Comet McNaught (2006/P1) - discussions

CometGuy · #1 31-12-2006, 07:22 PM

Comet McNaught (2006 P1) is now expected to become a very nice comet for observers in the Southern hemisphere in the second half of January. People in high latitudes are favoured for this, so South Island of NZ and Tasmania have front row seats. Positions for the comet are provided here:

http://cfa-www.harvard.edu/iau/Ephem.../2006P1_1.html

The brightness of the comet (m1) given in the link above is way too conservative. For instance it gives m1 = 8.1 for December 29, but actual observations indicated m1 = 3.9, so it is currently running 4 magnitudes ahead of the predictions! Here is an image that was made just this morning deep in twilight (from the northern hemisphere).

http://kometen.fg-vds.de/pix/2006P1/2006P1_30122006.htm

The comet should first come visible very low in the SW evening twlight sky around January 18th, although experienced observers may get it as early as January 13th depending on the actual brightness. During these times it will be only visible low in twilight and a clear unobstructed western sky is essential. Good sky transparency will also help greatly as the comet will hover just above the horizon. It is also hoped a bright tail may stretch up into the evening sky.

Fingers crossed this could be the best comet for the southern hemisphere in nearly 11 years!

Terry

[edit by iceman]

Post discussions about the comet in this thread. Use the threads below for images and maps/charts.

- Post your Images and Pictures here
- Maps, charts, where/how to find here

h0ughy (David) · #2 31-12-2006, 08:42 PM

OHHHH maybe one for lostock and beyond!!! this is exciting!!

fringe_dweller · #3 31-12-2006, 08:43 PM

Hi Terry,
tassie and NZ also have a front row seat to the antarctic weather systems and longer polar summer days too

P1's progress and future progress has been, and will continue to get my full as possible attention - looking forward to the SOHO C3 images soon

but we are definately due for a really good one after 11 years eh - the odds should just get better and better!?

HNY!

CometGuy · #4 31-12-2006, 09:08 PM

The other interesting point is around January 13-15 the comet is between us and the sun. This situation (small phase angle) can, depending on the composition of the comet, cause forward scattered of sunlight in the comets dust. This in turn temporarily enhances the brightness as has happen to a few comets like Comet Skjellerup-Maristany in 1927 and a few years ago with Comet Machholz 96P in SOHO. It can amount to as much as 5 magnitudes brightness enhancement! There is no guarantee this would happen, so I'll stop right there in case I raise too many hopes

.

Terry

alan meehan (Alan) · #5 31-12-2006, 10:28 PM

Go on Terry raise some hopes ,thats a good picture on the links,we could use a good comet for 2007,

fringe_dweller · #6 01-01-2007, 04:07 PM

I remember at one stage JB talking on c-ml about a period where the ion tail (no head) could be possibly be observed as a bright laser beam type thing poking over the horizon (at a low angle) for a brief time during perihilion, was this also forward scattering/same time? sorry i have forgotten what he said

pity about the new moon waxing in evening sky for latter part of jan

looking forward to it becoming circumpolar/allnighter in feb also

iceman (Mike) · #7 02-01-2007, 07:08 AM

Excellent news! Will have a look during IISAC, if it's visible!

Ric · #8 02-01-2007, 12:32 PM

Thanks for the info Terry, I'll definitely have a look for this one.

Sounds great

tornado33 · #9 02-01-2007, 04:28 PM

Weather permitting I will attempt (carefully) observing it at perihelion in daytime round Jan 12 if weather permits. Its orbit has been entered into my Argo Navis in readiness. Ive heard of some sun grazers becoming extremely bright round perihelion (if they survive that is) to be seen in daytime shielding ones self from the suns glare
Scott

CoombellKid · #10 02-01-2007, 05:27 PM

Scott,

Could be interesting to try, SNP places it a lil over 5 degrees west of the
Sun at around 2pm on the 14th. This appears to be it's closest aproach
form our perspective, but I'm not sure whether closest is best.

Quote:

Originally Posted by tornado33

Weather permitting I will attempt (carefully) observing it at perihelion in daytime round Jan 12 if weather permits.

Scott

regards,CS sunny days

CometGuy · #11 02-01-2007, 09:10 PM

Just an update, David Moore in Ireland spotted the comet easily in 20x80 binoculars on january 1 and estimated the comet at magnitude 2.5-3.0. This observation was made with the comet just 3 degrees above the horizon in very bright twilight (sun 9 degrees down).

Scott, make sure the sun is obscured by a building and ensure there is no sunlight shining into the tube (it will scatter light and greatly reduce contrast). John Bortle determined mag -1.5 as the minimum brightness for daylight detection near the sun, but it takes some practice to achieve this. In the nineteenth century there were a few skill visual observers that were able to follow these objects close to the sun (these same observers followed planets through solar conjunction), but few people do this these days.

Terry

spacezebra (Petra) · #12 02-01-2007, 09:48 PM

thanks for the heads up - made a note in my observing journal.

Cheers Petra

tornado33 · #13 02-01-2007, 10:10 PM

Thanks Terry. I will also clean the primary mirror, (10 inch f5.6 newtonian) its recently been recoated but has some light dust on it. Will also put on my foot long light/dew shield. Got to hope for nice blue dust free skies too. Lets hope it flares in brightness nicely for us as well.
Scott.

CometGuy · #14 03-01-2007, 07:49 AM

I've seen some predictions on foward scattering enhancement of the comet and although the amount is very uncertain it predicts the peak effect will be on January 14, with some possible enhancement still remaining as late as January 19. Interestingly the comet is just over a degree away from Mercury on January 14 (which is mag -1). Another safer possibility for observing the comet may come just after sunset the following evening when it is better placed for observation, and hopefully nearly as bright.

Terry

tornado33 · #15 03-01-2007, 10:52 PM

The mirror of my scope is now pristine, to keep glare down. 3 days before the transit of venus, I observed venus as a very thin crescent, so close to the Sun, that sunlight was falling on the primary mirror, and focussing to a point roughly 1/2 way between the secondary and the tube, actually that was ideal as it wasnt going to damage anything. If it was a bit further out it would have fell on the tube and possibly damaged the paint on the inside. I had the drive locked on securely to prevent any chance of the focussed sunlight falling on the secondary (either blinding the observer or wrecking the camera) I will again be especialy careful when trying for this comet. I only hope to see some clear skies, cant believe the amount of cloud this last month. It will be real exciting to get a clear sky at perihelion day and have the comet brighten into negative magnitudes

Scott

tornado33 · #16 04-01-2007, 01:12 PM

Update:
Totally optomistically I tried to observe it in daytime today without success. Its far too early in the sequence but thought Id have a practice run. I set up the scope accurately polar aligned, put on solar filter, and aligened the Argo navis off the Sun. The comet is still a distance north, all I could see between clouds was blue sky. To test the setup I then dialled up venus, and it was near centre of field, so I am confident the comet was well in the FOV of my 16mm nagler on the 10 inch scope, but no sighting. Will keep trying day after day as it plunges sunward. Gee its closing on the Sun fast too.
Scott

venus (Lydia) · #17 04-01-2007, 02:17 PM

A 'mag 2' late January. I can see the IIS'ers at Lostock climbing the hill for a better view

CometGuy · #18 04-01-2007, 06:18 PM

More updates...

Haakon Dahle from Norway just spotted the comet on January 3 with the naked eye and estimated the coma as mag 1.5. Although his latitude is optimal for viewing the comet, it was still very low in bright twilight. A number of observers also described the coma as extremely condensed and blazingly bright. Michael Jaeger, also on January 3, made a magnificent image clearly showing a small brilliant coma and intense dust tail sitting amongst distant clouds.

An article I read by noted comet researcher, Joe Marcus, is predicting that forward scattering will enhance the brightness by 2 magnitudes Jan 13.0-15.5. I don't think there is much doubt the comet will go negative magnitude, its now a question of how negative!

Scott, wish you well. I haven't checked up its position but I Mercury might be a good test target to practice on.

Terry

Sausageman (Mike Boggan) · #19 04-01-2007, 07:04 PM

Don't forget that IISAC is in a valley, I would love to find a comet, but is it going to visible from our position over the weekend?
I have only ever seen one comet, and would love to see another.
I have never seen a naked eye one, in the wrong place at the wrong time always.

I will stay hopeful though.

Mike.

h0ughy (David) · #20 04-01-2007, 07:16 PM

Quote:

Originally Posted by Sausageman

Don't forget that IISAC is in a valley, I would love to find a comet, but is it going to visible from our position over the weekend?
I have only ever seen one comet, and would love to see another.
I have never seen a naked eye one, in the wrong place at the wrong time always.

I will stay hopeful though.

Mike.

yes the camp is in the valley but not the way in. Very high on the mountain