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most people think of astronomy as a
nighttime activity
but if you're like me and hate staying
up late you're in luck
as it turns out there's a whole lot of
fascinating celestial objects and
phenomena
that can only be observed in the bright
light of day
and this is great news for you city
dwellers you can get just as good of you
as stargazers
located in places where light pollution
isn't an issue
from the moon to the stars to various
planets and astronomical events
there's a whole sky to explore before
the sun
dips below the horizon
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it may not seem obvious but as i like to
remind my students
the closest star to us is actually the
sun
that massive glowing ball of mostly
hydrogen and helium is pretty hard to
miss especially considering that it
fuels
all life on earth paradoxically the sun
is also an
object that we really need to avoid
looking at directly
but safely observing the sun is possible
with some creative maneuvering
one approach is to take a telescope and
fit a special solar filter over its
front end
so that the sun's brightness and its
harmful wavelengths get blocked
another safe way to get a look at the
sun is to project its image
onto a white card place the card behind
a small telescope or a pair of
binoculars
focus the eyepiece a little and the
sun's visible surface will come
into view but what do actual astronomers
use to view the sun
we asked gerald mckeegan an astronomer
who actually works right here at chabot
space and science center
okay this is a specialized telescope
this telescope is designed
only for looking at the sun and it looks
at
the sun using only one wavelength of
light that's produced by
hot hydrogen on the sun which is kind of
a reddish orange color
so when i look into the telescope i can
see a lot more detail
i can see faculae these are like bubbles
on the surface of the sun
it's caused by the convection in the sun
we can also see
solar prominences some gas being pushed
off
the surface of the sun i can see
a couple of flares so if we put this
type of a white light
filter on the telescope it blocks more
than 99
of the light as i look through here i
can see
the white disk of the sun and one of the
cool things that i can see right away
is there are a couple sunspots on the
sun
sunspots are the darker regions of our
star's surface
they can be as big as the size of our
planet
the sun's magnetic field lines are so
tangled up in these regions
that heat can no longer escape but
occasionally
a sudden release of this concentrated
energy will happen
resulting in solar flares and coronal
mass ejections
that carry radiation and energetic
particles out
so far that they disrupt our power grids
here on earth
just like the sun the moon can also be
seen during the day
it just doesn't always grab as much of
our attention
look for it before a full moon in the
afternoon and
after a full moon in the morning when
it's in a thick crescent phase
and the sky is clear and blue and if you
look
really close on the right day you might
even see
a smaller crescent sitting beside the
moon
that bright spot is venus if venus is up
in the daytime which it often is
and if it's far enough away from the sun
you can actually point this telescope
that venus without a filter if venus is
at the right angle you'll see it
having phases like the moon has phases
venus changes position in the sky from
day to day and even hour by hour
you have to be able to point the
telescope accurately
and to do that you need to know the
coordinates of
venus on the day that you're going to be
looking
for nearly all astronomical pursuits
timing is
everything but for daytime astronomy it
can be especially important
one of the things you've got to keep in
mind is that the earth is
orbiting around the sun at 30 kilometers
per second
so if your clock is off by just a few
seconds
and you're trying to accurately plot the
position of
an object in the sky being off by three
or four seconds means
your position is going to be off by 30
60 90 or more kilometers
so it's real important that you have
very accurate timing if you're going to
be making
scientific observations with your
telescope
a prime example of this is a phenomenon
you may have heard of
and even tried to see yourself the green
flash
this flash happens when the sun's upper
rim turns green
for a few split seconds as it sets and
rises beyond the horizon
it's most commonly spotted over the
ocean but
mountaintops and high buildings offer a
good vantage point too
another site worth catching during the
dwindling daylight is earth shadow
that's right if you find yourself in a
place that's wide open
to the east at sunset or to the west at
sunrise
you'll actually be able to see our
planet's shadow
reflected on the atmosphere just look
for a blue grey band
across the horizon that's opposite the
sunset or sunrise
it'll resemble a haze or an approaching
storm
one of my favorite daytime viewing
experiences
is when there is a solar eclipse if
you're in the right place
on the earth at the right time you can
actually watch the moon
passing in front of the sun you not only
see the detail on the sun like sunspots
but you can see the silhouette of
mountains
as the edge of the moon passes in front
of the sun
so there you have it astronomy isn't
just for those of us who
like to or have to stay up late
next time you're outside look for venus
beside the moon
or earth casting its shadow on us it's a
vast sky
and there's truly something for everyone
to discover
i'm seraphina nance and this is seeker
constellations
if there's another astronomy topic you'd
like to see us cover
let us know down in the comments thanks
for watching
you