Post-Eclipse Update: Here is a mid-eclipse photo from
my back porch.
Multiple eclipse images seen in tree shadow - Joe Cahak
It's finally here - the Great North American total solar eclipse of 2017! The amateur astronomy
community has been anticipating and preparing for the event for a couple years.
(to which I subscribe) dedicated the entire August issue to providing detailed information
on viewing suggestions along the entire path. Traffic from the Pacific Coast of Oregon to
the Atlantic Coast of South Carolina will probably be a challenge as people vie for positions
as close to the centerline as possible. Those who manage optimal locations will see about
2 minutes and 40 seconds of total darkness. Others within the 68-mile-wide path of totality
will see from a fraction of a second up to the full extent.
According to a calculator on the
Vox website, we in Erie will only see a 76.2% eclipse, which will barely
darken our skies. The app on the webpage detects your location and displays an animation showing
the moon's transition across the sun, with an approximation of the relative degree of darkness
as it passes. According to astronomers who have witnessed many solar eclipses in varying degrees
of totality, you need to be within about 95% to have a very noticeable change in light level.
They compare it to a dark cloud moving in front of the sun. By comparison, a full moon at
perigee reflects around 12% of the sun's light.
Melanie and I had planned to drive the 475 miles down
to South Carolina to view the eclipse in the path of totality, but won't be able to go so
we'll just have to rely on reports of others. Bummer. If I manage to live until April 8, 2024
- a mere 6-½ years away, the next total solar eclipse will run right through my back
yard (see 2024
eclipse map to right). That will be convenient.
Amateur radio operators have a full slate of events, tests, and measurements planned for
the day. Visit the
ARRL website for information about the
Eclipse QSO Party and other goings on. Data regarding propagation properties along the
path of totality will provide indirect observation of ionospheric activity in the various
layers. Will the F1 and F2 layers which typically combine at nightfall do so during totality?
Direct measurements of the ionosphere were first made in the 1950s, with much effort being
expended during the International Geophysical Year of 1957-58 (see "Electronics and the IGY,"
Part I and
Part II, in the February and March 1958, respectively, Radio Electronics
magazine). Measurements have been made previously during total eclipses in other parts of
the world, of course, but this is the first chance American Hams have had the opportunity
since February 6, 1979. Hams participated in the August 31, 1932, total solar eclipse which
crossed the United States, whereupon a report titled, "Amateur
Observations During the Total Eclipse of the Sun," appeared in the January 1933 issue
of QST magazine.
NASA has a web page with
tips for viewing the solar eclipse safely. I have a couple large pieces of#14 welders glass
to use. Lots of stories have appeared recently about how to
protect your pets' eyes in case they're curious (or unlucky) enough to
look at the sun during the partial eclipse phases. Be sure to not let babies or incapacitated
people face the sun during that time, either. Finally, be vigilant during the eclipse, especially
during totality, since there are plenty of scumbag people who will be roaming about looking
for victims. Don't let the criminals exploit what they believe will be a gun-free zone - if
you get my drift!
Posted August 21, 2017
These original Kirt's Cogitations™
may be reproduced (no more than 5, please) provided proper credit is given to me, Kirt
– noun: Concerted thought or reflection; meditation; contemplation.
Kirt [kert] – proper noun: RF Cafe webmaster.
These items are an archive of past Topical Smorgasbord items that have appeared on the RF Cafe homepage. In keeping with the "cafe"
genre, these tidbits of information are truly a smorgasbord of topics. They all pertain to topics that are related to the general engineering
and science theme of RF Cafe. Note: There is also a huge collection of my 'Factoids' (aka 'Kirt's Cogitations') that might interest you as well.
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