Comet 103p Hartley

[Brian Emfinger]

It looks like Comet 103p Hartley is increasing in brightness pretty good.  I tried to image it a week ago but it was too dim.  Tonight, it was quite easy to photo (this is just shot with my camera and a 75-300mm lens w/ a motorized eq mount).

80mm showing half of Cassiopeia (the 3 bright stars on left side) and the comet at right center (the bluish smudge)



and 300mm

[Ron]

Brian,

That's looking great!  I can't wait to give a it try, maybe this coming New Moon.

What were your exposure times and are they single frames.

Thanks for sharing,

Ron

[Brian Emfinger]

Yep single frames.  Both of these are 30 second exposures at high ISO (12800).  I was trying to get done before moon rise so I wanted to keep the exposures as short as possible.  I am going to do it again tonight with the same settings and see how much it brightened.  I cant find much recent information (within the last week) on its brightness..... anyone know where to look that has updated data?

[Ron]

Yep single frames.  Both of these are 30 second exposures at high ISO (12800).  I was trying to get done before moon rise so I wanted to keep the exposures as short as possible.  I am going to do it again tonight with the same settings and see how much it brightened.  I cant find much recent information (within the last week) on its brightness..... anyone know where to look that has updated data?

My SNP gives the approx mag at 6.03 and it's pretty much up to date, and I'm sure there are other places to find it also.

What kind of camer are you using to get that high of ISO?

Thanks,

Ron

[lindendave]

Okay, just to throw in some more, and extra, data here is what Guide 8 has on Hartley;

P/Hartley (103P)  mag 6.1
Period of orbit       6.47 years (2363.3 days)
Perihelion distance   1.0586680 AU
Aphelion distance     5.89 AU
Orbital elements:
   Semimajor axis           3.4723177 AU
   Eccentricity             0.6951120
   Inclination of orbit    13.6168000 degrees
   Argument of perihelion  181.1953000 degrees
   Long. ascending node    219.7663000 degrees
   Date of perihelion   JD 2455497.76040 (28 Oct 2010  6:14:58)
Right ascension: 00h19m45.662s
Declination: +53 42' 10.28"
Mean position at current epoch:
Right ascension: 00h20m20.400s
Declination: +53 45' 44.73"
Apparent position at current epoch:
Right ascension: 00h20m23.414s
Declination: +53 45' 56.62"
Dist from home planet:  0.19800087 AU (29,620,509 km)
Heliocentric position:  lon 8.31085  lat 7.20439
Heliocentric radius 1.13549 AU
86.09% illuminated
Phase angle: 43.79 degrees
Elongation from Sun 128.35 degrees (morning sky)
Speed of apparent motion: 3.328'/hour at position angle 66.4
Motion is -1.22 degrees/day in RA, 0.53 degrees/day in dec

[Brian Emfinger]

Its just a Canon T1i.  I have hardly used that high of ISO but it worked decently last night.  

I am guessing that last week the comet was dimmer than was forecast since I can pick up pretty dim objects and I couldnt see it (in the photo).  Now, I imagine its at least on target now with the brightness level that was forecast if not more.  Anyway, that's what I am guessing from reading several reports and predictions.  In any case its definitely brightened considerably since a week ago.  

edit:  and I guess I would estimate brightness right around 6-7 as it seems to be on par with NGC 7789 (mag 6.7) which is visible in that wide angle image.

[lindendave]

Side note:

Though not yet naked eye there are reports that observers are able to resolve it through binoculars.....darned and I left mine at home!

[Brian Emfinger]

It looks about the same from last night to tonight.  I may try and image once a day to keep this going for a little movie. 

[Ron]

Brian,

Nice movie!  It's amazing how much these Comets move in a short period of time.

Are you still shooting from a fairly dark site?  How is the noise level on your T1i?  The noise level on my Xti is pretty bad at 1600 Iso.

Thanks,

Ron

[Brian Emfinger]

yeah my site is borderline 2/3 on that Bortle Dark Sky Scale.  The NE half is solid 2 though.  The dark skies and the tracking seem to really cut down on the noise issues.  Last night I did a better job at aligning and was able to go with ISO1600 for 5 minutes.  I usually use ISO1600 or 3200.

[lindendave]

There seems to be enough interest in Hartley here to share an animation that was posted on the mpml Yahoo group. Patrick Wiggins was the poster and I am posting the content of his explanation of the details below.

"Tonight I noticed I'd just passed 103 nights of imaging in my observatory this
year. 103 reminded me of Comet 103P/Hartley (yeah, my mind is wired weird).

So to commemorate the event I shot a series of 13 ten second exposures of the
comet each spaced 5 minutes apart between 0901 and 1004 UTC and strung them
together in an animation.

Specs: C-14 @ f/5.5, ST-10 binned 3x3, C filter, FOV ~ 18' x 26'. North is up,
east to the left.

http://users.wirelessbeehive.com/~paw/temp/103PHARTLEY20101001.GIF

I didn't do anything special to the raw files other than apply a master dark and
master flat and remove several hot and cold pixels. If anyone would care to have
a go at bringing out more cometary structure I'd be happy to email them the
original images.

patrick"

[Ron]

Thanks Dave,

His movie even shows a hint of a tail.  He has some nice dark skies out in Utah.

I've tried to meet up with him several times during my visits to Utah and Bryce Canyon NP where he does Star Parties, but I always seem to miss him when he is there doing  his lectures.

I've been wanting to meet him ever since he used my Mars picture for his lectures on Mars' close encounter back in 2003.

Maybe some day,

Ron

[Brian Emfinger]

wow very nice!

and I have updated my little gif to show the last two nights.  You can see its increasing speed across the sky in just the last 4 nights pretty easily.



ive put up a page with my photos... im going to try and continue to take a picture every night.

http://www.realclearwx.com/comet103phartley.htm

[Ron]

Nice job Brian, that thing sure is move'n on

Keep up the good work

Thanks,

Ron

[Brian Emfinger]

Comet 103p Hartley near its closest approach to the Double Cluster from 540am this morning...quite the nice sight!!