Starship Asterisk*

Rosetta's Target Comet

Explanation: The Rosetta spacecraft captured this remarkable series of 9 frames between March 27 and May 4, as it closed from 5 million to 2 million kilometers of its target comet. Cruising along a 6.5 year orbit toward closest approach to the Sun next year, periodic comet 67P/Churyumov-Gerasimenko is seen moving past a distant background of stars in Ophiuchus and globular star cluster M107. The comet's developing coma is actually visible by the end of the sequence, extending for some 1300 km into space. Rosetta is scheduled for an early August rendezvous with the comet's nucleus. Now clearly active, the nucleus is about 4 kilometers in diameter, releasing the dusty coma as its dirty ices begin to sublimate in the sunlight. The Rosetta lander's contact with the surface of the nucleus is anticipated in November.

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Should be some pretty cool photos of the comet's nucleus when Philae lands on it. Landing on something with such low surface gravity has its own challenges. How many engineers does it take to screw in a Philae? http://www.esa.int/spaceinvideos/Videos ... touch_down

Hi
I am curios what are all the other flashing lights in the photos
Doug

M107, not M104

http://www.esa.int/spaceinimages/Images ... n_30_April

P.S. finding astronomers' names for captcha is a REAL pain because I don't know some of the cheese names.

DougF wrote:Hi
I am curios what are all the other flashing lights in the photos
Doug

+1 for DougF's question.
I am hoping some experts will shed some light

What are these dot spots appearing in some iamge of the sequence ? is it noise ?
Alex

DougF wrote:Hi
I am curios what are all the other flashing lights in the photos
Doug

I was wondering the same thing. Could these be objects from the asteroid belt? It doesn't seem random noise to me.

Very cool....

And M104 is the Sombrero Galaxy...no doubt a Typo....

:---[===] *

melikamp wrote:...

P.S. finding astronomers' names for captcha is a REAL pain because I don't know some of the cheese names.

If it doesn't sound familiar, it's cheese. Tip: Use internet search to beef up your cheese and/or astronomers knowledge.

DougF wrote:Hi
I am curios what are all the other flashing lights in the photos
Doug

Cosmic rays. These are high energy particles which strike the camera sensor but they are cleared off next time an image is taken so they only appear for one frame at a time. These are also what will give astronauts cancer if they are not careful. Sometimes they are so energetic that they can damage a camera sensor, creating a permanent bad pixel.

Mmmmmmmmm ,,, gob-ular

geckzilla wrote:

DougF wrote:Hi
I am curios what are all the other flashing lights in the photos
Doug

Cosmic rays. These are high energy particles which strike the camera sensor but they are cleared off next time an image is taken so they only appear for one frame at a time. These are also what will give astronauts cancer if they are not careful. Sometimes they are so energetic that they can damage a camera sensor, creating a permanent bad pixel.

As someone who often processes these images taken by cameras in space these cosmic ray flashes must cause you grief too (not nearly as bad as cancer, of course) as you painstakingly remove them. How difficult is that process Geck?

If the globular cluster is M107, then the background starfield belongs to Ophiuchus.

I've let the editors know re: Sagittarius and gobular star cluster M104.

BDanielMayfield wrote:As someone who often processes these images taken from cameras in space these cosmic ray flashes must cause you grief too (not nearly as bad as cancer, of course) as you painstakingly remove them. How difficult is that process Geck?

Depends on how many exposures there are. If there are a lot of exposures then it becomes largely automated. Fewer exposures results in uncertainty and a lot more manual removal. In cases where stars do not overlap between color channels such as when infrared light is used and many stars are invisible in shorter wavelengths, it is very difficult for me to make the distinction between a stellar point source and a cosmic ray which struck the sensor straight on. Hubble processing problems.

Thanks Geck. And here's a wish for clear skies for everyone in North America southeast of Alaska for tonight's possible meteor storm!

What is the star that winks on and off just to the right of the globular cluster in comet photo position 6 (by my count)?

Curious

Omaha science wrote:What is the star that winks on and off just to the right of the globular cluster in comet photo position 6 (by my count)?

Curious

All I see is a cosmic ray. It's one of the brighter ones.

Very helpful, Geck, it's highly appreciated!

starsurfer wrote:If the globular cluster is M107, then the background starfield belongs to Ophiuchus.

Yes, thank you. The APOD has now been updated with this more accurate information. We apologize for the oversights.

M104 is the Sombrero galaxy in Corvus. I don't see comet 67P close to M107 in Starry Night Pro.

dickfrom1929 wrote:M104 is the Sombrero galaxy in Corvus. I don't see comet 67P close to M107 in Starry Night Pro.

We're seeing it by M107, not M104. That said, however, you can't evaluate a picture like this using a planetarium program unless you change your viewpoint from Earth to Rosetta. The comet is currently in Sagittarius as seen from the Earth, but in Ophiuchus as seen from Rosetta.

Very nice sequence of images. It's surely a very exciting time for those who planned and executed this mission and have waited so long. I noticed that today (+/- 1) is listed as the "rendezvous" date in some of the materials describing this mission. Today's APOD ends with an image on May 4, about 19 days ago. You can clearly see the comet waking up and getting close. But if the Rosetta craft has now truly "reached" the comet, how long does it take for images to get here and to be processed for the awaiting public? I gather this will be a really wonderful ride. There's no substitute for being there!

MarkBour wrote:I noticed that today (+/- 1) is listed as the "rendezvous" date in some of the materials describing this mission.

That's confusing, isn't it? I think that what they are calling the "rendezvous" would be better described as the beginning of the rendezvous phase. The 21 May deceleration burn created the largest delta-V of any planned maneuvers. It began the process of putting the spacecraft in orbit.

Today's APOD ends with an image on May 4, about 19 days ago. You can clearly see the comet waking up and getting close. But if the Rosetta craft has now truly "reached" the comet, how long does it take for images to get here and to be processed for the awaiting public?

It hasn't reached the comet. Currently, the spacecraft is 27 light minutes from Earth (and 3 light seconds from the comet). ESA decides how quickly data is released, but it's generally almost immediately.