Comet C/2011 W3 (Lovejoy) approaches the Sun

Australian amateur astronomer Terry Lovejoy discovered on Nov. 27.7 his third comet, designated C/2011 W3 (Lovejoy). On our previous post about this comet you can see our follow-up image and animation.

C/2011 W3 is a Kreutz sungrazer, a family of sungrazing comets that are named after German astronomer Heinrich Kreutz who first studied them in the details. These comet fragments passes extremely close to the Sun at perihelion and usually they completely evaporated during such a close approach. 

Many Kreutz sungrazer comets are observed each year by SOHO Sun-observing satellite. SOHO provides a constant view of the immediate solar vicinity and it has now discovered more than 2000 of new sungrazing comets, some just a few metres across. About 83% of the sungrazers found by SOHO are members of the Kreutz group, with the other being referred to as 'non-Kreutz' or 'sporadic' sungrazers (Meyer, Marsden, and Kracht 1 & 2 families).

Comet C/2011 W3 will probably be the brightest Kreutz-group comet that SOHO has ever observed. It will reach the perihelion on 2011 Dec. 16.02 when it will be it within 880,000 km of the center of the Sun (the comet will pass just 180,000 km from the Sun’s surface).

According to Karl Battams, the new comet Lovejoy:

1. The comet should enter the STEREO/SECCHI HI-1B images on Dec 11, and HI-1A on Dec 12

2. The comet will enter the SOHO/LASCO C3 field of view early on Dec 14
3. The comet will enter the STEREO/SECCHI COR-2 A & B fields of view early on Dec 15 (UT time), and the COR-1 fields later that day.


We downloaded "Secchi" spacecraft FITS of the Dec. 11 & 12, 2011, and played a little bit with them. Using the image processing algorythms (developed for the CARA collaboration by our fellow collaborator Martino Nicolini). On those images, it's already possible to appreciate a narrow tail, in excess of about  1 deg. Below you can see our renditions (click on the images for a bigger version):

While below you can see an animation showing comet Lovejoy in SECCHI HI-1B on December 11 & 12, 2011 (click on the thumbnail for a bigger version).

According to Dr. Matthew Knight (Lowell Observatory/JHU-APL), Comet Lovejoy was at approximately magnitude 2.0 as on the LASCO C3 images of 16:32UT, Dec 14, 2011). While the peak magnitude is still uncertain, C/2011 W3 could reach the peak brightness at mag -3 or -4 and the comet will probably not survive perihelion. If Comet Lovejoy gets as bright as magnitude -4 or -5, there is a tiny but non-zero chance that it could become visible in the sky next to the sun. But extreme care is needed due to the comet's small solar elongation angle and close proximity to the Sun in the sky.

Below you can see the comet on latest LASCO C3 data available (08:30UT of December 15, 2011). Click on it for a bigger version:

(Credit: SOHO)

Stay tuned for more updates coming soon!!

UPDATE - December 15 at 12UT

Thanks to Karl, new STEREO-B, SECCHI fits dated back to December 13, 2011 are available. In spite of the fact that the image scale factor is a little small, it's possible to appreciate the growing of a slight asymmetry of the coma (toward the north-east):

Below an animation of Dec. 11, 12 and 13 stackings (or click here to see it):

Comet Lovejoy looks to be around mag -1 now and only has ~12hrs left. The comet will reach LASCO C2 around 1500 - 1600UT of today.  The animation below shows the comet in the SOHO C3 field (click on the thumbnail for a bigger version):

(Credit: SOHO)

UPDATE - December 15 at 20UT


New STEREO-B, SECCHI fits dated back to December 14, 2011 are available. Below you can see our new image processing on the STEREO/SECCHI HI-1A FITS for Dec 14.5 (click on the image for a bigger version):

In the meantime, new SOHO C3 image dated Dec, 15 at 16:30UT is available (click on the image for a bigger version):

A new narrow tail is visible in these images. This extremely narrow features recalls the Na or Fe tails already featured on a few extremely bright comets close to the Sun, e.g.:  http://tinyurl.com/cck9pbn  and http://tinyurl.com/ctun5cy

Matthew Knight of the Lowell Observatory and JHU-APL reports on Spaceweather website: "As of 16:30 UT on Dec. 15th, Comet Lovejoy has reached magnitude -3, possibly brighter. It is starting to saturate SOHO images even with narrow filters and shorter than normal exposure times." The comet is now brighter than Jupiter, but not quite as bright as Venus. If these developments continue apace, Comet Lovejoy could become visible to the naked eye in broad daylight before the end of Dec. 15th.

Again: extreme care is needed due to the comet's small solar elongation angle and close proximity to the Sun in the sky. Do not look at or near the sun through unfiltered optics; focused sunlight can seriously damage your eyes.

Comet Lovejoy's perihelion is roughly 5 hours from now, on Dec 16 at 00:30UT. Next SOHO images will be available after 22:20UT.

UPDATE - December 16 at 11UT

Surprisingly as it may seem, comet Lovejoy appears to have survived its close encounter with the sun. Video and images relased by the  NASA's Solar Dynamics Observatory (SDO) caught the comet reemerging on the other side of the Sun after its perihelion!!

SDO video showing the comet C/2011 W3 (LOVEJOY) flying towards the Sun:

While in the SDO video below you can see the comet incredibly emerging from perihelion:

Using the images taken from 04:39UT to 10:54UT by the SECCHI outer coronagraph (COR2) on the STEREO Ahead observatory on December 16, we have made this animation clearly showing what is left of the comet nucleus after the close approach with the Sun (at present no one can say how much of the comet's core remains intact). Click on the thumbnail for a bigger version:

Using images taken from SOHO C3 from 15:54 of December 15 to 09:30UT of December 16, we made this animation showing the comet on its course pre and after the perihelion. Click on the thumbnail for a bigger version:

Note how in the last frames the remnant of the pre-perihelion tail is still visible but completely disconnected from the comet:

(Credit: SOHO)

UPDATE - December 17 at 12UT

The missing SOHO C2 post-perihelion fits are now available. We just made this short animation showing the comet C/2011 W3 (Lovejoy) reemerging behind the solar disk after the perihelion on the first hours of December 16, 2011:

As we saw on the previous update, at first the emerging comet was missing its tail. Now on the latest C3 images, it is evident that tails are forming again (with the inclusion of the very narrow tail we saw just before the perihelion, possibly NA or Fe  related)  and that the comet is still very bright!!

In fact the comet has been succefully observed visually with a 10x50 binoculars by Alexandre Amorim from Brazil on Dec 17.34. He estimated the comet magnitude at -2.9. Here is its report:

C/2011 W3 (Lovejoy)
2011 Dec 17.34 UT: m1= -2.9*, Dia= <1', DC=9, tail= 0.2 in P.A. 240...10x50B...Alexandre Amorim(Florianopolis,Brazil)[comet alt. 4 deg, sun alt. -0.9 deg]

While below you can see a groud-based image taken at dawn by Jan Ebr with the FRAM remote telescope (0.3-m SCT) located in Argentina, Malargue:

UPDATE - December 19 at 15UT

Below you can see a beautiful image of the tail of comet C/2011 W3 (Lovejoy) taken on December 19, 2011 by FRAM team (Malargue, Argentina) with 200 mm telephoto lens piggybacked on the main telescope, using also a KAF-1603 camera (from FLI). Click on the image for a bigger version:

UPDATE - December 20 at 13UT

Thanks to Jakub Černý we had the chance to works on the FRAM team fits of December 17, 2011. We sorted and stacked the best V-filtered frames, and have done some image processing on it. Basically, it appears that, apart the two "tail branches", we have an asymmetric coma. In some treatement, there is the hint of a "curved jet" or "shell" (or whatever you would call it) in the inner coma, that appears to originate from the central condensation, developing in a "counterclockwise" direction. Obviously this stuff has to be confirmed in further images, to make sure it's not an artefact of my image processing. You can see below the result (click on the image for a bigger version):

On December 17, 2011 the comet has been imaged in daylight also by amateur astronomer Vincent Jacques of Breil-sur-Roya, France. Images and video below taken with an 80mm refractor at 80x + near IR filter and camera DMK21 from 09:00 UT to 13:00 UT.

(Credit: Vincent Jacques)

(Credit: Vincent Jacques)

Australian amateur astronomer Vello Tabur captured a 5-degree-long tail of comet Lovejoy on December 19.7 with a DSLR in the bright twilight.

(Credit: Vello Tabur)

Finally a new image by the FRAM team obtained on December 20, 2011 with a 30-cm Meade SCT F/10 (0.66x) located in Argentina, Malargue.

UPDATE - December 21 at 15UT

The comet has put on a great show for Southern observers. Amateur astronomer Colin Legg has been able to image (with a 5D2 digital camera) the beautiful tail of comet Lovejoy from the Mandurah Estuary on Western Australia around 3:30 WST of December 21, 2011. Below you can see his image and the stunning timelapse of his observing session.

While another observer (Grahame) from Australia  took the following image taken on December 21, 2011 at 0400 local time of Perth with canon 7D, 17-85mm lens, ISO 800 F4.5. Click on the image for a bigger version.

UPDATE - December 27 at 14UT

International Space Station Commander Dan Burbank captured spectacular images of Comet C/2011 W3 (Lovejoy) as seen from about 386 Km above the Earth’s horizon on Wednesday, Dec. 21.

(Credit : NASA)

Many beautiful images are arriving from observers in the Southern Hemisphere, you can find a very good selection here & here

Comet Lovejoy on 2011 Dec 23.7 UT, Michelago, NSW, Australia

(Credit: Vello Tabur)

by Ernesto Guido, Giovanni Sostero & Nick Howes

"Centaur" minor planet 2010 XZ78

2010 XZ78 is an object found on December 2010 by G96 professional survey and classified as a Centaur. To date, 17 total observations of 2010 XZ78 are present in the MPC database over interval: 2010 11 13.34 – 2011 01 08.25.

Centaurs, defined to have their perihelion outside of Jupiter (5.2 AU) and semimajor axis inside of Neptune (30.0 AU), have unstable orbits and have been extracted from the transneptunian objects (TNOs) population through perturbations by Neptune. So far only a few Centaurs have presented unambiguous evidence of cometary activity (see for example 174P/Echeclus). The first Centaur known to present cometary activity was Chiron.

We performed some follow-up of 2010 XZ78 on 2011 December 06, 2011 to lengthen the observational arc and to search for cometary activity. We found it roughly 2.2 arcminutes west of its nominal position. Stacking of 13 R-filtered exposures, 60-sec each, obtained remotely, from the Haleakala-Faulkes Telescope North on 2011, Dec. 6.4, through a 2.0-m f/10.0  Ritchey-Chretien + CCD, shows that this object has a stellar aspect, with its PSF profile being the same of the nearby field stars of similar brightness  (FWHM of 1.2").

Our image of 2010 XZ78:

by Giovanni Sostero, Nick Howes & Ernesto Guido

C/2011 W3 (LOVEJOY) - Kreutz Sungrazing Comet

Cbet nr.2930, issued on 2011, December 02, announces the discovery of a new comet (discovery magnitude 13) by Terry Lovejoy on three CCD images obtained each on Nov. 27.7 and 29.7 UT with a Celestron 8 0.20-m f/2.1 Schmidt-Cassegrain reflector (+ QHY9 camera). The new comet has been designated C/2011 W3 (LOVEJOY).

The comet appears to be a Kreutz sungrazer, a family of sungrazing comets that are named after German astronomer Heinrich Kreutz who first studied them in the details. These comet fragments passes extremely close to the Sun at perihelion and usually they completely evaporated during such a close approach. 

This is the first ground-Based discovery of a Kreutz Sungrazing Comet since 1970!!

We performed some follow-up measurements of this object remotely from the GRAS Observatory (Australia - MPC Code  E03) on 2011, December 04.7 through a 0.10-m f/5 reflector + CCD.

Our image of comet C/2011 W3 (LOVEJOY):

Below you can see an animation showing the fast movement of the comet in the sky. Each frame is a 30-second exposure. Click on the thumbnail for a bigger version.

M.P.E.C. 2011-X16 assignes the following preliminary orbital elements to comet C/2011 W3: T 2011 Dec. 15.99; e= 1.0; Peri. = 57.14; q = 0.005 AU; Incl.= 135.93

The comet is now rapidly brightening but seems intrinsically faint. It may not survive its close perihelion  (at 0.0058936AU, which is a little over 1.2 solar radii) passage on December 16th that will bring it within 880,000 km of the center of the Sun (comet C/2011 W3 will pass just 180,000 km from the Sun’s surface).

The following ephemeris (from Cbet 2930) assumes H = 14.0 and 2.5n = 8.  Note that the rate of brightness  increase is highly uncertain.

Date    TT        R. A. (2000) Decl.     Delta      r     Elong.    Mag
2011 12 06    15 35.96   -47 53.6    0.708    0.505    29.3   11.4
2011 12 07    15 53.78   -46 18.1    0.716    0.470    26.5   11.2
2011 12 08    16 10.34   -44 31.1    0.727    0.434    23.8   10.9
2011 12 09    16 25.59   -42 34.2    0.742    0.397    21.1   10.6
2011 12 10    16 39.54   -40 28.8    0.759    0.358    18.5   10.3
2011 12 11    16 52.22   -38 15.8    0.780    0.316    15.8   10.0
2011 12 12    17 03.68   -35 55.6    0.804    0.272    13.1   9.5
2011 12 13    17 13.96   -33 27.7    0.833    0.223    10.4   8.9
2011 12 14    17 23.07   -30 48.9    0.869    0.169     7.7   8.0
2011 12 15    17 30.86   -27 50.3    0.914    0.105     4.7   6.5
2011 12 16    17 32.18   -23 05.4    0.989    0.006     0.2  -3.4
2011 12 17    17 16.52   -25 17.7    0.919    0.104     4.9   6.4
2011 12 18    17 10.86   -27 27.6    0.873    0.169     7.8   8.0
2011 12 19    17 06.90   -29 31.8    0.835    0.223    10.5   8.9
2011 12 20    17 03.78   -31 35.1    0.802    0.271    13.0   9.5
2011 12 21    17 01.19   -33 39.8    0.771    0.316    15.4   9.9

Extreme care is needed due to the comet's small solar elongation angle and close proximity to the Sun in the sky.

Congrats to Terry Lovejoy his third comet discovery!! On comets-ml mailing list you can read the full discovery  story written by Terry himself.

By Ernesto Guido, Giovanni Sostero & Nick Howes

Update on 2011 RC17

M.P.E.C. 2011-W34, issued on 2011 Nov. 22, 02:33 UT, announced the discovery by Leonid Elenin (H15 ISON-NM Observatory, Mayhill) of a new unusual minor planet, with the temporary designation of 2011 RC17. At that time, its preliminary orbital solution provided a comet-like orbit, with a= 6.3 AU, e= 0.53, Incl. = 11.3 deg, and a period of nearly 16 years.

At first we observed this object on 2011 Nov. 22.4, remotely, through the Haleakala-Faulkes Telescope North 2.0-m f/10.0 Ritchey-Chretien + CCD. On our stacking it appearance was stellar, however we wanted to secure more images about it, in order to obtain a higher S/N, to make sure about its nature.

Then, on 2011, December 1.4, we were able to obtain another observing session through the Siding Spring-Faulkes Telescope South 2.0-m f/10.0 Ritchey-Chretien + CCD.

Stacking of 16 R-filtered exposures, 60-sec each, showed that this object had a stellar aspect, with its PSF profile being the same of the nearby field stars of similar brightness (FWHM of 1.4").

Our image of this object (click on it for a bigger version):

by Nick Howes, Giovanni Sostero and Ernesto Guido

New Comet: P/2011 W2 (RINNER)

Cbet nr.2922, issued on 2011, November 29, announces the discovery of a new comet (discovery magnitude 17.9) by Claudine Rinner on CCD images obtained on November 28, 2011 taken with a 0.5-m f/3 reflector located at the Oukaimeden Observatory near Marrakech, Morocco. The new comet has been designated P/2011 W2 (RINNER).

We performed some follow-up measurements of this object, while it was still on the neocp. Stacking of 14 unfiltered exposures, 120-sec each, obtained remotely, from the GRAS Observatory (near Mayhill, NM) on 2011, November 29.3, through a 0.25-m, f/3.4 reflector + CCD, shows that this object is a comet: diffuse coma nearly 15-arcsec in diameter.

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

M.P.E.C. 2011-W80 assignes the following preliminary orbital elements to comet P/2011 W2: T 2011 Oct. 10.62; e= 0.51; Peri. = 210.50; q = 2.32 AU; Incl.= 14.20

Congratulations to Claudine Rinner for this new amateur comet discovery!!

by Ernesto Guido, Giovanni Sostero & Nick Howes

COMET P/2010 UH55 (SPACEWATCH)

Cbet 2923, issued on 2011, November 30, reports that an apparently asteroidal object reported by the Spacewatch survey and designated 2010 UH55 by the Minor Planet Center last year, has been found to show cometary activity. H. Sato (Tokyo, Japan) first reported the appearance of a condensed coma of size 6"-8" on 2010 Nov. 17.4 UT. Sato's report remained unconfirmed until the past month, when he again found the object on 2011 Nov. 3.5 to show a cometary appearance. Other observers have confirmed the cometary nature of this object. The new designation is P/2010 UH55 (SPACEWATCH).

Prompted by an alert note of Dmitry Chestnov, we performed some follow-up about this object. Stacking of 5 R-filtered exposures, 40-sec each, obtained remotely, from the Haleakala-Faulkes Telescope North on 2011, November 28.6, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, shows that this object is a comet: diffuse coma about 9" in diameter, and a faint, broad tail, nearly 20" long toward west-northwest. Total magnitude m1 R about 18.2

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

M.P.E.C. 2011-W82 assignes the following orbital elements to comet P/2010 UH55 (SPACEWATCH): T 2011 May 10.36; e= 0.58; Peri. = 221.62; q = 2.77 AU;  Incl.= 8.67


Giovanni Sostero, Krzysztof Rochowicz, Ernesto Guido and Nick Howes

2005 YU55 - Close Approach

On November 08, 2011 at 23:28 Universal Time (UT), the Near-Earth asteroid 2005 YU55 passed within 0.85 lunar distances (or 319,000 km or 0.00217 AU) from Earth's surface.

Asteroid 2005 YU55 was discovered by Robert McMillan during the Spacewatch survey on December 28, 2005. The 2011 approach is the closest that we know about in advance by an asteroid with an absolute magnitude this bright since 2010 XC15 (H = 21.4) approached within 0.5 lunar  distances in 1976 (although astronomers did not know about this flyby at the time), and until 2028, when 2001 WN5 (H = 18.2) will approach within 0.65 lunar distances.

The object has been previously observed on April 2010 by Mike Nolan, Ellen Howell and colleagues with the Arecibo radar on April 19-21, 2010 and shown to be a very dark, nearly spherical object 400 meters in diameter with a relatively long rotation period, 18 to 20 hours. 


Trajectory of Asteroid 2005 YU55 - November 8-9, 2011. Click on the thumbnail to see a bigger version:

(Credit: NASA-JPL)

We have been able to follow-up this object on November 09.25 remotely from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD. At the moment of our observing session the asteroid was moving at about 260.07 "/min and it was of magnitude ~11. The image below is a single 60-second exposure (click on it for a bigger version).

While this is an animation showing the object movement in the sky. Each image was a 2-second exposure. Click on the thumbnail to see a bigger version:

Scientists working with the 70-meter Deep Space Network antenna at Goldstone, California, have generated a short movie clip of asteroid 2005 YU55 from data  collected on November 07, 2011. These are the highest-resolution radar images ever obtained for a near-Earth object:

Due to its size and proximity to Earth, the Minor Planet Center has designated 2005 YU55 as a "Potentially Hazardous Asteroid". Although classified as a potentially hazardous object, 2005 YU55 poses no threat of an Earth collision over at least the next 100 years, the entire interval over which its motion can be computed reliably.

For more info about this close approach:

http://www.skyandtelescope.com/observing/home/133013563.html

http://echo.jpl.nasa.gov/asteroids/2005YU55/2005YU55_planning.html

https://www.nasa.gov/mission_pages/asteroids/news/yu55-20111108.html


by Ernesto Guido, Giovanni Sostero and Nick Howes

Recovery of comet 171P/Spahr

On October 19.5, 2011 we started an observing session to recover the periodic comet 171P/Spahr. T. B. Spahr (then at University of Arizona, Arizona, USA - now Director, Minor Planet Center) discovered this comet with the 0.41-m f/3 Schmidt telescope in the course of the Catalina Sky Survey on 1998 November 16.39.

We found an object of magnitude ~20.6 with the following offset from the nominal position of comet 171P (RA 2.5'W  DEC 0.6'S). We found again the same object on October 20.5 & October 24.5. A faint possible tail, about 20-arcsec long toward North-East is visible. We imaged it remotely with the 2.0-m f/10 from the Siding Spring-Faulkes Telescope South.

Below you can find our recovery image of October 24, 2011:

While below you can see an animation showing the movement of the comet (click on the thumbnail for a bigger version):

Before our recovery, comet  171P/Spahr was last observed on February 06, 2006.

by Ernesto Guido, Giovanni Sostero, Nick Howes & Antoni Kasprzyk

New Comet: C/2011 U2 (BRESSI)

Cbet nr.2875, issued on 2011, October 26, announces the discovery of a new comet (discovery magnitude 19.4) by Terry H. Bressi on CCD images obtained on September 24, 2011 with the Spacewatch 0.9-m f/3 reflector at Kitt Peak. The new comet has been designated C/2011 U2 (BRESSI).

We performed some follow-up measurements of this object, while it was still on the neocp. Three stacked 60-s R-band exposures taken remotely on Oct. 25.5 with the 2.0-m f/10 "Faulkes Telescope North" at Haleakala show that this object is a comet with a compact coma about 4" x 3" in size, elongated toward p.a. 250 deg, with a sharp central condensation and a tail about 20" long in p.a. 250 deg.

Our confirmation image (click for a bigger version):

M.P.E.C. 2011-U85 assignes the following preliminary orbital elements to comet C/2011 U2: T 2012 Oct.  9.20; e= 1.0; Peri. = 222.89; q = 2.49 AU; Incl.= 9.81

by Ernesto Guido, Giovanni Sostero, Nick Howes & Daniel Cirelli

"Debris cloud" of comet C/2010 X1 (Elenin)

The *big* problem imaging the "debris" of C/2010 X1 (Elenin), is the low S/N of the little cloud it left away. If you want to integrate enough, in order to increase the S/N of yours images, then you face the problem of the trailed stars that are crossing the field, producing an annoying interference with the faint cometary cloud.

A professional astronomer (CARA's collaborator Gian Paolo Tozzi, Arcetri Observatory, Italy), suggested to shoot again the field of the comet with the same instrumentation when the comet moved away, and then to subtract the field stars from the cometary original images you want to enhance.  In principle, this would help to eliminate at least some part of the disturbing effect produced by the trailed stars.

We tried this interesting technique on the images we obtained on 2011 Oct. 23.37 (see our previous post), and we obtained the following result (click on the thumbnail for a bigger version):

We have still to improve this method (we found some issues matching the size of the field stars, due to the different seeing conditions and/or focus on two consecutive nights), anyway the results looks pretty promising. The image treated in this way, is significantly cleaner, and some features of C/2010 X1 (Elenin) are easier to be seen. In particular, the sunward part of the "cometary cloud" appears much sharper compared to the antisolar direction. The diffuse shape of the comet appears to be somehow "conical", about 1.5 deg long overall, with a maximum thickness of about 10-arcmin in the solar direction: the ovate shape of the "cometary cloud" than thinners tailward. We failed to find any convincing condensation within it, provided that the few "knots" visible on our image, are probably due to some noise left by the star profile removal process.

Talking about morphology, it's interesting to notice some similarities of what we found in our image, with this archive image of comet Shoemaker-Levy 9, seen after its break-up (Lowell Observatory 1.1m Hall telescope of 23 June 1993):

UPDATE OCTOBER 25, 2011

Below you can see a new elaboration of the previous image (click on the thumbnail for a bigger version):

by Giovanni Sostero, Ernesto Guido and Nick Howes

Another recovery attempt on C/2010 X1 (Elenin)

Today, we imaged again the field of C/2010 X1 (Elenin) remotely, from the GRAS network (Mayhill station, NM). We used two scopes, nearly simultaneously: the 254mm, f/3.4 reflector + CCD, and the 0.1m, f/5 APO refractor + CCD.

The first observing session, on 2011 Oct. 21.3861 UT, through the 10" reflector (15x20sec, unfiltered exposures, scale 1.6"/px, field of view 59'x40'), provided no obvious moving objects in the field of view.

The second observing session with the APO refractor, was scheduled on two separate slots, spaced by about 2h, on 2011 Oct. 21.38392 and Oct. 21.47579. The first sequence was a stacking of 9x30sec, the second was 11x30 sec (unfiltered exposures, scale 3.5"/px, field of view 3.9 degx2.6 deg). Blinking the two fields, we found something moving on the sky background (moonlight interference).

After some image processing, to clean a bit the image, we get this result (click on the thumbnail below to see the animation):

If this *extremely* faint and diffuse blob of light is not an artefact (stray light reflection, ghost image, etc.), it is very close to C/2010 X1 ephemerids position, and it seems to moves with the appropriate proper motion.

Tentatively we measured a 14'x8' (kind of) extremely faint cloud, elongated toward PA 300.


The provisional astrometry we obtained from these two set of data is listed below (very difficult measurement, since there isn't any obvious condensation):

COD H06
OBS E. Guido, G. Sostero, N. Howes
MEA E. Guido, G. Sostero. N. Howes
TEL 0.10-m f/5 reflector + CCD
ACK MPCReport file updated 2011.10.21 16.54.10
NET UCAC-2
   CK10X010 KC2011 10 21.38392 07 55 08.81 +28 41 56.3          x.xx N      H06
   CK10X010 KC2011 10 21.47579 07 53 48.16 +28 45 45.0          x.xx N      H06


We encourage other observers to confirm or refute this possible find we made, with their own observations/images. We suggest the use of wide-field, fast focal ratio scopes, possibly under very good sky conditions.


UPDATE October 23, 2011 

Following our yesterday's report of the recovery of the remains of comet C/2010 X1 (Elenin), we confirm the detection of the "cloud" on today observations too.

Here is again the "cloud" imaged by our team few hours ago on October 23.4, 2011 remotely from the GRAS network (Mayhill station, NM) by 0.1m, f/5 APO refractor + CCD (12x300-seconds exposures). Click on the thumbnail for a bigger version:

The "cloud" is roughly 40' long with an extension of 6' near the expected position of the comet.

Here you can see an image where the X marked the ephemeris position for comet C/2010 X1 (Elenin). Click on the thumbnail for a bigger version:

 

And this is an animation showing the movement of the "cloud" along with to the movement of the expected comet's position (click on the thumbnail for a bigger version):

The fast streak moving on the right side of the animation is the PHA asteroid (138524) 2000 OJ8 (magnitude 14.5).

After our request to other observers to try to confirm our find, we have received the following images and animation by fellow observers that seems to confirm the presence of this faint and diffuse "cloud" moving at the same speed and PA of the comet C/2010 X1 (Elenin) very close to C/2010 X1 ephemerids position.

The image by Rolando Ligustri obtained remotely from New Mexico on October 22, 2011 (the image processing was particularly forced to highlight the faint nebulosity):

The animation by Leonid Elenin on October 22, 2011 (click for a bigger version)

The animation by Juanjo González Díaz on the evening of October 21, 2011 (click for a bigger version)

by Ernesto Guido, Giovanni Sostero and Nick Howes

New Comet: P/2010 TO20 (LINEAR-GRAUER)

Cbet nr.2867, issued on 2011, October 21, announces the discovery of a new comet (discovery magnitude 19.1) by A. D. Grauer on CCD images obtained on October 19, 2011 with the Mount Lemmon 1.5-m reflector.

According to the CBET: "After two nights of observations of Grauer's comet had been received at the Minor Planet Center, T. Spahr realized that this object was identical with an object discovered a year ago by the LINEAR project (discovery observation tabulated below; cf. MPS 351583) that appeared to be a Jupiter Trojan minor planet."

The new comet has been designated P/2010 TO20 (LINEAR-GRAUER).

We performed follow-up measurements of this object on 2 different nights, while it was still on the neocp. 

Stacking of 6 R-filtered exposures, 60-sec each, obtained remotely, from the Siding Spring-Faulkes Telescope South by G. Sostero, I. Melville, A. Kasprzyk, N. Howes, E. Guido on 2011, Oct. 19.6, through a 2.0-m f/10.0 Ritchey-Chretien + CCD under good seeing conditions, shows that this object is a comet: sharp  central condensation, compact coma about 5" in diameter, and a wide, fan-shaped tail, at least 45" long toward PA 250

Stacking of 5 R-filtered exposures, 60-sec each, obtained remotely, from the Haleakala-Faulkes Telescope North by G. Sostero, N. Howes, E. Guido on 2011, Oct. 20.4, through a 2.0-m f/10.0 Ritchey-Chretien + CCD, confirms that this object is a comet: we found again a sharp central condensation, a compact coma about 6" in diameter, and a tail, at least 30" long, toward PA 247.

Our confirmation image:

M.P.E.C. 2011-U41 assignes the following very preliminary orbital elements to comet P/2010 TO20: T 2008 Aug. 27.9; e= 0.09; Peri. = 250.17; q = 5.06 AU;  Incl.= 2.65


by Giovanni Sostero, Ernesto Guido and Nick Howes

Observations of astronomy satellite Spektr R

On Saturday October 15, 2011 a bright (magnitude 13.5) and fast object (observed by 703 Catalina Sky Survey) was published on the Neocp list with the designation ST37690.

We performed some follow-up measurements of this object while it was still on the neocp on October 15.5 remotely from the GRAS Observatory (near  Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD. Soon after ST37690 object was removed from Neocp list because it was not a minor planet.

As it turned out, ST37690 was actually the artificial satellite SPEKTR-R (official designation 2011-037A). Spektr R is a Russian orbital radio telescope, and currently the largest space telescope in orbit.

According to Nasa website:

"Spektr R, a Russian radio astronomy satellite, was launched from Baikonur on 18 July 2011 at 02:31 UT by a Zenit 3F rocket. Spektr R is one element of an international network of observatories in a project called RadioAstron. Funded by the Russian Astro Space Center, Spektr R features a 10-m diameter antenna reflector designed to help astronomers see deeper into supermassive black holes, obtain views of collapsed stars, and better measure the influence of dark energy on the cosmos. When linked together, RadioAstron's telescopes have a resolution of 7 microarcseconds"

More info about it on "Sky & Telescope" website.

Below you can see the animation showing the fast movement of Spektr R in the sky (10 frames of 20-seconds exposure each):

by Ernesto Guido, Giovanni Sostero & Nick Howes

C/2010 X1 (Elenin) post solar conjunction recovery attempt

Recently we tried to image C/2010 X1 (Elenin) after its solar conjunction. The observing conditions for this comet are currently quite difficult: very low in the morning sky at twilight, within the zodiacal "light pollution".

Anyway we decided to go with several robotic scopes, operating under excellent sky conditions (New Mexico and Mauna Kea). At first we aimed at the expected comet's position (MPC ephemerids) on 2011, Oct 09.5, through a 0.25-m f/3.4 reflector + CCD and, nearly simultaneously, through a 0.10-m f/5 APO refractor + CCD, from the Global Rent a Scope facility (near Mayhill, NM).

Stacking of a number of images, we observed no distinct evidence of the comet within about 30 arcmin of the expected position, with a limiting magnitude around 17, and to limiting magnitude about 15, within about 2 deg from the expected position. Below you can see the crop of the 0.25-m reflector stacked image set (click on the image for a bigger version):

On 2011, Oct. 10.6, we imaged the area where comet Elenin was supposed to be, through the 2.0-m f/10.0 Ritchey-Chretien + CCD of Faulkes Telescope North (Mauna Kea, Hawaii). Stacking several exposures, with limiting magnitude at around 20.5, doesn't show any trace of the comet within the 10'x10' field of view centered on the comet's ephemerids (while stacking these images along the proper motion of the field minor planets, we can easily distinguish the asteroid (43629), with its magnitude at 20.3 (click on the image for a bigger version):

by Ernesto Guido, Giovanni Sostero and Nick Howes

New Comet: C/2011 S2

Cbet nr.2852, issued on 2011, October 02, announces the discovery of a new comet (discovery magnitude 15.7) by R. A. Kowalski on CCD images obtained on September 30, 2011 with the Catalina Sky Survey's 0.68-m Schmidt reflector. The new comet has been designated C/2011 S2.

As noted on both the discovery Cbet & Mpec:

"The orbit of this object is essentially indeterminate at the present time. It is possible that this is a short-period comet.  Among the wide range of possible short-period orbits are orbits that appear similar to P/2006 T1 (Levy).  Initial attempts to link the two apparitions have not been successful.  Further observations are encouraged."

We performed some follow-up measurements of this object, while it was still on the neocp. Stacking of 30 unfiltered exposures, 30-sec each, obtained remotely on 2011, October 01.4 from the GRAS Observatory (near Mayhill, NM) through a 0.25-m, f/3.4 reflector + CCD, shows that this object is a comet with a condensed coma about 10-arcsec in diameter, elongated, toward PA 295.

Our confirmation image:

Animation showing the movement of the comet:

M.P.E.C. 2011-T12 assignes the following very preliminary orbital elements to comet C/2011 S2: T 2011 Oct. 23.52; e= 1.0; Peri. =188.83; q = 1.13 AU; Incl.= 17.32

by Ernesto Guido, Giovanni Sostero & Nick Howes