Aboard the Navy ship, Captain Steven and Lt. Cooper appear to be peering through a typical pair of binoculars at 2:38 on the DVD. But instead of the typical conjoined-circular POV used for most filmed productions, a conjoined-square image is used. The conjoined-squares POV is used to better effect later in the episode when Colonel Lake is looking through futuristic-looking rectangular binoculars.

The actor playing Captain Steven, Philip Madoc, also plays the second husband of Straker's ex-wife Mary, Steven Rutland, in "A Question of Priorities" and "Mindbender". As far as is known, however, these are intended to be two entirely different characters. It is odd that both characters have the name "Steven" in common.
Captain Steven	Steven Rutland

The rings on the cuffs of the naval jackets worn by Steven and Cooper indicate their rank as Captain and Lieutenant, respectively. Later, Sheringham's cuffs indicate his rank as an Admiral.

At 3:13 on the DVD, as the two naval officers observe the UFO through their binoculars, the wire supporting the UFO model is visible above it.

The newspaper read by Straker, after the Navy UFO incident, appears to have a date of Friday, February 3. The year is difficult to make out, but looks like 1969 more than anything else, but February 3 fell on a Sunday in that year. The episode was probably shot in 1969 (or maybe 1970), but is supposed to take place in the 1980s; in my chronology, the episode is set in 1984 and the date does, in fact, fall on Friday in that year.

Notice in the headline at left that "correspondent" is incorrectly spelled with an "A".    The story that follows has nothing to do with the headline; it is about a play called "Pools Paradise" performed by the Slough Centre Players at the Slough Community Centre. The Slough Community Centre existed in the London borough of Slough from 1937-1997. Pools Paradise is a 1961 play written by Philip King (1904-1979).

Captain Steven gestures to an area off the northwestern coast of Africa as the location of the trench the British Navy plans to dump the drums of deadly nerve gas. Colonel Lake later refers to that trench as "virtually bottomless." But there are few sizable trenches in the Atlantic Ocean and none in that location that I've been able to uncover in my research.

This episode reveals that Straker enjoys playing golf as a hobby.

Discovering she is an astronomy hobbyist, Foster quizzes Sarah Bosanquet on her star knowledge by asking about a certain bright star within her telescope's field of view. She responds, "Spica, magnitude one point two. Forms an isosceles triangle with Arcturus and Bootes and Denebola and Diadem," and "By studying Spica and the star Rigel in Orion, Hipparchus discovered the precession of the equinoxes." Spica is a real star, but has an apparent magnitude of 0.91-1.04 due to a binary companion star that, while non-eclipsing, causes visual distortion from gravitational interaction. Arcturus and Denebola are also real stars and Bootes and Diadem are constellations. Her second statement about Hipparchus' discovery of the precession of the equinoxes (Earth's tilt which brings the spring and autumn seasons) is true.

The shot at 22:01 on the DVD is of Trafalgar Square in London.

At 22:48 on the DVD, Sarah's telescope is seen to be a Fullerscopes brand. This was an actual telescope brand at the time, now manufactured under the Meade name.

At 25:39 on the DVD, a wire is visible holding the Interceptor model against the star field.

At 28:59 on the DVD, three wires are clearly visible holding the UFO model against the star field.

This episode reveals that a man named John Bosanquet was one of the experts who helped build Moonbase. He is the father of Sarah Bosanquet who appears as Admiral Sheringham's secretary in this episode.

The clock seen in Sarah's apartment at 32:27 on the DVD is a Seiko transistor clock.

The shot of the Admiral's car and escort at 33:12 on the DVD was originally shot as the Cabinet minister's car in "Identified".

Various shots of the Royal Navy Destroyer reveal a pennant number of D06. This reveals it as the County-class destroyer HMS Hampshire. The ship was decommissioned in 1976 in our world, but was apparently still in service in 1984 in the UFO universe.

At 38:30 on the DVD, the image of the Interceptor cockpit interior is flipped, as evidenced by the mirror-image writing on the Gyro Pilot cylinder.

At 40:57 on the DVD, SHADO's trackers estimate the remaining UFO to be headed for Newfoundland. This is the province of Canada now known as Newfoundland and Labrador since 2001.

The shot of the missile launcher at 43:16 on the DVD is reversed as evidenced by the mirror-image letters-numbers on the missile.

At 46:44 on the DVD, the Navy men are rolling the same container they already disposed of just seconds before, as evidenced by the code number on the container label. 

MEMORABLE DIALOG

almost a complex.wav

UFOs are a fact.wav

the aliens know about it.wav

destroy every form of life known on this Earth.wav

the ocean's a big place to look.wav