The comet is certainly sporting "two" tails, in fact it's an optical illusion. When we start to cross the comets orbital plane, we see the tail "sprayed" out from behind the comet giving the appearance of a sunward spike or "Anti-tail", in fact it's the dust spreading out behind the comet.
Other comets with more famous "Anti-tails" are Arend-Roland, Halley and Kohoutek.
I viewed Lulin this morning through 12x50 binos and found the comet, as you said, to be smaller and fainter than M4.
The binos were hand held which made it impossible to see it as anything but a shaky fuzzy blob. If the sky is clear tomorrow morning I must point the Gstar at it and see what I can capture.
We've had a drought of astronomical events, nothing really since Comet Holmes, finally something to get excited about!!
I viewed Lulin this morning through 12x50 binos and found the comet, as you said, to be smaller and fainter than M4.
The binos were hand held which made it impossible to see it as anything but a shaky fuzzy blob. If the sky is clear tomorrow morning I must point the Gstar at it and see what I can capture.
We've had a drought of astronomical events, nothing really since Comet Holmes, finally something to get excited about!!
Hi Nettie and others,
The comet certainly is a fuzzy blob! My mag estimate from the morning of the 29th was 6.7, other mag estimates have it around 6.5. I tried to see it naked eye but the zodiacal light interferes with trying to make it out. The comet has a small coma dia of around 8', but if you look closely you might notice a bright point of light in the middle which is the "false nucleus", giving the comet a degree of condensation of around 6.
When the comet brightens this point of light becomes larger and more noticable, and the Degree of Condensation will increase, C/2007 P1 McNaught at the time of it's apparition had a DC of 9, which means the comets coma appeared "star-like" without the fuzzy edges noticable.
The way you would compare brightness of the comet is to memorise the apparent brightness of the comet, then de-focus a nearby star to around the same diameter of the comet and compare the brightness of the de-focussed star to the IN-FOCUS comet. Never compare an out of focus star to an out of focus comet. This is called the In-Out or VSS method of measuring a comet's brightness, and should always be made with the smallest instrument as practicable.
When there is a definite stellar-like point in the coma, the method you use is called a "Modified In-Out" method. This is where you would de-focus the comet slightly so that the point of light is smeared out as even in brightness as possible, then memorising the comet image with a suitable out of focus star comparable in brightness.
The 3 basic measurements are : estimated magnitude, estimated diameter of the coma, and the Degree of Condensation.
A DC of 1 will give you a faint uniform coma with no central brightening, a DC of 3 means that a central brightening is noticable. A DC of 6 means the central brightening is star-like, and a DC of 9 means the central brightening is uniform across the entire coma giving the coma a star-like appearance.
Other things to note are a tail (length and position angle from North), or the shape of the coma (Such as a fan like appearance or bar-like such as in the case of N3 Lulin), the time and date of your observation, the number of the comaprison star you use and the catalogue of the comparison star measurement (Such as GSC, Tycho, Hipparcos, ASAS-3 etc) Not all catalogues are recommended, such as USNO magnitudes.
The Central Bureau for Astronomical Telegrams have a link to International Comet Quarterly pages which outline the correct methods and catalogues to use.
Your G-Star should capture N3 Lulin no worries!
Good luck, and here's to a bright comet!
Last edited by Outbackmanyep; 30-01-2009 at 01:22 PM.
I had a look through 12x50 binocs this morning, and it seems quite bright - SB seemed brighter than M4 (although it is a lot smaller) and it must be naked eye. Comet was a bright, slightly oval smudge with the start of the tail extensions visible.
I'd killed my night vision unfortunately, by hand-guiding off a lap-top screen to get the following image. Faint tail extensions appear to go well over a degree.
Looked at Lulin this morning with 20x80s and a 10" scope. The tail is at least 30' long. It is hard to pick its length and width. It might be fan shaped near the comet.
I saw the anti-tail this morning for the first time, it was about 20' long. I also saw the main tail, it was about 40' long. My observations were made with a 12" Dob at 71X, field 65'. Mag 2.7+5.2 alpha Lib is near the comet this morning and that makes it hard to see the end of the tail. The core of the comet is almost stellar at 188X, field 25'.
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Faint tail extensions appear to go well over a degree.
