Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early Jan

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Re: Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early J

Post by starfinder »

After another stretch of several continuous days of almost total cloudiness, I observed Comet C/2014 Q2 (Lovejoy) again today (Sat 3 Jan 2015), from Singapore city centre.

At around 8.10pm this evening, I viewed it through my Meade LX90 8" SCT. The comet was in Eridanus, at 45 deg above the ESE horizon, and 8 deg southwest of Rigel.

Despite the 92% Moon being only 35 deg away to the left, the comet was obvious and easy to see in the eyepiece (20XW for 100x), but it was not very bright, certainly not in the league of the Orion Nebula.

The coma appeared whitish, and had a strong condensation in the centre.

With a Lumicon Comet (swanband) Filter added, the coma was discerned as a very large object, especially when it was moved left and right. I also suspected perhaps seeing parts of the tail, but could not be sure.

At 11pm, I viewed the comet using my Canon 15x50 IS binos. The comet was then 74 deg above the SSE horizon. It was very obvious in the bino and fairly large, reminding me of Omega Centauri in overall appearance, but perhaps half as wide and also half as bright.

Comparing it with nearby stars of mag 4.0, 4.3, 4.4, 4.5 and 5.0, I estimated the comet to be at around mag 4.6. Method used was the Sidgwick method (putting the stars out-of-focus to match the in-focus comet). It's likely that if I had viewed the comet from a dark-sky site with no Moon, I would have arrived at a brighter estimate.

Try as I might, I could not discern its greenish hue through the binos.

It's really a rare treat to be able to view a bright comet from Singapore city, so high overhead, and with a nearly full Moon nearby to boot!

Moon and city light-pollution aside, the sky conditions were very good. Constellation stars were pin sharp and contrasty, which is quite uncommon here.
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Re: Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early J

Post by Canopus Lim »

Got your heads up and went out to view with 10x50 Fujinon binoculars, 88mm refractor and 60mm refractor. It was obvious in the 10x50 being a glowing ball, something like a globular cluster without the stars. With the refractors I could make out the brighter portion and notice the elongation (with around 2mm exit pupil) in the tail direction; cannot make out a distinct tail though.
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Re: Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early J

Post by starfinder »

I've made some further observations of Comet Q2 Lovejoy:

1. As reported on the other thread, at the Comet Party on Sat 10 January 2015 at East Coast Park, I viewed the comet through my 12.5" dob. The comet was then at its brightest on the light-curve, in Taurus. It was reported by experienced comet observers elsewhere variously to have been at mag 3.7 to 4.1, averaging about mag 3.9. The comet culminated over Singapore at 9.44pm at 87 degrees above the northern horizon; at that moment, I lay down on the field and looked straight up and easily saw the comet in 10x42mm binos; no need to look for it as it was there right near the zenith. Neat!

In the eyepiece through the 12.5" dob, the comet's coma was bright, large and easily seen by everyone. It was diffuse but had an almost star-like point of a condensed centre. No tail was seen however, only a slight protusion from the coma. I found it remarkable that 2-3 kids of about 3-8 yrs old remarked, without prompting, that it was "green" (no filter was used then).

2. On Tues 12 Jan, my brother and I both managed to see the comet with unaided eyes from the ground floor grounds of my flat in the city. Using averted vision, we could see it as a faint patch fleetingly and with some difficulty, but it was there. Comet was in Taurus.


3. On Wed 13 Jan 2015, I viewed the comet from Labrador Park. The sky transparency was very good, except for passing low and mid level clouds. The view overhead and out to sea (south) was excellent, reminding me of the best views I've had from Changi beach.
The constellation stars of Orion, Canis Mgr and Taurus were bright and sharp! I could see a star at mag 4.8 near Rigel (Psi Eridani), and am sure slightly fainter ones too had I the time to find them.

With a 120mm ED refractor, I managed to view the comet's tail! It was very faint but distinct enough to be unmistakable. It was seen as straight sets of rays from the coma that emanated to the 10 o'clock position (strongest), 12 o'clock (broad but weaker) and 2 o'clock position, up to the end of the eyepiece field of view (20mm for 45x, 1.5 deg) and slightly beyond. The comet was in Taurus, forming a triangle with the Pleiades and Hyades clusters.

It needed very careful looking to see the tail, and I moved the scope left to right and up-down several times to be sure.

The tail was seen with and without filters, though the contrast was higher with. An Orion Skyglow broadband, Orion Ultrablock narrowband and Lumicon Comet line filter all worked, though the strength of effect was of course different. The Comet Filter also increased the visible size of the coma significantly.

Could not see the tail through 15x50 binos.

Nevertheless, I'm glad I finally got to see this comet's very faint and elusive tail.
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Re: Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early J

Post by Airconvent »

Congrats Gavin....you have so much energy!
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Re: Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early J

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I've made an attempt at calculating the actual size (in km) of the coma of Comet C/2014 Q2 (Lovejoy). I was wondering about this but could not find the info on the net.

The coma's recent reported apparent size, visually, is about 30 arc mins (i.e. 0.5 deg):
http://cobs.si/recent

It's recent distance to Earth (delta) is about 0.49 AU (which is 73.3 million km):
data obtained from here:
http://ssd.jpl.nasa.gov/horizons.cgi?fi ... /2014%20Q2

With these two figures, the comet's actual (absolute) size is derived, as we know the length of 2 sides of a triangle (73.3m km) and the angle in between (0.5 deg) as:
0.64 million km.
(using http://www.calculator.net/triangle-calc ... &x=67&y=12)

So if the above is correct, then the comet's coma has a diameter of 640,000 km.

This is just over 1.5x the distance from the Earth to the Moon. Also, it means that the coma is much larger than Jupiter, which has a diameter of about 140,000 km.

Is the above correct?

(I'm using visual-based estimates of the coma's apparent size here. Will soon also examine images posted online and compare it against star charts; this will likely give larger numbers.)
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Re: Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early J

Post by starfinder »

Yesterday (Sat 17 Jan 2015), I drove up to the Sedili region with Thomas to ob for a few hours. I simply had to do this comet justice by viewing and imaging it from a rural/dark area!

Comet C/2014 Q2 (Lovejoy) was an easy naked eye object, seen with the slightest effort with direct vision. At first I mistook it for a star as it appeared almost pinpoint, but the view through binoculars immediately showed that it was a comet. The comet was then in Aries, about 8 deg SW of the Pleiades. Thomas remarked that it was a very large object through his 15x70mm binos. Indeed, it seemed to me to be as large as the Moon in binos.

The comet formed a roughly equilateral triangle formation with 2 other mag 4 stars, Delta Artietis (mag 4.3) and Zeta Arietis (mag 4.9). I would estimate that the comet was about midway between the two stars in brightness. The comet was then just about 0.2 mag dimmer on its light curve than during its peak brightness a week ago (estimated at mag 3.9 on average).

Through the eyepiece in a 12.5" Obsession dob, the comet was very bright. Its coma filled at least half of the field of view of a 14mm eyepiece. It had a very sharp, small central condensed core like a disc (the false nucleus), and around this were about 3 other increasingly dimmer spheres of light. Colour wise, the green tint was subtle at best, and if I was not looking for colour I would have said that it was greyish-white. The coma protruded in the direction of its tail and extended somewhat beyond. No doubt about the tail being there, as the opposite direction was clearly dimmer.

Through a Canon 15x50 binos, at around midnight when the sky transparency improved, I could see a tail extending for approx. 1.5 deg: it was a very faint extension like a dim beam of light, but it was definitely there. I was glad to be able to see the tail, but then again, this must be considered quite a mediocre tail visually speaking compared with some other great comets of the past, even though in long exposure images with lots of adjustments this comet's tail looks quite spectacular.

Apart from the comet, we viewed several DSOs, mainly the brighter ones. With unaided eyes, the winter Milky Way could be seen as a faint band extending from Puppis, through Gemini and Auriga and beyond to Perseus. Through 15x50 binos, countless thousands of stars could be seen in the rich star fields esp in Puppis and Auriga, with some Open Clusters such as M46/47 (Puppis), M35 (Gemini), and M36/37/38 (Auriga) peppering the field of view. Through the dob, M35 was particularly bright, large and impressive, with another small and faint open cluster (NGC 2158, mag 8.6) appearing as a smudge in its periphery. We ended the session at around midnight and drove back to Singapore shortly thereafter.

Back to the comet: here is an image which I took during the observing session using an Astrotrac (rough alignment with a compass). The field of view extends from Orion, to the Hyades and Pleiades star clusters, with the comet at bottom right.

Click here to see the entire image: http://img10.imagefra.me/i21i/starfinde ... _u8s7b.jpg

Canon EOS 60D, Canon EF 24mm at f/2.8 30s ISO 1600. Lighting and colour levels adjusted.
Image
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Re: Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early J

Post by acc »

Nice!! :-)
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Re: Comet C/2014 Q2 (Lovejoy): 4th mag in late Dec / early J

Post by Airconvent »

wow...nice report, Gavin. Wished I could have seen it too from dark skies... Looks like you are now a regular at Sedili! :)
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