C/2012 V1 (PANSTARRS) was discovered by the PANSTARRS survey using a 1.8-m f/4.4 reflector from Haleakala, HI.
Larry Denneau, Richard Wainscoat and Henry Hsieh noted a diffuse, non-stellar appearance on four 45 seconds w-band images, and subsequently it was posted on the NEO Confirmation Page under the temporary designation P104XVd, with also a 100% NEO score.
At first I was able to confirm its cometary appearance with the 2.0-m Faulkes Telescope North, from the same site, under very good seeing conditions (stars FWHM 0.9″-1.0″). In the image below (stack of 9×45 seconds with Bessel R filter) its nature is clear, with a diffuse 4″ coma, and a FWHM 70% larger than stars nearby.
The weather was good also at Schiaparelli Observatory on the same day, so I was able to image it with a 0.38-m f/6.8 reflector. Visually (i.e. on the screen) its aspect was stellar, but the “FWHM method” clearly revealed its nature: profile 30% larger than stars nearby, and a coma 8″ wide.
Also ARI Observatory (H21) detected it on Nov. 05.26, and in the image below, taken with the very good 0.81-m f/4 astrograph stacking 30×60 seconds images, the FWHM method revealed a profile 30-35% larger than stars, and a coma 11″x7″.
This is again a demonstration of how good is the FWHM method (used largely in our T3 project) in discerning comets among asteroids.
Results were published in CBET 3289 (subscription required) and astrometry, together with preliminary parabolic orbital elements, in MPEC 2012-V40.
204 image (and FWHM boxes):
F65 image (and FWHM boxes):
H21 image (and FWHM boxes):
C/2012 T5 (Bressi) was discovered by Terry Bressi, Spacewatch survey, on images taken with the 0.9-m f/3 reflector telescope from Kitt Peak, on Oct. 14.4. She noted the object to be diffuse with an apparent faint tail about 9″ long in PA 260°, and she obtained confirmation images with the 1.8-m f/2.7 reflector (diffuse with a broad tail extending about 10″ in PA about 270 deg).
It was posted on the NEO Confirmation Page under the temporary designation SW40uN, and several other observers noted its cometary appearance, including me at 204-Schiaparelli on Oct. 17.0.
Results were published in CBET 3261 (subscription required) and astrometry, together with parabolic orbital elements, in MPEC 2012-U38.
Some images are visible below.
Image from 204-Schiaparelli:
Image from J04-ESA Optical Ground Station-Tenerife (Image credit: ESA/Knöfel):
Image from F65-Faulkes Telescope North:
Image from H21-ARI:
Image from H06-INet telescopes:
Image from 113-Volkssternwarte Drebach:
P/2012 T7 (Vorobjov) was discovered on 2012, Oct. 15.3 by Tomas Vorobjov from Bratislava, Slovak Republic, using remotely a 0.81-m f/7 Ritchey-Chretien reflector located at the Mt. Lemmon SkyCenter via the Sierra Stars Observatory Network, during a minor-planet search survey undertaken as part of the International Astronomical Search Collaboration (IASC) school campaigns, which I’m proud to be part of.
Three 120 seconds images that he took with Alexander Kostin (Houston, TX, U.S.A.) revealed its cometary appearance, with a tail in PA 270°.
A confirmation set of images were taken by R. Holmes the following night with a 0.61-m f/4 astrograph from Westfield-H21, showing a 6″ coma and a tail 25″ long in PA 260°.
Due to its cometary appearance, it was posted on the NEO Confirmation Page under the temporary designation TOV7DD.
I was able to image it under good seeing conditions but with passing high, thin clouds on Oct. 17. Several other observers then noted its features, including many from IASC and T3 project, and results were published in CBET 3260 (subscription required) and astrometry, together with elliptical orbital elements, in MPEC 2012-U40.
Some images are visible below.
Well done Tomas, let’s hope this is only the first of a long series!!!
Original T.Vorobjov discovery animation from G84:
Confirmation image by ARI-H21:
Image from E10-Faulkes Telescope South:
Image from 204-Schiaparelli:
Image from G96-Mt.Lemmon Survey (thanks to Andrea Boattini):
P/2012 T1 (PANSTARRS) was discovered by the PAN-STARRS survey on 2012, Oct. 06.53 with a 1.8-m reflector + CCD located at Haleakala, HI, USA.
Richard Wainscoat, Henry Hsieh and Larry Denneau described the object to have a PSF larger than stars nearby (1.5″ vs 1.07″). The object was posted on the NEO Confirmation Page under the temprary designation P104kFN.
Apart from their internal confirmation team from Hawaii (Dave Tholen, Marco Micheli and Garrett T. Elliott using the UoH 2.24-m reflector), observatories from the “T3 project” were the only ones to confirm it as a comet.
The first who reported to us cometary activity was Hidetaka Sato, using a 0.43-m remotely from New Mexico on Oct. 10.3, noted that “P104kFN is a potential comet with a round coma of 10″ in diameter. A tail was 12″ toward PA 250 degree.”
After his observation I managed to observe it under a clear sky the following night (the first after three weeks of bad weather in northern Italy!), confirming its clear cometary appearance: in a stack of 56 minutes of total exposure time in good conditions, it has a diffuse aspect, with a coma 10″ wide elongated in PA 253° for at least 15″.
Also H21-ARI confirmed it with a 0.61-m f/4 astrograph from Westfield, IL, USA, on Oct. 11.29: round 12″ coma and a tail 15″ long toward PA 240 degrees.
Also Lulin Observatory from Taiwan confirmed it with the LOT 1.0-m f/8 telescope, but for some reasons they were not included in the circular.
Results were published in CBET 3252 (subscription required) and astrometry, together with elliptical orbital elements, in MPEC 2012-T55. Gareth Williams found prediscovery observations from PAN-STARRS back to 2011, Jul. 28, so the orbit is already pretty solid.
With a semimajor axis of 3.05 AU, low eccentricity and inclination and a Tj parameter of 3.18, P/2012 T1 belongs to the Main-Belt Comets group.
In all the images, visible below, it’s clear the faint and diffuse tail.
H06 (H. Sato) image:
2011 KP36 was originally discovered as an asteroid by T. H. Bressi of Spacewatch survey on 2011, May 21. Its orbit was unusual (actually a=38.6 AU, e=0.87, i=19°), belonging to the outer Solar System. Its T3 parameter (respect to Jupiter) is 2.64, so it entered our T3 internal list of targets.
During observations of NEO 1998 OK1 with the 0.81-m f/4 of ARI Observatory (Westfield, code H21) on Apr. 19 Tomas Vorobjov serendipitously detected also 2011 KP36 in the same FOV. Stacking all the images together (totalling 30 minutes) with its proper motion vector, Tomas Vorobjov firstly noted its cometary appearance, with a coma 6″ wide and a possible tail 9″ long in PA around 10°. Its FWHM was 4.4″ while stars nearby were 3.5″. Here is an animation from two cropped stacks (30×30 seconds each):
After his alert, Sergio Foglia and myself observed it the following day with the 2.0-m f/10 Faulkes Telescope North at Haleakala. Conditions were nearly the best possible and stacking 4×180 seconds images its cometary activity was quite clear. FWHM was 1.3″ while stars 1.1″, but the real confirmation was the presence (visually) of a round faint coma at least 7″ wide. Here is the image:
On Apr. 21, under good seeing conditions I obtained 60×30 seconds images with the 0.38-m f/6.8 reflector from Schiaparelli Observatory: its faint coma was visible for 13″ wide even if its FWHM was only 10% larger than stars nearby (3.7″ vs 3.4″).
Another confirmation came from Tomas Vorobjov using th RCT 1.3-m f/13 from Western Kentucky University located at Kitt Peak (diffuse object with a 8″ coma and a hint of tail in p.a. 80 deg).
Discovery was announced on CBET 3109 on May 17, together with the orbital elements on MPEC 2012-K12.
2011 FR143 was discovered by the Mt.Lemmon Sky Survey (part of the Catalina Sky Survey) on 2011 Mar. 29 and followed until Apr. 26. Its orbit was quite unusual (a=6.83 AU, e= 0.45 and a period of 17.9 yrs) and with a Tisserand parameter of 2.73 it was put in our special list of the T3 observing project.
Thanks to Sergio Foglia, who alerted me about this particular target, we successfully recovered it at mag. 20.3 R on 2012, Mar. 29 (exactly one year after its original discovery!). Stacking all images together (73 minutes of total exposure time) we noted its cometary appearance, with a 6″ coma and a tail 10″ in PA around 270°.
Soon after I alerted Tomas Vorobjov, who confirmed its cometary appearance with the 1.3-m f/13 RCT telescope of Western Kentucky University located at Kitt Peak (code 695) on the night of Mar. 31.
Another confirmation came from images obtained by Robert Holmes from ARI Observatory six days past (and measured by Sergio Foglia). Both observatories noted a coma 6″ wide and a tail 10-12″ long in PA about 270°.
I also observed it using the 2.0-m f/10 Faulkes Telescope North located at Haleakala, Hawaii: with a total exposure time of 15 minutes in good seeing the object was clearly diffuse respect to stars nearby, with a coma at least 5″ wide. The presence of the Moon just 25° away prevented me to see the tail, however.
After all these confirmations, MPC/CBAT staff released circulars CBET 3082 and MPEC 2012-G36 with the discovery circumstances and all the astrometry available.
This is my image:
and this is H21 image from Apr. 6 (0..81-m telescope, 45 minutes of total exp. time):
P/2012 F5 was discovered by Alex Gibbs on images taken with the 1.5-m f/2 reflector of the Mount Lemmon Sky Survey (part of the CSS) on Mar. 22.28. He described the comet having a stellar coma and a long, narrow tail of length 7.3′-7.4′ in PA 292.5 deg.
The object was placed on the NEO Confirmation Page under the temporary designation TF85899. I observed it on Mar. 23.02, and I confirmed its cometary appearance.
Stacking all my images (conditions were not optimal and flat field was not very good) a straight and narrow tail is visible for at least 6.5′ in PA 292°.
The nuclear condensation was only slightly brighter than the tail, so astrometry was quite difficult.
Results were published in CBET 3069 (subscription required) and astrometry, together with preliminary elliptical orbital elements, in MPEC 2012-F87.
MPC subsequently linked this object with other one-nighters back to Feb. 20: with this arc, its short period was confirmed (MPEC 2012-F91).
Here is the image (cropped):
P/2012 F6 was also discovered by Alex Gibbs the following night with the same telescope, but it was officially named Lemmon because he did not recognize its cometary appearance. It was in fact placed on the NEO Confirmation Page as an asteroid.
It was then observed by several observers, including me on Mar. 24.94, and its cometary feature was detected. My stacked images revealed a softer appearance on the object’s eastern edge with a possible extension in PA around 120 deg, even if conditions were not optimal, as the night before.
Results were published in CBET 3070 (subscription required) and astrometry, together with preliminary parabolic orbital elements, in MPEC 2012-F88.
Here is the image:
C/2012 A2 (LINEAR) was discovered by the LINEAR survey on 2012, Jan. 15.41 with a 1.0-m f/2.15 reflector + CCD located near Socorro, New Mexico.
It was subsequently placed on the NEO Confirmation Page, where other observatories (including me at 204, P. Birtwhistle from Great Shefford-J95, H. Sato remotely from GRAS-H06 and R. Holmes et al. from H21-ARI) confirmed it as a comet.
I observed it in good sky conditions but in presence of the Moon (54% illuminated about 55° away): I measured a compact coma 15″ wide, elongated toward the west.
Results were published in CBET 2977 (subscription required) and astrometry, together with preliminary parabolic orbital elements, in MPEC 2012-B05.
Here is the image:
(99942) Apophis (formerly known as 2004 MN4) was discovered on 2004 Jun. 19 by R. Tucker, D. Tholen and F. Bernardi from Kitt Peak National Observatory, and observed just for a 1-day arc.
On 2004 Dec. 18, in the normal course of the Siding Spring Survey conducted with the 0.5-m Uppsala Schmidt, G. Garradd discovered an object that was subsequently linked by the MPC to 2004 MN4. With a 6 months arc, one-night prediscovery observations were found by 691 Spacewatch back to Mar. 15.
Orbital elements calculated with all these observations indicated a probability up to 2.7% (1 in 37) that it would strike the Earth in 2029. It broke the record for the highest level on the Torino Scale, being, for only a short time, a level 4.
Additional optical and (especially) radar observations conducted in early 2005 eliminated this threat: it will pass very close to the Earth, but at a “safely” distance no closer than 29,470 km, inside the geosynchronous belt.
At closest approach, it will reach naked-eye magnitude of around 3.4, with a maximum speed of 42°/hour.
A small probability (around 1 in 250,000) however remains for an impact in April, 2036. Radar observations will be conducted again in 2013, and from those measurements astronomers will confirm or (most surely) eliminate this possibility.
Actually Apophis, which has an estimated diameter of around 350 meters, is in constellation Pisces at 67° Sun elongation, and its magnitude is close to 20.5 V, the brightest since the beginning of the next year, when it will reach perigee (2013 01 09) at a distance of 0.0967 AU (or 37 LD).
Astronomical Research Institute (ARI, code H21) and our observatory (code 204) conducted observations on 2012 Jan. 10 and 11, producing astrometry that was published on MPEC 2012-A51.
Here is my image:
and an animation by H21 with the 0.61-m (R. Holmes, S. Foglia, T. Vorobjov and myself):
2011 UF305 was discovered by the LINEAR survey on 2011, Oct. 31.07, and subsequently placed on the NEO Confirmation Page. It was confirmed by several observatories and MPEC 2011-V16 was released on Nov. 3.
Its very unusual preliminary orbital elements (a=16.94, e=0.86, i=95.45) yield a Tj around 0.13, making it one of the primary T3 project targets.
After the MPEC was released, Hidetaka Sato wrote to our internal mailing-list about its possible cometary feature, describing the object having a FWHM larger than stars nearby (4.9″ vs 3.5″).
After his alert, I managed to observe it on Nov. 12 and 14: in the first night seeing was not good, but two days after conditions were very good, and I was able to confirm its cometary feature, with a coma 7″x5″ and a FWHM 25% larger than stars nearby (2.9″ vs 2.4″).
After a private e-mail exchange with Jim Scotti from Spacewatch, I knew that he also observed its cometary aspect on Nov. 2 and 3 with the 1.8-m f/2.7 reflector + CCD, with a 10″ coma and a tail 0.14′ in PA 99°.
So we all waited for an official announce, which arrived a bit later on Dec. 29 with CBET 2960 (subscription required) with observations and orbital elements on MPEC 2011-Y51.
Here is our image from Nov. 14:
No clear tail can be seen, only the eastern edge of the coma seems less defined than the western edge, but nothing more. In good seeing conditions the “FWHM method” is the most reliable instrument we have to understand if we are in presence of a coma or not.
Now the object is slowly emerging from the solar conjunction, and it will be soon visible in the morning skies.
The comet will pass perihelion on 2012 Jul. 22.1 at a solar distance of around 2.14 AU, reaching an apparent magnitude between 14 and 15 and located in the northern circumpolar sky.