raptop 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. | We can haz pdf
* UmbralRaptop
hands egg|cell|egg a bag of frozen peas?
* B787_300
hands egg|cell|egg some of the 8 inches of snow he got on saturday
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<UmbralRaptop>
"FaNTOmM Fabry-perot of New Technology for the Observatoire du mont Megantic"
<UmbralRaptop>
… a Franglish acronym?
<B787_300>
UmbralRaptop: can we get spectra from exoplanet atmospheres using transit method spectroscopy?
<UmbralRaptop>
Yes!
<B787_300>
also wouldnt that be kinda combined transit method and R-V Method detection methods?
<UmbralRaptop>
kinda, but not really?
<B787_300>
i mean you would want to have large amounts of specta of the star without the transit to increase confidence levels of detection right?
<B787_300>
and because you want large amounts couldnt you also use it to look for r-v shifts?
<UmbralRaptop>
iffy. let me think about it and get on something with a proper keyboard
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<raptop>
Okay, my understanding is that for transit spectroscopy, there's a tendency to look for atoms/molecules that are relatively rare in the star, though common in the planet's atmosphere.
<raptop>
Or, because of temperature stuff don't show up in the star.
<B787_300>
so look for a water vapor absorbtion line because the sun shoundnt have noticable water?
<raptop>
as an example, yes.
<B787_300>
or other complex molecule absorption
<raptop>
Fortunately, planets are usually way cooler than stars.
<B787_300>
i would hope so
<B787_300>
so and this is where i could be totally wrong... because the planet atmosphere is so much cooler than the star shouldnt there be absorption on the main emission spikes of the star if the atmosphere contains a good amount of that element?
<raptop>
(Silliness like Kepler-70b and KELT-9b are still cooler than their host stars)
<raptop>
Yes, but with a bunch of caveats.
<B787_300>
i assume one of those is that it would be incredibly hard to see within the uncertainty of the measurements
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<raptop>
eg: stellar emission spectra usually are just from the upper most layers, while most of the light is blackbody with an absorption spectra. To the point that if you can't spacially resolve the star, you only see absoprtion lines barring special cases like extreme mass loss.
<raptop>
Also, 'elements' is doing a lot of work. AIUI, molecular hydrogen lines are different from atomic?
<raptop>
Similiarly, ionization states (eg: sodium gets ionized easily, though atomic sodium has been found in some hot jupiters)
<B787_300>
if you had a spectrometer with enough resolution could you also try doing exoatmospheric soundings? or can you do that right now by knowing when the transit is starting and increase temporal frequency?
<raptop>
I think you already can to some extent.
<raptop>
There are things like measuring linewidths also to try to get pressure-temperature models of atmospheres.
<raptop>
I'm afraid I don't know much of the details.
<B787_300>
just thoughts i had
<raptop>
Eh, it's fine. I just feel like you're assuming that the eggsoplanet community has way more telescope time than we actually do. Like if my Earthfinder(tm) stuff results in a NEID key project survey, we get ~90-120 nights a year.
<raptop>
Normal eggsoplanet surveys are, uh, amusingly limited. I think often <30 nights/year
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<B787_300>
well they should get more telescopes
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<raptop>
Ideally yes, but there's a trend towards fewer larger scopes >_>
<B787_300>
has there been any work on the equivalent of an optical VLB Array?
<B787_300>
although i guess the timing accuracy you would need for the images would be insane
<B787_300>
" Light from the individual telescopes is transported through vacuum tubes to a central Beam Synthesis Facility in which the six beams are combined together." GAHHHHHHHH
<B787_300>
that sounds expensive
<B787_300>
(and a pain to maintain)
<B787_300>
why not use something like an SPD or SPD array and good timing from GPS or other atomic clock source?
<raptop>
SPD?
<B787_300>
Single Photon Detector
<B787_300>
although i guess you would want a really really narrow FOV for that to try to maximize the chance that the photon you are seeing actually came from the desired source
<raptop>
Heh
<raptop>
Hrm. A V = 23.90 star has a flux (in V-band) of 2.42 photons/s/m^2.
<raptop>
So a magnitude 3.9 star (which is actually more reasonable for something like CHARA?) would be about two and a half million photons/s/m^2 o_O
<B787_300>
but that inst inculding the r^4 loss is it?
<raptop>
...r^4 as in (1+z)^4 losses over cosmological distances, or as in radio silliness where photons aren't entirely real?
<B787_300>
which ever makes me sound smarter
<raptop>
If the latter, I would rant about how optical and radio are different, but I don't know enough about radio to do that properly.
<raptop>
If the former, I become mildly concerned at the possibility that someone is trying to do interferometry on objects at non-trivial redshifts.
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<_whitenotifier-1656>
[Principia] eggrobin commented on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhC1S
<_whitenotifier-1656>
[Principia] scimas commented on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhCy3
<_whitenotifier-1656>
[Principia] scimas edited a comment on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhCy3
<SnoopJeDi>
bofh, I feel like you'll appreciate this. I've been doing more footwork for my rat-vocalization project concept, and learned about the basics of SPI in the process. The Broadcom in the RPi zero supports an SCLK up to ~100 MHz, but it turns out that above ~24 MHz, resonance with the trace structure basically destroys any signal!
<SnoopJeDi>
or at least I think that's the right way to phrase it. I don't poke my nose into this electronics business all that often
<whitequark>
it's not resonance
<whitequark>
crosstalk, probably
<SnoopJeDi>
I wish I'd bookmarked it
<SnoopJeDi>
only just now starting to throw the assorted bookmarks and misc. into a doc for design
<SnoopJeDi>
I only need 100+ ksps though, which puts me ~ 10 MHz for the ADC that I think I want to use
<_whitenotifier-1656>
[Principia] eggrobin commented on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhC96
<kmath>
<StandefordO> Because facebook news travels faster than a furloughed NASA … WFC3 UVIS is back online thanks to a fantastic group… https://t.co/kzdgwo5F5L
<_whitenotifier-1656>
[Principia] pleroy commented on issue #2056: Crash when craft breaks in atmosphere with explosions in KSP 1.3.1 with RP-1 (Erdos) - https://git.io/fhCxq
<SnoopJeDi>
explosions causing a crash? ho ho
<_whitenotifier-1656>
[Principia] scimas commented on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhCjm
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<_whitenotifier-1656>
[Principia] eggrobin commented on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhWI9
<_whitenotifier-1656>
[Principia] eggrobin commented on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhWmm
<bofh>
egg: okay, I'm actually starting to have time again, so I'll take a look at it tonight.
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<egg>
bofh: UmbralRaptop: is siging kerman related to sigfig
<raptop>
Yes, via the flower operator
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* egg
meows at Iskierka
<egg>
bofh: ... when I add traces to debug #1868 i can no longer reproduce it
<egg>
Geoffal Kerman
<raptop>
Geopotential Kerman
<raptop>
Karman Kerman
<egg>
Sigly Kerman
<egg>
Newbal and Ferbal Kerman
<bofh>
egg: what the actual hell
<bofh>
load-bearing debug
<egg>
bofh: no but now i can reproduce it again
<egg>
it still makes no sense
<bofh>
ROFL ubuprofen
<bofh>
also what in the hell?
<_whitenotifier-1656>
[Principia] eggrobin commented on issue #1868: Plotting Frame's interaction with stock SAS is inconsistent - https://git.io/fhWZE