00:03 <mofh> ahh yes, the obelisk

00:04 <UmbralRaptor> Technically, would ‡ be the dual of †?

00:35 <UmbralRaptor> Note to self: if ever DMing an RPG with Ellied, include dire raccoons

01:58 <mofh> egg: https://twitter.com/ka3v33/status/1122689367716388865

01:58 <kmath> <ka3v33> https://t.co/wyvVRIp8Ol

06:32 <mofh> oeuf: miaou

06:35 <egg|laptop|egg> mofh: CDDIS

06:36 <egg|laptop|egg> mofh: also have you considered https://esper.irclog.whitequark.org/kspacademia/2019-04-29#1556571757-1556571785;

06:38 <mofh> sec

06:39 <mofh> wait, am I reading this right? they claim they relate the sidereal day to the tropical *year* and the tropical day to the sidereal year?!?

06:43 <egg|laptop|egg> mofh: no, the stellar day corresponds to the sidereal year

06:44 <egg|laptop|egg> mofh: but other than that, yes, that's the standard convention

06:45 <egg|laptop|egg> mofh: tropical year which is defined as the draconitic period is for a satellite, not to be confused with the draconitic year which involves the moon

06:48 <mofh> egg|laptop|egg: well, it seems silly to call the time that the earth returns to its original position around its axis the stellar day and the same for it around its orbit the tropical year when they're both the same underlying concept, but calling the latter the "stellar year" seems wrong as it feels like it implies position against fixed stars, which is the sidereal year. :P

06:49 <mofh> but why the hell is the sidereal day defined wrt the node and the sidereal year NOT?

06:49 <mofh> or rather

06:49 <mofh> if that's the case, why use the same term for two different definitions?

06:50 <egg|laptop|egg> the same for it around its orbit the tropical year << no, that's the sidereal year

06:50 <egg|laptop|egg> the tropical year is the draconitic period of earth

06:50 <mofh> I was sure the sidereal year is position wrt fixed stars

06:50 <egg|laptop|egg> yes

06:57 <mofh> the time it takes for the sun to go from maximum declination to minimum and then back to maximum

06:57 <mofh> i.e. from vernal equinox to vernal equinox

07:07 <egg|laptop|egg> mofh: note that whereas for a satellite that period differs from the sidereal period mostly because the orbit precesses due to oblateness, here i think the dominant effect is that the reference plane precesses (precession of the equinoxes)

07:08 <egg|laptop|egg> mofh: the sidereal year would be the sidereal period, which is not often properly defined but the definition i've found is time between crossings of an arbitrary half-plane orthogonal to the reference plane

07:09 <egg|laptop|egg> not sure which reference plane one would take in this case

07:09 <egg|laptop|egg> probably the egguator?

07:22 <mofh> I presume so

07:23 <mofh> also wait a second, I thought the draconitic period considers the precssion of the equinoxes and the nodal period eggsplicitly does *not*?

07:23 <egg|cell|egg> O_o

07:24 <mofh> like I assumed that nodal period assumed a fixed reference plane

07:27 <egg|laptop|egg> mofh: but J2 is tied to the true equator, not to the equator of J2000, so with the ICRS reference plane your nodes would have wonky precession

07:27 <mofh> okay now see I thought J2 was tied to the equtor of J2000 and that was *why* the nodal period assumed a fixed reference plane

07:27 <mofh> what the heck?

07:30 <egg|laptop|egg> mofh: isn't the precession of the eggquinoxes precisely *due* to a torque on the bulge anyway

07:39 <egg|laptop|egg> mofh: also there are squirrels

08:30 <egg|laptop|egg> B787_300: yup it was a stupid bug, I was interpolating the latitude over half an orbit instead of over 1 min or so. now i'm getting +98.74037(26)° from max latitude and +98.72941(26)° at the ascending nodes, which is a lot more reasonable

08:34 <egg|laptop|egg> in terms of ranges, inclination measured at max latitude ranges from 98.737 to 98.743°, inclination measured at the node ranges from 98.727° to 98.732°

09:21 <egg|laptop|egg> mofh: you might like https://www.imcce.fr/newsletter/medias/2019/01/docs/Paris_2019.pdf

09:24 <egg|laptop|egg> !acr -add:ACME Astéroïdes – Comètes – Météores – Éphémérides

09:24 <galois> Definition added!

09:24 <egg|laptop|egg> IMCCE?

09:24 <galois> IMCCE: Institut de Mécanique Céleste et de Calcul des Éphémérides

09:44 <egg|laptop|egg> mofh: aaaaa http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1992JBAA..102...40M&defaultprint=YES&filetype=.pdf

12:05 <UmbralRaptor> https://twitter.com/xdroop/status/1123193877395959809

12:05 <kmath> <xdroop> Somebody shipped me an empty box! https://t.co/jVd6cnhyjw

13:26 <mofh> egg|work|egg: ooh

14:00 <UmbralRaptor> Apparently today is a buses don't show up day?

14:02 <UmbralRaptor> Or one that I eggspected to be early can be 7 minutes late

14:04 <UmbralRaptor> Also, the app gave confusing information ¯\_(ツ)_/¯

16:07 <egg|laptop|egg> mofh: which thing are you ooing at,

16:09 <egg|laptop|egg> mofh: oh it has the correspondence with the republican calendar under its astronomical definition

16:09 <egg|laptop|egg> (the IMCCE thing)

16:56 <egg|laptop|egg> mofh: that article on the history of the tropical year is very aaaaaaaaaaa

16:58 <egg|laptop|egg> "at the time of Hipparchus [...] the length of the tropical year was 365 days 05 hours 48 minutes 56 seconds. However, the unit of time here is the so-called ephemeris day, which is practically equal to the mean solar day at the epoch 1900. At the time of Hipparchus, the Earth's rotation was very slightly more rapid, so there were approximately 13 more 'instantaneous' mean seconds than ephemeris seconds in the tropic

16:58 <egg|laptop|egg> al year."

17:06 <egg|laptop|egg> "Copernicus [...] observed an equinox on the 18th Calendae of October [14 September] 1515 (The old Roman manner to reckon the days was still in use in the 16th century!)"

17:29 <mofh> egg|laptop|egg: it's downright mind-boggling, tbh

17:41 <_whitenotifier-3d18> [Principia] peraktong starred Principia - https://git.io/fjZk5

19:09 <UmbralRaptor> aaaaaa https://twitter.com/astromarkmarley/status/1123234374181240832

19:09 <kmath> <astromarkmarley> How many ExoEarth candidates do you want to find? This plot tells you how big you need to go. https://t.co/Xrrrtg0eZ5

19:12 <SnoopJeDi> "You made an attempt at petty vengeful retaliation toward a student and you failed. I know you have been under severe stress, but this is all getting to be ridiculous. You need a rest, and you have my sympathy,"

19:12 <SnoopJeDi> the bad blood surrounding the existence of clockwise (???) is apparently only growing stronger

19:15 <UmbralRaptor> Ꙫ_ꙫ

19:43 <UmbralRaptor> ;8ball will this class kill me?

19:43 <kmath> UmbralRaptor: It is decidedly so

20:00 <UmbralRaptor> "You should be aware, by the way, that there is no firmly established sign convention for the Riemann tensor"

20:43 <mofh> SnoopJeDi: what the hell?

20:51 <SnoopJeDi> me too thanks

21:14 <UmbralRaptop> egg|work|egg: does ANBOcat understand GPS orbits?

21:16 <B787_300> UmbralRaptop: why does that tweet annoy you

21:17 <UmbralRaptop> B787_300: not so much annoy as mean we might need a >8 m space telescope

21:17 <UmbralRaptop> And, well, *gestures at WFIRST and especially JWST delays*

21:17 <B787_300> it bothers me because there should be a lot more than 50 found with a 6sih meter scope

21:20 <B787_300> also putting a 8 m scope in space with a free flying coronograph wont be cheap and doing it for *only* 50ish exo earths wont get it funding

23:19 <UmbralRaptop> ;8ball Is math fake?

23:19 <kmath> UmbralRaptop: As I see it, yes

23:20 <UmbralRaptop> ;8ball Is math arbitrarily pushing around arbitrary symbols?

23:20 <kmath> UmbralRaptop: Ask again later

23:33 <egg|laptop|egg> SnoopJeDi: do clocks exist

23:33 <egg|laptop|egg> mofh: meow

23:35 <RiemannianRaptor> egg|laptop|egg: yes, but good luck synchronizing the infinite grid

23:40 <SnoopJeDi> egg|laptop|egg, clocks do, but I remain skeptical about time

23:43 <egg|laptop|egg> RiemannianRaptor: Jupiter!

23:44 <SnoopJeDi> egg|laptop|egg, oh also do you know anything about Orthodox Greek Easter? I found out it's distinct from the holiday celebrated in the US and found myself wondering if that amounts to "calendars are hard" somewhere.

23:52 <RiemannianRaptor> egg|laptop|egg: 3 moons should be easily visible

23:52 <egg|laptop|egg> RiemannianRaptor: yeah

23:52 <egg|laptop|egg> RiemannianRaptor: bands less so, quite low

23:53 <egg|laptop|egg> also clouds

23:53 <egg|laptop|egg> here not there

23:54 <RiemannianRaptor> aww

23:59 <egg|laptop|egg> RiemannianRaptor: clouds preventing me from staring at clouds

23:59 <RiemannianRaptor> hm