UmbralRaptor changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> … one of the other grad students just compared me to nomal O_o | <ferram4> I shall beat my problems to death with an engineer.
<Ellied>
"How's the experiment coming?" "not great, we can barely see the x-rays through all the dark counts in the way"
* egg
gives Ellied a radiography of dracula
* Ellied
biases the SiPM and generates over 100000 dark counts per second
<UmbralRaptor>
"Work hard, time is short. But it'll all be over soon."
<UmbralRaptor>
That's mildly ominous coming from the QM prof.
<kmath>
<BMatB> I have a quiz for you all - here we have titanium, zirconium, and hafnium balencing on an aluminium bar. Which shee… https://t.co/T5ZF9JUlmn
egg is now known as egg|zzz|egg
* egg|zzz|egg
pets UmbralRaptor with a Hamiltonian
<SnoopJeDi>
Thought provoking enough for someone who doesn't grok black holes or much QFT, "soft/infrared structure" seems interesting enough with the analogies to the soft photon theorem
<SnoopJeDi>
he also has occasion to say "using the technology of Feynman diagrams" which I found to be a hilarious turn of phrase
<rqou>
egg (or others): math question:
<rqou>
suppose i have a quaternion that is supposed to represent the orientation of an object relative to some fixed reference
<rqou>
but this quaternion has errors in the yaw of the fixed frame
<rqou>
how do i get the roll angle?
<rqou>
e.g. if you use the normal way of calculating the roll angle, it'll work initially
<rqou>
and then errors in the world yaw will cause this to eventually become pitch angle
<UmbralRaptor>
SnoopJeDi: my QM teacher also uses "technology" that way.
<SnoopJeDi>
I mean...they're not wrong?
<UmbralRaptor>
(Is he also from somewhere Slavic?)
<SnoopJeDi>
It tickled my brain pleasantly
<UmbralRaptor>
heh
<SnoopJeDi>
oh no Strominger is from the UK
<SnoopJeDi>
uh, or the US? I don't know why Google reported UK, he has no accent and all his accolades are US so that's probably wrong
<UmbralRaptor>
hm
<bofh>
UmbralRaptor: sheet is Ti almost certainly based just on reflectivity, the other two are easy to figure out by densities (so yes, left Zr, right Hf). At least that's also my guess.
<bofh>
egg|zzz|egg: what about busy beavers, are those neat as well?
<SnoopJeDi>
a lot of his talk today was *mumble mumble* how you can posit that black holes really *should* have hair, but it's really really subtle and all encoded in these zero-energy particles at the surface or something? It was difficult to follow beyond a sketch of "there are an infinity of conserved quantities"
<rqou>
egg|zzz|egg: plz 2 halp with math
<egg|zzz|egg>
zzz
<egg|zzz|egg>
ask bofh who is less asleeeep
<bofh>
?
<rqou>
rqou> suppose i have a quaternion that is supposed to represent the orientation of an object relative to some fixed reference
<rqou>
<rqou> but this quaternion has errors in the yaw of the fixed frame
<rqou>
<rqou> how do i get the roll angle?
<rqou>
<rqou> e.g. if you use the normal way of calculating the roll angle, it'll work initially
<rqou>
<rqou> and then errors in the world yaw will cause this to eventually become pitch angle
<rqou>
essentially the pitch angle is ignored/unneeded, and i need to combine pitch/roll into one angle
<bofh>
that or someone decided to encode H.264 using only 16x16 macroblocks for some insane fucking reason.
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<bofh>
Also I love how fucked the metadata headers are
<bofh>
videodatarate : 1104758
<bofh>
I think not.
<Ellied>
what's a typical video datarate?
<Ellied>
60Hz * [your monitor size here] * 3 colors is going to be really freaking fast, isn't it?
<Ellied>
I know hardly anything about monitors lol
<bofh>
I'unno, I typically go with whatever x264 --crf 22-28 (depending on quality) spits out. at 720p that's usually 1-3MB/sec depending on input, sometimes less. sometimes much less.
<Ellied>
oh, we're talking about video files. I did my usual thing and only read the last three lines and assumed we were talking about interface buses.
<bofh>
No, that was from the metadata of the above mp4 I'm rtmpdumping (WHICH IS ACTUALLY AN FLV CONTAINER BTW)
<Ellied>
ah
<bofh>
SnoopJeDi who is the multimedia tech at TAMU I want to yell at them
<SnoopJeDi>
It's normally slightly better quality but...yes, our IT is awful.
<SnoopJeDi>
Please direct as much invective as you can to central IT and/or the state legislature.
<SnoopJeDi>
I like buying our dept IT guy a drink at happy hour because he has to put up with those nitwits
<Ellied>
Is IT at universities ever good?
<SnoopJeDi>
UMBC's was great!
<bofh>
UIUC's is *okay* most of the time.
<rqou>
UCB's is "fun" because it's one of the oldest ecosystems
<rqou>
e.g. you can _still_ use "mail" to check email for lab computer accounts
<SnoopJeDi>
my math advisor used `pine` heh
<bofh>
Same with my master's supervisor (who also always mixed up arguments to ln -s, amusingly)
<SnoopJeDi>
I should just alias ln to ln --help | head -5 because same
<SnoopJeDi>
...actually, I may well do exactly that for bare ln because "ln: missing file operand Try 'ln --help' for more information." is worthless
<Ellied>
Slide A should be after slice B. Slide C should be before slide B. Slide C should be after slide A.
* Ellied
is gripe
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<egg|zzz|egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor an electromagnetic mesolect
<kmath>
<bofh453> @diodelass So I've accidentally keyed down a 100W class-AB amplifier made of a pair of 6146es into a dead short for… https://t.co/woBLTZEAGW
<bofh>
nothing like sinking 100W into a dead short.
<UmbralRaptor>
At least nothing caught on fire?
<bofh>
Everything was perfectly fine, hilariously.
<bofh>
Oh man that reminds me of the second-weirdest feeling I've ever had, which was keying down ~80W (or thereabouts) at ~7.2MHz into a portable dipole about 20cm away from my head.
<bofh>
I can't describe it, it was incredibly strange. I'm also not in the mood to ever repeat it
<bofh>
(solution btw was to step back a meter & try again. <3 inverse-square law)
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<bofh>
Turns out accidentally TMSing yourself with the Barkley Shut-Up & Jam: Gaiden theme modulated to LSB-LC is not a good idea, who knew.
<Ellied>
bofh: if it's a dipole, wouldn't that be inverse-cube?
<SnoopJeDi>
oh that reminds me. bofh one of the more tractable portions of Strominger's lecture yesterday was some discussion of "gravitational memory" which was new to me, but apparently LISA should be able to observe it?
<Ellied>
...did we lose net neutrality already? a bunch of sites are suddenly failing to connect when I'm on uni wifi but not when I'm on mobile data.
<Ellied>
twitter doesn't go through, but facebook does. google is fine.
<Ellied>
onion.link doesn't go through either, so my easy method of getting to sci-hub is now a no-go :I
<Ellied>
still holding out hope that this is just some kind of transient error on the network but I don't know how reasonable that is :/
<Ellied>
the DNS still resolves, but no pings return from the associated addresses
<SnoopJeDi>
that sounds like uni is just filtering your traffic
<SnoopJeDi>
or rather, those routes fail and *maybe* it's a deliberate filter, heh
<SnoopJeDi>
also speaking of which, tracert maybe?
<Ellied>
oh, heh, just as I was getting screenshots to post on twitter those sites started going through again
<Ellied>
strikes me as a weird thing to have happen by accident though :?
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<SnoopJeDi>
networking is impossible even on a trivial scale :(
<SnoopJeDi>
"the ping's the thing to check the connectivity of the king" - Billiam Shakespeare
<egg|afk|egg>
bofh: yeah so in a sense the central finite difference is has order n+1, since you don't use f(0), so it's actually a formula with one less point
<egg|afk|egg>
bofh: but if you compare with the equal-order backward difference formula, the error term is nicer on the backward difference
<Ellied>
I can never type "ping bing.com" with a straight face
<egg|afk|egg>
!wpn Ellied
* Qboid
gives Ellied a graphite greebled endomorphism which strongly resembles a decagon
<Ellied>
!wpn egg|afk|egg
* Qboid
gives egg|afk|egg an ISO 8601-compliant ███████
<UmbralRaptor>
SCP 8601
<egg|afk|egg>
!wpn UmbralRaptor
* Qboid
gives UmbralRaptor a license
egg|afk|egg is now known as egg
<egg>
!wpn Fiora
* Qboid
gives Fiora a dysprosium ꙮ with an atom attachment
<kmath>
<MrsHebertMath> If Elizabeth is terrified of spiders, she's not going to stand in the room long enough to figure out if the spider… https://t.co/5UY4laFQrg
<kmath>
<stephentyrone> @rygorous @FioraAeterna @2pi_dk Be careful with the commutative diagrams, you'll attract the Haskell Strike Force.
<SnoopJeDi>
Magnetism is an illusion, teach the controversy!
<Ellied>
I never quite grasped that in E&M. Is the magnetic field a literal thing, or can all of its behavior be explained by time-dependent electric fields?
<Ellied>
there are several small reasons why I want to call that nonsense but I'm not sure enough of any of them to dismiss the idea completely
<bofh>
(extremely field theorist hat) there is no electric or magnetic field, only Zuu^H^H^Hthe electromagnetic tensor
<bofh>
s/hat/voice/
<Qboid>
bofh meant to say: (extremely field theorist voice) there is no electric or magnetic field, only Zuu^H^H^Hthe electromagnetic tensor
<UmbralRaptor>
I want to say that there's a formulation where Maxwell's equations can be written as 2 functions instead of 4.
<egg>
UmbralRaptor: nah, there's a formulation where it's *eldritch rune* = 0
<kmath>
<ManishEarth> @ken_lunde Also can we take a moment to appreciate the smorgasbord of Han Unification variations in the background… https://t.co/6NjqAdKMHT
<egg|nomz|egg>
(via whitequark)
* UmbralRaptor
still likes that there's an alchemical symbol unification.
<UmbralRaptor>
egg|nomz|egg: generally if your eyes are dewing over, that's not the weather.
egg|nomz|egg changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> egg|nomz|egg: generally if your eyes are dewing over, that's not the weather. | <ferram4> I shall beat my problems to death with an engineer.
egg|nomz|egg is now known as egg
<egg>
tbh "<UmbralRaptor> Either that's not a cat, or we're talking about the meowing kind." is quite quotable too
<egg>
UmbralRaptor: but inaccurate?
<egg>
UmbralRaptor: like, клевцов-cassegrain is a thing, same for field-максутов
<egg>
and then vixen's weird refracting train in the focuser
<UmbralRaptor>
hrm
* UmbralRaptor
also ignores lens madness in the optical trains of lots of photometric and spectroscopic systems.
<egg>
kitties!
<rqou>
er, why are we discussing lenses?
<egg>
rqou: because cats
<rqou>
what
<egg>
rqou: see the /topic
<UmbralRaptor>
Catadioptric systems involve both reflective and refractive components.
<rqou>
"Spiders are cat interferometers"?
<egg>
yes
* egg
stares at Fiora's profile picture and is confused by the chirality change
<UmbralRaptor>
eg: maksutov-cassegrain telescopes, and the eyes of many animals (housecats, dogs, spiders…)
<UmbralRaptor>
Hence dogs are cats. And as (some) spiders have 8 eyes…
<egg>
rqou: see, it makes sense,
<rqou>
i see
<rqou>
btw, can someone try pinging 128.32.42.40 for me?
<rqou>
the entire EECS infrastructure is down apparently. this is going to be fun for all the people that have to turn in projects
<egg>
UmbralRaptor: also what kind of mount
<Fiora>
egg: are you saying i don't obey CP symmetry
<egg>
Fiora: try reversing time too, maybe it looks right then
<UmbralRaptor>
egg: dob or unpowered EQ for visual, some sort of goto for photography.
<egg>
UmbralRaptor: there are a bunch of gotos that don't have nice manual controls, which sounds unpleasant
<egg>
also, Ꙩ_ꙩ at the upper reaches of the price ranges of mounts as usual
<UmbralRaptor>
Very
* egg
stares at Astro Physics
* UmbralRaptor
hands egg a Planewave.
<egg>
UmbralRaptor: also, I'm looking at this on a german site right now, it's a parallaktische Montierung (although they do say 'die man in Fachkreisen auch "Deutsche Montierung" nennt')
<UmbralRaptor>
?
<egg>
UmbralRaptor: the german mount
<UmbralRaptor>
GEM?
<Qboid>
UmbralRaptor: [GEM] => German Equatorial Mount
<UmbralRaptor>
Planewave Optics has a 24" RCT for $65k.
<egg>
UmbralRaptor: it's called a parralactic mount, and they say that it is also called german mount in the trade
<UmbralRaptor>
(Mount is extra)
<egg>
astro physics mount on that site: "STATT 12.798,32 EUR
<egg>
Nur 12.394,96 EUR"
<UmbralRaptor>
Hah
<egg>
save a whole three percent!
<egg>
they carry losmandys, which iirc have a nice manual override as well as either a clock drive or a goto?
<egg>
s/rral/ral/
<Qboid>
egg meant to say: UmbralRaptor: it's called a paralactic mount, and they say that it is also called german mount in the trade
<egg>
s/lac/llac/
<Qboid>
egg meant to say: UmbralRaptor: it's called a parrallactic mount, and they say that it is also called german mount in the trade
<egg>
no I mean both you silly bot
<egg>
blarg
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