Surprised Stranger hasn’t assailed the above on the basis of the precession of the equinoxes. The “right” hole 2500 years earlier wouldn’t be the correct one in 1938, unless the entire room was designed to take that into account, which I rather doubt.
What kind of crystal concentrates light into a focused beam, and makes a “voof” sound when doing so? Memory test: when the light beam hit its target, did it kick up a little puff of dust?
Well, in the film the Well of Souls is apparently hermetically sealed, and is also full of snakes that have apparently been collected from all over Africa, Europe, Asia, and even the Americas, and have somehow survived for almost three millennia. So, the fictional Raiders New Kingdom of Egypt clearly had some pretty robust construction and HVAC technology, as well as a real long term focus on planning.
Well, it all begs the question of why the Egyptian builders would go to such elaborate measures to identify the location of the Well of Souls when in their day it would all just be laid out in the open. One would think that the priests responsible for it would remember where they kept this fearsome superweapon without having to go through an elaborate ritual with staffs and headpieces even absent of all of the problems with celestial mechanics and ancient solar beam pointers. Like many traps and puzzles in movies and RPGs, it really exists in anticipation of future tomb raiders than of any necessity for protection in contemporary usage. But it makes for a cool moment, especially when followed by Saliah tossing down an improvised climbing rope made from a Nazi flag.
Stranger
Divine guidance, obviously.
It was hermetically sealed, not herpetically sealed.
I remember a scene in which a snake crawled through a wall in or out of the Well of Souls.
I’ve always wondered how the orientation of Stonehenge, the pyramids, and other such places always lines up with today’s equinoxes, solstices, and constellations. Is it possible archaeologists have been hoodwinking us all along? 
As a general rule, solar alignments persist pretty much perfectly on historical time scales. The angle of sunrise/sunset at solstice remains the same over the years. The timing of of the solstices relative to a sidereal year drifts over millenia, so the sun is in a different constellation at winter solstice from where it was at winter solstice when Stonehenge was in active use, but the sun still shone across the stones at the same angle.
Stellar alignments of all sorts drift. The precession of the equinoxes takes 25 thousand years and change to complete a cycle. This is caused by the earth’s axial “wobble”, which also causes the stellar north pole to describe pretty large circle in the night sky, spanning 46.8 degrees or twice earth’s axial tilt. From Polaris now, in 12k years the pole will point at Vega which is the brightest star in Lyra and one of the three super-bright stars in the so-called Summer Triangle. The apparent motion of the stars changes when we’re talking millenia, and so if you’re going to hypothesize stars lining up with the pyramids or whatever you’d have to take that into account, because what they’d line up with now is not the same as when they were built.
Yeah, the alignment to the Sun at the same point in the solar year will be virtually the same; the change in the ecliptic plane (the angular tilt of the equatorial plane to the Earth’s orbital plane about the Sun) is only about 0.1 degrees over a millennia, so if the precision of your solar observatory is on the order of a degree, it will only get out of an alignment over periods on the order of ten thousand years. However, the alignment of the Sun will change over the year with seasonal declination change, so I guess Indy lucked into taking his measurements at just the right time of year.
But again, the entire map room/headpiece/solar ray/hidden vault is complete nonsense that only makes sense in an action-adventure movie or a Pulp Cthulhu scenario, and if you start breaking the plot elements of the movie down with logic and critical analysis the entire thing falls apart. I mean, the United States Army is sending this one archeology professor who is most known for grave robbing and sleeping with his mentor’s underage daughter to collect a powerful superweapon before the Nazis get to it instead of consulting Howard Stark about building an orbital satellite detector and accelerating his Vita-Ray machine to produce a legion of genetically enhanced Hitler-punching supersoldiers, so it clearly isn’t based upon fact.
Stranger
They ought to have just used the Vita-rays on the professor. Problem solved!
The sequel to Raiders was going to be called The Shoshenq Redemption, but that title was problematic.
Stranger
Rubindium, the same crystals used in Starfleet subcutaneous transponders.
Well, first of all, even if this is true, it isn’t a plot hole. But… there’s no reason to think that there was literally no other way in the world for the Nazis to find Marion. Maybe it would have taken longer, but it likely would have happened eventually.
And if everything happens without Indy there, and the Nazis get their faces melted, but Indy and Marion aren’t there, well, that certainly proves that the Ark is a powerful weapon, but it’s one the Nazis still have, and they’ll keep doing experiments, and, who knows what might eventually happen?
My issue with any movie with booby traps, and this was a concern I even had as a kid watching these movies, is how do the traps reset? Let’s set aside how implausible it is that an ancient trap made from vines, wood, and stone stays functional for centuries. Let’s say it’s able to shoot darts or drop a boulder or whatever. Then what? Isn’t the trap done with? How do new darts get loaded? Who puts a new boulder in place? Yet you’ll see the trap function again, where Jim gets skewered, so Joe goes in after and carefully avoids it, then Jack slips and dies too.
It just makes the “one and done” nature of the Home Alone traps that much more realistic by comparison (though the burglars having the impervious nature of cartoon characters is the problem in that film).
They don’t need to find Marion, or the “Headpiece of the Staff of Ra”, or figure out the map room. All they have to do is start excavating the big hill right in the middle of their encampment which is apparently located between the mess table and the airfield. Even a “shallow reflection” like Belloq is eventually going to figure that out.
The Ark is clearly a weapon of incredible destructive power which is as dangerous to the ostensible wielder who isn’t servile and pious as the armies it is employed to defeat. It certainly didn’t do any good for the Philistines when they possessed it, and clearly didn’t keep the Israelites from eventually being defeated. If Belloq had taken the Ark back to Germany for inspection and display, it might have Tarantino-ed the entire Oberkommando and the Nazi leadership, preemptively ending the Third Reich and forestalling World War II.
Stranger
It’s not a problem, it’s a feature.
Sure. My point is, the relatively-frequently-repeated contrarian canard that if Indy had just stayed home, things would have worked out exactly the same; is pretty thin.
Yes, the Nazis would have eventually found it. But the urgency of the sub-plot was getting the Ark before the Nazis could find it and use it as a weapon of war, and perhaps turn the tide in their favor. The sooner they (Germany) got their hands on it and understood how to wield it, the better - that’s why the hanger dude was sent to interrogate Marion about the headpiece (and get his hand burned). Until our heros foil the plan.