Editing To Fly! (section)

==== Space sequence ====
[[File:Apollo 4 separation of interstage ring.webm|thumb|upright=1.2|Video of the [[Saturn V]]'s [[interstage]] ring, also shown in the film]]

''To Fly!''{{'s}} space sequence depicts the launch of the [[Saturn IB]], before showing a fictional spaceship [[Interplanetary spaceflight|voyaging around]] the [[Solar System]]. Five [[nebulae]] are then depicted before ending with a view of Earth.<ref name=":41" />

The filmmakers were given permission to film the launch, marking the first time such was filmed in IMAX.<ref name=":8" /> They took this part more seriously because it could not be repeated.<ref name=":35" /> After filming {{Convert|1,200|ft|m|abbr=none}} away from the [[launch pad]], they left their camera outside for a day, forming condensation inside and exacerbated by seasonal thunderstorms. It was found wet and jammed, and the crew spent three hours cleaning it to recover the recording. Meanwhile, a shot of the [[Saturn V]]'s [[interstage]] ring jettisonning back to Earth was filmed in [[16 mm film]] from the actual rocket's [[S-II|second stage]], during [[Apollo 4]] in 1967.<ref name=":28" />

With a low budget, they initially conceived the space sequence as merely a compilation of astronomical images but realized they needed some kind of movement for an IMAX film, and thus saved money on the live-action filming in order to achieve a better space sequence. They expected ''To Fly!'' to be compared with the film ''[[2001: A Space Odyssey (film)|2001: A Space Odyssey]]'' (1968), and tried to make the sequence as reminiscent of that film as possible. They learned that small objects like stars on an IMAX screen are much smaller on a traditional presentation, and typical small stars would be oversized in IMAX; after some difficulty, they were able to create perfect-sized stars on an {{Convert|8|×|360|in|cm|abbr=none|adj=on}} [[Lith print|Kodalith]] [[Negative (photography)|negative]] [[sheet film]]. Because of the nature of IMAX, filming some scenes at six and twelve [[frames per second]] (fps) was preferred over [[stop motion]]. George Casey and [[Lester Novros]] of special effects company Graphic Films{{Efn-la|They had worked on another IMAX film, ''[[Voyage to the Outer Planets]]'' (1973).<ref>{{Cite web|last=Bear|first=Greg|author-link=Greg Bear|url=https://www.gregbear.com/pages/fleet.php|title=The Reuben H. Fleet Space Theater: the Early Years, and Before|access-date=September 7, 2023|archive-url=https://web.archive.org/web/20230321121036/https://www.gregbear.com/pages/fleet.php|archive-date=March 21, 2023|url-status=live}}</ref>}} provided planetary models and a studio, and also assisted the crew.<ref name=":28" />

The spaceship seen was a transparent {{Convert|2|in|cm|abbr=none|spell=in|adj=on}} portion of a larger {{Convert|36|in|m|abbr=none|adj=on}} model built by MacGillivray and Freeman, backlit on a glass frame.<ref name=":28" /> As [[special effects supervisor]],<ref name=":8" /> Blyth designed it to have the same color palette as the 747, and inspired by concepts of advanced [[ion thruster]]s and [[magnetically confined fusion]]s like [[deuterium]] and [[helium-3]]. It took 150 hours to create, with Collins as technical advisor. For a shot in which the spaceship passes [[Jupiter]] and [[Io (moon)|Io]], the crew filmed each object one by one; the film would be rewound back to layer in the next object. The camera was placed on a motorized dolly. Some shots, including the one of [[Saturn]], were filmed at an [[animation stand]]. Others used a faux version of the [[slit-scan photography]] kit used for ''2001: A Space Odyssey'': the sheet film was projected onto a white board, which the fisheye-lensed camera was put close to. Models were attached to a [[peg bar]], near where their glass frame was suspended on. To film extreme slow shots with distinct movement, a [[geared head]] and a zoom-motored gear were used, creating a slight [[Panning (camera)|pan]]. They filmed all these on 16&nbsp;mm first to see if it could be done on IMAX.<ref name=":28" />

[[Bellows (photography)|Bellows]] and close-up lenses by Hasselblad were used for the penultimate nebulae shots; the camera was facing a tray filled with water and a mixture of black ink and white [[enamel paint]] lit by [[color gel]]s. The materials' temperature, thickness, size, and type had to be precise to achieve the reaction. Unable to film at the desired 96 fps, [[mineral oil]] and [[paint thinner]] were poured into the tray to slow down movement; the thinner was favored because it created more interesting 3D-like movements. Often, a short wire was shaped and dipped in to create specific patterns.<ref name=":28">{{Cite magazine|last1=Blyth|first1=Jeff|date=July 4, 1976|title=Filming the Space Sequences for "To Fly"|magazine=[[American Cinematographer]]|location=[[Hollywood, Los Angeles|Hollywood]]|volume=57|issue=7|url=https://proquest.com/docview/196331873|via=[[ProQuest]]|url-access=subscription}}</ref> [[Special effects]] designers Jim Palmer and Barney Kaelin created laser patterns, the first in any IMAX film.<ref name=":8" /> Overall, the space sequence took four and a half months to prepare, test, and film.<ref name=":28" />