APOD: Periodic Comet Swift-Tuttle (2024 Aug 08)

[APOD Robot]

Periodic Comet Swift-Tuttle

Explanation: A Halley-type comet with an orbital period of about 133 years, Comet 109P/Swift-Tuttle is recognized as the parent of the annual Perseid Meteor Shower. The comet's last visit to the inner Solar System was in 1992. Then, it did not become easily visible to the naked eye, but it did become bright enough to see from most locations with binoculars and small telescopes. This stunning color image of Swift-Tuttle's greenish coma, long ion tail and dust tail was recorded using film on November 24, 1992. That was about 16 days after the large periodic comet's closest approach to Earth. Comet Swift-Tuttle is expected to next make an impressive appearance in night skies in 2126. Meanwhile, dusty cometary debris left along the orbit of Swift-Tuttle will continue to be swept up creating planet Earth's best-known July and August meteor shower.

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[Ann]

I knew it! Today's APOD sure looks like a circa 20-30 year-old comet picture - and it is, too!

Periodic Comet Swift-Tuttle
Image Credit & Copyright: Gerald Rhemann

You can tell the picture is old because of the lovely colors. The comet head is cyan-green, not grass green, and the ion tail is a lovely shade of blue. And ion tails of comets are blue, really!

Case Western Reserve University wrote:

The ion tail is made up of ions (surprise!) - mostly CO+, N2+, CO2+. As the comet comes into the inner solar system, the Sun's radiation heats up the nucleus, "boiling off" and ionizing these gases.
These ions are electrically charged particles, and interact with the sun's solar wind (charged particles coming from the sun). The interaction between the comet and the solar wind distorts magnetic field lines, causing a cometary magnetotail which points away from the Sun. The charged ions stream along the magnetic field lines in the magnetotail, so the ion tail always points away from the Sun.

CO+ absorbs sunlight and flouresces, emitting energy at a wavelength of 4200 Angstroms, which is blue light.

Right! Ion tails are blue. But many of today's comet photographers don't seem to know that. Take a look at a sample of Comet Lovejoy images:

Comet Lovejoy. Credit: Jim Miller.

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Comet Lovejoy. Credit: Justin Ng.

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Comet Lovejoy. Credit: Parks Squyres

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Comet Lovejoy. Credit and copyright: SEN/Damian Peach.

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Okay, comet photographers of today, I know you like to be creative. But ion tails of comets are blue, can we agree on that?

But even I have to like this last portrait of Lovejoy, where the comet has captured a nice galaxy in its non-blue net!

Comet Lovejoy on February 4, 2015. Credit: NASA’s Goddard Center for Astrobiology/L. Paganini et al.

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Actually, I think I have identified the galaxy in the comet's tail. Not only does it look an awful lot like NGC 891, but it is NGC 891!

Oh, and HD 14633 is a lovely rare O-type star, almost 5,000 light-years away! Isn't that nice?

Ann

[JimB]

You can tell the picture is old because of the lovely colors.

The random hairs caught on the negative are also a giveaway - but maybe less intrusive than satellite trails!

[Chris Peterson]

I knew it! Today's APOD sure looks like a circa 20-30 year-old comet picture - and it is, too!

Rhemann799_109P_24_11_92_1100px[1].jpg

Periodic Comet Swift-Tuttle
Image Credit & Copyright: Gerald Rhemann

You can tell the picture is old because of the lovely colors. The comet head is cyan-green, not grass green, and the ion tail is a lovely shade of blue. And ion tails of comets are blue, really!

Hmm. And I was going to say that I could tell this was shot on film because of the poor dynamic range and poor color accuracy. (Not a criticism of the image... for film, it is excellent. But no film image of any astronomical object comes close to what modern electronic cameras capture.)

[wilddouglascounty]

Modern digital astronomical image making has opened up capturing the spectacular nature of celestial objects to a much larger number of astronomy buffs than was possible when I was younger, and we are all the richer for it. Not only are these images qualitatively head and shoulders above the imagery I grew up with, the larger number of astrophotographers no doubt are capturing phenomena that would have otherwise been missed. But I also feel a bit of a double edged sword quality to the jump in quality and quantity: My first look through a telescope was at the University of Kansas 6 inch refractor looking at Saturn when I was in grade school. Having seen pictures of it before, I was surprised and a little disappointed at how small Saturn looked through the refractor, but I was hooked nevertheless. I learned my constellations, got a 4/1/2 inch Newtonian reflector from Sears, and checked out from the Library Menzel's Peterson Field Guide to the Stars and Planets to help me learn what to look for and where, and this has led to a lifelong appreciation of the skies using mostly my eyes, a pair of binoculars, and now a 6" reflector or larger ones owned by friends.

The double edged sword side of the changes has to do with the leap between the imagery seen on screens or paper vs what is visible to the naked eye. Menzel's Peterson's Field Guide had very crude photos of the stars, planets and nebulae, but those images were not all that far from what I could see through the eyepiece, and loving dark skies and all they hold became strong and lifelong. While I love all the new imagery and look at APOD daily, I also worry some about how a young kid looks even at a digital image of the Milky Way draped across the sky and compare it to what they see with their own eyes, and fail to bond with it. That's why I like binoculars so much: to show a child the Moons of Jupiter or Saturn, actual craters on the waxing/waning moon, and get lost in the starfields of the Milky Way is the gateway drug to the wonders of a small telescope, where you really ought to pick up the constellations to use well, and then the sky becomes yours for a lifetime. The awe and wonder that all of humanity had before the electric light is lost to most of us, but we can still seek out dark skies if there is motivation to pursue that. Experiencing the skies through our own eyes provides us with both a hard wired sense of awe and probably the original source for science. So I guess my take home message for these meanderings is: don't forget to keep looking at the primary source and help others to do the same: it is an inexhaustible and lifelong source for wonder, an a path to both the past and the future that we all have direct access to if we choose to seek it out.

[Chris Peterson]

Modern digital astronomical image making has opened up capturing the spectacular nature of celestial objects to a much larger number of astronomy buffs than was possible when I was younger, and we are all the richer for it. Not only are these images qualitatively head and shoulders above the imagery I grew up with, the larger number of astrophotographers no doubt are capturing phenomena that would have otherwise been missed. But I also feel a bit of a double edged sword quality to the jump in quality and quantity: My first look through a telescope was at the University of Kansas 6 inch refractor looking at Saturn when I was in grade school. Having seen pictures of it before, I was surprised and a little disappointed at how small Saturn looked through the refractor, but I was hooked nevertheless. I learned my constellations, got a 4/1/2 inch Newtonian reflector from Sears, and checked out from the Library Menzel's Peterson Field Guide to the Stars and Planets to help me learn what to look for and where, and this has led to a lifelong appreciation of the skies using mostly my eyes, a pair of binoculars, and now a 6" reflector or larger ones owned by friends.

The double edged sword side of the changes has to do with the leap between the imagery seen on screens or paper vs what is visible to the naked eye. Menzel's Peterson's Field Guide had very crude photos of the stars, planets and nebulae, but those images were not all that far from what I could see through the eyepiece, and loving dark skies and all they hold became strong and lifelong. While I love all the new imagery and look at APOD daily, I also worry some about how a young kid looks even at a digital image of the Milky Way draped across the sky and compare it to what they see with their own eyes, and fail to bond with it. That's why I like binoculars so much: to show a child the Moons of Jupiter or Saturn, actual craters on the waxing/waning moon, and get lost in the starfields of the Milky Way is the gateway drug to the wonders of a small telescope, where you really ought to pick up the constellations to use well, and then the sky becomes yours for a lifetime. The awe and wonder that all of humanity had before the electric light is lost to most of us, but we can still seek out dark skies if there is motivation to pursue that. Experiencing the skies through our own eyes provides us with both a hard wired sense of awe and probably the original source for science. So I guess my take home message for these meanderings is: don't forget to keep looking at the primary source and help others to do the same: it is an inexhaustible and lifelong source for wonder, an a path to both the past and the future that we all have direct access to if we choose to seek it out.

Binoculars (and just my eyes, of course) are my favorite way of looking at the sky. Telescopically, the Moon, Saturn, and Jupiter are fantastic high magnification objects. Pretty much everything else is boring through an eyepiece. At star parties I run, we mostly limit the telescope to those bright objects (and maybe the occasional globular cluster) and do most of the program with a green laser pointer and people just standing under the stars, with and without binoculars.

[Ann]

Modern digital astronomical image making has opened up capturing the spectacular nature of celestial objects to a much larger number of astronomy buffs than was possible when I was younger, and we are all the richer for it. Not only are these images qualitatively head and shoulders above the imagery I grew up with, the larger number of astrophotographers no doubt are capturing phenomena that would have otherwise been missed. But I also feel a bit of a double edged sword quality to the jump in quality and quantity: My first look through a telescope was at the University of Kansas 6 inch refractor looking at Saturn when I was in grade school. Having seen pictures of it before, I was surprised and a little disappointed at how small Saturn looked through the refractor, but I was hooked nevertheless. I learned my constellations, got a 4/1/2 inch Newtonian reflector from Sears, and checked out from the Library Menzel's Peterson Field Guide to the Stars and Planets to help me learn what to look for and where, and this has led to a lifelong appreciation of the skies using mostly my eyes, a pair of binoculars, and now a 6" reflector or larger ones owned by friends.

The double edged sword side of the changes has to do with the leap between the imagery seen on screens or paper vs what is visible to the naked eye. Menzel's Peterson's Field Guide had very crude photos of the stars, planets and nebulae, but those images were not all that far from what I could see through the eyepiece, and loving dark skies and all they hold became strong and lifelong. While I love all the new imagery and look at APOD daily, I also worry some about how a young kid looks even at a digital image of the Milky Way draped across the sky and compare it to what they see with their own eyes, and fail to bond with it. That's why I like binoculars so much: to show a child the Moons of Jupiter or Saturn, actual craters on the waxing/waning moon, and get lost in the starfields of the Milky Way is the gateway drug to the wonders of a small telescope, where you really ought to pick up the constellations to use well, and then the sky becomes yours for a lifetime. The awe and wonder that all of humanity had before the electric light is lost to most of us, but we can still seek out dark skies if there is motivation to pursue that. Experiencing the skies through our own eyes provides us with both a hard wired sense of awe and probably the original source for science. So I guess my take home message for these meanderings is: don't forget to keep looking at the primary source and help others to do the same: it is an inexhaustible and lifelong source for wonder, an a path to both the past and the future that we all have direct access to if we choose to seek it out.

Binoculars (and just my eyes, of course) are my favorite way of looking at the sky. Telescopically, the Moon, Saturn, and Jupiter are fantastic high magnification objects. Pretty much everything else is boring through an eyepiece. At star parties I run, we mostly limit the telescope to those bright objects (and maybe the occasional globular cluster) and do most of the program with a green laser pointer and people just standing under the stars, with and without binoculars.

I loved looking at bright blue stars, such as Vega, through a telescope. Its blue color just popped out.

Ann

[zendae]

I have a not-too-expensive Orion refractor, which does nicely with Jupiter, Saturn, Andromeda, and the like. But I get happily lost gazing through my very nice birding binoculars, especially the Moon. More than anything, it's how they transform a disc into a sphere. It's given me goosebumps on warm nights...

[Christian G.]

Same enthusiasm here for binoculars! I have both small hand-held and large tripod-mounted ones (120 mm), the latter being the perfect star-chasing machine with 24 mm eyepieces, you can enjoy bright views of collections of stars, see most of M24 or the Scutum star cloud in one view or the Pleiades entire etc. and get "lost in starfields" as per wilddouglascounty's wonderful reflection above.