Starship Asterisk*

Night Sky Reflected

Explanation: What's that in the mirror? In the featured image of the dark southern sky, the three brightest galaxies of the night are all relatively easy to identify. Starting from the left, these are the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC), and part of the central band of our Milky Way Galaxy. All three are also seen reflected in a shallow pool of water. But what is seen in the mirror being positioned by the playful astrophotographer? Dust clouds near the center of our Milky Way -- and the planet Jupiter. The composite was carefully planned and composed from images captured from the same camera in the same location and during the same night in mid-2019 in Mostardas, south Brazil. The picture won first place in the Connecting to the Dark division of the International Dark-Sky Association's Capture the Dark contest for 2021.

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The Pipe Nebula.

Beautiful APOD with a lot to annotate!


1) NGC 3532. Image by ESO/G. Beccari.

2) The Carina Nebula. Image by Harel Boren. The brightest light in Boren's image , just above and slightly to the left of the large V-shaped dust lane, is Eta Carina. Ultraviolet image by ESA/Hubble.

3) IC 2602. Picture by Fred Espenak. Hope I get to keep it!

4) NGC 3114. Picture by Sergio Eguivar.

5) Just some random stars with Iota Carina and HD 79351 in the center.

6) NGC 2516. Image by Mike O'Day.

7) Canopus?

8) Large Magellanic Cloud. Robert Gendler/ESO.

9) The Tarantula Nebula. Image: TRAPPIST/E. Jehin/ESO.

10) Small Magellanic Cloud. Image: ESA/Hubble.

11) 47 Tucanae, 47 Tuc, second brightest globular cluster of the Milky Way. Image: ESA/Hubble.

12) 47 Tuc reflected.

13) Small Magellanic Cloud reflected.

14) Pipe Nebula. Brightest blue star above the Pipe Nebula is Theta Ophiuchi. Image: ESO/Yuri Beletsky.

15) Jupiter! Image: NASA, ESA, A. Simon (Goddard Space Flight Center), and M.H. Wong (University of California, Berkeley).

16) Large Magellanic Cloud reflected.

17) Tarantula nebula reflected.

18) NGC 2516 reflected.

19) Iota Carina and HD 79351 reflected.

Phew! Time for a break now.

Ann

Wonderful APOD! Congratulations!!!!!

Ann, you are a wonder! Thanks so much.

The double reflection is the face of the mirror holder.

I like how the SMG & LMG show up in this beautiful Photo!
The lake being frozen hard helps tht photographer do his thing! Be nice kitty!

Is anyone else bothered/confused by the mirror's impossible reflection in the lake?

DeepintheHeartofTexas wrote: ↑Mon Sep 13, 2021 1:48 pm Is anyone else bothered/confused by the mirror's impossible reflection in the lake?

Yeah, now that you mention it Also, clearly, the guy can't be standing IN the lake, so now I don't understand what I'm looking at all! The links don't seem to provide any more info about how this image was created.

EDIT: oh wait - is the lake actually frozen? I see the guy is wearing a hat, and now also the snow in the background. D'oh! But I still don't understand the mirror's reflection in the ice (or water).

EDIT #2: on the other hand, this pic was taken from Mostardas, south Brazil. Does it ever get cold enough there for snow or frozen lakes?

orin stepanek wrote: ↑Mon Sep 13, 2021 12:35 pm I like how the SMG & LMG show up in this beautiful Photo!
The lake being frozen hard helps tht photographer do his thing!

The lake isn't frozen. He's standing in shallow water.

Hope that isn't the primary for his square telescope. I guess those are actually round.

Chris Peterson wrote: ↑Mon Sep 13, 2021 2:10 pm

orin stepanek wrote: ↑Mon Sep 13, 2021 12:35 pm I like how the SMG & LMG show up in this beautiful Photo!
The lake being frozen hard helps tht photographer do his thing!

The lake isn't frozen. He's standing in shallow water.

Yes, that's how I understood it. The night must have been extremely calm, with no wind.

Ann

The star tracks in the lake are much longer than in the sky or upper mirror image. I assume a longer exposure was needed because the reflection from the lake surface is not so bright as the sky light. It's all very interesting.

Chris Peterson wrote: ↑Mon Sep 13, 2021 2:10 pm

orin stepanek wrote: ↑Mon Sep 13, 2021 12:35 pm I like how the SMG & LMG show up in this beautiful Photo!
The lake being frozen hard helps tht photographer do his thing!

The lake isn't frozen. He's standing in shallow water.

Yup; being in Brazil; you're right about it not being frozen; but look at the wheels on the cart! They are not in water! Me thinks a lot of photo tricks going on!
Oh wait; That's not a cart; but the shadow of his mirror1 How did he accomplish that!

MarkBour wrote: ↑Mon Sep 13, 2021 3:26 pm
The star tracks in the lake are much longer than in the sky or upper mirror image. I assume a longer exposure was needed because the reflection from the lake surface is not so bright as the sky light. It's all very interesting.

The star tracks in the lake are much longer than in the sky or upper mirror image because of motions on the lake surface. (A time exposure would spread the starlight left-to-right not up & down.) Chris has pointed out before that lake surfaces spread bright point-like starlight over multiple pixels such that saturated bright stars are actually more prominent in the reflection. Dim and/or extended objects do not share in this enhancement.

orin stepanek wrote: ↑Mon Sep 13, 2021 3:38 pm

Oh wait; That's not a cart; but the shadow of his mirror1 How did he accomplish that!

That's a water reflection of his mirror containing his own face against an unrevealed piece of sky that RJN has put forth a Quiz challenge.

Anyone figured it out yet

neufer wrote: ↑Mon Sep 13, 2021 3:59 pm

orin stepanek wrote: ↑Mon Sep 13, 2021 3:38 pm
Oh wait; That's not a cart; but the shadow of his mirror1 How did he accomplish that!

That's a water reflection of his mirror containing his own face against an unrevealed piece of sky that RJN has put forth a Quiz challenge.

Anyone figured it out yet :?:

What's reflected in the mirror is trivial to identify, a very well known dusty section of the Milky Way lying between Sagittarius and Scorpius... and in 2019, hosting Jupiter, the bright "star" in the lower right of the mirror. The section of the sky seen in the reflection of the reflection, however, is not so simple. It's clearly almost directly behind the guy's head, so not far from what we see in the upper right of the APOD. But it's pretty distorted to pick out more than that.

This is what I can see in the doubly reflected image:

1: A very blue star. Note that almost all the stars in the doubly reflected image looks more or less bluish, but this one stands out. I'd say that the light that reaches us from this star is at least as blue as Vega's and probably bluer.

2) This star looks almost completely non-blue. Since we definitely expect to see some yellow or orange stars in a patch of sky as big as the doubly reflected image appears to be, I'd say that this is a yellow or orange star, most likely of spectral class K. But other spectral classes are also possible.

3) This looks like a pretty big fat dark dust cloud to me.

4) This looks like a patch of clear galactic sky where myriads of Milky Way stars are looking down on us. Yeah! I know that's his head. But look behind him!

So where in the sky are we? D'uh! I really don't know.

Ann

Ann wrote: ↑Mon Sep 13, 2021 8:27 pm

Doubly reflected sky APOD September 13 2021.png

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This is what I can see in the doubly reflected image:

1: A very blue star. Note that almost all the stars in the doubly reflected image looks more or less bluish, but this one stands out. I'd say that the light that reaches us from this star is at least as blue as Vega's and probably bluer.

2) This star looks almost completely non-blue. Since we definitely expect to see some yellow or orange stars in a patch of sky as big as the doubly reflected image appears to be, I'd say that this is a yellow or orange star, most likely of spectral class K. But other spectral classes are also possible.

3) This looks like a pretty big fat dark dust cloud to me.

4) This looks like a patch of clear galactic sky where myriads of Milky Way stars are looking down on us. Yeah! I know that's his head. But look behind him!

So where in the sky are we? D'uh! I really don't know.

Ann

I'm probably being obtuse if not downright dumb but why shouldn't we be seeing exactly the same piece of sky in the mirror below the red line as we see above the red line? (Though less of an area of it, and possibly overlaid on the direct reflection of the sky.) We clearly see the man in apparently the same pose both above and below the red line.

johnnydeep wrote: ↑Mon Sep 13, 2021 8:43 pm I'm probably being obtuse if not downright dumb but why shouldn't we be seeing exactly the same piece of sky in the mirror below the red line as we see above the red line? (Though less of an area of it, and possibly overlaid on the direct reflection of the sky.) We clearly see the man in apparently the same pose both above and below the red line.

We clearly see a very different view of the man's face in the two reflections! Look again.

Try drawing a little ray diagram from the side, and you'll quickly see that the light is following two different paths.

Chris Peterson wrote: ↑Mon Sep 13, 2021 9:06 pm

johnnydeep wrote: ↑Mon Sep 13, 2021 8:43 pm I'm probably being obtuse if not downright dumb but why shouldn't we be seeing exactly the same piece of sky in the mirror below the red line as we see above the red line? (Though less of an area of it, and possibly overlaid on the direct reflection of the sky.) We clearly see the man in apparently the same pose both above and below the red line.

We clearly see a very different view of the man's face in the two reflections! Look again.

Try drawing a little ray diagram from the side, and you'll quickly see that the light is following two different paths.

I'm saying the man's face in the mirror above the line appears to be the same as his face below the line. (He says, getting more confused by this picture by the post )

johnnydeep wrote: ↑Mon Sep 13, 2021 9:23 pm

Chris Peterson wrote: ↑Mon Sep 13, 2021 9:06 pm

johnnydeep wrote: ↑Mon Sep 13, 2021 8:43 pm I'm probably being obtuse if not downright dumb but why shouldn't we be seeing exactly the same piece of sky in the mirror below the red line as we see above the red line? (Though less of an area of it, and possibly overlaid on the direct reflection of the sky.) We clearly see the man in apparently the same pose both above and below the red line.

We clearly see a very different view of the man's face in the two reflections! Look again.

Try drawing a little ray diagram from the side, and you'll quickly see that the light is following two different paths.

I'm saying the man's face in the mirror above the line appears to be the same as his face below the line. (He says, getting more confused by this picture by the post :( )

I disagree completely. In the mirror, we're looking up at his chin from below it. In the water, we're looking almost directly into his face. I'd say there's at least a 30° difference in the viewing angles there.

Chris Peterson wrote: ↑Mon Sep 13, 2021 4:14 pm

neufer wrote: ↑Mon Sep 13, 2021 3:59 pm

orin stepanek wrote: ↑Mon Sep 13, 2021 3:38 pm
Oh wait; That's not a cart; but the shadow of his mirror1 How did he accomplish that!

That's a water reflection of his mirror containing his own face against an unrevealed piece of sky that RJN has put forth a Quiz challenge. Anyone figured it out yet

What's reflected in the mirror is trivial to identify, a very well know dusty section of the Milky Way lying between Sagittarius and Scorpius... and in 2019, hosting Jupiter, the bright "star" in the lower right of the mirror. The section of the sky seen in the reflection of the reflection, however, is not so simple. It's clearly almost directly behind the guy's head, so not far from what we see in the upper right of the APOD. But it's pretty distorted to pick out more than that.

johnnydeep wrote: ↑Mon Sep 13, 2021 8:43 pm
... why shouldn't we be seeing exactly the same piece of sky in the mirror below the red line as we see above the red line? (Though less of an area of it, and possibly overlaid on the direct reflection of the sky.) We clearly see the man in apparently the same pose both above and below...

Both the mirror and its reflection are picking up a vertical axis parallel to & slightly to the left of the left edge of the APOD (& "almost" perpendicular to the SMC/LMC axis). This axis (lies a little further left of the SMC than the SMC lies to left of the LMC and) passes past zenith through The Pipe Nebula. The mirror image is of an upside down Pipe Nebula. The reflected mirror image is of an upright asterism of comparable size but somewhat further past zenith through the same vertical axis.

neufer wrote: ↑Mon Sep 13, 2021 10:40 pm

Click to view full size image

Both the mirror and its reflection are picking up a vertical axis parallel to & slightly to the left of the left edge of the APOD (& "almost" perpendicular to the SMC/LMC axis). This axis (lies a little further left of the SMC than the SMC lies to left of the LMC and) passes past zenith through The Pipe Nebula. The mirror image is of an upside down Pipe Nebula. The reflected mirror image is of an upright asterism of comparable size but somewhat further past zenith through the same vertical axis.

Let me see if I got this straight.


Should we imagine a vertical line through the Pipe Nebula, a line that is almost perpendicular to the axis between the LMC and the SMC? And what we see in the doubly reflected mirror image should lie somewhere along this perpendicular axis through the Pipe Nebula?

Ann

Why do we see brighter stars in the lake and mirror than in the sky?