The Summer Triangle Photographed with an iPhone 7 – October 2017
I took a few photos of the well-known asterism, The
Summer Triangle, on a recent very clear October evening, with my iPhone 7
camera. The early fall can be a great
time for very clear skies around my area, even in a fairly large light polluted
city. I should note that the iPhone takes
a remarkably good “point and forget” astrophotography, but you generally do
have to push it a bit in an image program, like Gimp or Photoshop (or the Apple
app provided). The brightness and
contrast filters are the main ones to use, though some of the other
enhancements can be useful too.
2017 iPhone 7 photo.
Here’s the result, with a little labelling and photo enhancement in
GIMP. I also drew in the imaginary lines, that connect the points of the
triangle.
iPhone Image vs Stellarium Image and Sky and Telescope Image
Below, I have included a picture from Stellarium (the astronomy program)
for comparison. Obviously, the
Stellarium image is designed to be easy to make out the key features of the
asterism – the iPhone image actually picked up a fair number of the brighter
stars. That’s easier to see in the
larger iPhone images, at the beginning of the blog.
And here’s a long exposure, from Sky and Telescope. The actual appearance of the Summer Triangle
will vary with the time of year, latitude and so forth.
Here’s an inverted image (black and white
interchanged). Sometimes those can be
easier to make out.
In some later blogs, I will key in on the constellations that
are part of the Summer Triangle, namely Cygnus, Lyra and Aquilla.
I will use Wiki’s article, to give a brief overview
of the Summer Triangle:
·
It is one
of the easiest asterisms to locate and recognize, on par with the Big Dipper.
·
Whereas
the Big Dipper is in the northern sky (circumpolar for many locations), the
Summer Triangle is in the southern sky.
As the name suggests, it is prominent in the later evening in the
summer, from northern hemisphere locations.
·
The three
bright stars that make up the Summer Triangle are Vega, Deneb and Altair. All are at least magnitude 1, so they are easily
visible even in a light polluted city sky.
·
Vega is
the brightest of the three, at magnitude 0.03.
It is the brightest star of the constellation Lyra.
o
Vega was
actually meant to be exactly magnitude 0, when the magnitude scale was
scientifically established, though it turned out to be off by a bit. Vega is quite big (A0 star) and close (25
light years), so it is very bright and easy to recognize.
o
Through
even a small telescope, it is quite a beautiful object, shining a pure white, a
veritable diamond in the sky.
o
It has
been extensively studied, due to its nearness and brightness. It is baseline star for the various luminosity
scales. Its nearness means that it has
also had its distance measured very accurately, by parallax.
o
It’s a
variable star, but only varies a bit in brightness.
o
It’s
about twice the radius of the sun, so it won’t last as long as our sun (bigger
stars burn out faster).
o
About
12,000 years in the past, it was the pole star, like Polaris is now. About 13,000 years from now, it will be so
again. The pole star changes over time,
due to the precession (wobble) of the Earth’s axis.
o
There is
a debris disc around the star, though it is not clear whether there are
actually any planets.
o
It has
been featured in a lot of stories and legends over the years. In “modern mythology”, it is notable for
being the source of the alien transmissions in Carl Sagan’s novel “Contact”, as
well as in the movie based on that book.
Both of those are highly recommended.
They also feature dodecahedrons and you can’t beat that.
·
Altair is
next brightest, at 0.77 magnitude (though it can appear dimmer, due to being
closer to the horizon, which causes extinction of light, due to the light
having to travel through a longer atmospheric path). It is the brightest star in the constellation
Aquilla.
o
Altair is another A class star, about 1.8
times the mass of our sun.
o
It rotates
very rapidly (about 9 hours vs 25 days for our sun), so is is quite oblate
(flattened).
o
Its
surface has actually been imaged, one of the few stars other than the sun for
which that has been accomplished.
o
It is
also quite close to us, at about 16 light years.
o
Altarian
planets are frequently mentioned in Star Trek. But, for my money, the greatest story that
features Altair is “Forbidden Planet”, a late 1950’s SF classic, that anyone
who is interested in Science Fiction really should see.
o
As of
this time, however, no actual planets have been detected around Altair.
·
Deneb is
the least bright (though still very bright) at magnitude 1.25. It is the brightest star in the constellation
Cygnus, and is part of the asterism the Northern Cross.
o
It is a
blue-white supergiant, with about 19 times the mass of the sun.
o
It is
quite distant, at about 2600 light years, but it’s great size means that it is
still bright in our sky (it’s intrinsic luminosity is about 200000 times that
of our sun).
o
It will
be the pole star in about 10000 years.
o
It will
probably go supernova in some millions of years. But, since it is so far away, that won’t be a
problem for the Earth.
o
There
have been no planets discovered circling Deneb.
Given its size, it is extremely unlikely that life could evolve in that
system, as the star’s lifetime would be too short for that.
o
It’s been
featured a lot in fiction, especially in Star Trek (Encounter at Far Point,
among others). Humphrey Bogart also refers
to it, in the Treasure of the Sierra Madres.
Also, it is featured in the pilot of Blake’s Seven, a fascinating
British SF series of the late 70’/early 80’s.
-----------------------------------------------------------------------------------------------------------------
Now that you have read some real science (astronomy and astrophysics), you
should read some science fiction. Since
the blog mentioned Star Trek, here’s one with some Star Trek references
(implied).
“The Zoo Hypothesis”, an Alien Invasion Story
Here’s a story giving a
possible scenario for the so-called Zoo Hypothesis, known in Star Trek lore as
the Prime Directive. It’s an explanation
sometimes given to account for a mystery in the Search for Intelligent Life,
known as The Great Silence, or Fermi’s Paradox.Basically, Enrico Fermi argued (quite convincingly, to many observers), that there had been ample time for an alien intelligence to colonize the galaxy since its formation, so where are they? The Zoo Hypotheses says that they are out there, but have cordoned off the Earth from contact, until we are sufficiently evolved or culturally advanced to handle the impact of alien contact.
This story takes a humorous tongue in cheek approach to that explanation. It also features dogs and sly references to Star Trek. Talk about man’s Best Friend.
Amazon U.S.: https://www.amazon.com/dp/B076RR1PGD
Amazon U.K.: https://www.amazon.co.uk/dp/B076RR1PGD
Amazon Canada: https://www.amazon.ca/dp/B076RR1PGD
I don't wish to rain on the parade but I was using a compact digital camera to get shots like this and better over 10 years ago. A DSLR gives much better results:
ReplyDeletehttps://www.flickr.com/photos/philippughastronomer/albums/72157666438989044
True, but nearly everyone has a cell phone that they usually carry with them, so it is interesting to see what you can get from a device that is simple to use, and always at hand. I think of it as an encouragement for non-star gazers to look at the sky.
ReplyDeleteBy the way, Philip, I looked at your site and you do some very nice astro-photography.
ReplyDelete