What did you see in the sky tonight?

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Chris Peterson
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Re: What did you see in the sky tonight?

Post by Chris Peterson » Tue Sep 15, 2020 5:18 pm

BDanielMayfield wrote:
Tue Sep 15, 2020 5:12 pm
Chris Peterson wrote:
Mon Sep 14, 2020 11:42 pm
Finally had a couple of clear nights, without snow, without clouds, without smoke, without a Moon. So I thought I'd point the scope at something and make sure things were still working. Picked NGC 6951 for no particular reason, except it was high in the sky and looked kind of cool in pictures- a slightly asymmetric barred spiral galaxy. And surprise! Turned out to be a very interesting choice, as it lies behind a nice band of dust in our own galaxy, sometimes called "galactic cirrus" or "integrated flux nebula". Local dust illuminated only by the glow of the Milky Way. I'm amazed how bright it is, showing up in just a few minutes of exposure. Anyway, I collected eight hours of light and ended up with this. Seeing the wisps of foreground clouds gives the scene a very 3D look to my eyes.
_
NGC6951_8h.jpg
Glad someone's skies have cleared, and to see the nice galaxy image you captured Chris.

Here in our part of Idaho the smoke has gotten bad again. Two nights ago I could just barely make out Saturn, with averted vision, and only because of knowing its location relative to bright Jupiter. There were only two stars visible in the whole sky, Vega and Altair high overhead. But last night nothing; not even Jupiter was visible.
Smoke has been on-again-off-again for us the last couple of months. Although we have some really bad fires here in Colorado, the worst smoke, based on looking at satellite loops, has come from California, Oregon, and Washington. And at its worst, it's been very bad. Like your experience, stars largely invisible, Saturn borderline, daytime visibility limited to a mile or so.
Chris

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Ann
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Re: What did you see in the sky tonight?

Post by Ann » Tue Sep 15, 2020 8:23 pm

Chris Peterson wrote:
Tue Sep 15, 2020 1:10 pm

I started out with this little project mainly just to get my observatory tuned up. I wasn't expecting the IFN, so that caught me by surprise. Most galaxies (to me) aren't overly interesting in color, so I just shot luminance data. But this is a pretty active galaxy, which could be fun to get some color info on, as well as color for the IFN. So I may go back and try that.

I don't think the IFN is actually all that red. It's dust which is illuminated by relatively white light. We see that in a lot of nebula images, and it always looks similar: brown. Because the "real" colors of most astronomical objects are fairly subdued, it is very common for imagers to boost saturation in order to emphasize color. Boosting brown makes it into orange or red. I think that's all that's going on in most of the color images. The IFN is best described as brown, visually.

I'm not sure that dust always looks brown, although it usually does. Dust is brown och black when it obscures light from behind it. But dust can also reflect light, and I think the IFN is doing that. Otherwise why would it be visible at all? Why wouldn't it be all black, if it wasn't illuminated? So what is it that illuminates it, if not the combined light of the Milky Way?

It is obvious from the picture at left that the dust between Perseus and Taurus is not the same color everywhere.

The Pleiades and the California Nebula are not seen in front of the most densely populated band of the Milky Way, but there is a sufficient number of stars in the direction of southern Perseus and Taurus that the dust in this region can obscure light from behind it. But surely the dust here also reflects light, and not just near the Pleiades.

Ann
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Chris Peterson
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Re: What did you see in the sky tonight?

Post by Chris Peterson » Tue Sep 15, 2020 8:32 pm

Ann wrote:
Tue Sep 15, 2020 8:23 pm
Chris Peterson wrote:
Tue Sep 15, 2020 1:10 pm

I started out with this little project mainly just to get my observatory tuned up. I wasn't expecting the IFN, so that caught me by surprise. Most galaxies (to me) aren't overly interesting in color, so I just shot luminance data. But this is a pretty active galaxy, which could be fun to get some color info on, as well as color for the IFN. So I may go back and try that.

I don't think the IFN is actually all that red. It's dust which is illuminated by relatively white light. We see that in a lot of nebula images, and it always looks similar: brown. Because the "real" colors of most astronomical objects are fairly subdued, it is very common for imagers to boost saturation in order to emphasize color. Boosting brown makes it into orange or red. I think that's all that's going on in most of the color images. The IFN is best described as brown, visually.

I'm not sure that dust always looks brown, although it usually does. Dust is brown och black when it obscures light from behind it. But dust can also reflect light, and I think the IFN is doing that. Otherwise why would it be visible at all? Why wouldn't it be all black, if it wasn't illuminated? So what is it that illuminates it, if not the combined light of the Milky Way?
It is precisely the light of the Milky Way that is illuminating it, said light being fairly white (perhaps slightly on the warm side). And in such light, dust is brown. About the only time we see illuminated dust as anything other than brown is when there's an intense blue star providing the majority of the light source.
Chris

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orin stepanek
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Re: What did you see in the sky tonight?

Post by orin stepanek » Wed Sep 16, 2020 3:00 pm

Since I am an early riser and blessed with clear skies; we have had nice eastern views! Could see Orion toward the South a week ago! This morning was a nice view of a crescent moon rise! bright star; probably Venus! 8-) Can't see much from other directions; too many trees! :cry:
Orin

Smile today; tomorrow's another day!

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Re: What did you see in the sky tonight?

Post by TheZuke! » Thu Sep 17, 2020 4:17 pm

Last night, (2020-09-16 20:30 Local) I was walking the dog, I looked up at Jupiter and Saturn, and then at the stars to their West.
For the first time in my life, I made out the "Teapot" asterism!
The feeling was like I had checked off an item on my (non-existent) "Bucket List". :D

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Chris Peterson
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Re: What did you see in the sky tonight?

Post by Chris Peterson » Thu Sep 17, 2020 4:40 pm

TheZuke! wrote:
Thu Sep 17, 2020 4:17 pm
Last night, (2020-09-16 20:30 Local) I was walking the dog, I looked up at Jupiter and Saturn, and then at the stars to their West.
For the first time in my life, I made out the "Teapot" asterism!
The feeling was like I had checked off an item on my (non-existent) "Bucket List". :D
Once you see the Teapot for the first time, you never lose it. That's all you can see when you look at Sagittarius.
Chris

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BDanielMayfield
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Re: What did you see in the sky tonight?

Post by BDanielMayfield » Fri Sep 18, 2020 1:36 am

Chris Peterson wrote:
Thu Sep 17, 2020 4:40 pm
TheZuke! wrote:
Thu Sep 17, 2020 4:17 pm
Last night, (2020-09-16 20:30 Local) I was walking the dog, I looked up at Jupiter and Saturn, and then at the stars to their West.
For the first time in my life, I made out the "Teapot" asterism!
The feeling was like I had checked off an item on my (non-existent) "Bucket List". :D
Once you see the Teapot for the first time, you never lose it. That's all you can see when you look at Sagittarius.
And now that you know Sagittarius, you can roughly locate the place where Sag A* lurks, the 4.1 million sun massed supermassive black hole at the center of our galaxy :!:
Just as zero is not equal to infinity, everything coming from nothing is illogical.

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Ann
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Re: What did you see in the sky tonight?

Post by Ann » Fri Sep 18, 2020 2:53 am

Well, I was up early for once - I used to get up in the small hours, but now that I've retired, I don't do that any more - so anyway, that's the black night sky before dawn, and yes, that's Venus. And that's Orion. And the Hyades, and the Pleiades - and, wait, wait, what's that? It's incredibly orange and bright!

Oh, that's Mars. I had no idea it is so bright right now.

Ann
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