Comet C/2007 N3 (Lulin)

[Roman White]

Roman, have you looked at the prospects for C/2007 N3 Lulin?, this could be one to watch to. Maximum brightness in feb of at least mag +6 and a great elongation from the Sun to.  Can someone on here check starrynight software for late Feb for this comet?. It will be in Virgo and Leo, I would like to know how far above the horizon this will be for us. An image saved from SNP would be great (but start a new thread). 

Yes, it will peak at +6.0mag on Feb.20-25, looks like a good one.
Here is its trajectory, Nov 2008 to May 2009:

Straight along the ecliptic, but it will be very fast moving during Feb-Mar 2009.

I'll try to analyze each month.
November 2008. Reaches +10.0mag on Nov.22. Moving very slow across Scorpius. Not visible.

December 2008. 9.7mag to 8.7mag. Moving very slow across Scorpius. Visible 10 min. in naut.dawn in the beginning of month and 1 hour before astr.dawn in the end of month.

January 2009. 8.7mag to 7.4mag. Moving across Libra. Visibility period increases up to 4 hours (morning) by the end of month.

February 2009. 6-7 mag. Moving very fast across Lib-Vir-Leo. In mid-month visible for almost 7 hours (23-5). In the end of month visible all night (almost 12 hours).

March 2009. 6.3mag to 9.5mag. Moving very fast across Leo-Cnc-Gem (passing close to M44 by the way). Visibility period reduces to 7 hours (19-2) by the end of month.

April 2009. Fades below 10.0mag on Apr.07. Moving very slow across Gemini. Visible over 6 hours after dusk.

P.S. This was calculated for Poltava (50N), make -5 degrees to altitude mentally.

[martinastro]

Thanks for that great chart and information Roman!. Let's keep adding any further data we get in the future to this thread. Thought I would copy you and Brian's comments on to this thread to keep everything tidy...

Took Feb 21 as "late Feb" & found dec -1 deg 16 min (and heading north), transit at 02:36 (from my site). So it's getting to a reasonable altitude from 55N. Saturn is nearby, stepping forward I found that the comet is about 1.2 degrees south south west of Saturn on Feb 24th (0300 UT), and estimated at mag. 6.0. Hopefully will be quite a reasonable show, at least up to 8P/Tuttle last year.

And also passing close to Regulus and M44 in Feb-Mar 2009. Should be as nice as 8P/Tuttle (or even more?)

I think we need to move this discussion to a new topic
http://astrophotoweather.smfforfree4.com/index.php/topic,223.new.html#new

[martinastro]

Check out the ephemeris...

http://cfa-www.harvard.edu/iau/Ephemerides/Comets/2007N3.html

On Feb 23rd the comet is a minimum mag of +6.0 and 159.7 degrees elongation from the Sun!, we can't get any better than that. This comet is going to be perfectly placed for observation and photography. The Moon is gone to 

[brianb]

The Moon is gone to 

Where's it gone to? Getting worried now....

OK, you mean it's nicely positioned (out of the night sky) when the comet is at its best.

[martinastro]

Yes, that's what I mean  .

The Moon is at a non-threatening phase so we will have plenty of dark skies to enjoy this comet. It's up to the comet now to put on a show....

[martinastro]

http://www.ast.cam.ac.uk/~jds/07n3.ukl

The updated BAA ephemeris is very optimistic giving a maximum magnitude of +4.0 in late feb. I hope they are correct 

[martinastro]

Two wide field finder charts from Seiichi Yoshida

[Roman White]

http://www.ast.cam.ac.uk/~jds/07n3.ukl
The updated BAA ephemeris is very optimistic giving a maximum magnitude of +4.0 in late feb. I hope they are correct 

If they are correct, it will be very good for us, 4mag comet is better than 6mag. But why there is so much difference between MPC and BAA predictions?

[brianb]

But why there is so much difference between MPC and BAA predictions?

I don't know ... but the predictions come from a formula which is basically

M = M0 + 5 log D + k log r

where M0 is the "absolute magnitude" (taken as the comet being 1AU from both Sun and Earth), D is the distance from the Earth and r is the distance from the Sun. k=5 for asteroids, around 10 for short period comets which have been around for a while and around 15 for "fresh" comets which have only newly been perturbed into orbits which bring them into the inner solar system.

Clearly the predicted magnitude depends on the value of k used.

[martinastro]

http://www.ast.cam.ac.uk/~jds/07n3.ukl
The updated BAA ephemeris is very optimistic giving a maximum magnitude of +4.0 in late feb. I hope they are correct 

If they are correct, it will be very good for us, 4mag comet is better than 6mag. But why there is so much difference between MPC and BAA predictions?

I don't know either Roman. Some sources go about these calculations in different ways as Brian said. I just hope the BAA are more accurate for our benefit  . 4th mag is a very respectable brightness, do you remember seeing Ikeya-Zhang a few years ago?. I thought that was a beautiful naked eye comet, in fact, the best I have seen since Hale Bopp because of it's long naked eye tail. I would be delighted if Lulin comes anywhere close to that.

[martinastro]

According to the BAA, 2007 N3 (Lulin) will pass through the SOHO C3 field between November 17 and December 4. It should be around 7th magnitude and may be visible. We may catch it visually in the morning sky after this in late Dec. This is one to watch. 

[Roman White]

We may catch it visually in the morning sky after this in late Dec. This is one to watch. 

Oh yeah, all my hopes are to this comet... _{(still no success with C/2008A1)}
I plan to start observing in mid-December or so, and to get ready for it until that date...
BTW, I recently noticed that N3 Lulin will pass 2^o away from Saturn on Feb.24 

[Tyler]

guys this would be visible from my location too, correct?

[martinastro]

It should be Tyler. It may even be visible earlier for you as your location is further south in Dec. Role on feb!!. By that time it will be well placed for many. 

[martinastro]

This comet has just been observed visually by J. J. Gonzalez from Spain..

C/2007 N3 (Lulin):
2008 Dec. 21.27 UT: m1=7.6, Dia.=2.5', DC=5, 25x100B.
[ Mountain location, very clear sky. Beginning of astronomical twilight;
some moonlight interference. Altitude: 7 deg.].