That is a lot of ground to cover while in lunar orbit, hurtling along with the landing ellipse only visible for a proportion of each orbit.
From a previous post, it appears Patrick has a romantic notion that the "sextant" Michael Collins used was some sort of handheld device, perhaps equivalent to the navigator's sextant or quadrant. The classic astronomer's sextant works according the same principle, but is generally fixed and sited so as to provide both a location and orientation reference.
Fundamentally all sextants provide the same service: measure the angle between some desired line of sight and some reference direction. In the case of the Command Module sextant, the reference angle is a boresight perpendicular to the spacecraft skin. That angle in turn is referenced to great precision with the spacecraft structural axis.
Here is the guidance platform from an Apollo command module, removed from the rest of the spacecraft structure. I've had the opportunity to inspect this particular item at great length and look through it.
http://www.nasm.si.edu/collections/artifact.cfm?id=A19761254000
This is the guidance assembly seen from the side. It forms the "floor" of the CM cabin if the CSM is oriented horizontally and the crew is heads-up in their couches. In the launch orientation, it would be the far wall of the CM cabin, across from the hatch.
Outboard is to the left; inboard is to the right. The upper half is the sextant. The outboard (left) side shows the windows through which the sextant sees. This assembly lies just inside the CM outer skin. The wiring harnesses at lower left are positioned where they can be worked on by technicians prior to launch, through the access ports around the lower rim of the spacecraft.
The inboard (right) side shows the sextant eyepiece. Behind it, out of view, is the optics control joystick.
The lower portion of this assembly, the bulkier section, contains the IMU (the gyroscopes etc. of the guidance platform) and the computer processor. There is also a duplicate DSKY (computer console) on this panel. As you can see, the structure is extremely robust. This is because the IMU and the optics must maintain a very high degree of angular fidelity throughout the mission. The difference between the orientation of the optics bearings and that of the IMU bearings cannot vary by more than about 1/1000 degree throughout the mission.
The large wheels on the near side are for ground calibration of the IMU and sextant.
The 28X sextant can be positioned relative to the IMU reference frame to an extremely high degree of reportable precision -- again, to approximately 1/1000 degree. This is done by driving the shaft-and-trunnion bearings of the optics to known positions. Normally that is done by placing the desired S-T bearing angles into Noun 92. However, several guidance programs automate this based on mission phase. Program P22 does this when the AGC is in an orbit around Earth or Moon, and thus the nouns containing orbital elements are known to be populated with good data. Programs such as P22 rely on the navigator first using routines R57 (zero the optics) and R52 (auto command optics).
The optics can be positioned semi-manually using the joystick to the navigator's right. While looking through the sextant eyepiece he can drive the shaft/trunnion servos at a fixed rate, much like panning a remote security camera. The resulting S-T angles are fed back into the computer.
P22 attempts to update the state vector and orbital elements based on a ground-track reference and precise time of intercept. It takes as its arguments a reference landmark whose coordinates on Earth or Moon are known, the desired spacecraft attitude (to which the navigator will position the spacecraft by sending appropriate commands to the autopilot), the desired sextant orientation relative to the final spacecraft position, and a set of mission timer readings. The "three miles south" data I'll cover later.
At MET (mission elapsed time) 110:18:39, Houston calls up the P22 data to Collins: "P22 landmark ID, LM. Tl, 110:26:56. T2, 110:32:06. Three miles south. Time of closest approach, 110:33:40. Shaft, 353.855. Trunnion, 46.495."
The flight plan, p. 3-86, has the PAD frame for this operation. The landing site as originally programmed is filled in already, and these are the values Collins punched in for Noun 89 -- the planetary coordinates of the desired landmark. But that's not where the LM was. T1 is the MET when the landmark is expected to be visible on the horizon. T2 is when the landmark is expected to be in the sextant field of view -- a mere six minutes after heaving into naked-eye view. The sextant shaft and trunnion angles are given.
Houston also calls up the reference spacecraft attitude: "Roll, zero. Pitch, 250. Yaw zero." Collins entered this into the autopilot to cause the spacecraft to maneuver to the appropriate attitude, so that the optics angles would be valid. Keep in mind that the spacecraft maintains a space-fixed orientation while in orbit, so through the sextant Collins is going to see the moonscape whizzing by. This is why the PAD calls for Collins to look ahead a bit in the ground track, rather than use the point of closest approach. Although he'll be seeing his landmark at an angle rather than from more directly overhead, he is less likely to miss it since it will be moving slower through his field of view.
Collins only has a few seconds to see if he can see the LM within the field of view, with those settings. Ordinarily, in P22, he would use the MARK command to designate the exact instant the landmark passed through the sextant reticule, and P22 uses the difference between expected time and actual time to derive new orbital elements. But since the location of the landmark is uncertain, Collins won't do that; he'll just try to see if the LM can be seen in the optics.
He can move the sextant slightly from the programmed position using the joystick. But the optics slew at a fixed rate -- a very slow one. This is because the main purpose of the sextant is to align the guidance platform, not search planetary surfaces. And he's on a moving platform, so he can't ask it to stand still while he pans and tilts the optics slowly to cover a larger area.
Normally the alignment procedure works like this. The navigator commands the spacecraft to a certain attitude. Naturally that attitude is reckoned according to the guidance platform and may not reflect real life. Then he commands the optics to focus on one of a couple dozen stars whose direction in the space-fixed reference frame is known. Conversationally stated, the computer muses: "If my attitude is correct, then that star should be at this specific direction from my spacecraft axis. Here are the appropriate S-T to point the sextant to it."
If everything is correct, the navigator should see the reference star centered in the sextant reticule. But typically the platform drifts over time, so the star will (hopefully) be in the field of view, but perhaps not centered. So the navigator operates the optics control joystick to center the star, then presses the MARK command. The computer picks up the new S-T angles and understands that the platform is off by just that much angle, and adjusts its reference matrix accordingly.
Do that twice using two stars separated by right angles and you'll have aligned your platform in all three cardinal axes. But because fine alignment requires the star to be very precisely centered in the crosshairs, the joystick drive is necessarily very slow. Accuracy is important here, not speed.
In P22 the reference is moving through the field of view. You can't make it stop while you fiddle with the joystick. So that's why the "three miles south" statement is given. The landmark may be slightly to the north or south of the telescope's ground track, and so the sextant is steered for P22 so that only the major dimension of motion is considered. (When you pass a mile marker on the freeway, it doesn't matter what lane you're in. Lateral differences aren't important.) So the CAPCOM tells Collins to look for his landmark three miles south of the reticule track; it's the time-track of the westward motion that's important here.
Patrick first wants to make a big deal out of Harland's statement that Collins "didn't know where to look," and that this degree of misplacement constitutes some proof for fraud. From the above description it should be clear that one can't simply scan the surface leisurely with the sextant like a pair of binoculars. In order to see something through the sextant from orbit, you need to have an already good idea where it is. All you can do, in the brief time and through the narrow field of view you have, is confirm whether it was seen or not. You can't systematically search the landing ellipse.
And so the response remains, "so what?" Asking Collins to use his tools to do something they weren't designed to do doesn't make a case for fraud.
Patrick also wants to make a big deal out of the inability to use surface reference map coordinates as direct input into P22. He says that's somehow proof of fraud. But P22 works for Earth too, as it was meant to. The CSM wants also to navigate in Earth orbit, especially prior to TLI. And P22 can use terrestrial coordinates on Earth, not just coordinates on the lunar surface. So the common input format for Noun 89 is the latitude, longitude, and geodetic altitude of the landmark, not some application-specific map-marking scheme.
Conversely the LAM maps were not for CSM navigation, but for ground reference only. It being the only way for Collins to mark his candidate LM sightings, matched visually, those were the coordinates he read back down to Houston. There was no easy way to capture them in terms of latitude and longitude, or S-T/time references. He saw a feature at a certain place he visually matched to locations on his familiarization chart, and called those down accordingly.
And there was never any need or plan to use LAM maps for navigation references for P22. Coordinates for P22 would always have been provided by some other means, especially since P22 would use landmarks that weren't on the LAM charts.
So as usual, Patrick is inventing new "requirements" for Apollo and then trying to cry fraud when his personal expectations aren't met -- Apollo was allegedly fake because the sextant wasn't also a ground-search telescope, and Apollo was allegedly fake because the computer didn't work the way he thinks it should have.
And the author of your quotation confirms that we did indeed go.
This is always an amusing rail split. Hoax theorists cite well-known authors as authority for the little tidbits that feed into their theories, but omit entirely that these authors disagree with the hoax believer's theory at large. So we're supposed to respect Harland when supposedly decries the horror of Collins being unable to sight the LM, but he doesn't have to respect Harland when the man's overall conclusion is that the Moon landings are genuine.
Very disingenuous, Patrick!
