100% tariff on the MM/DD/YY date format.
-
>the primary cause of the failure with the Hubble Space Telescope's mirror was spherical aberration caused by a miscalibrated, faulty testing device during manufacturing.
Here are the key details regarding the failure as discussed by users:
The Root Cause (The "Why"): The primary mirror was ground and polished by Perkin-Elmer to the wrong shape because a device called a "null corrector"—used to measure the mirror's surface during polishing—was assembled incorrectly.
The Specific Error: A spacing error of 1.3 millimeters in the null corrector (caused by a missing cap on a rod) led to the mirror being polished too flat at the edges by roughly 2.2 microns (1/50th the width of a human hair).
Ignoring Data: Users noted that a second, independent testing device actually indicated the mirror was flawed, but this data was ignored because the, albeit faulty, "new" null corrector was trusted more.
The Fix: Because the mirror was ground so accurately (just wrongly), scientists knew exactly how to fix it. The 1993 servicing mission (STS-61) installed COSTAR (Corrective Optics Space Telescope Axial Replacement), which acted as "glasses" to correct the aberration.
>One report explained it this way;
If you took a finely polished mirror and enlarged it to the size of the Gulf of Mexico, you'd have a surface with +/- 80 foot swells.
If you enlarged the Hubble mirror to the same scale, you'd have a surface with +/- 3 inch swells.
>Imagine you are trying to make a perfectly shaped, giant, curved mirror for a space telescope (like Hubble). Because it’s so large, you need to check if you are grinding the glass into the exact right shape.
The Problem: The mirror is a weird shape (aspheric). If you shine a light on it to check the shape, the light bounces back looking crazy and blurry. You can’t tell if the mirror is wrong, or if it just looks that way because of the weird curve.
The Solution (The Null Corrector): You put a special lens or mirror between your eye (or camera) and the giant mirror. This device takes the messy, distorted light and "fixes" it.
"Null" Means Zero Error: If the giant mirror is ground perfectly, the null corrector makes the reflected light look completely flat (or "null" of errors).
https://en.wikipedia.org/wiki/Null_corrector
>Why an Aspheric Shape is Needed
Spherical mirrors (like a perfect bowl) focus light from distant objects to different points depending on where the light hits the mirror, causing blur.
Aspheric mirrors, with a more complex curve, can focus all light rays to a single, sharp focal point, producing clearer images. Hubble's design used this superior shape.
@amiserabilist @wendinoakland @renwillis @Natasha_Jay @stux
+5 for Gulf of Mexico
I dunno what "finely polished mirror" they're talking about. Maybe they're talking a bathroom mirror? That mirror would be unsuitable for astronomical purposes
I've got a 47 cm diameter mirror with an error of about 20 nanometers.
My error translated to 1500 km diameter would be about 6 cm, so yeah. If you can't piss with the tall dogs, stay out of the high grass.the Hubble mirror had 2 null testers, one all lenses, one lenses and mirrors. The latter one showed an error, the former one did not. They got lazy and said "the second null tester is screwed up". They were wrong.
-
@amiserabilist @wendinoakland @renwillis @Natasha_Jay @stux
+5 for Gulf of Mexico
I dunno what "finely polished mirror" they're talking about. Maybe they're talking a bathroom mirror? That mirror would be unsuitable for astronomical purposes
I've got a 47 cm diameter mirror with an error of about 20 nanometers.
My error translated to 1500 km diameter would be about 6 cm, so yeah. If you can't piss with the tall dogs, stay out of the high grass.the Hubble mirror had 2 null testers, one all lenses, one lenses and mirrors. The latter one showed an error, the former one did not. They got lazy and said "the second null tester is screwed up". They were wrong.
@glasspusher @amiserabilist @renwillis @Natasha_Jay @stux I posted a Wikipedia link — it’s in there, someplace. Oh, Paul quoted the deets above.
-
And what do you with "DD/MM/YYYY"?
@agowa338@chaos.social @Natasha_Jay@tech.lgbt that would no longer be valid
-
100% tariff on the MM/DD/YY date format.
@Natasha_Jay You mean you don't like wondering what 12/11/12 represents?
-
@zed @bsdphk @Natasha_Jay Wristwatches solve a different use case. When you look at them, chances are you know if it's a quarter to midnight or to noon.
When you represent date/time in a globalised world, it's an entirely different matter. An event at 11:45 is totally ambiguous, so you need 4 digits + the AM/PM bit to be unambiguous. With 24h time, you only need the four digits.
@vonxylofon but when I wear a watch (which is every day), and my train leaves at 18h, I don’t want to have to do math while looking at my watch to see if I’m going to be on time or not.
-
100% tariff on the MM/DD/YY date format.
and miles/feet/pounds/°F
-
@glasspusher @amiserabilist @renwillis @Natasha_Jay @stux I posted a Wikipedia link — it’s in there, someplace. Oh, Paul quoted the deets above.
@wendinoakland @amiserabilist @renwillis @Natasha_Jay @stux
See me after class, ma'am.
-
100% tariff on the MM/DD/YY date format.
@Natasha_Jay 2026-01-19. As a Usian I am in agreement.
-
100% tariff on the MM/DD/YY date format.
@Natasha_Jay I think we should just drop drone bombs on the shadow fleet of date formats.
-
100% tariff on the MM/DD/YY date format.
YYYYMMDD
-
@Natasha_Jay
Yes, and 100% tariff on any country that does not use the metric system.@sloanlance @Natasha_Jay
good idea!let's ban celsius and km/h measurements, and replace them proper metric units. kelvins and m/s.
-
@WTL @Wen @Natasha_Jay @renchap I regret to inform you that my country abandoned reason long ago. See also the metric system, the government, guns, etc.
Some of us coders are counterculture malcontents, rejecting MM/DD/YYYY because we have also experienced the nonsense that it brings. There just aren't enough of us.
-
100% tariff on the MM/DD/YY date format.
@Natasha_Jay the Little Endian versus Big Endian war should have ended years ago but we can all agree that this Middle Endian idea is a psychosis
-
@bsdphk @Natasha_Jay metric or die!
@wendinoakland @bsdphk @Natasha_Jay F*ck the imperial system!
-
100% tariff on the MM/DD/YY date format.
...and all products in packaging with imperial measurements.
-
100% tariff on the MM/DD/YY date format.
@Natasha_Jay American spelling a $ each one that is not English spelling
-
100% tariff on the MM/DD/YY date format.
@Natasha_Jay $1 every time someone says gas for a liquid
-
@vonxylofon but when I wear a watch (which is every day), and my train leaves at 18h, I don’t want to have to do math while looking at my watch to see if I’m going to be on time or not.
@zed @vonxylofon “Have to do the math”?! HAHA!
Oh, sorry, you say math as singular not maths as plural. I apologise for your education system. I’ll speak slowly from now on.
-
@WTL @Natasha_Jay @renchap I’ve never understood the U.S. obsession with getting it wrong. It’s not even simple to sort by date.
@Wen @WTL @Natasha_Jay @renchap
Half-assed guess: it came, or at least got more firmly entrenched, when US English stopped referring to dates as something like “the 19th of January, 2026” and started using “January 19, 2026” instead. The older form is still around, but outside of fixed expressions like “the 4th of July” for US Independence Day, it’s decidedly old-fashioned and not common anymore.
“1/19/2026” is a crappy way to write this from a numeric perspective, but it is a pretty direct transcription of the verbal date format into numbers.
-
@pms @Natasha_Jay @bsdphk One I specifically want abandoned is comma as thousand separator, as otherwise it would be just non-breakable space as thousands separators, and either dot or comma as decimal separator.
Although could also use units as separator, like done with height (1m60) and time (1h30m)@lanodan @pms @bsdphk @Natasha_Jay In Indian Subcontinent , we use Lakh, Crore instead of millions and billions. So instead of 1,000,000,000.00, we write 100,00,00,000.00
https://en.wikipedia.org/wiki/Indian_numbering_system
