In an aircraft, can you look at the sky to get your bearing and position like sailors do?
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3$\begingroup$ The Zeppelins used a sextant quite often. In the times before radionavigation that was the best they could do when ground was obscured or of no help (like over deserts or open water). $\endgroup$– Peter KämpfMar 12, 2020 at 12:27
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3$\begingroup$ In Canada knowledge of how to get a fix with a sextant was included in the Airline Transport exam until the 80s. $\endgroup$– John KMar 12, 2020 at 13:03
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2$\begingroup$ Yes, but for most of us, it's far more useful to look at the ground. E.g. IFR = I Follow Roads :-) $\endgroup$– jamesqfMar 12, 2020 at 16:40
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1$\begingroup$ Related: aviation.stackexchange.com/questions/25096/… $\endgroup$– AndreKRMar 13, 2020 at 9:58
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3 Answers
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You sure can! It's not really done all too much any more in the days of GPS but it was done quite a bit in the early days of aviation. Historically, this was done by the "flight navigator" a position that no longer really exists. Some aircraft even had mounted sextants.
(source)
Here is a video of it being done in practice (fanta optional)
This was even automated on the SR-71's Inertial Astro-Navigation system which used the stars to align itself.
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2$\begingroup$ The SR-71 operated in the 1960s and 1970s, long before high-resolution light-sensors (i.e. CCD/CMOS sensors) and computer-systems powerful enough to process a raster graphics of the night-sky existed (let alone a frame-buffer big enough) - so on what basis did the SR-71's NAS-14V2 operate? Surely there's too many bright stars visible in the sky for a computer system back then to reliably know which star it's looking at from what I assume was a 1960s-era vidicon tube output signal? $\endgroup$– DaiMar 13, 2020 at 5:44
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4$\begingroup$ @Dai You don't need a computer to process raster graphics. The Russians sent back images of the moon in 1959. They scanned an analog TV camera and converted it to a fax signal. The format of the images was basically fax. You can do something similar to process star locations - point an analog TV camera at the sky and process the signal in analog. Of course, a standard analog TV signal is essentially 320x240 but a custom camera can be any resolution you're willing to process $\endgroup$ Mar 13, 2020 at 8:44
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3$\begingroup$ @Dai you're assuming that a general-purpose digital computer is required. Dedicated analog computers can sometimes achieve performance levels that general-purpose computers can't. $\endgroup$– barbecueMar 13, 2020 at 16:35
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3$\begingroup$ @Dai if you are curious the full POH has been declassified, containing operational instructions. There is not all that much out there on how it worked but if you watch some of the -71 interviews they talk about it tacking certain bright stars. $\endgroup$– DaveMar 13, 2020 at 18:21
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3$\begingroup$ @Dai here is another copy of the manual that discusses a bit more in depth how the unit works $\endgroup$– DaveMar 13, 2020 at 18:24
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It has in the past. Though the process for both pilots and sailors is a little more complex than just looking at the stars. See a previous AviationStackExchange question.
Do pilots need to know how to use a sextant?
Modern aviation has so many other navigation tools:
GPS
Radio NavAids
Inertial Navigation Systems
They make Celestial navigation obsolete. Although, it is not required pilot training. And you won’t see it used in GA aircraft. It is still in use by the military. Especially in ICBMs. My understanding is that the automated celestial navigation system used by the military was too expensive for widespread use.
Chapters 8-13 of the FAA Flight Navigator Handbook are dedicated to the subject. Sadly, the position of a Flight Navigator is also all but obsolete.
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$\begingroup$ FWIW, I spoke with a chief engineer about how often all navigation sources you listed simultaneously fail, and the answer was that you might never see it happen over an entire fleet's lifetime. The only cases I've seen in ASRS of total position loss are for AHRS planes. $\endgroup$– Cody PMar 13, 2020 at 17:31
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Of course it can be done, and astronavigation was often used in long-range flights, and transatlantic passenger liners such as the Super Constellation were fitted with a plexiglas astro-dome so that the navigator might 'take' the stars with a bubble sextant.
