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Hi There!
I'm Dave Hearn, and I'm the Director of Kissimmee Park Observatory, and the Creator
of Star Hopping.
In this week's Star Hopping "Extra", we'll begin a series of episodes dedicated
to help you to plan for and view the Great North American Solar Eclipse in August 2017!
More great stuff about that right after this - Stay Tuned!
<Intro Theme>
Hey Hello Hi and welcome to Episode 54 of Star Hopping!
I'm Dave Hearn, and it just makes me glow to be your host.
In this series of programs we'll show you the most beautiful sights in the night sky,
and explain exactly how to find them with your binoculars or telescope.
So this week we're starting a series of Extra episodes to get you excited and informed
about the Great North American Solar Eclipse, coming up on Monday, August 21st.
For that event, I'm headed to the Mountains of North Georgia, more specifically, the Summit
of Brasstown Bald, the highest point in the state of Georgia.
For this amazing celestial occurrence, I plan to be live streaming coverage of the progress
of the Moon's shadow.
This assumes that the Internet does not completely crash, due to all the information that everyone
will be posting.
If by some chance it does, I'll be creating a documentary of the event, to post here on
YouTube afterwards.
So there are many things to know about this event.
Most basically, what are the celestial mechanics that let a solar eclipse occur?
A total solar eclipse occurs when the Moon, just as it reaches it's New Moon phase,
passes between the Sun and the Earth.
The Sun casts a shadow of the Moon onto the surface of the Earth, and we see a Solar Eclipse.
Now the Moon varies in its orbital distance, so depending on how close or far the Moon
is, we see a different type of eclipse.
If the moon is farther away from the Earth, it doesn't completely cover the Sun, so
we see A Ring of Fire, or Annular eclipse.
If the moon is closer into Earth, it completely obscures the Sun, so we have a Total Eclipse.
That's the case with the August 21st event; with the magnitude of the eclipse being 1.03;
barely large enough to cover the entire sun.
The maximum duration of the eclipse will be 2 minutes, 41 seconds, in or around Carbondale,
Illinois.
The actual path of the eclipse runs from Oregon the whole way to South Carolina, crossing
10 states, so it will be relatively easy for very large numbers of people to see this amazing
solar system event.
Where will you be on that day?
Post your viewing site for watching the eclipse in the comment section below, or on our website
show notes, found at StarHopping.org/sh054/.
There is a lot of hoopla surrounding this eclipse.
With tens of millions of people headed for the zone of totality, it's going to be the
biggest science event in history.
Hotel rooms are being snapped up all along the path of the eclipse, so if you are interested
in standing in the shadow of the moon, you need to book now.
Let's take a short break, and when we come back, I'll give you more info about eclipse
basics - I'll see you right after this.
So now we know what causes the eclipse, so let's talk about some other basic information.
In any eclipse, whether it is of the Sun (known as a solar eclipse) or of the Moon (known
as a lunar eclipse), there are five main events.
The first is First Contact - that's the point where the limb of the Moon first starts
to obscure the disk of the Sun.
The Moon will continue in its path, taking bigger and bigger bites out of the Sun.
Finally we reach the next main event: Second Contact, which is when the total eclipse begins.
Just before this occurs, it is common to see the "Diamond Ring effect", and "Baily's
Beads".
These are caused by valleys on the limb of the moon, that allows sunlight to stream through.
Just after Second Contact, we see the wispy and delicate solar corona; hot gasses that
extend far out into the space around the sun.
This can never be seen normally because the sun's photosphere is too bright.
Minutes later, we reach the third event known as "Maximum Eclipse"; the point when we
are halfway through the entire eclipse event.
In just a few more minutes, we reach the next event: Third Contact, which heralds the end
of the total eclipse, with another appearance of Baily's Beads.
Now we watch more and more of the solar photosphere being exposed, until we reach the last event,
when the limb of the moon passes off the disk of the Sun - this is known as Fourth Contact.
At this point the entire eclipse event is over, and we can pack up our gear and head
back home.
So what other events can we see during a total solar eclipse?
One of the very neat phenomena is the patterns of the sun cast by everyday objects, such
as trees.
Normally, the sun has a perfectly round disk shape, and the patterns seen on the ground
are round.
But between First and Second contact, the sun is shaped like a crescent.
On the ground you will see tiny projections of the solar crescent, formed by the spaces
between the leaves or anything with small holes that let the sunlight pass through.
Another interesting phenomenon is the approach of the moon's shadow as it races across
the land.
If you are high up, the Moon's shadow will be seen approaching from the northwest.
I am really looking forward to see this from the summit of Brasstown Bald.
The shadow will overtake you at the point of Second Contact.
At this event the sky will darken, birds will return to their roosts, the temperature will
drop, and brighter stars and planets will appear in the sky.
It's hard to take the time to note all these events, because the delicate solar corona
will also appear, which is very literally the star of the show.
So with all these wondrous and beautiful events occurring, it is a common reaction to stare
and gaze directly at the Sun.
This is a fairly dangerous situation, and without adequate protection, your eyes can
be damaged by the sun's powerful radiation of light.
Let's take a quick break, and when we come back we'll discuss safety practices during
a total solar eclipse.
Stay Tuned
for more.
All of us have looked
at the sun from time to time, mostly around sunrise or sunset, when the Earth's atmosphere
filters a very large percentage of the illumination.
But once the Sun rises about 20 degrees or so, it becomes blindingly bright, and if you
try to gaze at it directly you are instinctively forced to look away.
Perhaps when you were young, you used a magnifying glass to catch leaves or paper on fire, using
the light of the sun and the magnifying glass to focus a white-hot laser beam of light.
The paper started to smoke and then burst into flames, right?
The lens of the magnifying glass is very similar to the lens in a telescope or binoculars.
So imagine using binoculars to look at the Sun.
Just imagine it, and DONT EVER DO IT!
The objective lenses of the binoculars will focus that intense laser beam of light onto
the retinas of your eye, and will burn them, affecting your vision for the rest of your
life.
Same goes for a telescope, except the light is brighter and hotter when focused.
So I repeat, never, never, NEVER look at the sun directly with an *unfiltered* set of binoculars
or telescope.
So I said "unfiltered" just then.
There are ways to look at the sun safely with binoculars or a telescope, using specially
made solar filters, mounted at the front end of the telescope.
These filters block out more than 99.999% of the heat and light BEFORE it enters your
optical instrument of choice.
This allows you to safely look at the sun and examine the eclipse progress, and hopefully
see a few sunspots on the solar surface.
When using full aperture solar filters, you need to take a few precautions, such as placing
the front lens caps on your finder scope and any guide scopes you might have mounted on
your main telescope.
This will save you in case you instinctively try to look through the finder scope when
trying to center the Sun.
You can look at the ground and line up the shadows of the telescope tube and finder scopes
with the sun.
When everything lines up, you should be able to see the solar disc in your wide field eyepiece.
The only exception to these warnings are during the total eclipse phase, between second and
third contacts.
At this time is is safe to look at the sun without the filters, as the brightness is
similar to that of the full moon.
But this time is brief, because with the appearance of Baily's Beads for the second time, you
will have to replace the solar filters again.
Don't forget to do this; you don't want to get a flash of the photosphere through
your telescope!
So even if you are not using binoculars or your telescope to watch the eclipse, you still
need to provide protection for your eyes.
Don't be fooled into thinking your sunglasses will save you; you need to find some special
eclipse glasses online.
These are essentially solar filters mounted in a pair of cardboard glasses that you can
wear.
These will safely allow you to look up at the sun with just your eyes.
Eclipse glasses are available all over the internet, but I'll provide a link to a good
source in the show notes of this episode, found at StarHopping.org/sh054/.
Again, don't wait to order, as it will be very difficult to get your hands on these
or any other solar observing equipment for that matter, as we get closer to the event.
So let's take another short break, and when we come back, we'll discuss the basic equipment
needed for observing the August solar eclipse.
So what equipment do you need to view the eclipse?
It depends on how much you want to see.
If you are using just your eyes, then eclipse glasses, that I mentioned just before the
break, will do the trick.
if you want to see things in more detail, then you'll need to use binoculars or a telescope.
For binoculars, you'll need to pick up two solar filters.
These will cover the front of the two objectives of binoculars, and should fit snugly.
If you're using a telescope, you'll need to find a larger filter, that will cover the
entire front aperture of the telescope.
The filter needs to fit rather snug so there's no chance of it falling off while observing
the bright sun.
If you are a binocular user, it's really nice to have a binocular stand to hold the binoculars
in place,
so you don't have to hold them up with your hands, which can get very tiring.
For your telescope, you'll need to bring your entire mount, so it can track the Sun and
you can continue to comfortably view as the eclipse proceeds.
If you're into trying to photograph or video the event, which I think will be a very popular
goal, there's a lot of other equipment that you might need and a lot of strategy and planning
that is required in order to capture all of the eclipse events.
I'll be covering that in a later episode in this series.
So that's our introduction to viewing the great American Solar Eclipse of August, 2017.
Stay tuned here in the coming weeks to see more discussions about this event.
Make sure to subscribe to my YouTube channel or the Podcast so you don't miss any of these
important episodes.
So we started out discussing the celestial mechanics that create a solar eclipse.
Then we talked about the five main events that occur in every eclipse whether it's a
lunar or solar eclipse.
Then we discussed the safety practices that you need to be aware of when observing a total
solar eclipse.
And finally, we talked about the basic equipment that you can use to view the eclipse whether
it's just with your own eyes or whether you're using binoculars or a telescope.
I would highly encourage you to really consider making an effort to go see the total solar
eclipse and finding a place in the Moon's shadow, on the centerline.
It's a major lifetime event at everyone should see, and make sure to bring a child with you.
So that does it for this week's episode.
You can find the show notes on our website at StarHopping.org/SH054, where you can comment
and leave any questions that you may have.
You can also contact me personally on Twitter @StarHoppingMan, where I'd love to help
you with any astronomy or observing questions.
So feel free to reach out with your questions - I'm here to help.
Well thank you very much for joining me here.
I know you have many choices of what you can watch online, and I'm very appreciative
that you spend your time learning about astronomy, and hanging out with me.
I'll see you next time with more Star Hopping tips and tricks.
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