Author Topic: Moon pics static shadows and moving stars.  (Read 151292 times)

Offline ka9q

  • Neptune
  • ****
  • Posts: 3014
Re: Moon pics static shadows and moving stars.
« Reply #210 on: January 10, 2017, 01:44:46 AM »
We leave Earth's orbit at what speed?  Traveling directly toward the moon? or at a trajectory that will allow the craft to meet with it 240 thou miles later  as it will have traveled in space?  (assuming it is the latter, why is the moon always visible as if straight ahead?  constant adjustments are not economical, so assuming minimal adjustments for course.  (3 days? - How far has the moon traveled thru space?)
Start here:

http://www.braeunig.us/space/orbmech.htm

Bate, Mueller and White's Fundamentals of Astrodynamics has the advantage of being available at a bargain price from Dover, but it's probably a little too mathematical as an introductory text for the layman.

The Apollo missions used highly elliptical near-Hohmann transfer orbits (eccentricity approx 0.97) to travel from an initial low altitude circular parking orbit to the moon's high altitude orbit. At no time were they actually on an earth escape trajectory. As they approached the moon, they passed ahead of it in its orbital path. With no further maneuvers, they would have passed over the lunar far side in a east-to-west (retrograde) trajectory and been flung back towards the earth. That's essentially what happened on Apollo 13 (the one where the landing was canceled due to an explosion in the service module). On all other missions they performed a braking maneuver with the service module engine that slowed them down sufficiently to be captured into a retrograde lunar orbit.

After doing its job sending Apollo toward the moon, the third stage of the Saturn V (the S-IVB) performed additional maneuvers to move it away from Apollo and to tailor its trajectory. On Apollos 8, 10, 11 and 12, the empty stage slowed itself down enough to pass behind the moon in its orbit, allowing lunar gravity to drag it along (a "gravity slingshot"), gaining enough energy to escape earth entirely and fly off into a separate orbit around the sun. On Apollos 13 through 17, less of a slowdown was performed so that the S-IVB actually hit the moon when it arrived.
« Last Edit: January 10, 2017, 02:25:05 AM by ka9q »

Offline ka9q

  • Neptune
  • ****
  • Posts: 3014
Re: Moon pics static shadows and moving stars.
« Reply #211 on: January 10, 2017, 02:07:07 AM »
Conspiracy Theorists are not all un-educated idiots.  You say you're an amateur Photographer?  Well I'm a Professional, and I think you may know less about Photography than you actually think you do.
I would have expected a professional photographer to understand the concepts of f-stop and shutter speed, and how they combine to establish an exposure value.

I would also have expected a professional to understand that both film and digital sensors have a limited dynamic range compared with the very wide range of intensities found in real world scenes, particularly between daytime and nighttime, and that's why a proper exposure setting is so important. Our eyes can work in both daylight and at night only because chemical changes in the retina effectively change its "ISO rating" by a very large factor. These changes are relatively slow, though much faster than the day-night cycle so normally we don't notice it. But you will notice that it takes time for your eyes to "dark adapt" when going quickly from a bright area into a dark one.

The irises in our eyes react more quickly (a second or so), but are limited to a much narrower brightness range that gets even smaller with age.

And I would have expected a professional photographer to understand that the daytime sun on the moon is roughly as bright as the daytime clear-sky sun on the earth (slightly brighter because of the lack of an lunar atmosphere) so that pictures taken of sunlit objects on the lunar surface require approximately the same exposure values as sunlit objects on the earth under a clear daytime sky. Because of the limited dynamic range of both film and digital sensors, such exposures are far, far too short to register stars even in a black sky.

But I wouldn't necessarily expect even a professional photographer to understand just how much brighter the sun is than even the brightest nighttime star. So here are the numbers:

Sol (our sun) has an apparent astronomical magnitude of -26.74. Sirius, the brightest star in the night sky, has an apparent magnitude of -1.46. Five magnitudes represent a brightness ratio of 100:1, so the 25.28 magnitude difference between Sol and Sirius is a brightness ratio of about 13 billion to 1, or almost 34 f-stops (1 f-stop being the difference between, say, f/5.6 and f/8). And that's for the brightest star in the entire night sky.
« Last Edit: January 10, 2017, 02:14:26 AM by ka9q »

Offline onebigmonkey

  • Uranus
  • ****
  • Posts: 1607
  • ALSJ Clown
    • Apollo Hoax Debunked
Re: Moon pics static shadows and moving stars.
« Reply #212 on: January 10, 2017, 02:08:02 AM »
We leave Earth's orbit at what speed?  Traveling directly toward the moon? or at a trajectory that will allow the craft to meet with it 240 thou miles later  as it will have traveled in space?  (assuming it is the latter, why is the moon always visible as if straight ahead?  constant adjustments are not economical, so assuming minimal adjustments for course.  (3 days? - How far has the moon traveled thru space?)

You'v been given the highly technical answers as to the trajectories and speeds involved but I'm wondering if there is a different meaning to your question?

My interpretation is that you think the moon always appears as it does from Earth - in fact if you compare the images taken from cislunar space en route there and back you can see that the views are not the same as can be seen from Earth. It's another telltale sign that the images weren't taken from the ground or in LEO.

To answer earlier points you made, a certain annoying Australian also cut his teeth in the subject at film school. Expertise in how to run a camera and its contents doesn't necessarily convey expertise in interpreting the results - other areas of expertise are necessary to do that. That expertise can be acquired with effort by amateurs and professionals alike. Capitalising your job title doesn't make it special and doesn't mean you are the only one with an opinion or knowledge about your profession. Getting paid to do something doesn't necessarily mean you are good at it. The world is full of people who manage to drive around in a nice car and a string of customers who have only ever used them once.

Conspiracy theorists may not be unintelligent - some of them are quite capable of stringing a sentence together, but they are quite often uneducated in the subject they examine. If they truly understood the subject they would reject the conspiracy angle as poorly founded and false. Others have selectively educated themselves. Others are just downright dishonest.

Offline Zakalwe

  • Uranus
  • ****
  • Posts: 1602
Re: Moon pics static shadows and moving stars.
« Reply #213 on: January 10, 2017, 03:35:58 AM »

How much energy or joule or whatever does it require to alter course? considering the lateral RCS Thruster are tiny? Do they blow Air or is it a fuel like a rocket?  How fast is the craft traveling as it reaches the moon and is it simply gravity itself that puts it into orbit?

You appear to know very, very little about the simplest of subjects relating to space travel. That's not an issue, we are all ignorant about the majority of human knowledge.
It would be helpful to bring yourself up to at least a base level of understanding about not only the Apollo program, but also the basics on how rockets work, basic physics and science. This will make it easier for you to frame your questions and not to get as frustrated as you clearly are when you don't understand the answers.

This is an excellent book on the subject:
https://www.amazon.co.uk/Apollo-Flew-Springer-Praxis-Books/dp/1441971785
It will answer many of the questions that you are asking and put you in a much better position to frame your questions.

Another excellent source is Jeff Quitney's YouTube channel:
https://www.youtube.com/user/webdev17/videos?view=0&sort=dd&shelf_id=1
He has uploaded many educational videos from the 1960s that explain a lot of the concepts in detail*

MSFC work and planning the flight:


1963 Overview of the flight. Note that this was produced before many of the details had been agreed- for example the LM final designs.


Ascent to orbit and Rendezvous:


Re-entry and Atmospheric Phase:



*On a side note, compare the quality of these educational videos to modern day ones. No over-dramatic music, constant repeats of what was said 5 minutes earlier. Just well thought out and well explained detail. There's more content in 10 minutes of these early videos than in a hour of modern programs that seem to infest the idiot lantern today!  :(
"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 smartcooky

  • Uranus
  • ****
  • Posts: 1968
Re: Moon pics static shadows and moving stars.
« Reply #214 on: January 10, 2017, 04:04:58 AM »
Icarus, a few things for you to consider

"We just put Sir Isaac Newton in the driver's seat"
-Astronaut Jim Lovell, Commander Apollo 13

Its all about gravity...

As I understand it we circled the earth gaining speed and used a figure 8 thru space to gravity shoot around the moon into a stable orbit.

A "figure of 8" is a very simplistic way of looking at it., You see this often in diagrams of Apollo. Those  diagrams assume the observer already takes into account the shifting frame of reference as the moon moves around in its orbit.

This is a more accurate representation...



...but even it has its limitations. The orbits were much, much closer to both the moon and the earth than this diagram indicates, and while the scale of the Earth/Moon sizes look about right, the moon is about 10 times further away (about 30 earth diameters instead of about 3 as shown here). This means the curved orbit is much more "stretched" and much straighter. This is why the moon appears straight ahead even though it isn't precisely..

Also, The Apollo 11 mission lasted 8 days... that is more than a quarter of full revolution of the Moon in its orbit around the earth. The moon moved a lot further in its orbit than the diagram shows. Apollo 17 lasted 12 days; between 1/3 and 1/2 of a lunar revolution.

If you want a more accurate mental picture of what the orbits and the TL trajectory look like, try to imagine this

The Earth is a basketball.
The Moon is a tennis ball, placed 24 feet away
Wrap a piece of string a few times clockwise around the basketball, and then run it over to the tennis ball and wrap it counter-clockwise around that. The string represents the height of the orbits above the earth and the moon and the TL trajectory.

We leave Earth's orbit at what speed?  Traveling directly toward the moon?

"No, not directly.

A spacecraft on any trajectory away from the earth after leaving orbit follows a path that is curved by the earth's gravity.  As the spacecraft moves further away from the earth, the earth's gravitational  influence lessens. If it is on a trans-lunar trajectory, as it approaches the moon, the influence of lunar gravity increases.

All the while, the Moon is moving so as it gets closer, the spacecraft is continuously being pulled in an ever-changing direction towards the moon

   
« Last Edit: January 10, 2017, 04:09:52 AM by smartcooky »
If you're not a scientist but you think you've destroyed the foundation of a vast scientific edifice with 10 minutes of Googling, you might want to consider the possibility that you're wrong.

Offline Zakalwe

  • Uranus
  • ****
  • Posts: 1602
Re: Moon pics static shadows and moving stars.
« Reply #215 on: January 10, 2017, 05:26:33 AM »
We leave Earth's orbit at what speed? 

Here you go:
http://history.nasa.gov/SP-4029/Apollo_18-24_Translunar_Injection.htm

Traveling directly toward the moon?

Of course not.

or at a trajectory that will allow the craft to meet with it 240 thou miles later  as it will have traveled in space?

What do you think?
1) Head for a point in space where the Moon actually is when you start, or:
2) Head for a point in space where the Moon actually will be when you get there?

why is the moon always visible as if straight ahead
It wasn't.
Where are you getting that piece of information from?




constant adjustments are not economical, so assuming minimal adjustments for course.

No need to assume. The mid-course correction burns were planned.


How far has the moon traveled thru space?)
All the information that you need to work this out can be found here:
https://en.wikipedia.org/wiki/Orbit_of_the_Moon
Let us know how you get on.

OR point me in the direction for this info?
http://www.braeunig.us/apollo/apollo11-TLI.htm


How much energy or joule or whatever does it require to alter course?

Here's the numbers for the Trans Lunar (outbound) phase
Apollo 8:
http://history.nasa.gov/SP-4029/Apollo_08f_Translunar_Phase.htm

Apollo 10:
http://history.nasa.gov/SP-4029/Apollo_10f_Translunar_Phase.htm

Apollo 11:
http://history.nasa.gov/SP-4029/Apollo_11f_Translunar_Phase.htm

Apollo12:
http://history.nasa.gov/SP-4029/Apollo_12f_Translunar_Phase.htm

Apollo 13:
http://history.nasa.gov/SP-4029/Apollo_13f_Translunar_Phase.htm

Apollo 14:
http://history.nasa.gov/SP-4029/Apollo_14f_Translunar_Phase.htm

Apollo 15:
http://history.nasa.gov/SP-4029/Apollo_15f_Translunar_Phase.htm

Apollo 16:
http://history.nasa.gov/SP-4029/Apollo_16f_Translunar_Phase.htm

Apollo 17:
http://history.nasa.gov/SP-4029/Apollo_17f_Translunar_Phase.htm

considering the lateral RCS Thruster are tiny?
What does that mean? Are you saying that you think that they are too small for the job? If so, on what basis are you making that judgement?

How fast is the craft traveling as it reaches the moon

I'm not listing them all- you can look them up in Apollo By The Numbers. Here's a couple for you (feet per second velocity at LOI ignition):

Apollo 10:
8,232.3

Apollo 11:
8,250

Apollo 17:
8,110.2


is it simply gravity itself that puts it into orbit?
No- the early missions were on a free-return trajectory.
"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 Zakalwe

  • Uranus
  • ****
  • Posts: 1602
Re: Moon pics static shadows and moving stars.
« Reply #216 on: January 10, 2017, 05:41:13 AM »

To answer earlier points you made, a certain annoying Australian also cut his teeth in the subject at film school. Expertise in how to run a camera and its contents doesn't necessarily convey expertise in interpreting the results - other areas of expertise are necessary to do that. That expertise can be acquired with effort by amateurs and professionals alike.

Indeed.
And it's always a good time to watch SG Collin's wonderful video:


And his masterful take-down of the Blunder's attempt to trash the initial video:

"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 Icarus1

  • Earth
  • ***
  • Posts: 186
Re: Moon pics static shadows and moving stars.
« Reply #217 on: January 10, 2017, 08:09:04 AM »
As I understand it we circled the earth gaining speed...

No, that's not how orbits work.

Quote
...and used a figure 8 thru space to gravity shoot around the moon into a stable orbit.

No, it's not a gravity "slingshot" maneuver.  It's a transfer orbit.  It requires a burn at the other end to enter an orbit around the Moon, and another burn to make that orbit circular and stable.

Quote
We leave Earth's orbit at what speed?

The translunar injection (TLI) maneuver added around 10,000 fps to the spacecraft velocity.  This raised the apogee of the orbit to bring it into the Moon's sphere of influence.  Until then it was still in orbit around Earth.  All paths through space are orbits.

Quote
Traveling directly toward the moon? or at a trajectory that will allow the craft to meet with it 240 thou miles later  as it will have traveled in space?

The latter, in the sense that all paths through solar-system space are orbits.  And yes, they're aiming for where the Moon will be when they get there.

Quote
why is the moon always visible as if straight ahead?

It doesn't have to be straight ahead to be visible out the window.

Quote
constant adjustments are not economical, so assuming minimal adjustments for course.

Two opportunities for mid-course corrections were provided on each of the outbound and inbound orbits.  They were generally not needed, except that in some missions MCC-1 was mandatory because that's what established the hybrid trajectory that made it possible to enter lunar orbit at an inclination that opened up other landing sites.

Quote
Does all of this make sense?

Vaguely, in that it's a pile of common misconceptions about how spacecraft work.

Quote
OR point me in the direction for this info?

Roger Bate, Fundamentals of Astrodynamics.  It's probably the most entry-level text you'll get on practical orbital mechanics.  One of our members, Bob Braeunig, maintains a number of helpful web pages:  braeunig.us

Quote
How much energy or joule or whatever does it require to alter course?

Lots, whatever.  The basic equation is that a change in velocity is proportional to the specific impulse of the engine times the natural logarithm of the ratio of spacecraft dry mass to its presently fueled mass.

Quote
considering the lateral RCS Thruster are tiny?

The translunar injection was performed with the J-2 engine on the S-iVB.  The return transearth injection (TEI) maneuver was performed with the SPS.  These are both considerably more powerful than the SM RCS.

Quote
Do they blow Air or is it a fuel like a rocket?

The J-2 burned hydrogen and oxygen.  The RCS and SPS burned hypergolic propellants:  a member of the hydrazine family oxidized with nitrogen tetroxide.  None of the Apollo rockets "blow air."

Quote
How fast is the craft traveling as it reaches the moon...

I probably would have to go look that up.

Quote
...and is it simply gravity itself that puts it into orbit?

Without the LOI-1 maneuver, the spacecraft would either swing around the Moon and return to earth (free-return trajectory) or fly off into solar orbit (hybrid trajectory).  The arrival at the Moon (and in fact into orbit around anything) is a combination of engine thrust and gravity.

Thank you so much for this JayUtah.  I understand everything you've said re: all being in an orbit.  Bob's name has popped up several times now across the internet.  He must be famous. :D

I'm hoping to find a visual illustration of trajectory and scale in relation to Earth, moon and craft; if it's even possible.  I'll keep looking.

Thanks.

Offline Icarus1

  • Earth
  • ***
  • Posts: 186
Re: Moon pics static shadows and moving stars.
« Reply #218 on: January 10, 2017, 08:17:52 AM »
Apart from being a little puzzled as to why a 'professional photographer' is so baffled as to why digital scans of old photos that were exposed for a bright lunar surface don't reveal stars at his command, I would suggest that Icarus1 looks at the Apollo photographs that were deliberately taken to show stars.

http://onebigmonkey.com/apollo/stars/starryskies.html


e2a: The length and movement of shadows is also entirely consistent with mission timelines:

http://onebigmonkey.com/apollo/shadows/shadindex.html

Neither puzzled nor baffled.

Thanks

Offline Icarus1

  • Earth
  • ***
  • Posts: 186
Re: Moon pics static shadows and moving stars.
« Reply #219 on: January 10, 2017, 08:35:01 AM »


All I can say to this is:

Where were you at the beginning? :D

To state once again, I asked if they were Stars, not Claimed it.

Thanks

That is not a useful stance for any kind of investigation.

If I am diagnosing a problem in a signal chain and hypothesize the fault might actually be in the brand-new replacement cable, I don't say, "Maybe it isn't the cable so I shouldn't bother testing because I'm not sure."

No. You take a stance, you say, "What if it IS the cable?" and you test appropriately.

You are trying to think about the marks on the pictures without formulating a hypothesis sufficiently defined to allow it to be tested. It doesn't matter if it is probably false, if you think it is false, if it turns out to be in the end false. One progresses anyhow. STATE, "Assume these are stars..." and then see if that hypothesis can be disproved. If it is, then move on to the next one.

Enrico Fermi is credited with a quote that applies to what you've been doing. That quote is, "Not even wrong."

To Hypothesize with limited knowledge is useless.  I came here for a Readers Digest or readily available info specific to my question.

However for this particular endeavor, my hypothesis was that of the doubt surrounding the Moon Landings, the millions made off it by way of books articles, and what now appears to be around 20% (dependent on the accuracy of the study) of Americans' who don't believe the Moon landings happened.

Therefore and Only! I took 2 images, and over exposed them.  Knowing all I know about photo's RAW digital, Film Latency and the futile and arbitrary attempt to recover info from a 50 year old scanned Jpeg!!!!!!!!!!! brought me here with what could be interpreted as a 'Rhetorical' Question!

To surmise, once again after another infurence that I am NOT a Professional Photographer, the question and doubt has been removed;  A long time ago!  MY error was at the beginning.  The photo's are tainted.  Others would say my error is my lack of knowledge to even question them in the first place, if I was indeed as I claim, a 'Professional Photographer'! then I would surely know the latency and sensitivity of the film used in the Blad's (WHY WOULD I KNOW THIS?) Yet I have stated how I have been able to retrieve info of Stars in under exposed Film Negatives from 20 years ago, thru further manipulation in the dark room. Evidence no longer available!

To further add to those that are either Professional Photographers, Amateur Photographers, Self Employed or simply defenders of the faith, for me to claim to be a 'Professional Photographer' is no Great feat!  You own a camera.  You know how to use it!  You make money with it!  It's NOT Rocket Science for god's sake!

Relax people.  Your truth is intact!  No Conspiracy here. :D

Offline Zakalwe

  • Uranus
  • ****
  • Posts: 1602
Re: Moon pics static shadows and moving stars.
« Reply #220 on: January 10, 2017, 08:44:31 AM »

I'm hoping to find a visual illustration of trajectory and scale in relation to Earth, moon and craft; if it's even possible.  I'll keep looking.


There's been a few links to Bob's excellent site already, so you don't have to look too far.
Here's  the pages you are after:
The Free Return Trajectory
http://www.braeunig.us/apollo/free-return.htm

and the Hybrid trajectory.
http://www.braeunig.us/apollo/hybrid-profile.htm
"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 Icarus1

  • Earth
  • ***
  • Posts: 186
Re: Moon pics static shadows and moving stars.
« Reply #221 on: January 10, 2017, 08:54:15 AM »
We leave Earth's orbit at what speed?  Traveling directly toward the moon? or at a trajectory that will allow the craft to meet with it 240 thou miles later  as it will have traveled in space?  (assuming it is the latter, why is the moon always visible as if straight ahead?  constant adjustments are not economical, so assuming minimal adjustments for course.  (3 days? - How far has the moon traveled thru space?)

You'v been given the highly technical answers as to the trajectories and speeds involved but I'm wondering if there is a different meaning to your question?

My interpretation is that you think the moon always appears as it does from Earth - in fact if you compare the images taken from cislunar space en route there and back you can see that the views are not the same as can be seen from Earth. It's another telltale sign that the images weren't taken from the ground or in LEO.

To answer earlier points you made, a certain annoying Australian also cut his teeth in the subject at film school. Expertise in how to run a camera and its contents doesn't necessarily convey expertise in interpreting the results - other areas of expertise are necessary to do that. That expertise can be acquired with effort by amateurs and professionals alike. Capitalising your job title doesn't make it special and doesn't mean you are the only one with an opinion or knowledge about your profession. Getting paid to do something doesn't necessarily mean you are good at it. The world is full of people who manage to drive around in a nice car and a string of customers who have only ever used them once.

Conspiracy theorists may not be unintelligent - some of them are quite capable of stringing a sentence together, but they are quite often uneducated in the subject they examine. If they truly understood the subject they would reject the conspiracy angle as poorly founded and false. Others have selectively educated themselves. Others are just downright dishonest.

From this point then I would have to agree.  I've came to a forum of well read people asking the most basic of questions and I'm starting to 'Get it'.  I appear to be like a child in school with a plethora of questions without the simplest fundamentals in place.

I think I'll leave this now.

I need to find a Moon Landings 101 forum.

I'm actually surprised and greatful too, at the sheer level of patience and time some of you have put to answering my one simple minded question; are these Stars?

Maybe If i wasn't painted as an uneducated (though I am on this topic) Conspiracy Theorist, this conversation would have gone very differently.

I no longer have the energy to tackle the individual onslaughts. 

Thank you all for your individual attention.  Over the top at times maybe, probably in an attempt to Shoot me down?  I don't know.

Nomuse has clearly pointed out I know very little about this subject.  Well done you for figuring that out!  Did I pretend otherwise?  I know NOTHING  at all about this.  I'm a lowly Photographer.  But you're right onebigmonkey, you don't need to be the best Photographer to claim to be one.  Yet can this not be said about every single profession in the world?  You can still have the title, but be better than others, or not as good as others!  I fail to see your point when my point was that I claimed to be a Photographer and it is constantly inferred that I am not.  What relevance does it have?  I could say I am a pilot, but have no grasp at all of what it means to be in orbit, of traverse thru the vacuum of space.

What is clear is this.  I don't have enough basic knowledge to be in here asking my rudimentary questions.

So with this, I bid you all Farewell. 

Live long and Prosper people.  It's been an education. :D

Cheers.

Offline Icarus1

  • Earth
  • ***
  • Posts: 186
Re: Moon pics static shadows and moving stars.
« Reply #222 on: January 10, 2017, 09:19:23 AM »

As I understand it we circled the earth gaining speed and used a figure 8 thru space to gravity shoot around the moon into a stable orbit.

(Note that, in all that follows, the formulae for orbital calculations were written by Johannes Kepler ~400 years ago, and the equations for rocket thrust were created by Konstantin Tsiolkovsky ~100 years ago.  They work and they are not terribly difficult to use.  The astronauts trained to work them with pencil & paper, which is all that Kepler and Tsiolkovsky had.)

The launch puts the spacecraft it a circular orbit of Earth at ~35,560 feet-per-second.  With the nose pointed forward in its direction of orbit, the S-IVB (third stage of the Saturn V) then fires its rocket to increase the orbital speed by ~10,000 ft/sec.  This changes the circular orbit at an altitude of ~100 miles to an elliptical orbit with a perigee of ~100 miles and an apogee somewhere out near the Moon.  If the Moon wasn't there, the spacecraft would follow its ellipse out to ~240,000 miles and return (the Soviet Zond 4 spacecraft did this).  When aimed towards the Moon, spacecraft gets to a point where it is attracted more by the Moon's gravity than the Earth's.  Thus its course transitions from an elliptical orbit of the Earth that is anti-clockwise (when seen from above the north) to a clockwise elliptical orbit around the Moon.  However, this new orbit has an aposelene towards the Earth and as it climbs up from its periselene, it crosses the boundary where the Earth's gravity dominates and and then starts falling towards the Earth.  This is what gives it its distinctive "figure-8" shape:



Quote
Here's part of the question, and I hope I can find the words to ask it correctly.

We leave Earth's orbit at what speed?

~35,500 feet-per-second

Quote
Traveling directly toward the moon? or at a trajectory that will allow the craft to meet with it 240 thou miles later  as it will have traveled in space?

The latter, since the apogee is on the opposite side of the Earth from the perigee, which is where the ~5 minute translunar injection burn (TLI) took place.

Quote
(assuming it is the latter, why is the moon always visible as if straight ahead?

It isn't.  They show it that way in the movies because it looks cool and the audience expects it (like showing stars in the background even though they would not be visible with sunlit objects in the foreground). 

Quote
constant adjustments are not economical, so assuming minimal adjustments for course.

Very little course adjustments were necessary.  The TLI burn would get them in the speed ballpark.  While the spacecraft was coasting its trajectory was measured and adjustments were made using the RCS.  Typically, these adjustments were on the order of only a few feet-per-second.

Quote
(3 days? - How far has the moon traveled thru space?)

Geometry problem:  The Moon orbits Earth at an average radius of ~240,000 miles and takes ~27 days to complete a 360° orbit.  How far will it travel in 3 days.  Show your work.

Incidentally, the 3-day flight time was peculiar to the "figure-8" orbit described and shown above.  It was not used for unmanned science probes.  The first Soviet moon probe (Luna-3) took only 23 hours to reach the Moon in 1959, and the ESA's Smart-1 probe took months to get there using an ion engine in the 1990s.  However, the 3-day trajectory is the only orbit that will swing your spacecraft around the Moon and send it back towards Earth with no extra rocket burns needed.  This "Free-Return Trajectory" was considered the safest for manned missions and was used by the Soviet Zond missions (which were unmanned tests of craft intended for manned missions) and the first four Apollo lunar missions.  Apollo 13 was the first mission to deviate from the FRT.  After they stabilized the spacecraft following the Service Module explosion, their first order of business was to use the Lunar Module's engine to put them back on a Free-Return Trajectory.

Quote
Does all of this make sense?

Yes

Quote
OR point me in the direction for this info?

Bob Braeunig's Apollo Pages
Apollo by Numbers
Encyclopedia Astronautica

Quote
Thanks

Sure!

Quote
How much energy or joule or whatever does it require to alter course?

That depends on how much mass you're moving.  Is the LM still attached?  How much fuel (i.e. mass) is still in your tanks?  Again, this is just stuff that you can plug into the Tsiolkovsky equation.

Quote
considering the lateral RCS Thruster are tiny?

It doesn't matter if they're small.  In space all thrust counts, and it add up.  Apollo 11 landed ~ 3 miles past its aim-point because the tunnel between it and the Command Module wasn't completely depressurized when they undocked.  This extra little puff of air affected the LMs orbit and it wasn't caught until they were well into their powered descent.  Fortunately they were more concerned with landing safely than landing accurately.

Quote
Do they blow Air or is it a fuel like a rocket?

They are hypergolic rockets that provide ~100lbs of thrust each.

Quote
How fast is the craft traveling as it reaches the moon...

I don't have the exact numbers handy, but a quick calculation shows that they were going at ~7,500 ft/sec as they rounded the Moon.

Quote
...and is it simply gravity itself that puts it into orbit?

No, to convert the elliptical orbit to circular, they had to burn their engine with the rocket facing the direction of travel to slow down by ~3,000 ft/sec.  This put them in a roughly circular 2-hour orbit at an altitude of ~60 miles.

Hope this helps.

(Edit:  Dang, ninja'd!)

Thanks for this.  While never truly understanding everything literally, I do see it.

I recently came across a video/article of the Spinning Corkscrew theory of our solar system, and in fact all stars within a Galaxy.  Namely that all planets 'follow' the Sun as it's hurtles thru space at ludicrous speed.  I'm trying to visualise what is happening as we move.  It may seem like I'm going off on a tangent but it's all relative, in my head at least.  I'm questioning the orbiting planets ability to over take the Sun as our Galaxy spins.  In an attempt to be more clear, IF our solar system was arranged on the same horizontal plane as the galaxy, how do the planets travel faster to move past apogee??? please fill in where I'm lacking here re; apogee etc.  How does earth move faster than the Sun if the Sun is moving faster round the galaxy?  Not sure how to ask the question.

Apologies also as this is not directly an Apollo question.

Are you familiar with the corkscrew theory?  Is it even a theory?
« Last Edit: January 10, 2017, 09:30:05 AM by Icarus1 »

Offline Zakalwe

  • Uranus
  • ****
  • Posts: 1602
Re: Moon pics static shadows and moving stars.
« Reply #223 on: January 10, 2017, 09:27:19 AM »


I recently came across a video/article of the Spinning Corkscrew theory of our solar system, and in fact all stars within a Galaxy.  Namely that all planets 'follow' the Sun as it's hurtles thru space at ludicrous speed.

Are you familiar with it?

If you mean the ridiculous animation produced by DJ Sadhu, then yes.

As a model of how the planets move, it's garbage
"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 Icarus1

  • Earth
  • ***
  • Posts: 186
Re: Moon pics static shadows and moving stars.
« Reply #224 on: January 10, 2017, 09:32:05 AM »


I recently came across a video/article of the Spinning Corkscrew theory of our solar system, and in fact all stars within a Galaxy.  Namely that all planets 'follow' the Sun as it's hurtles thru space at ludicrous speed.

Are you familiar with it?

If you mean the ridiculous animation produced by DJ Sadhu, then yes.

As a model of how the planets move, it's garbage

Oh really? 

Now, before we go half cocked on me being a crazy un-educated basement rat, this 'theory' actually makes sense to me!  Why is it garbage?