Celestia Forums

I noticed this just today. Sorry I didn't run across it earlier. Did any of you get to see this???

Comet McNaught -

ESA's news release
http://www.esa.int/esaCP/SEMMCRSVYVE_index_0.html

Space.com's article
http://www.space.com/spacewatch/070104_comet_mcnaught.html

Nice picture!
http://antwrp.gsfc.nasa.gov/apod/ap070105.html

I wanted to, but here in the St. Louis area it's been nothing but cloudy for like the last week.

An eccentricity greater than 1?

Hungry4info wrote:An eccentricity greater than 1?

Correction: An eccentricity not less than 1?

I had the opportunity to see it last Friday. We've been over cast for the last few weeks, but on that day, not only was there a break in the clouds, but the sky itself was completely cloudless!

To the naked eye, it appeared like a bright star, just a bit less so than Venus (located near it), though this was due to it being closer to the setting sun. But I could also discern a bit of the tail, especially if I let my eye drift just a bit off-center of it.

Through the binoculars, it was a grand vision. I hope northern hemisphere viewers get to see more of it after it rounds the sun. I tried to take a photo of it, but my digital camera only has a 4x optical zoom, and so I really doubt that I caught anything worth seeing.

...John...

Yes, we're pretty clouded over with crappy weather at the moment too. I guess I'm going to have to check on its return dates (from around the sun), as just for once I'd like to actually see one (a comet). I've managed to miss all the others thusfar.

Thanks for posting that symaski62! I'll have to plug that in and take a look. I'll presume the code goes into an SSC file and saved in the Extras folder?... I'll give it a try.

This is Comet McNaught right now from where I live. (well, in Celestia anyway...courtesy of Symanski's SSC).

This is the only view I've had of it so far. (I can't confirm if this is realistic as it's only visible in Celestia at present due to 100% cloud cover where I am).
Actually, I doubt it looks at all like this at present, as I've used the halley.cmod as a mesh, with a radius of 10km.

Another hour before it sets, but PROB(clouds lifting) = 0.
Click for bigger picture:


Here's the code:

and...
heres a clickable (1.4.1) URL to take you there.

Despite all my best efforts, I only caught a glimpse of it at sunset before clouds came by. Brightest (mag -5) comet in decades. Dammit....

Have a great view my southern hemisphere friends... I wonder if I could convince my wife that a South America weekend trip is a good idea.

Hi. Comet McNaught started to be visible shortly after sunset on Saturday (the day before yesterday) from here. It was very beautiful, we were on the beach since the afternoon, and we stayed until 21:30 when it set. Yesterday we went with the telescope (20cm Sch-Cass.) to take pictures. It was even better, since it was up until later, even when it has started to dim. The best view was through binoculars, excellent tail, slightly curved. Today we will go also. I will post some picture if any comes out nice.

I witnessed Hale-Bope 10 years ago (from the northern hemispher, I lived in Italy then), and I remember it more visible, perhaps because of a different geometry, which made it visible against a darker sky.

Cheers,

Guillermo

Guys, you may find this difficult to believe, but I have just seen the comet in palin daylight. It's half past noon. By hiding the Sun behind a roof, and with a 10x25 mini-scope, it was easy to find it. The tail is visible against the blue sky! It's a weird view, it looks like it's within the atmosphere.

Here I go again aoutside...

Guillermo

Where do I put the code for the comet?

An SSC file describing the comet's orbit would go in the /extras/ directory.

I created this one from orbital parameters downloaded from Horizons today. Unfortunately, Celestia does not draw hyperbolic orbital paths. It'd be nice if it did, if only while they're inside the orbit of Pluto.



.

selden wrote:An SSC file describing the comet's orbit would go in the /extras/ directory.

I created this one from orbital parameters downloaded from Horizons today. Unfortunately, Celestia does not draw hyperbolic orbital paths. It'd be nice if it did, if only while they're inside the orbit of Pluto.

I must've screwed something up very badly Selden. Your ssc puts a rather monsterous comet opposing the one from symaski62 up above... If I change the radius to 1 everything is fine...

Unfortunately, symaski62 and Chuft Captain both specified the wrong combination of MeanAnomaly and Epoch. The MeanAnomaly is the location of the body along the orbit at the specified Epoch.

If you specify a comet's MeanAnomaly to be 0, then you must specify as Epoch the date when it is closest to the sun (aka Tp: time of pericenter passage): MeanAnomaly is 0 when a body is at pericenter.

If you specify an Epoch which corresponds to the date when the body's orbital elements were calculated, then the body's MeanAnomaly will have a non-zero value on that date.

Hi. I posted a picture of comet McNaught in the Physics and Astronomy forum, it seemed more appropriate than here.

http://shatters.net/forum/viewtopic.php?p=83302#83302

Guillermo

selden wrote:Unfortunately, symaski62 and Chuft Captain both specified the wrong combination of MeanAnomaly and Epoch. The MeanAnomaly is the location of the body along the orbit at the specified Epoch.

If you specify a comet's MeanAnomaly to be 0, then you must specify as Epoch the date when it is closest to the sun (aka Tp: time of pericenter passage): MeanAnomaly is 0 when a body is at pericenter.

If you specify an Epoch which corresponds to the date when the body's orbital elements were calculated, then the body's MeanAnomaly will have a non-zero value on that date.

oups



http://www.astrobgs.dyndns.org/astro/cmt2007/06P1.HTM

Passage au P?©rih?©lie (Jours Juliens, ET) 2454113.29895 YES !

0.0 MeanAnomaly <=> Epoch 2454113.29895

update version 0.2

Just wanted to thank everyone for taking the time to post that SSC data (symaski62, Chuft-Captain, Selden). I also want to thank Guillermo for posting that picture.