsewhere) 'see I was right, no-one contradicted me!!!'
I've noticed this tactic being used a few times...

Offline JayUtah

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Re: Suspect DAC Footage - Part 2 Apollo 11-12 LM Rendezvous
« Reply #72 on: May 04, 2019, 10:32:27 AM »
then they claim (either there or elsewhere) 'see I was right, no-one contradicted me!!!'
I've noticed this tactic being used a few times...

Quite right, which is why moderators sometimes have to restrict some people's posting privileges and behavior so as to make evident the conflation.  "No one could refute me, so they all fell silent" looks a lot like "I'm a rude, annoying s.o.b. that no one wants to waste any more time on."

But also, "We debated the issue and arrived at an impasse" looks a whole lot like "I got backed into a corner, so I changed the subject and refused to continue the original topic."  The latter governs debates like these where the claimant participates solely at his pleasure and cannot be held responsive.  At forums such as Cosmoquest, they have tighter system of rules for controversial debates that suspends posting privileges if someone avoids hard questions.  However implemented, the point is to lay bare when a claimant is being dishonest.

On the issue of LM stability we are not at an impasse.  We are at the point where Jr refuses to acknowledge facts from his own sources.
"Facts are stubborn things." --John Adams