New Comet: C/2010 S1 (LINEAR)

IAU circular No. 9170, issued on September 24, 2010, announces the discovery by the LINEAR survey of an apparently asteroidal object found to show cometary appearance by other CCD astrometrists. The discovery observation was obtained by LINEAR on Sept. 21.3 UT with a 1.0-m f/2.15 reflector + CCD. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18 magnitude object, designated C/2010 S1 (LINEAR).

We have been able to confirm this object remotely, through the GRAS network, using a scope located in Mayhill (NM): 0.25-m, f/3.4 reflector + CCD.: on Sept. 24.3, co-adding of 18 unfiltered exposures, 120-seconds each, show that this object appears soft compared to nearby field stars of similar brightness with a slight elongation in the east-west direction.

Our confirming image (click on the image for a bigger version):

The preliminary orbit for comet C/2010 S1 (LINEAR) shows perihelion on May 09, 2013, at about 4.4 AU.

According to COCD website, this is the 199th comet discovery for LINEAR.

by Ernesto Guido & Giovanni Sostero

New Comet: P/2010 R2 (LA SAGRA)

IAU circular No. 9169, issued on September 20, 2010, announces the discovery by La Sagra Sky Survey (LSSS) of a new comet on Sept. 14.9 UT with a 0.45-m f/2.8 reflector. After posting on the Minor Planet Center's NEOCP webpage, some observers have commented on the cometary appearance of this 18.4 magnitude object, designated P/2010 R2 (LA SAGRA).

We have been able to confirm this object remotely, using a 0.15-m f/7.3 refractor at the Tzec Maun Observatory (near Moorook, Australia): on Sept. 17.6, co-adding of 12 unfiltered exposures, 300-seconds each, show a condensed coma nearly 10-arcsec in diameter.

Our confirming image (click on the image for a bigger version):

According to the IAUC No. 9169 & the latest orbital elements on MPEC 2010-S28, this object appears to be another "main-belt comet", similar to 133P = (7968) Elst-Pizarro.

This is the 4th discovery for the amateur survey La Sagra. Congratulation to the LSSS team members. The full discovery story has been posted on LSSS website.


by G. Sostero, E. Guido & L. Donato

Recovery of Comet 123P/West-Hartley

MPEC 2010-R111, issued 2010 Sept. 14, reports our recovery of comet 123P/West-Hartley. We found the comet on September 12, 2010 at magnitude 19.8. We imaged it from Malina River Observatory, Povoletto (B90) using a 0.25-m f/10 reflector + CCD.

We performed the second night of follow-up on September 13, 2010. In our stackings the comet appears shows a narrow tail about 15-arcsec long toward PA 267

Our recovery image (details on image):

Please click on the image for a bigger version.

Comet 123P/West-Hartley was last observed (before our recovery) on July 20, 2004 by Siding Spring Survey (E12).

by G. Sostero, E. Guido, L. Donato & V. Gonano

Asteroids Flyby: 2010 RF12 & 2010 RX30

Two small asteroids (2010 RF12 & 2010 RX30) will pass within the Moon's distance of Earth today, September 08, 2010. Both objects were discovered by the professional "Catalina Sky Survey" on September 05, 2010 with the 1.5-m telescope at Mount Lemmon in Arizona.

According to Nasa JPL website, 2010 RX30 has a value of H=27.1 and is estimated to be 10 to 20 meters in size and will pass within 0.6 lunar distances of Earth (about 248,000 km) at 9:51 Greenwich standard time. While 2010 RF12 With an absolute magnitude of H=28.1 is estimated to be 6 to 14 meters in size will pass within 0.2 lunar distances (79,000 km) a few hours later at 21:12 Greenwich standard time.

Although both objects are coming inside the orbit of the Moon, there is no danger of impact!! (anyway objects of these dimensions would mostly burn up in the Earth’s atmosphere in case of an impact)

We have been able to follow-up 2010 RF12 few hours ago, on September 08 at at 06:45am UT (00:45am local time) through the GRAS network, using a scope located in Mayhill (NM). Below you can see our animation composed of 4 unfiltered exposures, 30-seconds each obtained by means of a 0.25-m, f/3.4 reflector + CCD:

Click on the thumbnail for a bigger version

While below you can see a single 120-second exposure showing the asteroid as a trail among the field stars:

When we shoot our image this rock was speeding at about 31 deg/day, shining at about magnitude 15.

By Ernesto Guido & Giovanni Sostero

Another Impact Flash on Jupiter

On August 20, 2010 a new optical flash has been observed on Jupiter. This is the third time in only 13 months that such events have been observed on the surface of this giant planet. Previous events occurred on July 19, 2009 and June 03, 2010. All these signs of impact have been recorded by amateur astronomers.

Masayuki Tachikawa, amateur astronomer from Japan, first reported his detection of the flash on August 20, 2010 at 18:22 UT with a Philips ToUcam Pro II attached to his 6-inch (150-mm) Takahashi TAO-150 f/7.3 refractor. Below you can see the detection image and the video showing the flash.

Credit: Masayuki Tachikawa

Credit: Masayuki Tachikawa

After the announcement by Tachikawa, another amateur astronomer from Japan, Aoki Kazuo, looking back at his Jupiter data taken independently, found what is the confirmation of the flash. In this case the two observers were separated by roughly 800 km, so Earth and its surrounding can be rule out as cause of the flash. These flashes are likely from meteors or small asteroid impact (~ less than 10 meters).

Credit: Aoki Kazuo

Like the event of June 03, this fireball did not produce any visible scar on the surface of Jupiter. (while the July 2009 event was detected just for the scar it left on Jupiter surface, due to a bigger impactor).

Thanks to their skill and new video cameras available on the market, amateur astronomers are now able to record short exposure videos necessary to detect these short-live events. It's now time to establish a worldwide network of telescopes to monitor Jupiter 24/7 to determine the current impact rate.

by Ernesto Guido

Recovery of comet P/2003 S2 (NEAT) = P/2010 P5

IAUC circular No. 9162, issued on August 17, 2010 announces our recovery of comet P/2003 S2 (NEAT) = P/2010 P5.

We found the comet on our first attempt to locate it on August 15, 2010. It was moving roughly 6 arc-minutes away from the nominal position at magnitude 19 (roughly 1 magnitude dimmer than predicted). We imaged it remotely, through the GRAS network, using a scope located in Mayhill (NM): 0.25-m, f/3.4 reflector + CCD.

We performed the second night of follow-up on August 17, 2010. Co-adding of 24 unfiltered exposures, 120 seconds each, showed the presence of a faint 15" tail in p.a. 356 deg.

Our recovery image of P/2003 S2 (NEAT)

According to the IAUC, the indicated correction to the prediction by B. G. Marsden on MPC62880 is Delta(T) = -0.33 day. The linked orbital elements by G. V. Williams and an ephemeris appear on MPEC 2010-Q08.

P/2003 S2 was last observed (before our recovery) on February 18, 2004.

By Ernesto Guido & Giovanni Sostero

Perseids 2010

The Perseid 2010 peak was expected on the night of August 12-13 between 18h and 07h UT with a ZHR (Zenithal Hourly Rate) of ~100 meteors per hour. (ZHR is a number that assumes a dark sky and the shower radiant at the zenith).

According to the first and preliminary results published on the IMO website, the observed ZHR maximum has been around 80-90 Perseids per hour in good agreement with the previsions of the dust stream models. The Perseid meteor shower is associated with the comet 109P/Swift-Tuttle. When the dust particles, spread out all along its orbit by this comet, strikes Earth's atmosphere, we see Perseids in the sky. The ZHR change accordingly to the Earth passing distance to the nearest comet dust trails and to its density. (the Perseid 2009 had a ZHR ~200)

Perseids 2010 - Activity Profile (courtesy IMO)

While the ZHR is decreasing, this meteor shower is not over yet and will last for the next few days.

Below you can find a meteor composite image (because the images were collected over several hours, the radiant of the shower is spread out) + animation. The images have been collected by our meteorcam located in Castellammare di Stabia (Italy) from 21h UT of August 12, 2010 to 03h UT of August 13, 2010. Most of this meteors are Perseids.

by Ernesto Guido