Starship Asterisk*

Posted: **Sat Feb 25, 2017 5:12 am**

All Planets Panorama

Explanation: For 360 degrees, a view along the plane of the ecliptic is captured in this remarkable panorama, with seven planets in a starry sky. The mosaic was constructed using images taken during January 24-26, from Nacpan Beach, El Nido in Palawan, Philippines. It covers the eastern horizon (left) in dark early morning hours and the western horizon in evening skies. While the ecliptic runs along the middle traced by a faint band of zodiacal light, the Milky Way also cuts at angles through the frame. Clouds and the Moon join fleeting planet Mercury in the east. Yellowish Saturn, bright star Antares, and Jupiter lie near the ecliptic farther right. Hugging the ecliptic near center are Leo's alpha star Regulus and star cluster M44. The evening planets gathered along the ecliptic above the western horizon, are faint Uranus, ruddy Mars, brilliant Venus, and even fainter Neptune. A well labeled version of the panorama can be viewed by sliding your cursor over the picture, or just following this link.

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Posted: **Sat Feb 25, 2017 6:02 am**

Great image! It's fun to see the sky between two horizons, the eastern morning one at left and the western evening one at right.

Thanks a lot for the annotation! I would never have found Uranus, let alone Neptune, without it.

The labeling of Mercury is slightly confusing, though. Immediately to the upper left of the "M" in Mercury is a faint pinpoint of light, and I found myself wondering if that was Mercury. Much further from the "Mercury" lettering is a much brighter light, which would seem to be a much better match for the brightness I expect from Mercury.

Currently Mercury is magnitude −0.9, which makes it brighter than any star in the sky except Sirius. So I guess it is the bright light some distance away from the Mercury lettering that is the real Mercury.

Ann

Posted: **Sat Feb 25, 2017 6:23 am**

Thanks Ann! Actually that faint looking dot is indeed Mercury. It was at mag. -0.2 back then; I had to shoot it with the intervening clouds and the twilight had already begun. The brighter light above Mercury is the Moon, which was a thin crescent with earthshine.

Tunç Tezel
http://www.twanight.org

Posted: **Sat Feb 25, 2017 6:41 am**

Terrific...very interesting to see them all in one view....

:---[===] *

Posted: **Sat Feb 25, 2017 9:34 am**

I count eight planets: I see Earth and 7 others.

Posted: **Sat Feb 25, 2017 11:18 am**

timclair wrote:I count eight planets: I see Earth and 7 others.

The description says, “...with seven planets in a starry sky.” The Earth isn’t in that starry sky, at least not from the photographer’s perspective.

Posted: **Sat Feb 25, 2017 12:17 pm**

Where's the Moon if this is a 360 degree panorama? According to Stellarium, on January 24 the Moon was closer to Saturn than Jupiter is to Spica in the picture. On January 25th the Moon was about 2/3rd closer to Mercury than to Saturn. On January 26 the Moon was closer to the Horizon than Mercury because the 27th was New Moon. That bigger star above Mercury could be the position that the Moon was sometime on the 25th, but the Moon is much bigger than Venus which this star isn't.

Posted: **Sat Feb 25, 2017 12:23 pm**

De58te wrote:Where's the Moon if this is a 360 degree panorama? According to Stellarium, on January 24 the Moon was closer to Saturn than Jupiter is to Spica in the picture. On January 25th the Moon was about 2/3rd closer to Mercury than to Saturn. On January 26 the Moon was closer to the Horizon than Mercury because the 27th was New Moon. That bigger star above Mercury could be the position that the Moon was sometime on the 25th, but the Moon is much bigger than Venus which this star isn't.

Given the date range, it would be possible to remove the Moon by overlapping the data in such a way to exclude it.

Posted: **Sat Feb 25, 2017 12:34 pm**

The Moon is just 2 degrees above Mercury, seen as a crescent with earthshine. It was 2 days before new Moon, as the left half of the panorama is from the morning of 26th January. The right half is from the evening of 24th January with the middle part after midnight, 25th January. I originally planned to shoot it all on a single night, but the morning horizon turned out to be partly cloudy and hazy, preventing a good view of Saturn, Moon and Mercury.

I used a diffuser filter while taking the pictures, which makes the brighter objects bigger in the picture. But the morning horizon part does not have filter, as it is partly cloudy and I did not want to diffuse the image of the Moon.

Tunç Tezel

Posted: **Sat Feb 25, 2017 1:40 pm**

Keeper

Posted: **Sat Feb 25, 2017 1:49 pm**

Wonderful image. Only one thing could have added a bit to helping me orient: maybe a faint pink line representing the celestial equator across the image....

Posted: **Sat Feb 25, 2017 9:46 pm**

Nice composition!

So, if I were to go outside on a typical night, and (in central Illinois, USA, the big news would be: "Hey, there aren't clouds everywhere spoiling the view tonight!"), then what is the probability that some time in that night between dusk and dawn, all 7 of our solar planetas would be in view (assuming I had the kind of magnification/brightening that could show them all)? I guess that question boils down to: how much of the plane does the Sun wash out, and what is the probability that on a given night not one of the planets is in that region ...

Posted: **Sun Feb 26, 2017 3:49 am**

tomatoherd wrote:Wonderful image. Only one thing could have added a bit to helping me orient: maybe a faint pink line representing the celestial equator across the image....

Here's a pretty accurate mapping of the equator onto the APOD:

Posted: **Tue Feb 28, 2017 6:48 am**

Hello.
This is 180 degrees panorama, not 360 degrees.
The camera shoot sky from west to east, in upward direction.
If this was a 360 degree panorama, then you could see the earth under your feet.
Am I right?

Thank you.

Posted: **Tue Feb 28, 2017 12:19 pm**

Atabakzadeh wrote:
This is 180 degrees panorama, not 360 degrees.
The camera shoot sky from west to east, in upward direction.
If this was a 360 degree panorama, then you could see the earth under your feet.
Am I right?

It's a space time composite shot from sunset west to sunrise east.

Posted: **Tue Feb 28, 2017 1:24 pm**

neufer wrote:
Atabakzadeh wrote:
This is 180 degrees panorama, not 360 degrees.
The camera shoot sky from west to east, in upward direction.
If this was a 360 degree panorama, then you could see the earth under your feet.
Am I right?
It's a space time composite shot from sunset west to sunrise east.

So, this should compose a 180 degrees panorama, not a 360 degrees.
Take your camera. Capture from west to east in upward direction. you should take about 10 pictures. Then combine theme.
It creates a 180 degrees panorama. You didn't take pictures from the earth under your feet. You just shoot from sky.

Posted: **Tue Feb 28, 2017 1:33 pm**

Atabakzadeh wrote:
neufer wrote:
Atabakzadeh wrote:
This is 180 degrees panorama, not 360 degrees.
The camera shoot sky from west to east, in upward direction.
If this was a 360 degree panorama, then you could see the earth under your feet.
Am I right?
It's a space time composite shot from sunset west to sunrise east.
So, this should compose a 180 degrees panorama, not a 360 degrees.
Take your camera. Capture from west to east in upward direction. you should take about 10 pictures. Then combine theme.
It creates a 180 degrees panorama. You didn't take pictures from the earth under your feet. You just shoot from sky.

There's an old internet troll where someone pretends to be wrong and say "turn 360 degrees and walk away" and then when people correct them they laugh and tell them they fell for it. The editor made a mistake and is not trolling us, but it made me think of it.

Posted: **Tue Feb 28, 2017 2:09 pm**

geckzilla wrote:
Atabakzadeh wrote:
neufer wrote: It's a space time composite shot from sunset west to sunrise east.
So, this should compose a 180 degrees panorama, not a 360 degrees.
Take your camera. Capture from west to east in upward direction. you should take about 10 pictures. Then combine theme.
It creates a 180 degrees panorama. You didn't take pictures from the earth under your feet. You just shoot from sky.
There's an old internet troll where someone pretends to be wrong and say "turn 360 degrees and walk away" and then when people correct them they laugh and tell them they fell for it. The editor made a mistake and is not trolling us, but it made me think of it.

Art (neufer) is right. This is a 4 dimensional sky (spanning three nights) mapped to a 2 dimensional surface. Count up the number of constellations. There's no way to see that many from the Earth's surface at any one time. Plus, you can't see both evening and morning twilight at the same time.

Posted: **Tue Feb 28, 2017 2:49 pm**

I get it now, but it's still a little under 360° due to whatever space the Sun takes up.

Posted: **Tue Feb 28, 2017 4:40 pm**

geckzilla wrote:
I get it now, but it's still a little under 360° due to whatever space the Sun takes up.

There is also the fact that one reason we can't see either Sun is that the land/sea gets in the way.
............................................................................................................................
Curiously enough the angular distance between Antares & Aldebaran is almost exactly 180°

so all one really needs is a ruler to measure the full width of the screen.

Code: Select all

                   ecliptic longitude       ecliptic latitude
-------------------------------------------------------------
Antares                249.762°                 -4.570°
Aldebaran               69.789°                 -5.467°

Posted: **Tue Feb 28, 2017 4:50 pm**

neufer wrote:
geckzilla wrote: I get it now, but it's still a little under 360° due to whatever space the Sun takes up.
There is also the fact that one reason we can't see either Sun is that the land/sea gets in the way.

In this image, that's only by the design of the imager. It could have included a full 360° and the Sun using the same technique.

Posted: **Tue Feb 28, 2017 4:57 pm**

Chris Peterson wrote:
neufer wrote:
geckzilla wrote:
I get it now, but it's still a little under 360° due to whatever space the Sun takes up.
There is also the fact that one reason we can't see either Sun is that the land/sea gets in the way.
In this image, that's only by the design of the imager. It could have included a full 360° and the Sun using the same technique.

Well, yes, but the question is whether the image as presented covers 360° along the ecliptic
(i.e., is the distance between Antares & Aldebaran half the width of the screen?).

Posted: **Tue Feb 28, 2017 5:15 pm**

neufer wrote:
Chris Peterson wrote:
neufer wrote: There is also the fact that one reason we can't see either Sun is that the land/sea gets in the way.
In this image, that's only by the design of the imager. It could have included a full 360° and the Sun using the same technique.
Well, yes, but the question is whether the image as presented covers 360° along the ecliptic
(i.e., is the distance between Antares & Aldebaran half the width of the screen?).

Well, that's not possible with an image that is made over only three days and which excludes the Sun. The Sun is at the western edge of Capricornus, so we are simply unable to record stars over much of Sagittarius and Capricornus. We can't help but to lose about 40° of stellar visibility along the ecliptic to the Sun's glare.

Posted: **Tue Feb 28, 2017 5:49 pm**

Chris Peterson wrote:
neufer wrote:
... the question is whether the image as presented covers 360° along the ecliptic
(i.e., is the distance between Antares & Aldebaran half the width of the screen?).
Well, that's not possible with an image that is made over only three days and which excludes the Sun. The Sun is at the western edge of Capricornus, so we are simply unable to record stars over much of Sagittarius and Capricornus. We can't help but to lose about 40° of stellar visibility along the ecliptic to the Sun's glare.

I measure the distance between Antares & Aldebaran to be just slightly less than half the width of the screen.

That qualifies as a full 360° panorama along the ecliptic so far as I'm concerned
regardless of whether land and sea get in the way of seeing Sagittarius & Capricornus.

Posted: **Tue Feb 28, 2017 5:57 pm**

neufer wrote:
Chris Peterson wrote:
neufer wrote:
... the question is whether the image as presented covers 360° along the ecliptic
(i.e., is the distance between Antares & Aldebaran half the width of the screen?).
Well, that's not possible with an image that is made over only three days and which excludes the Sun. The Sun is at the western edge of Capricornus, so we are simply unable to record stars over much of Sagittarius and Capricornus. We can't help but to lose about 40° of stellar visibility along the ecliptic to the Sun's glare.
I measure the distance between Antares & Aldebaran to be just slightly less than half the width of the screen.

That qualifies as a full 360° panorama along the ecliptic so far as I'm concerned
regardless of whether land and sea get in the way of seeing Sagittarius & Capricornus.

That's fine, if you like that definition. I wouldn't put it that way, since the image and the context lead most people to see this as a sky panorama, and calling it 360° from that viewpoint is confusing and possibly misleading.

Starship Asterisk*

APOD: All Planets Panorama (2017 Feb 25)

APOD: All Planets Panorama (2017 Feb 25)

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