Friday, October 21, 2011

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):

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
   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


Kevin Heider said...

Looks like a disintegrated comet to me.

Kevin Heider said...

What was the limiting magnitude with the 4" APO refractor?

Team said...


Yes, but our observation needs to be confirmed on a second night in order to rule out definitively the hypothesis of an artefact due to the proximity of the moon

The limiting magnitude is aroud 15!


Anonymous said...

And so what kind of path expectation, density -- great find!

Ramon van der Hilst said...

If Elenin was originally thought to come very near the Earth, then this cloud will come very near the Earth too.
Is it possible already, based on these measurements, to estimate whether the cloud will have expanded enough by the time of the encounter?

It would make for an awesome meteor show, I presume...

Ramon van der Hilst said...

Never mind: the close encounter happened back in October 2010 already, and the orbital period is >10ky. Looks like we're not getting an extra show...

Anonymous said...

Why is the "cloud" oriented vertically on the second image whereas the others are horizontal? All the stars are oriented the same but the "cloud" turned 90 degrees. Ideas?

Team said...


Just to show it from a different angle. Anyway in the case of astronomical images, it is conventional to show them north up, east left. So the image with the cloud oriented "horizontal" is more correct in terms of representation.