What did you see in the sky tonight?

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

Post by Ann » Tue Jul 07, 2020 9:29 pm

Noctilucent clouds July 7 2020.jpg
There are noctilucent clouds outside my window again tonight. This time of year is noctilucent clouds season at my latitude, but you can never predict when these delicate silver-blue veins of the sky will show up. It always makes me happy to see them.

But I'm not going out for them tonight. I'll stay inside and watch them from my kitchen.

Ann
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Jerome68
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Re: What did you see in the sky tonight?

Post by Jerome68 » Thu Jul 09, 2020 3:56 pm

I am sorry but I had to share it, but this summer in Germany the only thing we are seeing is clouds... :(.

First said that I am 100% against climate change, but last year at least it was some nice sky nights without clouds and illuminated by the moon. But this one, already in July.... it seems almost like a lottery if we get a night like this than other things. However, for the rest of you, if you are leaving in a sunny place (yes, sunny for me it means basically no clouds), enjoy the nights during this summer!

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

Post by Chris Peterson » Mon Jul 13, 2020 1:23 am

Still following NEOWISE, at the thoroughly unpleasant hour of 4am. Looking forward to it being an evening object in a week or so. This is processed from a stack of nine images exposed from 0.25 to 60 seconds to bring out the detail. Whatever is going on in that coma is very interesting. (The second shot is pushed in the blue channel to emphasize the ion tail.)
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E7_44966_stack9.jpg
E7_44966_stack9-enhblue.jpg
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Orca
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Re: What did you see in the sky tonight?

Post by Orca » Tue Jul 14, 2020 4:56 pm

I caught a glimpse of NEOWISE! It was still visible just above the horizon around 10:00. The comet just happened to end up in a gap between trees. The tall trees around my area can make it difficult to see objects that are near the horizon.

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Re: What did you see in the sky tonight?

Post by BDanielMayfield » Wed Jul 15, 2020 6:23 am

Caught my first ever view of a comet at about 10:15 local time, (Mountain Daylight Saving Time), 7/14/20. NEOWISE was just barely visible to the naked eye, but was impressive in my 7x50 binoculars.

Also got a look at Jupiter and three of its moons in my spotting scope while waiting for the sky to darken enough to find the comet.
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Re: What did you see in the sky tonight?

Post by rstevenson » Sun Jul 19, 2020 12:54 am

I was ready to go out for a look at the comet this evening but the sky is too hazy at the moment. That’s generally true here, being on a sea coast and our location on the downwind side of the city, so no surprise there. But I happened to notice in another app that the ISS would be passing almost directly overhead — just a degree off the zenith, and just an hour or so after sunset. I had high hopes it would be bright enough to cut through the haze and it did. So I had 5 minutes of mild excitement and mosquito swatting, then back inside. What a life of excitement I lead!

Rob

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Re: What did you see in the sky tonight?

Post by BDanielMayfield » Sun Jul 19, 2020 3:52 am

I made another attempt to see NEOWISE last night, but an hour or so later than the successful try my previous post reported. I drove out of town to a nearby dark sky site but found the northwestern sky littered with unforecasted broken cloud cover and found nada. I drove home, parked in our brightly light polluted apartment parking lot and took a look back toward the northwest. Hay, what's that light streak above the trees, could it be? I walked beyond the parking lot, got in the shadow of a large pine, pointed my binoculars and bam, their it was, looking much finer in the darker sky than it had three nights before.

Moral of the story is keep trying. ''Tis well worth the effort.

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

Post by Cousin Ricky » Mon Jul 20, 2020 1:07 am

I saw comet C/2020 F3 NEOWISE tonight. I needed binoculars to find it, but once I did, I just needed averted vision to keep up with it naked eye. I wasn’t able to make out the split tail.

Six other people showed up on the same quest, so I got in an impromptu sidewalk astronomy session, my first since the pandemic arrived. It was different, staying 2 meters apart, speaking through masks, unable to share binoculars, and my laser pointer decided to die, forcing me to resort to things like “lower left of that cloud,” and “7 o’clock below the Big Dipper’s bowl,” but we managed.

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Re: What did you see in the sky tonight?

Post by gntekas » Mon Jul 20, 2020 7:45 am

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Re: What did you see in the sky tonight?

Post by Chris Peterson » Wed Jul 29, 2020 7:05 pm

Now that NEOWISE is moving away from the Sun, the cyanogen glow of the coma is no longer overwhelmed by scattered sunlight. Quite beautiful. Stacked from 15 each 1-minute RGB exposures (45 minutes total) taken with my RC10.
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c2020f3_20200729.jpg
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Re: What did you see in the sky tonight?

Post by neufer » Wed Jul 29, 2020 7:54 pm

Chris Peterson wrote:
Wed Jul 29, 2020 7:05 pm

Now that NEOWISE is moving away from the Sun,
the cyanogen glow of the coma is no longer overwhelmed by scattered sunlight.
  • However, the violet CH cyanogen glow IS overwhelmed by the green C2 glow:
https://steemit.com/steemstem/@terrylovejoy/comets-a-brief-primer wrote:
<<When distant from the sun a comet looks like an asteroid, however, as it approaches the sun its surface begins to warm which in turns starts to sublimate its constituent ices which include Water, Carbon Dioxide and others. In the vacuum of space most ices sublimate, that is pass from the solid to gas phase without becoming a liquid. Because of outgassing dust and ice grains are also released, and these all combine to form a large cloud around the nucleus which typically extends 100,000 km or more, which is about the size of Jupiter. During the Rosetta mission it was found that Water and Carbon Dioxide liberated from the nucleus of Comet 67P were dissociated from free electrons, creating other products (like Diatomic Carbon and Hydrogen, among others).

Often coma shine a vivid green, something some people can see even by direct observation by eye. Spectroscopic observations of coma reveal the main cause of this to be fluorescing diatomic carbon (C2) and Cyanogen (CN) which are presumably the byproduct of the dissociation of ices containing Carbon (CO2) and Nitrogen (Ammonia) from the nucleus surface. This can be seen in the adjacent (COMET LOVEJOY : 2013) spectra obtained by renown French amateur astronomer Christian Buil.

Surround the nucleus and coma, but not visible in the visual spectrum is a large cloud of Hydrogen atoms, which extends well beyond the normal coma and most likely is derived from the dissociation of water from the nucleus. It can only be detected from outside the earth's atmosphere because of the wavelengths it emits. In the case of Comet Hale-Bopp in 1997 the Hydrogen envelope extended 1 Astronomical Unit!>>
Art Neuendorffer

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

Post by Ann » Thu Jul 30, 2020 5:31 am

Thanks for posting that comet spectrum, Art. It demonstrates perfectly why comet comas are not only green, but a bluish shade of green.

Comet Lovejoy (2013) was seen to have two bright emission lines in the green part of the spectrum at around 520 nm, but it also had a "cluster" of emission lines at around 470 nm. And as you said, Art, this comet also had a bright spike deep in the violet (ultraviolet?) part of the spectrum at about 390 nm.

Compare the difference between shades of "comet green" and "aurora green" (and yes, I realize that there are yellower comet comas and bluer auroras, but these are typical hues to me):


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