APOD: A Picturesque Equinox Sunset (2016 Mar 20)

[Chris Peterson]

I'll bite on this one. I notice that the picture taker's company is located in Laurel, MD. And living in the DC area, it seems that the trees look right for being in the area.

The caption identifies the image as being made in Illinois. And the author of the image lives in Illinois.

I think we can assume Illinois.

[Yhaal House]

The picture is of Tooting High Street, LONDON, SW17

[neufer]

Click to play embedded YouTube video.

Pfft.

Just don't live to the west of your place of work.

[MarkBour]

I'm going to go out on a limb here...the pictured road? Forest Hills Road...perhaps somewhere near...11250 Forest Hills Road

Which by the way, is home of the best optics maker in the solar system, bar none.

I think you're getting very warm. The address you listed is the home of Roland Christen's Astro-Physics in Machesny Park, IL. That fits the hints, as a location in NW Illinois. However, that exact address does not match the picture, which is looking west down a rural scene, with only what looks like a farm house and barn to the north side of the road. So, I have begun looking at east-west roads in the area, such as state roads 20, 75, 173, etc. 173 was intriguing , because it also has the name West Lane Road, and goes right through Rock Cut State Park. But Google's street view is not finding a match for me yet. I live close enough that I am now interested in this very random challenge, and could go visit them and try to find out more. I'm assuming the picture is taken somewhere in the vicinity, perhaps a road where Mr. & Ms. Christen live.

... Pfft. Just don't live to the west of your place of work.

Well, you also would need to avoid being in the path of any one who does, as well.

[Wolf]

I'm going to go out on a limb here...the pictured road? Forest Hills Road...perhaps somewhere near...11250 Forest Hills Road

Which by the way, is home of the best optics maker in the solar system, bar none.

I think you're getting very warm. The address you listed is the home of Roland Christen's Astro-Physics in Machesny Park, IL. That fits the hints, as a location in NW Illinois. However, that exact address does not match the picture, which is looking west down a rural scene, with only what looks like a farm house and barn to the north side of the road. So, I have begun looking at east-west roads in the area, such as state roads 20, 75, 173, etc. 173 was intriguing , because it also has the name West Lane Road, and goes right through Rock Cut State Park. But Google's street view is not finding a match for me yet. I live close enough that I am now interested in this very random challenge, and could go visit them and try to find out more. I'm assuming the picture is taken somewhere in the vicinity, perhaps a road where Mr. & Ms. Christen live.

... Pfft. Just don't live to the west of your place of work.

Well, you also would need to avoid being in the path of any one who does, as well.

I also went down the West Lane road path, but also route 20 is the longest east-west road in the country, but not much of a two-laner in Illinois. My other thought was that the author was on his way to an observatory, but tracing the most efficient routes to those finds no Google streetview matches.

I thought I could get lucky and find GPS coordinates from this sites copy of the photo --> https://www.buytelescopes.com/gallery/photo/65238 I can tell he used a Sony NEX-7, but no GPS location data!

Its definitely a very rural road with old telephone poles and an an intersection that curves slightly to the south before meeting it Ii.e. the sign)... I think I'm done...

[orin stepanek]

wherever it was taken; it made a nice background!

[Wolf]

Okay, the wolf tracked the rascal down! --> https://www.google.com/maps/@42.4118081 ... 56!6m1!1e1

Roscoe Road!

[MarkBour]

Okay, the wolf tracked the rascal down! --- https://www.google.com/maps/@42.4118081 ... 56!6m1!1e1

Roscoe Road!

How certain are you of this? The precise location your link leads to has some good features. Right kind of poles, beautiful mailbox, similarity in trees near it. But it does not seem to have the right buildings, or this sequence of poles, and there is no dip in the road. I realized you might have just been linking to Roscoe Road, not the precise location. So I looked down the length of the road, but still did not find what seemed like a match to me.

[Wolf]

Okay, the wolf tracked the rascal down! --- https://www.google.com/maps/@42.4118081 ... 56!6m1!1e1

Roscoe Road!

How certain are you of this? The precise location your link leads to has some good features. Right kind of poles, beautiful mailbox, similarity in trees near it. But it does not seem to have the right buildings, or this sequence of poles, and there is no dip in the road. I realized you might have just been linking to Roscoe Road, not the precise location. So I looked down the length of the road, but still did not find what seemed like a match to me.

Hey,

I am very certain of my hypothesis.

Here was my method if you want to reproduce it yourself:

Downloaded a jpeg of the picture from the website mentioned earlier (may be taken down now).
Enhanced and brightened the picture and found a street number.
Used MellisaData after plugging in just two zip codes nearby and the address street number -> https://www.melissadata.com/lookups/zipnumber.asp
Brought me to Roscoe road.

... not sure if this was the desired APOD editor's method, but one that worked...

The reason it doesn't look right from Google Street View is that he used a near telephoto lens; maybe his own creation. It compresses all the electric/telephone poles, the road dip and the curve at the west end of Roscoe Road.

This hunt is over, move on to your next one!

[geckzilla]

Wolf's right. It's also a good example of how funky telephoto lenses make things. It makes it look like that prominent farm house on the horizon is right next door when in reality it's quite a way down the road. And it makes what's a pretty flat road look like it's got a steep slope to it.

[MarkBour]

I am very certain of my hypothesis.
Here was my method . . .

Wolf, congratulations on your sleuthing skills! I could not have teased that street number from the image on APOD, at least not with my limited skills and tools. But when I looked at the other image you found and referenced (at the highest resolution there), I could clearly make out the number 2465. So then, that distinctive white-on-red sign, which should not be very common, and then the mailbox across the street from it, with what appears to be some sprayed-on graffiti of a word sort of like "Sassy", really seems to leave us with a match that could not be repeated anywhere. I think once you have those two items across the street from each other (and clearly the right kind of street), then you must have nailed it. I'm leaving out, though, the work you went through to get to the right spot on the right road, though, which was another fine piece of work.

Wolf's right. It's also a good example of how funky telephoto lenses make things. It makes it look like that prominent farm house on the horizon is right next door when in reality it's quite a way down the road. And it makes what's a pretty flat road look like it's got a steep slope to it.

Geck, this sounds like an official pronouncement, and I'm assuming that you have the inside knowledge that it is correct.
I had to examine it further, but I had come to the conclusion that the Wolf was correct.

The thing I was last struggling with, though (at least until I could read the 2465), was the building that I could not find anywhere. I eventually found a building that could match, clear down at 3357 Roscoe Road, about 3/4 of a mile away. It was a good lesson for me, Geck, a telephoto lens can indeed cause things that are hard to get, and (for me) even harder to describe. I mean, the house must have been there, on that line from Roland's vantage point, but why it shows up and other things did not is still partly mysterious to me. One factor, is that there is a farm with metal silos and roofs in the right position that it may have been reflecting a fair amount of sunlight back towards the photographer-facing wall of that house, giving it enough illumination to stand out well. A funny thing in Google maps for that house is that the overhead (Earth view) shows a building next to it, but when you switch to street view, the building vanishes. I wonder which image is the more recent, the overhead or side view.

[geckzilla]

I do not have any inside info. I am armed only with a little more intuition about telescopic views because I've played with the settings of virtual cameras in Blender when I wanted to simulate one. It can be very disorienting. Keep in mind this is how we are viewing the entire Universe outside of planet Earth and sometimes on Earth, as demonstrated by this APOD! It's why everything looks so flat. Perspective flies out the window.

[Wolf]

Keep in mind this is how we are viewing the entire Universe outside of planet Earth and sometimes on Earth, as demonstrated by this APOD! It's why everything looks so flat. Perspective flies out the window.

Geck, thanks for keeping us on a universal perspective!

A funny thing in Google maps for that house is that the overhead (Earth view) shows a building next to it, but when you switch to street view, the building vanishes. I wonder which image is the more recent, the overhead or side view.

As Geck points out, perspective is everything. We have to take into account a space-time perspective. This was a point in time of March 20, 2015 with no leaves on the trees and probably higher up on the z-axis. Looking at a Google terrain map, he probably took the shot from this https://www.google.com/maps/@42.4118625 ... 56!5m1!1e4 intersection. Just my perspective!

[alter-ego]

...
As Geck points out, perspective is everything. We have to take into account a space-time perspective. This was a point in time of March 20, 2015 with no leaves on the trees and probably higher up on the z-axis. Looking at a Google terrain map, he probably took the shot from this https://www.google.com/maps/@42.4118625 ... 56!5m1!1e4 intersection. Just my perspective!

Using the approximate road width (~7m between the white lines) and Sun angular diameter (0.5°), the photographer's location is approximately 100 to 200 meters east of the pictured mailbox, and roughly 500 meters west of that intersection. Interestingly, the road direction deviation after the second hump is not the "sharp" bend encountered at the end of Roscoe Rd. Instead the deviation starts at the N. Rockton Ave intersection, not visible between the 2nd and 3rd humps. According to Google Earth, the elevation difference between the photographer's location and the highest point ≈12 meters.

[bob_h]

I was skeptical until I found a second red and white sign in the image, for the next driveway down the road, 2485.
https://goo.gl/maps/7AZMgKc8j7R2 shows that next driveway, but looks backwards to reveal the number in the vegetation.

The house in the distance is similar to the house style, garage and tree locations at 3279 Roscoe Rd.
https://goo.gl/maps/nVvv68G3ePr

There are a lot of telephone poles in the image. Google Earth shows they're generally spaced 220 ft along that road.
Working backwards from the estimated peak in the distance, StreetView and Google Earth show 8 poles to Rockton Ave, 8 more to blue silo driveway, and 3 more to the wooded area near the photographer, which is reasonably consistent with the image.

The clincher for me was this view, from Rockton Ave, showing the broadside of the white building.
https://goo.gl/maps/qTpCRFUcSAF2

Outstanding work, Wolf!

bh

[MarkBour]

Using the approximate road width (~7m between the white lines) and Sun angular diameter (0.5°), the photographer's location is approximately 100 to 200 meters east of the pictured mailbox, and roughly 500 meters west of that intersection.

This is actually fascinating, that you can determine that. Then I suppose you could use the dimensions of the white house as well to determine its approximate distance? And this sounds like a basic calculation one must do all the time with astronomical images. I guess you have to know the angular diameter separately, though. You can't just look at an image and have any way of knowing it from the image, I believe.

The clincher for me was this view, from Rockton Ave, showing the broadside of the white building.
https://goo.gl/maps/qTpCRFUcSAF2

Yes, for me, too. I mean Wolf's evidence was very convincing, but I couldn't feel settled until I got over what at first seemed like a contradiction of the otherwise perfect match.

Earlier, I conjectured that the farm near that house might be reflecting sunlight back to it, somewhat illuminating it. Since then, I've gone outside on a couple of sunsets. I don't think I was correct. A white house can be quite visible even at sunset in this orientation, even though many other objects have become mere silhouettes. It would not need a particular object reflecting light onto it. And I looked at that farm more on the Google imagery and am doubtful it could reflect much light on the house. So yeah ... it's not a reflection nebula. I think it appears "white" partly thanks to the nature of human light/dark and color perception, which is sometimes mysterious to me.

[alter-ego]

Using the approximate road width (~7m between the white lines) and Sun angular diameter (0.5°), the photographer's location is approximately 100 to 200 meters east of the pictured mailbox, and roughly 500 meters west of that intersection.

This is actually fascinating, that you can determine that. Then I suppose you could use the dimensions of the white house as well to determine its approximate distance?

Yes, if one knows the dimension(s), the distance to the house from the photographer can be calculated but you'd still need a known angular dimension to calibrate the image FoV and thus locate the photographer; in this image it's the Sun.

And this sounds like a basic calculation one must do all the time with astronomical images.

For typical astronomical images, only angles are measured unless there is an independently determined size dimension. More routinely a size is estimated from an independently determined distance, e.g. images of red-shifted galaxies of measurable angular size yield distance and galaxy size.

I guess you have to know the angular diameter separately, though. You can't just look at an image and have any way of knowing it from the image, I believe.

Yes, at least one, independently known angular size is required. Astronomical objects provide angles, e.g. known celestial bodies or angular separations of stars.

[DavidInCambridgeUK]

The equinox APOD is a striking picture, as always, but the accompanying text is not entirely correct. It states that the day of the equinox is a day of equal night and day time. That's not true.

Here in Cambridge, England, the Sun rose on 20 March 2016 at 06:01 and set at 18:14 according to the web site of Her Majesty's Nautical Almanac Office. That gives 12h 13m of day time and 11h 47m of night.

According to the HMNAO sunrise/sunset table for Cambridge, day and night were of equal length on Thursday 17 March, when the Sun rose at 06:08 and set at 18:08.

The explanation involves two factors. The equinox is defined as the instant when the centre of the Sun's disk has a true ecliptic longitude of exactly zero. At that instant, the centre of the Sun's disk is also exactly on the celestial equator, with declination of zero.

However, when calculating the time of sunrise or sunset, it's the upper limb of the Sun that touches the horizon, not the centre of the disk. Also, atmospheric refraction tends to raise objects by about 34 arc-minutes at the horizon. That is to say, when an object appears to be on the horizon, a purely geometric calculation which ignored refraction would show it to be 34 arc-minutes below the horizon.

Consequently, HMNAO and other almanac producers define sunrise and sunset to be the instant when the geometric centre of the Sun's disk is 50 arc-minutes below the horizon -- that's the sum of 34 minutes for refraction and 16 minutes for the average semi-diameter of the disk.

Those effects, combined, mean that sunrise and sunset are exactly 12 hours apart on a date a few days before the spring equinox and a few days after the autumn equinox, but never on the equinox itself.

[neufer]

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Sunset at the South Pole

<<March 21, 2013: The Equinox – the technical date that the sun, as a point, sets at the South Pole. On a perfectly spherical earth, with no topography, no atmosphere, no height above the ground the sun would be exactly halfway below/above the horizon on this day …Of course this isn’t the case, so our sunset is a little more variable. Since reaching a peak height of 23.5º (the tilt of the earth) on the December solstice the sun has slowly spiraled towards the horizon.

Due to a combination of phenomena, the sun is still visible today and will likely remain so for a few days yet. Even after the orb ducks below the horizon we will have a few weeks of light, phasing from daylight to civil twilight (0-6º below horizon) to nautical twilight (6-12º below) astronomical twilight (12-18º below) and eventually to full darkness. The moon rises and sets on a two week cycle, the brightness of which can be significant, so we will not be in full darkness for the entire winter. That said, it will be pretty dark for a good ~4 months.>>

According to the NOAA Sunrise/Sunset Calculator daytime always exceeds nighttime within 2º latitude of the equator.

[bjmb]

i'm happy that finally someone (actually two someones) agree with me in trashing the 'equinox = equal night & day' idea. the earth is no bald marble, the sun is not a point, and the poles are flattened, all three of which combine - conspire? - to put the 'equal night & day' idea on a par with the music of the spheres or the baleful influence of comets.

[Chris Peterson]

i'm happy that finally someone (actually two someones) agree with me in trashing the 'equinox = equal night & day' idea. the earth is no bald marble, the sun is not a point, and the poles are flattened, all three of which combine - conspire? - to put the 'equal night & day' idea on a par with the music of the spheres or the baleful influence of comets.

Not all of us agree.

[neufer]

i'm happy that finally someone (actually two someones) agree with me in trashing the 'equinox = equal night & day' idea. the earth is no bald marble, the sun is not a point, and the poles are flattened, all three of which combine - conspire? - to put the 'equal night & day' idea on a par with the music of the spheres or the baleful influence of comets.

• Not Equine-Ox .... the two Chinese guardians of the Underworld:

[b][color=#0000FF]Ox-Head and Horse-Face in the Hell Scroll at Nara National Museum[/color][/b]

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<<Ox-Head and Horse-Face are two guardians or types of guardians of the Underworld in Chinese mythology. As indicated by their names, both have the bodies of men, but Ox-Head has the head of an ox while Horse-Face has the face of a horse. They are the first beings a dead soul encounters upon entering the Underworld; in many stories they directly escort the newly dead to the Underworld.

In the Chinese classical novel Journey to the West, Ox-Head and Horse-Face are sent to capture Sun Wukong, but he overpowers them and scares them away. He then breaks into the Underworld and crosses out the names of himself and his primate followers from the record of living souls, hence granting immortality to himself and his followers. In Japanese mythology, Ox-Head and Horse-Face are known as "Gozu" and "Mezu" respectively.>>