Solved A Possible Naked-eye Comet in March, A Better One in December.

[ICIT2LOL]

hmm that is very close eh just hope it doesn't get sucked in and expecting rain the next few days so might not get a chance to see it

 

[Anak]

Had a slim chance to see it this morning, the cloud deck from a rain event just cleared our location, but the Sun was rising.

I could see Mercury at -0.2 and Spica at -3.58 magnitude, but my 10x50's couldn't pick ISON (4.9) out.

Comet ISON: What's Next?

Nov. 14, 2013: Comet ISON is now inside the orbit of Earth as it plunges headlong toward the sun for a fiery close encounter on Nov. 28th. Although the comet is not yet as bright as many forecasters predicted, the comet is putting on a good show for observatories around the solar system. NASA spacecraft and amateur astronomers alike are snapping crisp pictures of the comet's gossamer green atmosphere and filamentary double-tail.

Source: Comet ISON: What's Next? - NASA Science

From the "When it rains it pours" Department:

Two Comets to Fly By Mercury

Nov. 15, 2013: What are the odds? On Nov. 18th and 19th not one but two comets will fly by the planet Mercury.

"This is a unique coincidence," says Ron Vervack an astronomer at the Johns Hopkins University Applied Physics Lab and a member of the science team for NASA's MESSENGER spacecraft, "and a golden opportunity to study two comets passing close to the sun.”

On Nov. 18th Comet Encke will pass within 0.025 AU of Mercury, followed a day later by Comet ISON at 0.24 AU (1 AU is the distance between the sun and Earth, 150 million km). The MESSENGER spacecraft, which is orbiting Mercury, will turn its sensors toward the passing comets for a point-blank investigation of both.



Source: Two Comets to Fly By Mercury - NASA Science

 

[Anak]

Science Channel will be hosting a special event showing of "Super Comet ISON 2013"

Sunday December 7th at 10pm est


This is only a 00:30second clip to advertise the show,
Be warned,
It starts automatically so you may want to adjust your machine sound levels.

SuperComet Ison 2013: Supercomet Ison on Science : Video : Science Channel​

 

[Anak]

The Public Broadcasting System (PBS) will be airing "Comet Encounter" This Wednesday evening (11-20-2013) at 10pm est.

About the Program
Comets have fascinated, even terrified us for thousands of years. For scientists though, comets are a great opportunity. This year, 2013, a particularly massive chunk of ice and rock is coming our way, an object that will fascinate billions and should create the space show of the century.

Right now Comet ISON, somewhere between one and 10 kilometers in diameter, is just beyond the orbit of Jupiter. As it races past us toward the sun it should develop a tail that will light up the skies brighter than a full moon. Then the comet will slingshot around the back of the sun and could emerge brighter than ever, treating the entire northern hemisphere to an unforgettable sight.

In this program, scientists all over the world follow a once-in-a-lifetime event and shoot breathtaking images, spewing its essence into the void. But there is jeopardy too; the comet could evaporate completely or the sun's massive gravity could tear it apart. If the latter happens it will produce a so-called "string of pearls," several much smaller comets arching right across the night sky.

Source: Comet Encounter | PBS

I hope the program isn't as dated as the promo byline and becomes more accurate as we approach the close encounter with the Sun on Thanksgiving day the 28th. ISON is now within the orbit of Venus and approaching Mercury.

Interactive Source: Comet ISON Model

This is nitpicking, but with the real time astronomy programs I'm using, ISON will only be viewable in the early morning sky here in the Northern Hemisphere; to the southeast before November 28th and towards the Northeast/North after the 28th.
I can understand the generalization, but using "the night sky" at the end of the quote implies to the novice that one could go out after their T-Day supper and see it when that is not the case.

The enthusiast should use real time programs to check the location and time for possible viewing opportunities.

   Note

From the "I don't like it, but it is a sign of the times" department.

If the source link to Comet Encounter doesn't pick up on your location and station by interpreting your IP address you can click on PBS below the menu bar that will then take you to the main site where above the menu bar you will see a link to change stations by using your postal zip code or regional area.

Also take note of a new development with the PBS site. It doesn't like it if you use any type of private browsing and will throw up nag screens to warn you. I clicked on one OK ten times before it finally allowed me to continue, and I wasn't using private browsing at the time. (FF25.0.1).

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I just found out about a free app called Comet Watch available for the iPhone or iPad. Updated by the minute, the app promises to point users in the direction of ISON, whose location can change quickly.

Source: Comet Watch-Powered by Distant Suns | itunes.apple.com

Well, not that quickly.

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Must be my night for nitpicking... and a small rant, but am I the only one to notice the carelessness in the use of verbal communication skills lately?

I'll be the first to admit that I probably have a dozen errors in this post, but I've been noticing it more and more with the "Fourth Estate".

 

[ICIT2LOL]

Watched the last couple of mornings but nothing pity as the sky has been as clear as hope you folks have had a good view.

 

[Britton30]

John I suspect you'll need a decent pair of binoculars, maybe in the 10X range at this time. It should be brighter later on. I can't see it yet either with my 8X glasses. They are 8X22 so slim on light gathering power.

 

[Anak]

John, not sure if you have seen this site, there is a map to help in locating ISON: Comet ISON from the Southern Hemisphere | Sydney Observatory

Gary, those 8x's should be able to pick up ISON now (4.10mag.), make sure you double check the location. At 5am tomorrow morning it will be 110° East/Southeast about halfway between Spica and your horizon at 4° altitude, and that's not much.
Glad to hear you and yours made it through the rough weather yesterday.


My next few mornings will have good seeing so I'll be out.

 

[ICIT2LOL]

Ok I am now guessing it is because the comet is obscured by the hills and trees at the critical point. I have some 10x binoculars and a 10x monocular but the obstructions are such that I think to get a clear view one would have to be at the top of a mountain or on the coast.

There has been that very large and bright "star" in out west at around 10pm that is I am thinking now either Mars or more likely Saturn as Mars usually is tinged a very faint red colour.

 

[Anak]

You've analyzed your predicament pretty well John, and I'm in the same Dire Straits. Now that ISON is bright enough on its own (3.4mag) it is getting too close to the Sun's glare to see it as it rises into the morning sky.

These are skymaps from the perspective of the Australian Astronomical Observatory.

This is 40" before Sunrise but ISON is barely 5° above the horizon:


This one is just before Sunrise at barely 10°:


So anyone trying to view ISON before it rounds the Sun on the 28th better have as clear as possible view of the horizon to have a chance to see it.


The bright object you mention seeing at 10pm is Venus, Saturn is following ISON there in the morning as shown in the first screenshot.


Mars has already risen about an hour before Sunrise and precedes ISON.



The waning gibbous Moon; It was full on the 18th doesn't help the seeing either.

 

[ICIT2LOL]

Ok mate I reckon maybe after it has flown by might be better then. What I thought was Saturn must be Venus though it is very much larger than normal.

 

[Anak]

I hope ISON is better in December also.

Venus's apparent magnitude can fluctuate in brightness from a low of -3.5 to a high of -4.4 depending on the percentage of illumination (It's phase like the Moon's) and its distance from the Earth, these two factors hold true for any of the Planets in our Solar System because the planets reflect light, albedo a third factor.

Venus has all three factors going for it making it a spectacular sight in the evening sky.

Star magnitudes are another matter, they still use + or - values, mostly +, but create their own light.
Stellar Magnitudes

Don't forget, magnitudes work in the opposite. A minus value (-) is brighter than a plus value (+)
The astronomical magnitude scale

Stellarium has Venus at -4.28 today, Saturn at 0.76

 

[Britton30]

The magnitude scale had always been a stick point with me. Why not make it similar to the decibel scale, larger number means louder noise and an increase of one whole DB number is a 10 fold increase from the next lower number. Magnitude could be the same so an object with a mag of 4 is brighter than one with a 3.

 

[Anak]

You are not alone Gary, many people find it counter-intuitive that a high magnitude star is dimmer than a low magnitude star. Although both scales are logarithmic (star magnitudes and the decibel scale) we can attribute this counter-intuitiveness to the ancient Greeks, your argument would pale against two millennia of history and custom.

Most ways of counting and measuring things work logically. When the thing you're measuring increases, the number gets bigger. When you gain weight, the scale doesn't tell you a smaller number of kilograms or pounds. But things are not so sensible in astronomy, at least not when it comes to the brightnesses of stars.

Star magnitudes do count backward, the result of an ancient fluke that seemed like a good idea at the time. Since then the history of the magnitude scale is, like so much else in astronomy, the history of increasing scientific precision being built on an ungainly historical foundation that was too deeply rooted for anyone to bulldoze it and start fresh.

The story begins around 129 B.C., when the Greek astronomer Hipparchus produced the first well-known star catalog. Hipparchus ranked his stars in a simple way. He called the brightest ones "of the first magnitude," simply meaning "the biggest." Stars not so bright he called "of the second magnitude," second biggest. The faintest stars he could see he called "of the sixth magnitude." This system was copied by Claudius Ptolemy in his own list of stars around A.D. 140. Sometimes Ptolemy added the words "greater" or "smaller" to distinguish between stars within a magnitude class. Ptolemy's works remained the basic astronomy texts for the next 1,400 years, so everyone used the system of first to sixth magnitudes. It worked just fine......

......Galileo forced the first change. On turning his newly made telescopes to the sky, Galileo discovered that stars existed that were fainter than Ptolemy's sixth magnitude. "Indeed, with the glass you will detect below stars of the sixth magnitude such a crowd of others that escape natural sight that it is hardly believable," he exulted in his 1610 tract, Sidereus Nuncius. "The largest of these...we may designate as of the seventh magnitude...." Thus did a new term enter the astronomical language, and the magnitude scale became open-ended. Now there could be no turning back. .......


.......The resulting magnitude scale is logarithmic, in neat agreement with the 1850s belief that all human senses are logarithmic in their response to stimuli. (The decibel scale for rating loudness was likewise made logarithmic.) Alas, it's not quite so, not for brightness, sound, or anything else. Our perceptions of the world follow power-law curves, not logarithmic ones. Thus a star of magnitude 3.0 does not in fact look exactly halfway in brightness between 2.0 and 4.0. It looks a little fainter than that. The star that looks halfway between 2.0 and 4.0 will be about magnitude 2.8. The wider the magnitude gap, the greater this discrepancy.

Source: Stellar Magnitude

Hipparchus only knew of one type of numbering system 1 to 9 and he gave the brightest stars the value of 1, any stars that diminished in his brightness scale were given an ascending number. There is some evidence he was aware of 0, but 0 wasn't used in his day as it is used now: Indo-Arabic numerals

With the advent of the telescope and its capability of seeing more and more stars the magnitude scale had to be expanded to include negative numbers.

If I understand the decibel scale correctly, 0db is the best quality signal. Anything above that is subject to distortion and anything below that represents a lower signal to noise ratio.

 

[Britton30]

Well using Hipparchus's logic it kind of makes sense, but people believed everything revolved around the Earth at one time.

Yeah the decibel scale is used for "loudness" and sound quality both.

 

[Anak]

The jury is still out whether or not ISON survived it journey around the Sun. There are pictures that something survived, but:

• Did the Sun corona blow out some of the coma and tail until it can rebuild?
• Did the Suns' corona reduce the size of ISON?

Comet ISON down … but not out?



On another note:

Well using Hipparchus's logic it kind of makes sense, but people believed everything revolved around the Earth at one time.

At one time.
That period of time from the early 4th century to the middle of the 17th century was a huge dis-service to the human condition.

Ancient Libraries in the known world from Eastern Asia to the Middle East and around the Mediterranean were well on their way in developing a storehouse of critical thinking.

The trouble started as usual because of religion and politics. The Roman Emperor Constantine I called The First Council of Nicaea in 325 a.d. and the human race suffered for the next 1,325 years until the Age of Enlightenment, and I fear that history is due to repeat itself because we as a people do not seem to learn from our past mistakes.

 

[Britton30]

It seems at least a good part of ISON made it through hell.

I noticed a very bright object in the early evening SW sky (6:48pm EST) a few days ago. It was about two out stretched arm hand widths up from the horizon. Two days later about 8;30pm EST I saw a similar object in the Eastern sky. This one was maybe 40-50 degrees up, I had not noticed either of them before.

The one in the SW sky was as bright as an aircraft landing light, the other slightly dimmer. The SW object turns out to be Venus, the other one Jupiter. I don't recall ever seeing them before.

Last night 28NOV about 10pmEST There was another oddity in the ESE sky, not nearly as bright but seemed to twinkle and flash with white, red, and blue colors, as if spinning fast.

 

[Anak]

I always find that writing the first line in a blog post is the hardest, and this has never been truer that now as I struggle to decide where I should even begin. My @SungrazerComets Twitter feed, and my email accounts, are all blowing up with questions about comet ISON. Many of them have already been answered, and many of them have unsatisfying answers, but I'll do my best. First, a little personal note...

Source: In ISON's Wake, a Trail of Questions | Comet ISON Observing Campaign

Determining Venus and then Jupiter was good sleuthing Gary!

If you noticed your oddity below the Constellation Orion and to the lower right of Jupiter, it would be Sirius which is also called the Dog star because it is in the Constellation Canis Major.


Why did it change colors?

This is because of scintillation ("Twinkling") as the light passes through the atmosphere of the Earth. As the air moves in and out, the starlight is refracted, often different colors in different directions. Because of this "chromatic abberation," stars can appear to change colors when they are twinkling strongly.

Source: Curious About Astronomy: Why do stars change colour when they twinkle?

 

[Britton30]

Yessir, indeed it is Sirius, I'm serious. Strange how it seems to be the only "twinkle" at about the same height on the sky. It would seem other stars ,whole not as bright, would show some sort of twinkling passing light through the same atmospheric thickness.

EDIT: I checked Sirius much later in the night when it was near 45° elevation and the twinkling and colors were gone.

 

[Anak]

Yessir, indeed it is Sirius, I'm serious. Strange how it seems to be the only "twinkle" at about the same height on the sky. It would seem other stars ,whole not as bright, would show some sort of twinkling passing light through the same atmospheric thickness.

Oh, but they do, but because of their lesser magnitude and greater distance from Earth it is harder to see.

It might be possible to see them twinkling in your 8power binoculars, but you would have to have them mounted on a tripod to keep them steady. A telescope would give you better results, 8power would be okay but a larger aperture/objective than 22mm, say 90mm would be better.

EDIT: I checked Sirius much later in the night when it was near 45° elevation and the twinkling and colors were gone.

There are several factors at play here; angle of incidence, extinction, and seeing.

Would you agree that the atmosphere is thinner as you go higher into it? It is this density difference that affects the twinkling.

I thought you would like to see this:

Twinkling is the rapid fluctuation in brightness and color of a star. It’s caused by slight changes in density of air pockets called “seeing cells” that move across the observer’s line of sight. Air’s refractive index is determined, in part, by its density. Such undulations cause slight, momentary defocusing of the starlight resulting in brightness changes, also called scintillation. In extreme cases, the star’s position hops around. Twinkling also produces rapid color changes because air is slightly dispersive, i.e. the index of refraction varies slightly with wavelength.

Both brightness and color twinkling are shown here in a five-second exposure of Sirius using a telephoto lens that was wiggled slightly during the exposure. As the star‘s twinkling image skated around the focal plane, it traced out graceful, colorful arcs, fading in some places, brightening in others.

Sources of both pic and quote: Sirius Twinkling - Earth Science Picture of the Day

 

[Anak]

Turn Out the Lights, the Party's Over....

It was a good run, but all good things must come to an end....

Dec. 4, 2013:
Astronomers have long known that some comets like it hot. Several of the greatest comets in history have flown close to the sun, puffing themselves up with solar heat, before they became naked-eye wonders in the night sky.

Some comets like it hot, but Comet ISON was not one of them.

Source: What Happened to Comet ISON?

In Memoriam | Comet ISON Observing Campaign


Thread is marked solved, but left open in case anyone has any astronomy questions, I'll be happy to try and answer.