View Full Version : SOHO - comet or space junk?
19th February 2003, 04:25 AM
Really cool images from the SOHO LASCO C3 camera over the last 24 hours or so:
Is this a comet, or some crud on the lens, or space junk, or what? Or a "Ra Cruiser" or whatever the spaced dingleberries call it?
Is the Bad Astronomer around to lend insight?
19th February 2003, 04:27 AM
Here's one of the images:
19th February 2003, 04:35 AM
On a comet, the tail would point directly away from the sun.
Its a bleed effect from a bright star. See the explanation here:
Edited t oadd:
Actually, its a planet, as you can see it moves with respect to the background stars.
19th February 2003, 06:01 AM
Looking at the whole series of images, I am still inclined to say it could be a comet. The hard horizontal line at the "head" of the object looks like typical CCD bleed. The big fuzzy area does not look like bleed to me.
Concerning the tail should point away from the sun comment, if you look at the whole series, the "tail" is certainly swinging towards the directly away from the sun direction the entire time, but just appears to be lagging a bit. It is also worth noting that each picture in the series is taken only one hour apart.
19th February 2003, 06:02 AM
Very cool if you scroll quickly from the bottom of the page to the top, generating a "time lapse" effect.
19th February 2003, 08:35 AM
It's a bird! It's a plane! No wait, it's a comet!
Soho has photographed hundreds of comets around the Sun but this one, known as Neat, has only just been seen.
It has been hovering in the evening sky for the past few weeks but is hardly visible without a telescope.
The comet, which goes by the official name C/2002 V1, is new to astronomers. Calculations show it has passed through the inner Solar System once before but this was 37, 000 years ago.
The comet is unusual in that it is very large and very bright. In fact it is the brightest comet ever observed by one of Soho's instruments.
19th February 2003, 08:55 AM
Ok, now that we know it is a comet.
If anyone spots an article that indicates its future path and possible visibility from Earth over the next couple of months, I would love to see a link to it.
19th February 2003, 09:07 AM
Yep, comet. Big'un, though not all that close to us. Space.com has info (http://www.space.com/scienceastronomy/neat_soho_030218.html) although I didn't see any references to where it will be over the coming weeks.
The flipbook-effect on the SOHO site is pretty cool too!
The Bad Astronomer
19th February 2003, 12:43 PM
The tail generally points away from the Sun in a comet, but not always directly away, since there are orbital velocities to consider.
Remember too that we are not seeing this in three dimensions. If the comet were on the far side of the Sun, but off to the right a bit in the image, the tail would look heavily foreshortened, but poking out to the right, even though in reality it is mostly headed away from us. This is hard to describe with images!
Think of it this way: a train might look really long when viewed from the side, but only a couple of meters across when viewed head-on. Same thing here.
19th February 2003, 12:50 PM
OK, point taken. Of course, once the particles have left the comet to form the tail, they are basically following their own individual orbits.
19th February 2003, 12:54 PM
Calculations show it has passed through the inner Solar System once before but this was 37, 000 years ago.
I just love this! One Young Earth Creationist argument is that all the comets would have burned out if the Solar System was really older than their roughly 6,000 years. I can't wait till next time that argument pops up. :rolleyes:
21st February 2003, 06:51 AM
I know I was actually shown pictures of identified CCD bleed with SOHO images lately.
Did you do that during your Planet X lecture during the amazing meeting?
The Bad Astronomer
21st February 2003, 01:27 PM
Yeah, I talked about CCD blooming. I have details on my website (http://www.badastronomy.com/bad/misc/planetx/soho.html).
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