Starship Asterisk*

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.
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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 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

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.

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! Can't see much from other directions; too many trees!

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".

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 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".

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

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

BDanielMayfield wrote: ↑Fri Sep 18, 2020 1:36 am
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

Actually, this was my underlying purpose!

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

Ann wrote: ↑Tue Sep 15, 2020 5:42 am

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.
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NGC6951_8h.jpg

That's a great image, Chris. The galaxy looks very fine, and the IFN looks fantastic.

I checked out some other pictures of NGC 6951. Many of them show galactic cirrus, and most of them show the cirrus to be reddish. This image is an interesting example.

I also checked out NGC 6951 with my software, and I was astonished at this galaxy's red color. Its B-V index is 0.99, which is very red indeed for a spiral galaxy and even redder than our big bully of a neighbor, Andromeda, which is itself really quite red as spiral galaxies go with a B-V index of 0.92.

This makes me ask two questions, maybe even three. Could the light of NGC 6951 be reddened by the IFN that might be located right in front of it from our point of view? Did you, Chris, use red-sensitive equipment for your image?

And why is the IFN so red? How red is our galaxy?

Ann

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.

So, I had a relatively clear night a few days ago. Not great transparency with some smoke still in the air, but not too bad. Got about 6 hours of additional data, 2 hours each of red, green, and blue. Combined with the previous luminance, I ended up with a fair color image. Could use some additional processing to eliminate a bit of gradient, but on the whole it convinces me that the best color description for the IFN is "brown". The color looks very similar to illuminated dust in a lot of nebula images.
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Chris Peterson wrote: ↑Wed Sep 23, 2020 4:45 pm
So, I had a relatively clear night a few days ago. Not great transparency with some smoke still in the air, but not too bad. Got about 6 hours of additional data, 2 hours each of red, green, and blue. Combined with the previous luminance, I ended up with a fair color image. Could use some additional processing to eliminate a bit of gradient, but on the whole it convinces me that the best color description for the IFN is "brown". The color looks very similar to illuminated dust in a lot of nebula images.
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Image10_DBE_registered_lrgb.jpg

Brown like this?

Isn't "brown" technically speaking a kind of dark and dirty red, or rather a kind of dark and dirty orange?

Well, maybe not. According to this page, brown is a mixture of both red, green and blue.

Although it's almost always predominantly red. And maroon is actually all red!

Ann

(Oh, and - I think I just discovered a really beautiful and lovely shade of blue - dodgerblue. Whatever the name means.)

Ann wrote: ↑Wed Sep 23, 2020 5:50 pm

Chris Peterson wrote: ↑Wed Sep 23, 2020 4:45 pm
So, I had a relatively clear night a few days ago. Not great transparency with some smoke still in the air, but not too bad. Got about 6 hours of additional data, 2 hours each of red, green, and blue. Combined with the previous luminance, I ended up with a fair color image. Could use some additional processing to eliminate a bit of gradient, but on the whole it convinces me that the best color description for the IFN is "brown". The color looks very similar to illuminated dust in a lot of nebula images.
_
Image10_DBE_registered_lrgb.jpg

Brown like this?

Isn't "brown" technically speaking a kind of dark and dirty red, or rather a kind of dark and dirty orange?

Well, maybe not. According to this page, brown is a mixture of both red, green and blue.

Although it's almost always predominantly red. And maroon is actually all red!

Ann

(Oh, and - I think I just discovered a really beautiful and lovely shade of blue - dodgerblue. Whatever the name means.)

In terms of light (as opposed to paint), brown is basically a low saturation orange. No significant blue component. My point was really only that, for most people, the color I got here, and the color we usually see for weakly illuminated dust, would be best described as "brown", not "red".

Chris Peterson wrote: ↑Wed Sep 23, 2020 6:03 pm
In terms of light (as opposed to paint), brown is basically a low saturation orange. No significant blue component. My point was really only that, for most people, the color I got here, and the color we usually see for weakly illuminated dust, would be best described as "brown", not "red".

Well, if IFN reflects light from our galaxy at all, then it makes sense that the reflected light can't be red, because no galaxy is red. At least no galaxy that is not too redshift-reddened.


















Isolated dust clouds seen in front of a rich star field are just dark, and stars peeking through them get their light increasingly reddened. But the IFN doesn't seem to do a huge lot of obscuring of light from behind (although that happens too, I'm sure), but rather they do seem to do some reflection, so that we can see some (visible) light coming from them.

If the dust particles making up IFN dust clouds are intrinsically dark brown (and they are), and they faintly reflect the predominantly yellowish light from our galaxy, then it makes sense that their light is very faintly orange (that is, brown). But they a much lighter brown than thicker and more obscuring dust structures.

I still think that the IFN in our galaxy would be another color if our galaxy had a much smaller yellow population and a lot more high-mass star formation. Imagine IFN in M101. I can't help thinking that the IFN of M101 would be bluer than the IFN of the Milky Way.

Ann

When I woke up this morning, the sky was already starting to lighten! Over to the East was this big bright light as per usual! Other than that you had to look hard to see many pin pricks of light1 Turning right was a nice star to the South and lots of tiny points of light! Because of neighbors big tree; you couldn't make out constellation star was from. I'm guessing Orion!

orin stepanek wrote: ↑Fri Sep 25, 2020 1:00 pm When I woke up this morning, the sky was already starting to lighten! Over to the East was this big bright light as per usual! Other than that you had to look hard to see many pin pricks of light1 Turning right was a nice star to the South and lots of tiny points of light! Because of neighbors big tree; you couldn't make out constellation star was from. I'm guessing Orion!

The big bright light in the east is Venus. I've seen it a couple of times myself.

Orion and Sirius are in the southeast, to the right of Venus. The nice star you saw was probably Sirius, brightest of the stars (apart from the Sun) in the Earth's skies. To the upper right of Orion are the Hyades, with bright orange Aldebaran, and the Pleiades.

In the southwest, even farther to the right, is Mars, which is always orange and currently very bright.

Ann

Ann wrote: ↑Fri Sep 25, 2020 3:22 pm

orin stepanek wrote: ↑Fri Sep 25, 2020 1:00 pm When I woke up this morning, the sky was already starting to lighten! Over to the East was this big bright light as per usual! Other than that you had to look hard to see many pin pricks of light1 Turning right was a nice star to the South and lots of tiny points of light! Because of neighbors big tree; you couldn't make out constellation star was from. I'm guessing Orion!

The sky in the morning of September 23. Created using Stellarium and GIMP. Bob Moler's Ephemeris Blog.

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The big bright light in the east is Venus. I've seen it a couple of times myself.

Orion and Sirius are in the southeast, to the right of Venus. The nice star you saw was probably Sirius, brightest of the stars (apart from the Sun) in the Earth's skies. To the upper right of Orion are the Hyades, with bright orange Aldebaran, and the Pleiades.

In the southwest, even farther to the right, is Mars, which is always orange and currently very bright.

Ann

T he==the sky was fairly bright when I got up this morning when I awoke; i figure I was lucky to see the bright stars; let alone the pin pricks! I figured that had to be the furthest east of Orion's stars as th rest were hidden ny neighbors tree!

OMG! Like the whole sky opened up this morning! Venus; Mars; Luna; Orion; etc, etc! Very nice at 5:30! What a nice reward for taking out the trash!

My sisters are in town, freshly tested negative, so we got together for some planet gazing. I showed them Mars, Jupiter, and Saturn at 200 power. As a nice surprise, we got to see some movement of the Galilean satellites—Io had moved out from behind Jupiter.

I was able to make out a broad stripe across the middle of Mars, which I think were Maria Tyrrhenum, Cimmerum, and Sirenum. One of my sisters saw a stripe near the “top.” My first thought was Utopia, but north was to the right in the eyepiece, so that suggests that she saw Syrtis Major. My secondary mirror is old, though, which may have compromised the detail.

The face mask really fogged up my glasses later in the evening, but I could make out two belts and the GRS on Jupiter.

The full Moon (Blue Moon) rising behind Pikes Peak. Tonight at sunset. You can see the edge of Venus's Belt at the top.
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Chris Peterson wrote: ↑Sat Oct 31, 2020 12:42 am The full Moon (Blue Moon) rising behind Pikes Peak. Tonight at sunset. You can see the edge of Venus's Belt at the top.
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E7_47208p.jpg

Beautiful picture as usual, Chris.

Here in Malmö the weather has been terribly overcast and rainy, but two nights ago I could see a lovely conjunction between the nearly full Moon and Mars.

Ann

Two nights ago. Coming down off a hard hike up and back from a 12,500 foot pass (In Colorado, in November!). Crescent moon, Jupiter, and Saturn. Only had my phone, but it didn't do bad.
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Saturn, Jupiter, the Moon, just after sunset. The second shot is photobombed by a jet.
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I had to dodge some clouds, which somehow materialized just as I finished aligning the finder scope, but I caught the Great Conjunction this evening at 133 power.

Naked eye, it wasn’t all that impressive; the 1999 conjunction of Jupiter and Venus looked much more dramatic and freaked out a lot of people in my community. But seeing Saturn, Jupiter, and the Galilean satellites all at the same time was cool!

I was trying to catch the pass of a string of Starlink satellites last night. Just a little to hazy to see them, but there was a very pretty halo around the Moon.
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Chris Peterson wrote: ↑Sat Nov 21, 2020 10:14 pm Two nights ago. Coming down off a hard hike up and back from a 12,500 foot pass...

That is a remarkably causal reference to a very big mountain! The highest point in OR is Mt Hood which is 11,250 feet - and that is a peak, not a pass.

Out of curiosity I compared the Cascades to the Rockies for highest peaks - Mt Rainier (14,411) is just a few feet shorter than the highest peak in the Rockies, Mt Elbert (14,433). Of course they are different types of mountain ranges and formed very differently. Not that it's a contest and I am comparing our mountains or anything!