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Astronomy Picture of the Day |
APOD: 2025 June 21 – Two Worlds, Two Analemmas
Explanation:
Sure, that figure-8 shaped
curve you get when you mark
the position of the Sun in Earth's sky at the same time each
day over one year is called an analemma.
On the left,
Earth's figure-8 analemma
was traced by combining wide-angle digital images
recorded during the year from December 2011 through December 2012.
But the shape
of an analemma depends on the eccentricity of a planet's
orbit and the tilt of its axis of rotation,
so analemma curves
can look different
for different worlds.
Take Mars for example.
The Red Planet's axial tilt is similar to Earth's, but its orbit around
the same sun
is more eccentric (less circular) than Earth's orbit.
As seen from the Martian surface, the analemma traced
in the right hand panel is shaped more like a tear drop.
The Mars rover Opportunity captured the images used
over the Martian year corresponding to Earth dates July 2006 to June
2008.
Of course, each world's solstice dates still
lie at the top and bottom of their different analemma curves.
The last
Mars
northern summer solstice was May 29, 2025.
Our fair planet's 2025 northern summer solstice is at
June 21, 2:42 UTC.
APOD: 2025 March 20 - The Solar Eclipse Analemma Project
Explanation:
Recorded from 2024 March 10, to 2025 March 1, this
composited series of images
reveals a pattern
in the seasonal drift of the Sun's daily motion
through planet Earth's sky.
Known to some as
an
analemma,
the figure-eight curve was captured in
exposures taken on the indicated dates
only at 18:38 UTC from the exact same
location south of Stephenville, Texas.
The Sun's position on the 2024
solstice dates of June 20 and
December 21 would be at the top and bottom of the curve
and correspond to the astronomical
beginning of summer and winter in the north.
Points that lie along the curve
half-way between
the solstices would mark the equinoxes.
The 2024 equinox on September 22,
and in 2025 the equinox on March 20 (today)
are the start of northern fall and spring.
And since one of the exposures was made on 2024 April 8 from the Stephenville
location at 18:38:40 UTC, this analemma project
also reveals the solar corona
in planet Earth's sky during a
total solar eclipse.
APOD: 2025 January 2 - Solar Analemma 2024
Explanation:
Recorded during 2024, this year-spanning series of images
reveals a pattern
in the seasonal drift of the Sun's daily motion
through planet Earth's sky.
Known to some as
an analemma,
the figure-eight curve was captured in
exposures taken only at 1pm local time on clear days from Kayseri, Turkiye.
Of course the Sun's position on the 2024
solstice dates was at the
top and bottom of the curve.
They correspond to the astronomical
beginning of summer and winter in the north.
The points along the curve
half-way between
the solstices, but not the figure-eight curve crossing point,
mark the 2024
equinoxes and the start of spring and fall.
Regional peaks and dormant volcano Mount Erciyes lie along the southern
horizon in the
2024 timelapse skyscape.
APOD: 2024 December 4 – Driveway Analemma
Explanation:
Does the Sun return to the same spot on the sky every day?
No.
A more visual answer is an
analemma, a composite of sky images taken
at the same time and from the same place over a year.
At completion, you can see that the Sun makes a
figure
8 on the sky.
The featured unusual analemma does not, however,
picture the
Sun
directly: it was created by looking in the
opposite direction.
All that was required was noting where the
shadow of an edge of a
house was in the
driveway every clear day at the same time.
Starting in March in
Falcon,
Colorado,
USA, the photographer methodically marked the shadow's 1 pm location.
In one frame you can even see the
photographer himself.
Although this analemma will be completed in 2025, you can start drawing
your own driveway analemma -- using no fancy equipment --
as soon as today.
APOD: 2023 September 23 - Afternoon Analemma
Explanation:
An analemma is that figure-8 curve
you get when you mark the position
of the Sun at the same time each day for one year.
To make this one, a 4x5 pinhole
camera was set up looking north in
southern New Zealand skies.
The shutter was briefly opened each clear day in the afternoon at 4pm
local time exposing the same
photosensitized glass plate
for the year spanning September 23, 2022 to September 19, 2023.
On two days, the winter and summer solstices,
the shutter was opened again 15 minutes after the main
exposure and remained open until sunset to create the sun trails at
the bottom and top of the curve.
The equinox dates correspond to positions in the middle of the
curve, not the crossover point.
Of course,
the curve itself is inverted compared to an analemma traced
from the northern hemisphere.
And while fall begins today
at the Autumnal Equinox for the northern hemisphere,
it's the Spring Equinox in the south.
APOD: 2022 October 10 - A Double Lunar Analemma over Turkey
Explanation:
An
analemma is that
figure-8 curve you get when you mark
the position of the Sun at the same
time each day for one year.
But the trick to imaging an
analemma of the Moon is to wait bit
longer.
On average the Moon returns to the same position in the sky
about 50 minutes and 29 seconds later each day.
So photograph the Moon 50 minutes 29 seconds
later on successive days.
Over one lunation or lunar month it will trace out an analemma-like curve
as the Moon's actual position wanders due to
its tilted and
elliptical orbit.
Since the
featured image was taken over two months,
it actually shows a double lunar
analemma.
Crescent
lunar phases too thin and faint to capture
around the
New moon
are missing.
The two months the persistent astrophotographer chose were during a
good stretch of weather during July and August, and the location
was Kayseri,
Turkey
APOD: 2022 September 18 - Analemma over the Callanish Stones
Explanation:
If you went outside at the same time every day and
took a picture that included the Sun, how would the Sun's position change?
A more visual answer to that question is an
analemma,
a composite image taken from the same spot at the
same time over the course of a year.
The featured analemma was composed from images
taken every few days at noon near the village of
Callanish in the
Outer Hebrides in
Scotland,
UK.
In the foreground are the
Callanish
Stones,
a stone circle built around 2700 BC during humanity's
Bronze Age.
It is not known if the placement of the
Callanish Stones has or had astronomical significance.
The ultimate causes for the
figure-8 shape of this and all analemmas are the
tilt of the Earth axis
and the
ellipticity of the
Earth's orbit
around the
Sun.
At the solstices,
the Sun will appear at the top or bottom of an analemma.
The featured image was taken near the December solstice and so the Sun appears near the bottom.
Equinoxes, however,
correspond to analemma middle points -- not the intersection point.
This coming Friday at 1:04 am
(UT)
-- Thursday in the
Americas --
is the
equinox ("equal night"),
when day and night are equal over all of planet Earth.
Many
cultures celebrate a change of season at an
equinox.
APOD: 2022 July 2 - Solargraphic Analemmas
Explanation:
For the northern hemisphere June 21 was the summer solstice,
the Sun reaching
its northernmost declination for the year.
That would put it at the top of each of these three
figure-8 curves, or analemmas,
as it passed through the daytime sky over the village of Proboszczow, Poland.
No sequence of digital exposures was used to construct the
remarkable image though.
Using a pinhole camera fixed to face south
during the period June 26, 2021 to June 26, 2022,
the image was formed directly on a single sheet of photographic paper, a
technique known as solargraphy.
The three analemmas are the result of briefly exposing the photo
paper through the pinhole each day at 11:00, 12:00, and 13:00 CET.
Groups of dashed lines on the sides show partial tracks of the Sun
from daily exposures made every 15 minutes.
Over the year-long
solargraphic photo opportunity
clouds blocking the Sun during the pinhole exposures created
the dark gaps.
APOD: 2022 June 21 - Analemma over Taipei
Explanation:
Does the Sun return to the same spot on the sky every day? No.
A better and more visual answer to that question is an
analemma,
a composite of images taken at the
same time
and from the same place over the course of a year.
The featured analemma
was compiled at 4:30 pm many afternoons from
Taiwan during 2021, with the city skyline of
Taipei in the foreground, including tall
Taipei 101.
The Sun's location in December -- at the
December solstice -- is shown on the far left,
while its location at the
June solstice is captured on the far right.
Also shown are the positions of the Sun throughout the rest of the day on the
solstices and
equinoxes.
Today is the
June solstice of 2022, the day in
Earth's northern hemisphere when the
Sun spends the
longest time in the sky.
In many countries, today marks the official beginning of a new
season,
for example winter in Earth's southern hemisphere.
APOD: 2020 May 7 - Analemma of the Moon
Explanation:
An analemma
is that figure-8 curve you get when you mark
the position of the Sun at the same
time each day for one year.
But the trick to imaging an
analemma of the Moon is to wait bit
longer.
On average the
Moon returns
to the same position in the sky
about 50 minutes and 29 seconds later each day.
So photograph the Moon 50 minutes 29 seconds
later on successive days.
Over one lunation or lunar month it will trace out an analemma-like curve
as the Moon's actual position wanders due to
its tilted and elliptical orbit.
To create this composite image of a lunar analemma,
astronomer Gyorgy Soponyai chose a lunar month
from March 26 to April 18 with a good stretch of weather
and a site close to home near Mogyorod, Hungary.
Crescent lunar phases too thin and faint to capture
around the New Moon are missing though.
Facing southwest, the lights of
Budapest
are in the distance of the base image taken on March 27.
APOD: 2019 September 28 - An Analemma of the Sun
Explanation:
This week the equinox found the Sun
near the middle, but not at the crossing point,
of an analemma in its
annual trek through planet Earth's skies.
In this
scenic view,
that graceful, figure-8-shaped curve
was intentionally posed above the iconic Danube River
and the capital city of Hungary.
Looking south from
Budapest's
Margaret Bridge
it combines digital frames taken at exactly the same
time of day (11:44 CET) on dates between
2018 September 24 and 2019 September 15.
That puts
the metropolitan Pest on the left, regal Buda on the right,
and the positions of the Sun on the solstice dates at the top and
bottom of the analemma curve.
December's near solstice Sun is just hidden behind a dramatic cloud bank.
APOD: 2019 June 21 - Sunset Analemma
Explanation:
Today, the
solstice
is at 15:54 Universal
Time, the Sun reaching the northernmost
declination in its yearly journey through planet
Earth's sky.
A June solstice marks
the astronomical
beginning of summer in the northern hemisphere and winter
in the south.
It also brings the north's longest day, the
longest period between sunrise and sunset.
In fact the June solstice sun is near the top, at the most northern
point in the analemma or figure 8 curve traced by the
position of the Sun
in this composite photo.
The
analemma was created (video) from images taken every 10 days
at the same time from June 21, 2018 and June 7, 2019.
The time was chosen to be the year's
earliest
sunset near
the December solstice, so the analemma's lowest point just kisses the
unobstructed sea horizon at the left.
Sunsets arranged
along the horizon toward the right (north)
are centered on the sunset at the September equinox and
end with sunset at
the June solstice.
APOD: 2018 September 23 - Equinox: Analemma over the Callanish Stones
Explanation:
Does the Sun return to the same spot on the sky every day at the same time?
No.
A more visual answer to that question is an
analemma,
a composite image taken from the same spot at the
same time over the course of a year.
The featured analemma was composed from images taken every few days at noon near the village of
Callanish in the
Outer Hebrides in
Scotland,
UK.
In the foreground are the
Callanish Stones, a stone circle built around 2700 BC during humanity's
Bronze Age.
It is not known if the placement of the
Callanish Stones has or had astronomical significance.
The ultimate causes for the
figure-8 shape of this and all analemmas are the
tilt of the Earth axis
and the
ellipticity of the
Earth's orbit
around the
Sun.
At the solstices,
the Sun will appear at the top or bottom of an analemma.
Equinoxes, however,
correspond to analemma middle points -- not the intersection point.
Today at 1:54 am
(UT)
is the
equinox ("equal night"),
when day and night are equal over all of planet Earth.
Many
cultures celebrate a change of season at an
equinox.
APOD: 2016 December 21 - Traces of the Sun
Explanation:
This
year the December Solstice
is today, December 21, at 10:44 UT, the first day of
winter in the north and summer in the south.
To celebrate, watch
this amazing timelapse video tracing the
Sun's apparent movement over an entire year from Hungary.
During the year, a fixed video camera captured an image every minute.
In total, 116,000 exposures follow the Sun's position across the field of
view, starting from the 2015 June 21 solstice through
the 2016 June 20 solstice.
The intervening 2015 December 22
solstice is at the bottom of the frame.
The timelapse sequences constructed show the Sun's movement over
one day to begin with, followed by traces of the
Sun's position during the days of one year, solstice to solstice.
Gaps in the daily curves are due to cloud cover.
The video ends with stunning animation sequences of analemmas,
those figure-8 curves you get by photographing the Sun
at the same time each day throughout a year, stepping across
planet Earth's sky.
APOD: 2016 August 22 - Tutulemma: Solar Eclipse Analemma
Explanation:
If you went outside at exactly the same time every day and took a
picture that included the Sun, how would the Sun's position change?
With great planning
and effort, such a
series of images can be taken.
The figure-8 path
the Sun follows over
the course of a year
is called an analemma.
At the
Winter Solstice in Earth's northern hemisphere, the Sun appears at the bottom of the analemma.
Analemmas created from different latitudes appear
at least slightly different, as well as
analemmas created at a different time each day.
With even greater planning and effort,
the series can include a
total eclipse of the Sun as one of the images.
Pictured is such a total solar eclipse
analemma or Tutulemma -
a term coined by the photographers based on the
Turkish word for eclipse.
The featured composite image sequence was recorded from
Turkey starting
in 2005.
The base image for the sequence is from the
total phase of a solar eclipse as viewed
from Side,
Turkey on 2006 March 29.
Venus was also visible during totality, toward the lower right.
If you want to create your own USA-based tutulemma ending at
next August's total solar eclipse, now would be good time to start.
APOD: 2016 July 29 - Blue Danube Analemma
Explanation:
The Sun's annual
waltz through
planet
Earth's
sky forms a graceful curve known as an analemma.
The
analemma's figure 8 shape is tipped vertically at far right in this
well-composed
fisheye view from Budapest, Hungary.
Captured at a chosen spot on the western bank of the Danube river,
the Sun's position was recorded at 11:44 Central European Time
on individual exposures over days spanning 2015 July 23 to 2016 July 4.
Of course,
on the northern summer solstice the Sun is at the top
of the curve, but at the midpoints for the autumn and spring
equinoxes.
With snow on the ground, the photographer's shadow and equipment bag
also appear in the base picture used for the composite panorama,
taken on 2016 January 7.
On that date, just after the winter solstice,
the Sun was leaving the bottom of the beautiful curve over
the blue Danube.
APOD: 2015 September 23 - Antarctic Analemma
Explanation:
Does the Sun return to the same spot on the sky every day? No.
A better and more visual answer to that question is an
analemma,
a composite image taken from the same spot at the same time over the course of a year.
The featured weekly analemma was taken despite
cold temperatures and
high winds near the
Concordia Station in Antarctica.
The position of the Sun at 4 pm was captured on multiple days in the digital composite image,
believed to be the first analemma constructed from
Antarctica.
The reason the image only shows the Sun from September to
March is because the Sun was below the horizon for much of the rest of the year.
In fact, today being an
equinox, the Sun rises today at the
South Pole
after a six month absence and won't set again until the next
equinox in March, baring
large atmospheric refraction effects.
Conversely, today the Sun sets at the
North Pole
after half a year of continuous daylight.
For all of the Earth in between, though, the
equinox means that today will have a nighttime and daytime that are both 12 hours long.
APOD: 2014 May 16 - Opportunity's Mars Analemma
Explanation:
Staring up into the martian sky, the
Opportunity rover
captured an image at 11:02 AM local mean
time nearly every 3rd sol, or martian day, for 1 martian year.
Of course, the result is this
martian analemma,
a curve tracing the Sun's motion through the
sky in the course of a year (668 sols)
on
the Red Planet.
Spanning Earth dates from July, 16, 2006 to June 2, 2008 the images
are shown composited in
this zenith-centered, fisheye projection.
North is at the top surrounded by a
panoramic sky and landscape made in
late 2007 from inside Victoria crater.
The tinted martian sky is blacked
out around the analemma images to clearly show the Sun's positions.
Unlike Earth's figure-8-shaped analemma,
Mars'
analemma is pear-shaped, because of its similar axial tilt
but more elliptical orbit.
When Mars is farther from the Sun, the Sun progresses slowly in
the martian sky creating the pointy top of the curve.
When close to the Sun and moving quickly, the apparent solar motion
is stretched into the rounded bottom.
For several sols some of the frames are missing due to
rover operations and dust storms.
APOD: 2014 March 20 - Solargraphy Analemmas
Explanation:
Today is the equinox.
The Sun crosses the celestial equator heading north at 16:57 UT, marking
the northern hemisphere's first day of spring.
To celebrate, consider this remarkable image following the Sun's
yearly trek through planet Earth's sky, the first
analemmas
exposed every day through the technique of
solargraphy.
In fact, three analemma curves were captured using a
cylindrical pinhole camera
by daily making three, separate, one minute long
exposures for a year,
from March 1, 2013 to March 1, 2014,
on a single piece of black and white photographic paper.
The well-planned
daily exposures began at 10:30, 12:00, and 13:30, CET
from a balcony looking south from the Kozanów district
in Wrocław, Poland.
That year's two equinoxes on March 20 and
September 22 correspond to
the
mid-points, not the cross-over points,
along the figure-8
shaped curves.
Apparent gaps in the curves are due to cloudy days.
Two solid lines at the lower left were both caused by a timer switch failure
that left the pinhole shutter open.
APOD: 2013 December 22 - Tutulemma: Solar Eclipse Analemma
Explanation:
If you went outside at exactly the same time every day and took a
picture that included the Sun, how would the Sun's position change?
With great planning
and effort, such a
series of images can be taken.
The figure-8 path the Sun follows over
the course of a year
is called an analemma.
Yesterday, the
Winter Solstice
day in Earth's northern hemisphere, the Sun appeared at the bottom of the analemma.
Analemmas created from different latitudes would appear
at least slightly different, as well as analemmas created at a different time each day.
With even greater planning and effort,
the series can include a
total eclipse of the Sun as one of the images.
Pictured is such a total solar eclipse
analemma or Tutulemma -
a term coined by the photographers based on the
Turkish word for eclipse.
The above composite image sequence was recorded from
Turkey starting
in 2005.
The base image for the sequence is from the
total phase of a solar eclipse as viewed
from Side,
Turkey on 2006 March 29.
Venus was also visible during totality, toward the lower right.
APOD: 2013 October 14 - High Noon Analemma Over Azerbaijan
Explanation:
Is the Sun always straight up at noontime?
No.
For example, the Sun never appears directly overhead from
locations
well north or south of the Earth's equator.
Conversely, there is always a place on Earth where the Sun will
appear at zenith at noon -- for example on the equator during an
equinox.
Turning the problem around, however, as in finding where the Sun
actually appears to be at
high noon,
is as easy as waiting for midday, pointing your camera up, and taking a
picture.
If you do this often enough,
you find that as the days march by, the Sun slowly traces out a figure
eight on the sky.
Pictured
above
is one such high noon
analemma --
a series of pictures always taken at exactly noontime over the course of
a year.
The above fisheye image, accumulated mostly during 2012,
also shows some buildings and trees of
Baku,
Azerbaijan around
the edges.
APOD: 2013 September 22 - Apollo's Analemma
Explanation:
Today, the Sun crosses
the celestial equator heading south at 20:44 Universal Time.
An equinox (equal night), this astronomical event marks the
first day of autumn in the northern hemisphere and spring in the south.
With the Sun on the celestial equator, Earth
dwellers will experience
nearly 12
hours of daylight and 12 hours of darkness.
To celebrate, consider
this
remarkable record of the Sun's yearly journey
through planet Earth's sky, made with planned multiple exposures
captured on a single piece of 35 millimeter film.
Exposures were made at the same time of day
(9:00am local time), capturing the Sun's position on dates from
January 7 through December 20, 2003.
The multiple suns trace an intersecting curve
known as
an analemma.
A foreground base exposure of the
Temple
of Apollo in ancient Corinth, Greece,
appropriate for an analemma,
was digitally merged with the film image.
Equinox dates correspond to the middle points
(not the intersection point)
of
the analemma.
The curve is oriented at the corresponding direction
and altitude for the temple,
so the Sun's position for the September equinox is at the
upper midpoint near picture center.
Summer and winter solstices are at analemma top and bottom.
APOD: 2012 September 22 - Austrian Analemma
Explanation:
Today, the
Sun crosses
the celestial equator heading south at 14:49 Universal Time.
An equinox (equal night), this astronomical event marks the
first day of autumn in the northern hemisphere and spring in the south.
With the Sun on the celestial equator, Earth
dwellers will experience
nearly
12 hours of daylight and 12 hours of darkness.
To celebrate, consider
this
careful record of the Sun's yearly journey
through southern Austrian skies.
The
scene is composed of images made at the same time each day,
capturing the Sun's position on dates from
September
29, 2011 through September 9, 2012.
The multiple suns trace an intersecting curve
known as
an analemma.
In fact, the past year's two equinox dates correspond to the middle
(not the intersection point)
of
the curve.
The summer and winter solstices are at the top and bottom.
Of course, many would also consider it a good idea
to travel the mountain road toward the left,
passing the vineyards along the way to reach the nearby town of
Kitzeck
and toast the equinox with a glass of wine.
Near the roadside bench is a
windmill-like
klapotetz,
traditionally used in this wine-growing region to keep the birds away.
APOD: 2012 September 20 - Sunrise Analemma (with a little extra)
Explanation:
An analemma is that figure-8 curve that
you get when you
mark the position
of the Sun at the same time each day
throughout
planet Earth's year.
In this case, a composite of 17 individual images taken at 0231 UT
on dates between April 2 and September 16 follows half the analemma curve.
The scene looks east
toward the rising sun and the Caspian sea from the boardwalk in the port
city of Baku, Azerbaijan.
With the sun nearest the horizon, those dates almost span the period
between the 2012 equinoxes on
March 20 and September 22.
The northern summer Solstice
on June 20 corresponds to the top of the
figure 8 at the left, when the Sun stood at its northernmost
declination.
Of course,
this year the exposure made on June 6 contained a little
something extra.
Slightly enhanced, the little black spot on the bright solar disk near
the top of the frame is planet Venus, caught in
a rare transit during
this well-planned sunrise analemma project.
APOD: 2010 December 31 - Analemma 2010
Explanation:
Looking
back on the year, have you wondered
where the Sun was in the sky each day during 2010 at exacty 9am
UT?
Of course you have. Search no further for the answer!
It was somewhere along this celestial figure 8 curve known
as an analemma.
Recorded from a residential backyard in the small town of
Veszprem, Hungary,
this
composite analemma image consists of
36 separate exposures of the Sun made at 9:00 UT, spaced
throughout the year, plus a background image made without a solar filter.
The background image was taken on the sunny afternoon
of October 9 (13:45 UT).
On the left is the photographer's shadow.
The positions of the Sun at the 2010
solstice dates
are at the upper (June 21) and lower (December 21) extremes of
the
analemma curve.
On the equinox dates (March 20, September 23) the Sun was
along the curve
half way between the solstices.
The tilt of planet Earth's axis and the variation in speed as it moves
around its elliptical orbit combine to produce the graceful
analemma curve.
APOD: 2010 December 21 - Tyrrhenian Sea and Solstice Sky
Explanation:
Today the solstice occurs at 23:38
Universal Time,
the Sun reaching its southernmost
declination in planet
Earth's sky.
Of course, the
December
solstice marks
the beginning of
winter in the northern hemisphere and summer in the south.
When viewed from northern latitudes,
and as shown in the above horizontally
compressed image, the Sun will make its
lowest arc
through the sky along the southern horizon.
So in the north, the
solstice day has the shortest length of time between
sunrise and sunset and fewest hours of daylight.
This striking composite image follows the Sun's path through the December solstice day of 2005 in a beautiful blue
sky, looking down the
Tyrrhenian Sea
coast from Santa Severa toward Fiumicino, Italy.
The view covers about 115 degrees in 43 separate, well-planned
exposures from sunrise to sunset.
APOD: 2009 December 20 - Tutulemma: Solar Eclipse Analemma
Explanation:
If you went outside at exactly the same time every day and took a
picture that included the Sun, how would the Sun appear to move?
With great planning
and effort, such a
series of images can be taken.
The figure-8 path the Sun follows over
the course of a year
is called an analemma.
This coming Tuesday, the
Winter Solstice
day in Earth's northern hemisphere, the Sun will be at the bottom of the analemma.
Analemmas created from different latitudes would appear at least slightly different, as well as analemmas created at a different time each day.
With even greater planning and effort,
the series can include a
total eclipse of the Sun as one of the images.
Pictured is such a total solar eclipse
analemma
or Tutulemma -
a term coined by the photographers based on the Turkish word for eclipse.
The composite image sequence was recorded from
Turkey starting
in 2005.
The base image for the sequence is from the
total phase of a solar eclipse as viewed
from Side,
Turkey on 2006 March 29.
Venus was also visible during totality, toward the lower right.
APOD: 2008 December 21 - Analemma Over the Porch of Maidens
Explanation:
If you took a picture of the Sun at the same time each day,
would it remain in the same position?
The answer is no, and the shape traced out by the
Sun over the course of a year is called an
analemma.
The Sun's apparent shift is caused by the
Earth's motion around the Sun when combined with the
tilt of the Earth's rotation axis.
The Sun will appear at its highest point of the
analemma during
summer and at its lowest during
winter.
Today, the Winter Solstice day in Earth's northern hemisphere,
the Sun is at the bottom of the analemma.
Analemmas
created from different
latitudes
would appear at least slightly different, as well as
analemmas
created at a different time each day.
This particular analemma was built up by 46 separate
Sun photographs taken during 2003 in
Athens,
Greece.
Pictured in the foreground of
this composite image are pillars called the
Porch of Maidens, part of the ancient
Erechtheum
which was completed in 407 BC.
APOD: 2007 December 4 - Movie: Analemma Over New Jersey
Explanation:
An analemma
is that figure-8 curve that you get when
you mark
the position of the Sun at the same time
each day throughout planet
Earth's year.
Above,
26 separate exposures were recorded to illustrate
the regular solar motion -- a difficult
project performed mostly during the calendar year 2006.
The images were taken at 8 am in the morning in northern
New Jersey,
USA,
and digitally combined with a single foreground image later.
The individual images have since been combined into
a movie.
Solstices
correspond to the top and bottom of the figure-8, indicating the
northern and southernmost excursions of the Sun in the sky.
The tilt of planet
Earth's axis
and the variation in speed as it moves around its orbit combine to
produce the graceful
analemma curve.
APOD: 2007 October 2 - Tutulemma: Solar Eclipse Analemma
Explanation:
If you went outside at exactly the same time every day and took a
picture that included the Sun, how would the Sun appear to move?
With great planning
and effort, such a series of images can be taken.
The figure-8 path the Sun follows over
the
course of a year
is called an analemma.
With even greater planning and effort,
the series can include a
total eclipse of the Sun as one of the images.
Pictured is such a total solar eclipse
analemma
or Tutulemma -
a term coined by the photographers based on the Turkish word for eclipse.
The composite image sequence was recorded from
Turkey starting
in 2005.
The base image for the sequence is from the
total phase of a solar eclipse as viewed
from Side,
Turkey on 2006 March 29.
Venus was also visible during totality, toward the lower right.
APOD: 2007 June 17 - Analemma over Ukraine
Explanation:
If you took a picture of the Sun at the same time each day,
would it remain in the same position?
The answer is no, and the shape traced out by the
Sun over the course of a year is called an
analemma.
The Sun's apparent shift is caused by the
Earth's motion around the Sun when combined with the
tilt of the Earth's rotation axis.
The Sun will appear at its highest point of the
analemma during
summer and at its lowest during
winter.
Analemmas
created from different Earth
latitudes
would appear at least slightly different, as well as
analemmas
created at a different time each day.
The analemma pictured to the left was built up by
Sun photographs taken from 1998 August
through 1999 August from
Ukraine.
The foreground picture from the same location was taken
during the early evening in 1999 July.
APOD: 2006 December 30 - Martian Analemma
Explanation:
On planet Earth, an analemma
is the figure-8 loop
you get when
you mark the position of the Sun at the same time each day
throughout the year.
But similarly marking the position of
the Sun in the Martian sky would produce the simpler,
stretched
pear shape in this digital illustration,
based on the Mars Pathfinder project's
famous Presidential Panorama
view from the surface.
The simulation shows the late
afternoon
Sun that would have been
seen from the
Sagan
Memorial Station once every 30
Martian days
(sols) beginning on Pathfinder's Sol 24 (July 29, 1997).
Slightly less bright, the simulated Sun is only about two thirds
the size as seen from Earth, while the
Martian
dust, responsible for
the reddish sky of Mars, also scatters some blue light around
the solar disk.
APOD: 2006 December 23 - The Analemma and the Temple of Olympian Zeus
Explanation:
An analemma
is that figure-8 curve you get when
you mark
the position of the Sun at the same time
each day throughout planet
Earth's year.
Above,
47 separate exposures (plus one foreground exposure)
were recorded on a single piece of film to illustrate
this annual cycle of solar motion from March 30, 2003 to March 30, 2004.
In the remarkable foreground are standing Corinthian columns of the
ancient
Temple of Olympian Zeus
in Athens, Greece.
Solstices, like the one
that occurred at 0022 UT on December 22,
correspond to the bottom of the figure-8 or the
southernmost excursion of the Sun in the sky.
The tilt of planet Earth's axis and the variation in speed as
it moves around its orbit combine to produce the graceful
analemma curve.
APOD: 2005 July 13 - Analemma of the Moon
Explanation:
An analemma
is that figure-8 curve you get when you mark
the position of the Sun at the same
time each day for one year.
But the trick to imaging
an analemma of the Moon is to understand
that on average the
Moon
returns to the same position in the sky
about 51 minutes later each day.
So, if you
photograph
the Moon 51 minutes later on successive days, over
one lunation or
lunar month it will trace out an
analemma-like curve as the actual position of the Moon
wanders compared to the average --
due to the Moon's tilted and elliptical orbit.
For this excellent demonstration of the lunar analemma, astronomer
Rich Richins chose the lunar month containing this year's
northern hemisphere
summer
solstice.
The southernmost
Full Moon rises at the lower right
above the Organ Mountains in southern New Mexico, USA,
with the New Moon phase at the upper left.
The multiple exposure image required some digital
manipulation, particularly to include thin crescent phases in
daytime
skies.
APOD: 2004 June 21 - Analemma Over Ancient Nemea
Explanation:
An analemma
is that figure-8 curve that you get when
you mark
the position of the Sun at the same time
each day throughout planet
Earth's year.
Above, 44 separate
exposures (plus one foreground exposure)
were recorded on a single piece of film to illustrate
the regular solar motion -- a Herculean task performed
during the calendar year 2003.
Appropriately, in the foreground are the ruins at
Ancient Nemea where the hero of Greek Mythology pursued
the first of his twelve labours.
Solstices, like the one
that occurred at 0057 UT on June 21,
correspond to the top and bottom of the figure-8 or the
northern and southernmost excursions of the Sun in the sky.
The tilt of planet Earth's axis and the variation in speed as
it moves around its orbit combine to produce the graceful
analemma
curve.
APOD: 2003 June 26 - Martian Analemma
Explanation:
On planet Earth, an analemma
is the figure-8 loop
you get when
you mark the position of the Sun at the same time each day
throughout the year.
But similarly marking the position of
the Sun in the Martian sky would produce the simpler,
stretched
pear shape in
this
digital illustration,
based on the Mars Pathfinder project's
famous Presidential Panorama
view from the surface.
The simulation shows the late
afternoon
Sun that would have been
seen from the
Sagan
Memorial Station once every 30 Martian
days (sols) beginning on Sol 24 (July 29, 1997).
Slightly less bright, the simulated Sun is only about two thirds
the size as seen from Earth, while the
Martian
dust, responsible for
the reddish sky of Mars, also scatters some blue light around
the solar disk.
Astronomer Dennis Mammana offers the illustration to mark
the hopeful beginning of an exciting new era of
robotic exploration
of the Red Planet, with two new
Mars missions
now enroute
and one preparing to launch.
APOD: 2003 March 20 - Sunrise Analemma
Explanation:
Astronomically speaking, at the Equinox on
March 21, 0100 UT (March 20, 8:00 PM ET) the season changes.
For this Equinox the Sun rises
due east as it crosses the celestial equator heading north.
In celebration, consider this spectacular sunrise analemma!
An
analemma is the figure-8 loop you get when you mark the
position of the Sun at the same time each day throughout the year.
In
this remarkable case, 38 separate exposures
(and 1 foreground exposure) were recorded on a single piece of film
between January 12 and December 21, 2002 at 0600 UT.
The tilt of planet Earth's axis and the variation
in speed as it moves around its
elliptical orbit combine to produce the
predictable analemma curve.
The top and bottom of the figure-8 correspond to the
Solstices -- the Northern
and Southern limits of the Sun's sky motion.
The two Equinoxes
find the
Sun at points along the
anelemma curve exactly half way between the Solstices.
Here, the analemma's Southern portion is partly hidden by
mountains.
In the foreground
lie the stone ruins of
the Tholos
at the ancient site of Delphi, Greece.
APOD: 2002 July 9 - Analemma
Explanation:
If you took a picture of the Sun at the same time each day,
would it remain in the same position?
The answer is no, and the shape traced out by the
Sun over the course of a year is called an
analemma.
The Sun's apparent shift is caused by the
Earth's motion around the Sun when combined with the
tilt of the Earth's rotation axis.
The Sun will appear at its highest point of the
analemma during
summer and at its lowest during
winter.
Analemmas
created from different Earth
latitudes would appear at
least slightly different, as well as
analemmas created at a different time each day.
The analemma pictured to the left was built up by
Sun photographs taken from 1998 August
through 1999 August from
Ukraine.
The foreground picture from the same location was taken
during the early evening in 1999 July.