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> 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
<egg|laptop|egg>
ok i have managed to get the pinwheel in the field
<egg|laptop|egg>
the cooling system cannot sustain -40 °C in the current weather, only -30 °C
<egg|laptop|egg>
cows are mooing
<raptop>
yay
<egg|laptop|egg>
raptop: should I do 60 60 s exposures, or 120, or more
<raptop>
Depends on how saturated your CCD is getting, how good your tracking is, etc
<egg|laptop|egg>
raptop: I don’t think I want to go beyond 60 s exposures for those factors
<egg|laptop|egg>
mostly wind & tracking
<egg|laptop|egg>
my question is how many exposures
<raptop>
Uh, I'll defer to iximeow
<egg|laptop|egg>
ixi : meow
<raptop>
I mean, "as many as possible" is probably best, but...
<egg|laptop|egg>
yeah more of a compromise with multiplo targots
<egg|laptop|egg>
coldd
<egg|laptop|egg>
typung hacd
<egg|laptop|egg>
put gloen oon
<egg|laptop|egg>
typinc diggeluntly hard
<raptop>
Also, my exposure time calculator is inappropriate for this problem
<raptop>
(though the dispatch scheduler might be okay)
<egg|laptop|egg>
what if i want to find eggsoplanets in M101
<raptop>
uh
<raptop>
May I suggest Lalande 21185, which is in a nearby part of the sky?
<egg|laptop|egg>
OK I can probably do 120 s exposures fine
<egg|laptop|egg>
and that might make stacknig easiel
<egg|laptop|egg>
starting 60 120 s exposures, lowest read noise, sensor at -30 °C
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<raptop>
Hrm, 2 hours plus readout time
<egg|laptop|egg>
readout is probably mostly negligible compared to 120 s :-p
<egg|laptop|egg>
it is cold
<egg|laptop|egg>
shoudl i go back in
<raptop>
Fun fact, NEID's readout time is 30 s
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<egg|cell|egg>
NEID?
<galois>
NEID: NN-EXPLORE Exoplanet Investigations with Doppler spectroscopy (pronounced [ɲɨi̯d], after the Tohono Oʼodham word ñeid)
<raptop>
Fancy visible speggtrograph made by Penn State people and installed on the WIYN
<egg|laptop|egg>
i think a limmit on tota egg/polsure time will be meridion flop
<egg|laptop|egg>
not going to de thue fgindig agains
<egg|laptop|egg>
hm, some image dlift
<egg|laptop|egg>
i shold correct...
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<raptop>
meridian flop... alt-az?
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<iximeow>
raptop: afaik most ccds can continue exposing during readout? so 2hr flat is probably right
<iximeow>
anyway if you can get clear 120s exposures, 120s!!
<SnoopJeDi>
what 9000
<SnoopJeDi>
!wpn iximeow, raptop, et al.
* galois
gives iximeow, raptop, et al. a mercury trachea with a diamond attachment
<raptop>
galois: that is not how you treat COVID-19!
<raptop>
SnoopJeDi: ?
<SnoopJeDi>
oh I was responding to 120s, which is indeed incredible
<SnoopJeDi>
but thinkin' about Dragonball Z because, y'know
<raptop>
Dr Vegeta, how deep is the well in the new CCD?
<raptop>
hrm. egg's scope is 20 cm, and I'm used to thinking about 80 cm - 840 cm ones...
<iximeow>
raptop: over 14 bits !!!
<SnoopJeDi>
mmmm bits
<iximeow>
!wpn bits
* galois
gives bits a cyclomatic accident
<iximeow>
oh no
<SnoopJeDi>
rofl
<SnoopJeDi>
In the words of the bot's alter ego: "Haha holy shit in Haskell"
<raptop>
Fortunately, FITS allows up to 32 bits per pixel
<raptop>
!wpn SnoopJeDi
* galois
gives SnoopJeDi a metalloid loop with a corvid attachment
<raptop>
birb!
<SnoopJeDi>
!wpn raptop
* galois
gives raptop a rusty Paris-Brest
<raptop>
uh
<SnoopJeDi>
!how much bioavailable iron
<galois>
SnoopJeDi: 996 bioavailables
<SnoopJeDi>
wow
<SnoopJeDi>
Can't argue with that
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<raptop>
!wpn egg|laptop|egg
* galois
gives egg|laptop|egg an adjoint Wheeler jump
<raptop>
er, !wpn egg|cell|egg
<egg|cell|egg>
Ok back by the fire waiting for another hour of exposures after correcting an hour's drift
<iximeow>
yay
<egg|cell|egg>
Quite cold, roughly freezing
* raptop
wonders what would happen if we fed the channel logs into GPT-2
<egg|cell|egg>
Not too much wind, forecast says 10 km/h
<galois>
raptop: Your options: wood fire, coal fire, propane/natural gas fire, thermal fission, fast fission, P-P chain, CNO cycle, triple alpha. My choice: CNO cycle
<egg|cell|egg>
Wood fire actually
<egg|cell|egg>
ANBO is primarily heated with fuel oil but there's a fireplace
* raptop
pokes the alternate universe where 100+ superphenix derived reactors were built
<egg|cell|egg>
Should I install a CNO heater as Galois suggests
<egg|cell|egg>
Cat is snoring
<SnoopJeDi>
That's the good stuff
<egg|cell|egg>
See a satellite
<iximeow>
wave hello
<egg|cell|egg>
Bit weird this late in the night
<egg|cell|egg>
Losing the sat at pretty high elevation
<SnoopJeDi>
Bit weird anytime innit? "I see you and will wave this meat so that you know that I see you"
<egg|cell|egg>
No I mean bit weird to see a sat
<egg|cell|egg>
Ixi should I take flats
<iximeow>
probably
<iximeow>
for 2hr i wouldn't be worried about not having flats, depends on how clean your sensor/filters/optics are
<raptop>
Dome flats or sky flats?
<egg|cell|egg>
What dome
<egg|cell|egg>
Could do rag flats maybe
<egg|cell|egg>
Note I have a colour CCD so I guess I should do my flats with a whitish light?
<raptop>
I think?
<raptop>
Cameras without filter wheels are confusing
<raptop>
I guess paper could also work
<raptop>
(for flats)
<egg|cell|egg>
I have white rags that might be easier to dump on the tube
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<egg|cell|egg>
Ixi: okay might skip flats then, but if I'm not taking flats I can take more
<egg|cell|egg>
Lights, should I or should I sleep
<iximeow>
always lights
<iximeow>
never enough lights
<egg|cell|egg>
Uh oh did the computer go to sleep
<raptop>
more lights
<egg|cell|egg>
Fuck it rebooted
<egg|cell|egg>
After 13 exposures of the second batch of 30...
<raptop>
*sad trombone*
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<egg|cell|egg>
Now have 2h of exposures, starting on a third one
<egg|cell|egg>
Will correct drift again
<egg|cell|egg>
Ixi if I do take flats how long should they be
<iximeow>
idk lol 8)
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<UmbralRaptop>
flats can be short
<UmbralRaptop>
Just need the defector to be reasonably illuminated
<UmbralRaptop>
… for eggstra precision, have darks for both flats and lights
<egg|cell|egg>
Hm it's astronomical twilight
<egg|cell|egg>
Maybe I should stop with the lights?
<UmbralRaptop>
yeah
<UmbralRaptop>
I bet you could get sky flats during nautical twilight?
<egg|cell|egg>
Also the field is partly occluded by the house
<egg|cell|egg>
So I guess I just have 2h of lights
<egg|cell|egg>
The wall of the house is white so house flats at dawn might work?
<egg|cell|egg>
But then I need to stay awake until dawn
<UmbralRaptop>
maybe
<UmbralRaptop>
dirty secret of GMU campus telescope dome flats: we just point the telescope at a closed shutter and turn on a 60 watt incandescent light
<egg|cell|egg>
Hah
<egg|cell|egg>
Meh I'll get the scope back in and zzz
<kmath>
<AcademicsSay> If I throw a manuscript into the forest did I just submit it to nature ⏎ ⏎ Contributor: Alexander Lin [FB]
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<egg|laptop|egg>
got the scope back in without detaching the instruments so modulo the fact that I put the lid back on it might be sound to take some flats later on
<egg|laptop|egg>
UmbralRaptop: I guess as long as I don’t disturb the scope further the validity of flats doesn’t degrade by waiting to take them until i have slept ?
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<_whitenotifier-d13c>
[Principia] pleroy closed pull request #2506: Before we had time to fully upgrade to 16.5.0, 16.5.1 was released - https://git.io/Jv9S1
<_whitenotifier-d13c>
[Principia] pleroy pushed 2 commits to master [+0/-0/±4] https://git.io/JvHsY
<_whitenotifier-d13c>
[Principia] pleroy cc40e55 - Before we had time to fully upgrade to 16.5.0, 16.5.1 was released.
<_whitenotifier-d13c>
[Principia] pleroy 649595a - Merge pull request #2506 from pleroy/16.5.1 Before we had time to fully upgrade to 16.5.0, 16.5.1 was released
<kmath>
<iximeow> i can take pictures of galaxies from my porch this is rad https://t.co/YsCpeGARKQ
<UmbralRaptop>
. o O (asymptomatic giant branch stars)
<egg|laptop|egg>
UmbralRaptop: ?
<UmbralRaptop>
asymptomatic looks like asymptotic
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<egg|laptop|egg>
iximeow: do you think taking flats the next day makes sense (not having detached/moved instruments nor touched focus since the observations, although I did move the scope back in and put the objective cap back on)
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<WeylandsWings>
egg|laptop|egg: i think that would be fine as long as the temp/RH is close to the time when you took the images, both ambient and ccd temp.
<egg|laptop|egg>
ah so I need to wait for night again
<egg|laptop|egg>
(the ambient temp has gone up, since my bedroom is not freezing ordinarily)
<egg|laptop|egg>
(and also it is daytime now)
<WeylandsWings>
it might be me over caring about how the air in/near the scope is behaving, os it might be fine now but i dont really know
<egg|laptop|egg>
I suppose I can take darks in the meantime
<egg|laptop|egg>
(assuming that the CCD will be able to cool down to -30 °C from ambient daytime temperatures that is…
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<raptop>
"Noo, you can't just take darks and flats at arbitrary times" "hehe, cooling fan go brr"
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<raptop>
Daytime might be more like -10
<SnoopJeDi>
I love that this meme is coming back for some reason
<SnoopJeDi>
Still used on their intranet I believe
<raptop>
hrm
<raptop>
Well, also, that site is a bit out of date
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<WeylandsWings>
idle thought, put a LSST like telescope in space and have it do planet hunting... could you imagine haw many candidates you would findd?
<raptop>
A lot
<raptop>
Also, all the variable stars
<SnoopJeDi>
Isn't that exactly what TESS is?
<SnoopJeDi>
I mean up to the scale of LSST heheh
<WeylandsWings>
SnoopJeDi: i want the large aperture
<WeylandsWings>
TESS is comparatively small in collection area
<SnoopJeDi>
Fair
<SnoopJeDi>
I don't know enough about the pressing questions to know what the implications would be. My understanding is that the statistics from Kepler are already pretty good, but the hard part is finding smaller and smaller exoplanets?
<WeylandsWings>
i think part of that can be helped by having more sensitivity
<WeylandsWings>
and sensitivity can be helped by collecting more photons
<WeylandsWings>
(and by more efficienctly converting said photons into electrons)
<SnoopJeDi>
well, I also don't know much of anything about TESS and how it differs from previous searches :)
<SnoopJeDi>
but you've sold me!
<WeylandsWings>
UmbralRaptop: would have a better grasp than I. I could help design the spacecraft and the orbit but the optics and post processing are a bit outside my area
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<egg|laptop|egg>
UmbralRaptop: hm I don't have a piece of paper large enough to cover the whole aperture of the scope
<raptop>
Put it a meter away from a wall, I guess
<egg|laptop|egg>
raptop: what are the downsides of just doing the flat on the blue sky
<raptop>
Need very short exposure mainly?
<egg|laptop|egg>
looks like I need to go down to 2 ms exposure with current sky luminosity to not saturate the sensor :-p
<egg|laptop|egg>
is that a problem
<raptop>
Might be other issues since I'm not sure what filters are like on multicolor CCDs
<egg|laptop|egg>
I mean it’s not like I can really do colour balance in a non-arbitrary way
<egg|laptop|egg>
if I just take the channels at face value the image is always green
<egg|laptop|egg>
is the short exposure a problem ? assuming I take a correspondingly short dark that is
<egg|laptop|egg>
I can go all the way to 5 ms now on 16 bits
<egg|laptop|egg>
(sun is setting)
<raptop>
I'd assume that it's bad in terms of some underlying ~systematics~, but that doesn't matter too much
<raptop>
Oh, right. Earth is a sphere
<egg|laptop|egg>
what do you mean re. systematics
<egg|laptop|egg>
also cooling system a bit strained to get to -30 still
<egg|laptop|egg>
I might have to wait some more…
<egg|laptop|egg>
literally watching the sun set on a histogram right now
<raptop>
Errors from making the flats less like the lights that I can't describe/model
<egg|laptop|egg>
ah
<egg|laptop|egg>
I guess if I wait enough for thermal reasons they will become dusk flats anyway
<egg|laptop|egg>
sunset in abotu 30 min
<raptop>
systematic errors as unknown unknowns
<egg|laptop|egg>
but the risk with waiting until sunset is public lighting
<egg|laptop|egg>
which might be worse than blue sky at being a standard light
<egg|laptop|egg>
(I mean, it is reproducible, but not useful)
<raptop>
heh
<egg|laptop|egg>
cooling maintaining 26.3 °C
<egg|laptop|egg>
uh
<egg|laptop|egg>
-26 °C obviously
<egg|laptop|egg>
CCD temp rising, now -26,0 °C…
<egg|laptop|egg>
should I put frozen goose next to the CCD to help the cooling system,
<WeylandsWings>
egg|laptop|egg: do you want to defrost the goose?
<egg|laptop|egg>
yes
<egg|laptop|egg>
but I don’t have a way to put it near the air intake of the CCD fan anyway
<raptop>
Throw the goose in the pond as revenge?
<egg|laptop|egg>
how big of an issue is incorrect CCD temperature for flats
<egg|laptop|egg>
(provided flat darks are consistent)
<egg|laptop|egg>
ah it’s cooling back down to -26,1 °C
<raptop>
shouldn't be a huge one
<raptop>
I hope
<egg|laptop|egg>
OK pointing at the eastern horizon 10-15 min before sunset I can do exposures of 25 ms
<egg|laptop|egg>
will do them at -26 °C
<egg|laptop|egg>
now at 35 ms
<egg|laptop|egg>
OK go for 180 exposures
<egg|laptop|egg>
sky is very much setting while I am doing these…
* egg|laptop|egg
stares at the histogram moving from frame to frame
<raptop>
heh
<egg|laptop|egg>
re. darks, should dark time be equal to light time ?
<egg|laptop|egg>
or longer ?
<raptop>
each dark frame should be the same as the light (or flat) frame. Total number can be lower
<egg|laptop|egg>
how much lower though :-p
<raptop>
*lots*
<raptop>
Like, I think we only do 10 darks for data that goes into actually finding planets
<egg|laptop|egg>
should I level the means of my flat frames before averaging them or should I average them directly
<raptop>
uh, unsure
<WeylandsWings>
egg|laptop|egg: as in normalize the means of all the flats?
<egg|laptop|egg>
yeah
<egg|laptop|egg>
it’s an option in SIPS
<WeylandsWings>
i dont know
<egg|laptop|egg>
(note that the sun was setting as the flats were taken so they do drift)
<WeylandsWings>
you are doing skyflats right?
<egg|laptop|egg>
(otoh, the drift occurs within each exposure as well, so this is just making it one giant exposure…)
<WeylandsWings>
so then maybe you should normalize before averaging
<_whitenotifier-d13c>
[Principia] DarthPointer edited a comment on issue #2507: Undocking causes gamecrash - https://git.io/JvHu0
<egg|laptop|egg>
otoh this has a bayer filter so with changing sky colour leveling means is meaningless
<_whitenotifier-d13c>
[Principia] DarthPointer edited a comment on issue #2507: Undocking causes gamecrash - https://git.io/JvHu0
<_whitenotifier-d13c>
[Principia] DarthPointer edited a comment on issue #2507: Undocking causes gamecrash - https://git.io/JvHu0
<egg|laptop|egg>
yeah the stacking leads to weirdly skewed histograms because of the drift luminosity drift…
<galois>
raptop: Your options: astrophotography, fancy coffee. My choice: fancy coffee
<egg|laptop|egg>
uh oh i am running of disk
<egg|laptop|egg>
s/running/running out/
<galois>
egg|laptop|egg meant to say: uh oh i am running out of disk
<egg|laptop|egg>
I should have turned compression on on the FITS directory…
<egg|laptop|egg>
ah and SIPS doesn’t check that it wrote successfully so I have a bunch of 3 KiB borked darks
<egg|laptop|egg>
hm i cannot see a difference between my dark-corrected and my non-dark-corrected flat
<egg|laptop|egg>
did I screw up,
<egg|laptop|egg>
;rpn 2806 1041 - 1712743 180 / /
<kmath>
egg|laptop|egg: 0.185491927276889
<egg|laptop|egg>
;rpn 1538 1325 - 1712743 180 / /
<kmath>
egg|laptop|egg: 0.02238514476486
<egg|laptop|egg>
most of the range of the dark signal is 2 % of the minimum value of the flat so I guess the only thing it does here is deal with hot pixels
<egg|laptop|egg>
augh the cooling is having trouble sustaining -30 °C even now…
<egg|laptop|egg>
yeah it is rising, now back up to -29 at full cooling utilization
<egg|laptop|egg>
blarg 28.5
<egg|laptop|egg>
how am i going to take my main darks.....
<egg|laptop|egg>
!wpn UmbralRaptop
* galois
gives UmbralRaptop a Linux rubidium enterprise with a moth attachment
<egg|laptop|egg>
!wpn iximeow
* galois
gives iximeow a fungal CCD
<egg|laptop|egg>
!wpn WeylandsWings
* galois
gives WeylandsWings a deadly zombie cat with a kindle attachment
<raptop>
oh no. A cordyceps zombie
<raptop>
!choose baked good|rabbit
<galois>
raptop: Your options: baked good, rabbit. My choice: rabbit
<egg|laptop|egg>
-28.3....
<egg|laptop|egg>
how do i cool the scope halp
<egg|laptop|egg>
(the night is 5 K warmer than yesterday)
<raptop>
Icewater on the warm side of the heat exchanger?
<egg|laptop|egg>
not sure watering the CCD is a very good idea