Observation from Kirby Storter Roadside Park in Big Cypress National Preserve, Florida. 1025 UTC - C/2007 N3 (Lulin). Wow! Very bright. Very easy at 90x in the XT8. Nicely formed coma like an unresolved globular, centrally concentrated with an even linear dropoff in brightness from center to halo. About 3' across. No tail seen. Using the defocused-star method, I estimate magnitude at around 8. About 5 degrees above horizon. Considering this is well within the Miami light cone and at a very low elevation, this should be at least a suburban object with any kind of scope. Also observed at 120x and 170x. Visible with effort and averted vision in the 10x50 Resolux's. This soon switched to direct vision as the comet rose away from the Miami light cone (1050 UTC).
C/2007 N3 (Lulin)
Posted 28 December 2008 - 08:04 AM
Posted 30 December 2008 - 09:31 AM
Thanks for the links. If you don't mind, I'll post my observation here--maybe we can make this the Comet Lulin thread for the next few months.
I observed C/2007 (Lulin) this morning for the first time. Conditions were cold (30Â° F/ -1Â° C) and very windy. It was hard to get the stars on the horizon into focus. I started out about 5:15 AM local time (1015 UT) by walking out into the pasture where I could get an unobstructed view to the ESE with the 12x36 image stabilized binoculars. The comet was about 5Â° above the horizon but I spent 15 minutes looking and could not spot it. The zodiacal light was fairly bright.
By this time, Scorpius and Libra had risen enough that I could use the telescope set up back at the house. Using the Astroscan at 29x, I found Comet Lulin almost immediately. I pumped up the mag to 37x but with the turbulent atmosphere and low altitude of the comet, the view was not pleasing so I went back to 29x for the sketch (also I could include Beta Sco in the wider fov).
Using the Sidgwick method, I estimated M1= 8.3. The degree of condensation = 2 and the diameter appeared to be ~10'.
Even though the skyglow from the Sun began to intrude by 1130 UT, the comet was at a higher altitude by then and held its own against the brightening sky for a while.
While the comet is still low in the early morning hours, I would recommend any observer having a good chart to find it. Let's hope Comet Lulin fulfills its promise and gives us a great show in the coming months.
Posted 30 December 2008 - 12:43 PM
Posted 31 December 2008 - 09:32 PM
Posted 01 January 2009 - 10:50 AM
BTW, Carlos Hernandez provided some links on this thread in the Sketching forum that you might want to include on your webpage.
I observed Comet Lulin again this morning (New Year's Day 1030-1130 UT) under very cold and clear conditions. I tried for it once again with the 12x36 IS binoculars under very dark skies (NELM 6+ in the vicinity of the comet) and thought I could just barely detect it at the threshold of vision.
Switching over to the 108mm reflector, it was still close to its position on 30 Dec.--not much apparent motion yet. Conditions were very cold (7Â° F/-14Â° C) but thankfully calm. Even still, the focuser on the Astroscan (always a weak point) froze up and I had to work to free it.
The seeing and transparency were better than my last observation and Lulin's altitude was a little higher, so I was able to refine my previous estimates. I now put the diameter a little smaller, ~8 arcminutes, and the DC= 3. The magnitude appears about the same at 8.3.
I've updated the sketch with the comet's latest position:
Posted 01 January 2009 - 04:07 PM
Posted 02 January 2009 - 11:49 AM
Posted 02 January 2009 - 02:17 PM
I enjoyed reading your report and I'm glad you hung in there until you found the comet. It would be fairly inconspicuous, even when using a fine instrument like the Canon 15x50 IS binoculars.
I think RevAaron and others have compared Lulin's appearance to an unresolved glob--M80 is close to the same angular size and magnitude and is in the neighborhood. It would be relatively easy to mistake one for the other right now.
Posted 03 January 2009 - 07:55 AM
I finally had time for another proper observing session this morning. From Fort Myers, FL, NELM was 4.5. Lulin was about 10 deg above the horizon when I first caught it with the 8" dob at 60x. Appearance unchanged from my previous sessions, I still think the best comparison is an unresolved globular. Having found the exact location, I decided to see what it looked like through some smaller instruments. My f/5 80mm achro showed it, but only because I knew exactly where to look. No luck with the 10x50's, but just as the eastern sky started to brighten, I was able to pluck Lulin out of the skyglow with my 15x70 Oberwerks. A nice session.
Posted 03 January 2009 - 09:42 AM
Nice report--thanks for the update. I was out again this AM too (between 1030 and 1130 UT) looking at the comet and made a new sketch. I included Lulin's position from my Jan. 1st observation to stay oriented.
The wind was calm, NELM in the vicinity of the comet was 6.0+, but the transparency was only average. Like RevAaron, I felt the comet's appearance was essentially unchanged.
m1= 8.3 DC= 3 Diameter= ~8'
I took the opportunity to look at Lulin at 37x and 42x. The coma appeared a little irregular at those higher magnifications. I also tried with the 12x36's but only suspected the comet.
The temperature was 27Â° F (-3Â° C) but after my last observation with temps at 7Â°, 27Â° felt positively balmy!
Posted 03 January 2009 - 03:18 PM
Thanks for posting the heads up on Comet Lulin.
Very nice sketch Ed!
As I am always curious to know right away, where is it? I go to many sites and I see no reference to the date or RA, DEC or mention of constellations. Or I bring up outdated website info that is still without a date from years ago.
Here is one site I thought was nice for a rough and fine sky chart...
But again, is it just me? I see no mention of a date on the charts. I would think if any profession in the world, that astronomy would be the first to always indicate dates in documentation as timing is so critical with change in the sky.
Posted 03 January 2009 - 03:30 PM
Caffeinated Astronomy Comet Lulin Links
Maybe you can find something useful there
Posted 03 January 2009 - 04:43 PM
Posted 03 January 2009 - 04:47 PM
Posted 06 January 2009 - 02:45 PM
However Lulin is unsual in that its orbit inclination is 179 degrees and the comet is thus spending a long time crossing Earths orbit. So the double tail view point should persist for a long time.
The 3rd tail is most likely the ion tail and should lie on the line extended from the sun to the comet.
So my prediction is a pair of tails will remain colinear on each side of the comet because they are in fact the same dust tail. The angle of the ion tail to these colinear tails will vary to some amount as the sun/comet/earth angle changes with time. Howver geometry wise as viewed from Earth the ion tail will always lie at a small angle to the dust tail
Only time will tell if I'm right
Posted 06 January 2009 - 03:04 PM
Posted 06 January 2009 - 03:39 PM
In other circumstances this would have been a very dangerous comet, since it moves in the same plane as Earth.
More interesting stuff - it passes close to Regulus - less than 1/2 degree - width of the Moon! - on the 27th at about 7:30 PM EST, It appears that for observers in far northern Europe and Asia, the comet comes near to being occulted by the Moon, near the Beehive!
Another odd fact - because we see it edge on, the tail will change directions as we pass through the plane of its dust fan near its opposition on the 26th.
Thank God we are modern, else one could only imagine what disasters astrologers would foretell, with a comet conjunct Saturn in Virgo opposite the Sun..