"G.V.Schiaparelli" Astronomical Observatory

New comet C/2012 A2 (LINEAR)

Luca Buzzi — Wed, 18 Jan 2012 19:27:40 +0000

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 observations

Luca Buzzi — Sun, 15 Jan 2012 13:32:43 +0000

(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):

Comet C/2011 UF305 (LINEAR)

Luca Buzzi — Fri, 30 Dec 2011 10:39:59 +0000

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.

New comet C/2011 Y3 (Boattini)

Luca Buzzi — Thu, 29 Dec 2011 11:34:14 +0000

C/2011 Y3 (Boattini) was discovered by Andrea Boattini on 2011, Dec. 25.24 with the 1.5-m f/2 reflector + CCD from Mount Lemmon Sky Survey (part of the Catalina Sky Survey). He described the comet as being very diffuse with central condensation: four 30-s exposures show a 6″ coma and a wide fan-shaped tail about 30″ long in p.a. 240-245 deg.
It was subsequently placed on the NEO Confirmation Page, where other observatories (including me at 204, H. Sato from I89-Nerpio, R. Holmes et al. from H21-ARI, P. Bacci et al. from 104-San Marcello Pistoiese, A. Novichonok et al. from C32-TAU station of Ka-Dar Observatory, R. Ligustri from H06-RAS and J. Lacruz from J87-La Canada) confirmed its cometary appearance.
I observed it less than 18 hours after the discovery: conditions were good so it was quite easy to confirm it as a comet. I measured a very diffuse 10″ coma and a broad tail at least 25″ long in p.a. around 250 deg.
Results were published in CBET 2959 (subscription required) and astrometry, together with preliminary parabolic orbital elements, in MPEC 2011-Y50.
This marks the 21st comet discovery for Andrea Boattini!
Here is the image:

New comet P/2011 Y2 (Boattini)

Luca Buzzi — Thu, 29 Dec 2011 10:39:15 +0000

P/2011 Y2 (Boattini) was discovered by Andrea Boattini on 2011, Dec. 24.12 with the 1.5-m f/2 reflector + CCD from Mount Lemmon Sky Survey (part of the Catalina Sky Survey). He described the comet as having a very condensed 5″ coma and no sign of a tail in 3″ seeing.
It was subsequently placed on the NEO Confirmation Page, where other observatories (including me at 204, H. Sato from I89-Nerpio, R. Holmes et al. from H21-ARI and P. Bacci et al. from 104-San Marcello Pistoiese) confirmed its cometary appearance.
I observed it the night following the discovery: transparency and seeing were good, but it was not easy to confirm it as a comet. I measured a 8″ coma slightly elongated in p.a. 140 deg.
MPC also found some prediscovery observations back to Sept. 4.
Results were published in CBET 2958 (subscription required) and astrometry in MPEC 2011-Y49.
Here is the image:

New comet P/2010 UH55 (Spacewatch)

Luca Buzzi — Wed, 30 Nov 2011 09:36:51 +0000

2010 UH55 was discovered by the Spacewatch survey on 2010 Oct. 29; it was soon clear that with its peculiar orbital elements and a Tj=2.61, 2010 UH55 could be in a possible cometary orbit. Earlier observations made remotely by H. Sato with a 0.51-m f/6.8 reflector from RAS Observatory (H06) on 2010, Nov. 17 reveal its possible softness and a hint of a tail on the west side.
He again observed it almost a year later (2011, Nov. 3) confirming its cometary appearance. He then contacted the T3 mailing-list, and I was able to observe it on Nov. 15 with a 0.38-m f/6.8 reflector from our observatory (204). That night had good seeing and transparency, but 83% Moon was 60° away. In a stack of images totalling 25 minutes of unfiltered exp. time (visible below) it has a compact coma 8″ wide and a faint tail 10-15″ long in PA 290°.
That feature was also confirmed by D. Chestnov and A. Novichonok remotely with a 0.40-m telescope at the TAU Station of Ka-Dar Observatory (North Caucasus, Russia) and from Sostero et al. using the 2.0-m Faulkes Telescope North at Haleakala.
Results were published in CBET 2923 (subscription required) and latest astrometry in MPEC 2011-W82, together with revised orbital elements.

New comet C/2011 Q1 (PANSTARRS)

Luca Buzzi — Tue, 23 Aug 2011 08:12:14 +0000

C/2011 Q1 (PANSTARRS) was discovered on 2011, Aug. 20.44 by PANSTARRS team with a 1.8-m f/4 reflector + CCD from Haleakala, Hawaii, USA.
Richard Wainscoat, Marco Micheli, Henry Hsieh and Larry Denneau described it as having a FWHM of 1.2″ while stars have 1.0″.
It was subsequently placed on the NEO Confirmation Page of the Minor Planet Center under the temporary designation P1012v1 and after then, some observatories confirmed the cometary appearance, including us.
The field of view was crowded with stars and there was a vast nebulosity in the area (Veil Nebula in Cygnus) so I took over an hour of total exposure time, to be sure to have several images free of stars. The image below (old DSS field) gives you an idea of the field in which the comet was:

Stacking all the “good” images, it was quite obvious its cometary nature: FWHM was around 30% wider than stars nearby, with a 8″ compact coma and a tail several arcseconds long in PA around 340°, even if it was quite difficult to estimate due to a nebulosity in the area.
The discovery was announced on CBET 2790 (subscription required) and the astrometry, with a preliminary parabolic orbital elements, published on MPEC 2011-Q12.
This was the 4th comet discovered by PANSTARRS survey.
Below is the image:

C/2009 S3 & C/2008 FK75 close approach

Luca Buzzi — Fri, 05 Aug 2011 17:40:06 +0000

On the night between Aug. 2 and 3 I was able to catch the close approach of two comets, C/2009 S3 (Lemmon) and C/2008 FK75 (Lemmon-Siding Spring), thanks to a previous “alert” made by Seiichi Yoshida from comets-ml.
The field was crowded with stars (Milky Way in Lacerta constellation), but fortunately the comets are both visible, with an apparent separation in the sky of 5.5′ (their closest approach was on Jul. 28 = 2.3′).
On the left is the faintest of the two, C/2009 S3, at mag. 19.7 N. However I had to use a small aperture due to the presence of a star, so its real magnitude is probably closer to 19 rather than 20. At the time of the image, it was at delta=6.210 AU and r=6.534 AU.
On the right, C/2008 FK75 is more easily seen at mag. 17.7, at delta=4.794 AU and r=5.140 AU.
Here is the image:

First Earth Trojan asteroid discovered: 2010 TK7

Luca Buzzi — Wed, 03 Aug 2011 19:06:32 +0000

Usually I update this blog with some interesting stuff done at Schiaparelli Observatory, but this time I will make an exception.
On July 27 a team led by Martin Connors of Athabasca University in Canada announced the discovery of the first Earth Trojan asteroid, 2010 TK7. Their work appeared in the current issue of the journal Nature.
2010 TK7 was originally discovered by NASA WISE survey on 2010, Oct. 01, then placed on the MPC NEO Confirmation Page, allowing astronomers to obtain some follow-up. It was observed for a 6-days arc, then recovered by Christian Veillet et al. using Canada-France-Hawaii Telescope on 2011 April 28-29, when it was at mag. 23.2 r.
Those observations were crucial to identify 2010 TK7 as the first Earth Trojan asteroid, which currently reside around L4 Lagrangian point, so leading the Earth in its orbit around
the Sun. It is estimated to be 150-500 meters across, depending on its albedo (from 0.25 to 0.04 respectively).
On Aug. 3, thanks to the Faulkes Telescopes collaboration (P. Miller, P. Roche, A. Tripp,
R. Miles, R. Holmes, S. Foglia and myself), I’ve been able to image it with the 2.0-m f/10
Faulkes Telescope North at Haleakala, in very good sky conditions (3% humidity, 1.1″ seeing, excellent transparency).
The result is below:

Now 2010 TK7 is in the southern constellation Fornax, so quite a bad place for northern observatories. In the next months it will be even worse, reaching declination -50° in November. Then it will start to move north, but never brighter than V=21 and less than 90° from the Sun.

2011 NZ and the (almost) occultation of a MBA

Luca Buzzi — Fri, 22 Jul 2011 14:48:36 +0000

It happens very often to have, in the same FOV of your target, another asteroid. Sometimes it can be a new one, but almost always it’s a known one. Sometimes it can be very near your target, but almost never it’s BEHIND your target.
That’s what’s happened to me during my last observing night (the 69th from the beginning of the year), between July 20 and 21. I was imaging NEO 2011 NZ, and I’ve noted that a MBA was very very close to it.
After stacking all my 20 images I measure them, with the appropriate motion vector for the both of them. The result was the following:
2011 NZ: 20h 11m 03.47s / -16° 51′ 53.1″
K1419: 20h 11m 03.50s / -16° 51′ 53.1″
If my math is correct, this means only 0.43″ from each other! That’s sounds pretty close!
In reality, the distance between them was 356.3 millions km (2011 NZ was 0.1944 AU from us while K1419 was at 2.5761 AU).
The image is not very good due to the presence of the Moon (71% 60° away), the altitude of the target (27°) and the bad seeing of that night.