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103P/Hartley 2

Posted: September 9th, 2010, 1:34 pm
by Christopher K.
Sunday the Deep Impact spacecraft sent back the first image of Comet Hartley 2. That spacecraft is now part of the EPOXI mission and will swing by Hartley 2 on 4 November. The distance between the two at this point is 60 million kilometers (0.4 AU).

Hartley 2 is expected to brighten to about magnitude 5 in October. At the beginning of October the comet will be near NGC 281 (the Pacman Nebula) and by 9 October, during New Moon, it will swing near Perseus' Double Cluster.

The EPOXI science team is actively promoting ground-based observations of this object at this time. A Java applet at the University of Maryland's Amateur Observers Program website shows the current position of Hartley 2.

This will be the best ever viewing and imaging of a comet visting the inner Solar System.

More information at:
October 2010 Astronomy, p. 42. ... 00908.html

Ground-based images of Hartley 2:

Re: 103P/Hartley 2

Posted: September 17th, 2010, 11:28 pm
by Christopher K.
A 10 September report from Sky & Telescope's Greg Bryant implies Hartley 2 should reach magnitude 7 or 8 by 22 September. The Minor Planet Center still only has magnitude estimates for this object up to 27 August. Bryant also states it should reach magnitude 6 by 1 October and stay that bright through October and most of November.

Hartley 2 was discovered in 1986 by Malcolm Hartley of Siding Spring Observatory.

More information: ... 32669.html

Re: 103P/Hartley 2

Posted: September 21st, 2010, 3:39 pm
by Christopher K.
As of this posting, the latest report to the Minor Planet Center is of a 7.9 magnitude and a 16’-diameter coma, from J. Cerny in Senohraby, Czech Republic, using 8x40 binoculars on the 20th.

Sky & Telescope's finder chart is probably the most useful on the internet... ... ey2-bw.jpg

...though some might say Gary Kronk’s is better.

Chris Peat has set up a 103/P Hartley 2 page; his current estimate is 6.8. ... t=0&tz=CET

So, what does all this mean as far as viewing from Baton Rouge goes? An excellent opportunity!

Within thirty-six hours the comet will be crossing from Andromeda into Cassiopeia. This is the listing (derived from Starry Night Pro) of when Hartley 2 clears 30° in the skies over HRPO…
24 September: 7:30pm [in Cassiopeia]
26 September: 7:35pm
28 September: 7:40pm
30 September: 7:50pm
2 October: 8:05pm
4 October: 8:20pm
6 October: 8:40pm [Perseus]
8 October: 9:05pm
10 October: 9:35pm
12 October: 10pm
14 October: 10:35pm
16 October: 11pm
18 October: 11:25pm [Auriga]
20 October: 11:50pm
23 October: 12:10am
25 October: 12:25am
27 October: 12:45am [Gemini]
29 October: 12:55am
31 October: 1:05am
2 November: 1:15am [Monoceros]
4 November: 1:25am
6 November: 1:30am [Canis Minor]
8 November: 12:35am (Daylight Time has ended)

In other words, Baton Rougeans will have the whole night each night for the next week, slowly diminishing to part of the night later, then the early morning during the final third of October. An excellent imaging opportunity! As Cassiopeia is close to the North Celestial Pole, Hartley 2 will basically trace a circular arc in the sky every night, from northeast to north to northwest.

By 6 October Hartley 2 will be in Perseus, and on the night of 7 October it should be less than 1° from the Double Cluster in Perseus. This will be about New Moon, so I guess 5 October to 9 October might be the best nights. By 10 October, the object will briefly nip the corner of Camelopardalis but won’t stay.

S&T is estimating a magnitude 5 for Hartley 2 by the end of October.

As always, any new information or descriptions of sightings or attempted sightings should be posted as a continuation of this thread.

Re: 103P/Hartley 2

Posted: September 24th, 2010, 9:03 am
by mcaramb
Attempted: 9/23/2010 @ 11PM
Location: Prairieville, LA
Equipment: 10x42 Binoculars, 10"/f5 Dob with 32mm Lense
Result: Not seen
Notes: It started out cloudy, but cleared up nicely. Although I could make out all 5 stars in Cassiopeia (including the dimmest, Segin, at mag [3.38]) I could not see 103P/Hartley 2, naked eye or otherwise. Using the telescope, I was able to verify the positions of the mag [>6] stars in the area where it was supposed to be, so I know I was looking in the right place. There was a chance I mistook one of the stars for the comet, but even after using the 10", I was unable to make out any coma around any of those tiny stars.

FYI: As a rule of thumb, if you can't see all 5 stars of Cassiopeia in your sky, you will not be able to see the comet with the naked eye. Segin is only mag [3.38], so even when the comet flares to just mag [5], it will be difficult to spot in town.

Re: 103P/Hartley 2

Posted: September 28th, 2010, 3:23 pm
by btoman
Hey All,

I attempted to see comet Hartley 2 last night (Sept 27th, 2010) and was....successful! I imaged it through the 20" scope at the HRPO between 11:31 PM and 11:51 PM CDT. After stacking the images at home today, I realized just how fast it is moving through the sky! Still not seeing much of a tail (if any) but it's definitely a "fuzzy star." I'll post the images I took last night in the Astrophotography section and on the Facebook page.


Re: 103P/Hartley 2

Posted: September 29th, 2010, 3:42 pm
by Christopher K.
Ben's images are really fine, and I hope this only encourages more people in the general area to attempt sightings of their own. Remember, we'll have to get out later and later as the weeks pass, but Hartley 2 should be getting brighter--at least to magnitude 5.

Astronomy's website has a nice four-minute introductory video from Senior Editor Richard Talcott. I feel this is perfect for any professional or informal educator wanting to introduce the comet to the uninitiated.

Re: 103P/Hartley 2

Posted: October 1st, 2010, 3:32 pm
by Christopher K.
Greg Bryant reports that Hartley 2 has been spotted with 8x40 binocs from dark-sky locations.

This might be frustrating for some in the greater Baton Rouge area. Hopefully light pollution, an expensive and completely avoidable malady, won't quash all that many attempts to see this visitor, which will not return until 2017.

Oh,well...the EPOXI mission released its fourth image (URL below) of the fuzzy blob everyone is hunting. Hartley 2 was approximately 172.4 million km from the Sun and 41 million km from the spacecraft.

Re: 103P/Hartley 2

Posted: October 5th, 2010, 3:04 pm
by Christopher K.
Yesterday S&T associate editor Tony Flanders has spotted Hartley 2 under "fairly dark sky" with 10x50 binocs. He also used a 12.5" Dob at 151x; the resulting estimated size of Hartley 2 is 8' x 6'.

Greg Bryant says, "The comet's halo is fairly diffuse, and most people who attempted to spot it from suburban skies either failed or had considerable difficulty." Tell us about it. This sentiment is echoed by Gary Kronk: "Despite it's bright magnitude and the attention this comet has received it is not as easy to observe as one might expect."

Chris Peat's current magnitude estimate is 5.4. The Minor Planet Center most recent posted estimate at this time is from 3 October; D.W.E. Green of Lexington, Massachusetts claims a spot with 20x80 binocs while Hartley 2 was 7.5 mag and 8'.

I am receiving queries about the date of maximum brightness for Hartley 2. Kronk is stating the early morning of closest approach--20 October--will be best. "Even then," says he, "I expect it will still not be obvious in binoculars and small telescopes from light polluted locations."

I hope this doesn't pan out to be a bittersweet lesson for those usually not concerned about light pollution.

Re: 103P/Hartley 2

Posted: October 12th, 2010, 11:15 am
by Christopher K.
S&T now reports Alan Whitman describes picking up Hartley 2 from a dark site south of Penticton, British Columbia "slightly easier than M33". M33 is the Triangulum Galaxy; the SEDS website lists its magnitude as 5.7 while Burnham's Celestial Handbook gives it as 6.0. Alan MacRobert viewed Hartley on the 10th under "moderately dark skies" in New Hampshire through 20x80 binocs and described the object as an "almost uniform glow of dim gray-green".

Right now the latest report to the Minor Planet Center (yesterday, no less) is from a C.S. Morris of Fillmore, CA. Morris estimates a 5.8 mag and 30' angular size using 10x50 binocs. The brightest estimate sent to the Center in the past thirty-six hours is from P. Horalek in Ustupky, Czech Republic on the 10th. Horalek estimates a 5.4 mag and 35' angular size using the unaided eye.

The National Weather Service is forecasting clear skies for Village St. George (the Baton Rouge suburb in which HRPO resides) for tomorrow through Sunday nights. During this time Hartley 2 will clear thirty degrees between 10:15pm and 11:15pm.

Re: 103P/Hartley 2

Posted: October 20th, 2010, 11:57 pm
by Christopher K.
On 14 October Tony Flanders viewed Hartley 2 from the suburbs of Arlington, Massachusetts. It was "visible though challenging" in 12×60 binos; he was also able to see it at 40× through a seven-inch Dob. Only the inner section, about 4' across, was visible. Sky & Telescope said "From a suburban location, Hartley 2 is comparable to a typical 8th-magnitude galaxy. Pinpointing the precise location is the key to spotting it."

S&T attributes the "wildly divergent magnitude estimates" to the fact that light pollution allows only that inner section to be seen.

Note this 8 October image (created from eighteen two-minutes exposures) from Wayne Fukunaga in Hawaii using a Tele Vue TV-102 refractor and Canon 20D DSLR:

Tonight is supposedly the brightest Hartley 2 will get.

More information at:
Astronomy, November 2010, p. 42. ... 32669.html