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The SR-71 Blackbird Astro-Nav System worked by tracking the stars

theaviationgeekclub.com

331–340 of 358 posts

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#331

Earlier quoted context omitted.

Also B-58

A college friend of mine who was at the Air Force Academy in the 1980s told me she was trained in celestial navigation in case they needed it in a pinch. Both of us were pretty interested in the math.

Older 737s have "Eyebrow" windows and mounting points for sextants for backup navigation.

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#333

Earlier quoted context omitted.

Put a lens cap on! Then shoot.

That is for taking "dark frames". "Flat frames" need light going through the optics so that things like dust and vengetting can be detected. This link explains them in more detail: https://www.highpointscientific.com/astronomy-hub/post/astro...

You're right! I read too quick.

Instead, you want one of these!

https://support.phaseone.com/knowledgebase/article/KA-01239/...

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#334

Earlier quoted context omitted.

The near entire majority of software development in the modern world is digital plumbing. Very very few organizations practice software engineering

What's ur definition of "engineering" then

Yeah, I've worked in structural engineering with real chartered professional engineers. Most of that work was relying on rules of thumb and bodging in hacks to fit around too small customer budgets, changing requirements, contractors trying to exploit loopholes, or bad designs from architects. No job ever had the budget to do anything "properly".

Software development usually seems far more controlled than that was.

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#335

Earlier quoted context omitted.

For reasons I still can't fathom, a contractor for the Israeli military purchased many copies, apparently so their tanks and troops could remain oriented after all other electronic systems failed. Possibly in case of EMP attack?

EMPs are a fantasy. Absolutely and unreservedly a complete fantasy. ZERO have ever been tested, and there’s literally a better use for a nuclear warhead. Not only is it a a completely hypothetical attack, it would look identical to a normal nuclear ICBM attack, and absolutely would result in a traditional retaliatory attack. Why would anyone trade an EMP for all their cities? Literally doesn’t make sense. No one in t…

[deleted]

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#336
post #232

Off tangent here but I thought I'd mention that yesterday a replica of a traditional Polynesian ocean-going canoe, the Hokulea, sailed into San Francisco, navigated with non-instrument methods including star observations. https://www.sfchronicle.com/bayarea/article/hokulea-polynesi... The Hokulea's maiden voyage was in 1975 and since then it has made global voyages to demonstrate and preserve ancient Polynesian wayfi…

That's incredible. I was just speaking with colleagues about the best conditions for surfing waves. The best waves here in California originate in storms on the opposite side of the Pacific. The waves travel thousands of miles over the course of days without appreciably dissipating.

For those interested...

The waves do dissipate, but the dissipation and attenuation is what makes the best waves. In the storm the waves are huge and messy with all kinds of frequencies interfering with each other. Attenuation means the high frequency / small amplitude waves dissipate the quickest and the lowest frequency / high amplitude waves dissipate the slowest.

By the time they've moved a long way, all that's left are the lowest frequencies which makes for a clean smooth wave. The amplitude will have reduced compared to the original storm, but that original long period is still there creating nice long gaps between the waves. This is why surfers care about the period of an incoming swell - it's a proxy for how the swell has cleaned up on it's travels.

The best waves come from the biggest storms the furthest away.

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#337

Earlier quoted context omitted.

Do you think the "software engineering" people are giving engineering a bad name? "Christian scientists" are Christians who attach themselves to the word science because science has such a powerful reputation. In their case I'm not worried about their trickery because everyone recognizes this. Everyone knows that Christian scientists are not scientists. With software engineering it's not as clear. It's possible to cr…

Software is engineering.

You didn't read anything I wrote, did you?

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#338
post #306
post #295

Earlier quoted context omitted.

It doesn't have to be a small team. See "They Write The Right Stuff".

And even they make mistakes, software contains much more moving parts than hardware. https://space.stackexchange.com/questions/37110/what-was-the...

> Use of pointers required a written, approved, variance from the SW standards board. All the code was formally peer reviewed by at least 6 people. More complicated code would be reviewed by 20+ people - in the same room.

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#339

Earlier quoted context omitted.

The near entire majority of software development in the modern world is digital plumbing. Very very few organizations practice software engineering

What's ur definition of "engineering" then

If you don't know what engineering means, why not check out Wikipedia?

https://en.wikipedia.org/wiki/Engineering

Re: The SR-71 Blackbird Astro-Nav System worked by tracking the stars

#340

Semi-related tangent: During the early 1990's I developed a star chart and ephemeris for the (momentarily) fashionable Windows Mobile platform called "Pocket Stars" that calculated one's geographical position from three or more sextant observations, mainly as backup for offshore sailors should their GPS system fail. For reasons I still can't fathom, a contractor for the Israeli military purchased many copies, apparen…

I wasn’t around for the 90s edition of windows phone (at least not enough to understand any of the tech) — i guess for lack of a camera and compass +gyro, would the observations be done out of band and just put into a form?

Correction to parent post: Pocket Stars and Windows Mobile were developed in early 2000s, not 1990s.
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