ActivityGuideforHowDarkDoestheSkyGetDuringaSolarEclipse?
www.globeatnight.org/eclipse-2017/
August21,2017
“On August 21, 2017, millions of people across the United
States will see nature's most wondrous spectacle — a total
eclipse of the Sun. It is a scene of unimaginable beauty; the
Moon completely blocks the Sun, daytime becomes a deep
twilight,andtheSun’scoronashimmersinthedarkenedsky.”
Formoreinformationonthetotalsolareclipse(e.g.,locations
for the eclipse path and the local times for totality), visit
www.greatamericaneclipse.com.
If you are on or near the centerline of the path of totality
during the solar eclipse on August 21, 2017, you are able to
participate in an activity to observe and record the faintest
stars visible as a means of measuring how dark the daytime
sky gets. By locating and observing the constellation Ursa
Major (e.g, the Big Dipper) midway during the solar eclipse
and comparing it to stellar charts, your “measurement” and
submission of that measurement to the online database will
documentdarknesslevelsofadaytimeskyduringatotalsolar
eclipse.Yourmeasurementwillhelpscientificresearch.
Tohelptheresearchmore,youcanalsotakeregularGlobeat
NightmeasurementsofthenightskybrightnessonAugust20
andAugust21forcomparisonwiththeeclipsemeasurements.
To take the nighttime Globe at Night measurements, go to
www.globeatnight.org/webapp/.Thestepsaresimilartothe
onesdescribedhereunder“EasyStepstoDoThisActivity”.
MaterialsNeededtoDoThisActivity:
All you need is a smart mobile device and internet access to
www.globeatnight.org/eclipse-2017/webapp/ for the report
page,
OR you can use the paper version of the report page in this
guide&submityourobservation(s)totheURLaddresslater.
Remember:SafetyFirst!
• When any part of the Sun is visible, do not look at the Sun
withoutapprovedsolarfilterssuchaseclipseglassesfroma
reputablesourcethatareusedproperly.Failuretoheedthis
rulemayresultinpermanenteyedamage.
•Duringthetwoandahalfminutesofthetotalsolareclipse,
itissafetolookdirectlyattheSun'scoronawithyoureyes.
However, when totality ends and the sky suddenly
brightens, immediately turn your eyes away and put your
solarfiltersoreclipseglassesbackon.
Spendthefirstminuteoftotalityconcentratingyourattention
ontheSun’scoronaandthelightshowinthesky.Thenspend
thenextminuteoftotalitydoingthefollowingGlobeatNight
activity to measure the darkness of the daytime sky during
totality.Noeclipseglassesareneededforthisactivity.
1) Record local time. Using the online report page, the time
will be automatically inputted if you are using a smart
device.Otherwiserecordthelocaltimeontheonlinereport
pageorthepaperversion(page3)ofthereportpage.
2)Recordyourlocation(latitudeandlongitude)usingeither:
a. The interactive tool on the online report page at
www.globeatnight.org/eclipse-2017/webapp/. With a smart
cell phone or tablet, the latitude and longitude are
automatically determined as you report the observation. If
you are reporting it later from your computer, input the
address of the observation or input your city. Zoom in/out
andpanarounduntilyoufindtheobservationlocation.The
latitudeandlongitudewillbedisplayed.
b. A GPS unit where you take a measurement. Report as
manydecimalplacesastheunitprovides.
c.Atopographicmapofyourarea.
3) Find your constellation. No matter where you are on the
solareclipsepathcenterline,theplanetVenusandthestar
Capella will be visible during totality. Besides the eclipse,
they will be the brightest objects in the sky. Look between
them and follow an imaginary line toward your eastern
horizon(fortheNWUSA)oryournortheasternhorizon(for
theSEUSA).Asyoudoso,youwillseestarsthatformabig
dipperorspoon(UrsaMajor).
4) Match your sky to one of our magnitude charts using the
online report page at www.globeatnight.org/eclipse2017/webapp/ or the paper version (page 2). Select and
reportthechartthatmostcloselyresembleswhatyousee.
5) Estimate the cloud cover. Select and report one of the 4
illustrationsthatmostcloselyresembleswhatyousee:clear
sky, 25% of sky covered by clouds, 50% covered, or more
than50%covered.
6) Sky Quality Meter measurements are optional. See
Unihedron.comformoreinformationonthesedevices.
Chartsinthisdocumentwereprepared
byJenikHollan,CzechGlobe
http://amper.ped.muni.cz/jenik/astro/maps/GaNight/2017/201708-21SolEcl/).
EasyStepstoDoThisActivity:
Compareyourobservation(s)toothersalongtheeclipsepath.
Check back at www.globeatnight.org/eclipse-2017/ at a later
datetoviewthemapofmeasurementsorbecomepartofour
GlobeatNightFacebookpagetobenotified.
ActivityGuideforHowDarkDoestheSkyGetDuringaSolarEclipse?
www.globeatnight.org/eclipse-2017/
August21,2017
Magnitude_Below_1_Chart:
Magnitude_1_Chart:
ter
Jupi
Jupi
ter
us
ur
ru
ctu
Ar
N
N
ct
Ar
s
E
E
< 0.50 mag
< 1.50 mag
Magnitude_2_Chart:
Magnitude_3_Chart:
Jupi
ter
ter
Jupi
s
ru
ctu
Ar
N
N
s
ru
ctu
r
A
E
E
< 3.50 mag
< 2.50 mag
Magnitude_4_Chart:
Magnitude_5_Chart:
rus
ctu
Ar
< 4.50 mag
< 5.50 mag
ActivityGuideforHowDarkDoestheSkyGetDuringaSolarEclipse?
www.globeatnight.org/eclipse-2017/
August21,2017
Onlyfieldsmarkedby*arerequired.
*Month:___August_____*Day:____21______
*Year:___2017_____
*ObservationTime:____:____PMlocaltime(HH:MM) *Country:___USA______________
*Latitude(indeg/min/sec _____deg____min_____sec
(North)
ordecimaldegrees): _________decimaldegrees *Longitude(indeg/min/sec _____deg____min_____sec
(West)
ordecimaldegrees): _________decimaldegrees
Commentsonlocation:(e.g.Thereisbuildingwithin50mtotheNEthatisblockingmyview.)
r
ctu
us
ctu
s
ru
er
Jupit
s
ru
N
E
< 1.50 mag
¡ Nostarsvisible
Ar
E
E
< 0.50 mag
ctu
Ar
N
N
Ar
Jupit
Jupit
er
er
* Matchyoursolareclipseddaytimeskytooneofourmagnitudecharts:
< 2.50 mag
¡ Magnitude1Chart
¡ Magnitude2Chart
Jupit
er
s
N
ru
ctu
Ar
s
uru
E
ct
Ar
¡ Magnitude3Chart
< 5.50 mag
< 4.50 mag
< 3.50 mag
¡ Magnitude4Chart
¡ Magnitude5Chart
ReadingfromtheUnihedronSkyQualityMeter(ifapplicable):_________
SerialnumberfromtheUnihedronSkyQualityMeter(optional):_________
*Estimatethecloudcoverinthesky:
¡ Cloudscover>½ofsky
¡ Clear
¡ Cloudscover¼ofsky¡ Cloudscover½ofsky
Commentsonskyconditions:(e.g.alittlehazetothenortheast)
Reportonlineatwww.globeatnight.org/eclipse-2017/.