The electromechanical angle computer inside the B-52 bomber's star tracker
by NelsonMinar on 4/18/2026, 4:26:47 PM
https://www.righto.com/2026/04/B-52-star-tracker-angle-computer.html
Comments
by: chiph
> The Atro Tracker also has declination limits of +90° and -47° and a lower altitude limit of -6°. The latitude is limited to the range between -2° and +90°; the system automatically switches hemispheres so both the North and South latitudes are usable.<p>Why would the system need to have a much greater range of declination (celestial sphere) than latitude (Earth spheroid)? Because the Astro Tracker and Angle Computer could flip over to the Southern hemisphere (was this automatic or was there a switch?) having that much declination range seems unnecessary. Perhaps to allow for pitch of the aircraft in flight?<p>BTW, being able to operate in both the Northern & Southern hemispheres was an important capability for the B-52. Previous bombers (B-36 mostly) had the range but not the reliability or in-flight refueling for global reach.<p>Sadly, I didn't get the chance to look at the B-52 at the Museum of Flight when I was there. If you ever meet Charles Simonyi, please thank him for his support of the museum.
4/18/2026, 6:15:36 PM
by: po1nt
Everytime I read articles like that, I envy the engineers that worked in development of such tools. First microprocessors in jet fighters, electromechanical celestial navigation...<p>And here I am fighting gitlab pipelines.
4/18/2026, 5:56:19 PM
by: pests
Read every word. i liked this detail in the footnotes:<p>> The Astro Compass needed to know approximately where in the sky to find the star, in order to point its sensor in the right direction. The direction didn't need to be exact because the Astro Compass performed a spiral search pattern to find the star. This search pattern covered ±4° in bearing and ±2.5° in altitude. In comparison, the Moon is 0.5° wide, so it's a fairly large target area. ↩
4/18/2026, 6:18:35 PM
by: t0mas88
> The Angle Computer is one piece of the Astro Compass, a system that locked onto a star and produced a highly accurate heading (i.e., compass direction), accurate to a tenth of a degree.<p>I think it provides ground track information not just heading? Which is far more valuable for aircraft navigation, because the main issue is unpredictable wind drift.
4/18/2026, 5:22:22 PM
by: kens
Author here if you have questions about this analog computer...
4/18/2026, 4:57:46 PM
by: black6
> Each knob on the Master Control Panel has a different geometrical shape, allowing the user to distinguish the knobs by feel.<p>Auto manufacturers should take a clue here.
4/18/2026, 6:16:27 PM
by: TMWNN
It's amazing, the things that can be done without what we would consider modern technology.<p>The 8-bit Guy recently released a video asking "What if everything still ran out vacuum tubes?" <<a href="https://www.youtube.com/watch?v=mEpnRM97ACQ" rel="nofollow">https://www.youtube.com/watch?v=mEpnRM97ACQ</a>>. Conclusion: A surprising amount of things we take for granted today would still be possible.
4/18/2026, 5:53:43 PM