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[Centaur]

Periodic comet 103P Hartley should generate a great deal of public interest this autumn, not only because it may get as bright as magnitude +4.5, but also because NASA’s Deep Impact vehicle is scheduled for a close flyby to study it on November 4. Before that the comet will pass 0.12 AU from Earth on October 20 and then reach perihelion of 1.06 AU from the Sun on October 28.

Prior to 1993 the comet’s perihelion was only 0.95 AU (closer to the Sun than Earth) but a close approach to Jupiter significantly altered its orbital characteristics. Its orbit is inclined only 13.6° to the ecliptic, which enhances the possibility of close approaches to Earth. Its orbital period is only 6.47 years.

This autumn we’ll be treated to a very close approach to Earth of the comet while it is not only near perihelion but also near opposition relative to the Sun. Its path this year is especially advantageous for northern hemisphere observers; right now it is circumpolar for most of us.

I’ve created three related graphics for display on my astronomical webpage. They are for the period from September 18 through December 1 when the comet may be visible for naked eyes. The first plots the positions of the comet in equatorial coordinates. The second shows the horizontal coordinates (alt-az) of the comet as seen from the Chicago’s Adler Planetarium each night at 23:30 CDT. The third is a graph of its stellar magnitude (brightness). They can be seen by clicking www.curtrenz.com/astronomical

Reports and photos of the comet would be welcome additions to this thread.

[patrickm]

Cool!! Had a great time and enjoyed the challenge of hunting 10P Temple 2, so look forward to an easier time with this one. Also fun to comet hunt while thinking of M. Messier doing the same and continuing to run into annoying stuff like galaxies, nebulae and clusters!

Always highly anticipate your posts Centaur!

[Paulie pchris00]

I'm going to try for it tonight.

[Chicago Astronomer - Astro Joe]

In a month's time, it should be a good object for public telescopic viewing.

[Paulie pchris00]

Okay Curt. I had an unsuccessful hunt for Hartley last Thursday night. I consulted your graphic first, but you don't have it plotted before September 18. I'm curious as to why not? I had to use Sky & Telescope's observing chart. It was helpful, I know I was looking in the right place, but no luck. I've only seen Halley (as a kid) and Lulin, so I don't have much experience observing comets. I've seen some imaging on EPOXI's Facebook fan page...

www.facebook.com/photo.php?pid=3397559&id=711717978&ref=notif¬if_t=photo_reply#!/EPOXI


...and I notice that even in long exposures, the comet is much fainter than the brightest surrounding stars. When will it be anything much to look at in a 6" scope?

Also, make a note to get out on October 9. Hartley will be passing about 1 degree south of the Double Cluster. That should be something to see, if this thing gets very bright at all!

[Centaur]

Sept 13, 2010 13:34:38 GMT -6 Paulie pchris00 said:

...I consulted your graphic first, but you don't have it plotted before September 18. I'm curious as to why not?...

My charts are for naked eye observers like me, so plots were only made for those dates on which that is close to possible. Those with telescopes know where to find more detailed maps. We’ll let you prepare an even better one for our use this week. My original intention was not to post until September 18th, but someone on another site asked me to put up an advance preview, so I bowed to request and did that for several sites. Sorry to have disappointed you.

[Paulie pchris00]

I wasn't disappointed, but I like to use your charts when I can. I thought it might have something to do with the magnitude.

[Paulie pchris00]

And by the way, you have a talent that I think few of us amateurs have, the ability to make good mathematical predictions and charts. Without out people like you, I would have a heck of a time finding my way around the sky. I always appreciate your work.

[patrickm]

Hear!! Hear!!!

Centaur, when will you be down to a Chicago Astronomer gathering so we can all shake your hand and ask you questions until you run away???

[Centaur]

Thank you for your kind words, Paulie and Patrick. Sorry, but I can’t get to the Adler very often nowadays, even though I know the Paul who runs it and interviewed him on my TV show. But you can talk with me after a show in Palatine at Harper College’s Performing Arts Centre during November when I’ll be playing a general in Bury the Dead: goforward.harpercollege.edu/page.cfm?id=4447&start=11/14/2010&verbose=4838

[patrickm]

Palatine?!? Holy cripes!! That might as well be...Blue Island or something!

Ummm...sorry for my blunt ignorance, but what tv show??

And you really don't have a scope at least some astro binos??

[patrickm]

Nice article with pics and links about your Comet Hartley.

cosmiclog.msnbc.msn.com/_news/2010/09/14/5110779-this-comets-ready-for-its-close-up

[patrickm]

As posted on Joe's ill-fated Comet Hunting thread (sorry gang!), I found the guy last night:

Comet spotted 21:45, Austin,TX with 15x70 binos under excellent seeing and above average transparency. Moon still not up yet at the time. Bluish smudgy blot moving in and out of view, but very easily ID'd.

Can't wait to get in scope! Hope you had success up in Chicago.

Tonight not looking food for you up there in Chicago, but here's a couple of Sky Voyager screen shots for Chicago tonight in case it clears up.



Good luck!

We are due for fantastic central Texas skies. Jordan is bringing over his scope this evening, so we will attempt it with 130SLT and hope to catch the GRS transit around 10pm CDT as well. Should be a fun night!

[patrickm]

Finally starting to hit the mainstream press. A few links from this morning's reading.

Space telescopes spot incoming comet

New photos of an icy comet taken from Earth and space are giving astronomers a tantalizing preview of the object ahead of an upcoming flyby of a NASA spacecraft.

Comet and Earth to Have Rare Close Encounter

On Oct. 20, Comet Hartley 2 will pass just over 11 million miles (18 million km) from Earth. During October it should be easily visible in small telescopes, binoculars and — from sites with dark enough skies — even with the naked eye.

[patrickm]

NASA's Deep Impact spacecraft took this image of its quarry, comet Hartley 2, on Sept. 5, 2010. Deep Impact will make a planned close flyby of the comet in November. Credit: NASA/JPL/UM

Attachments:

[patrickm]

From MSNBC Cosmic Log

This Comet's Ready for Its Close-Up.
Earthly observers are getting nicer pictures and posting them to EPOXI's Facebook page. The color pictures show the comet surrounded by an eerie greenish glow.

Comet 103/P Hartley 2 glows green in this image captured by Italian astrophotographer Rolando Ligustri using the Global Rent A Scope system in New Mexico. Credit: Rolando Ligustri / CAST / CARA

Attachments:

[RobbW]

Just thought I'd post up my attempt to image Hartley. This was from the same Saturday night that everyone else was out at the Indiana Dunes. Processed from 21 subframes exposed at ISO800 for 30 seconds and stacked in DeepSkyStacker. It's the blurry ball of fuzz in the top 1/4 of the image and slightly left of center:

[Chicago Astronomer - Astro Joe]

Robb...

Slick.

Tracking looks great.

But wondering where the greenish glow of the comet went considering the stars are shifted to that hue in your pic?

It's near Capella tonight and gonna hit the feet of the twins soon.

Good catch!

[RobbW]

You know, Joe, I really don't know what happened to the greenish cast.I had adjusted the white balance of the original photos in Lightroom to get rid of some of the LP. Then I converted to TIFFs and stacked in DSS. I think stacking may have been where it lost its color. I then tried to get rid of the noise in the background in Photoshop (It didn't really help much as I am not very good at manipulating my images. I've always tried to keep them as natural as possible.). Below is an upload of a single frame from the series. It definitely has the greenish cast. And actually looks a little better than the stacked version except for being darker and noisier.

[Chicago Astronomer - Astro Joe]

Robb,

I tried to clean up the noise, but the image wouldn't allow much...

But here is a version...

Showing a brighter nucleus.

[Paulie pchris00]

I'm not sure what you mean by noise, but I think the single frame untouched looks the best of the three.

This image reminds me of a great night of astronomy not too long ago...

[RobbW]

Paulie, it's a little difficult to see all the noise in the reduced JPG image, but trust me, in the RAW/TIFF full image, it is very pronounced. It's all the noise from using a higher ISO on a DSLR; similar to film grain when you use a high ISO film. Ideally, I'd like to remove the noise leaving a nice black background and all the stars, comets, galaxies, etc. untouched. It's tough to do without harming some other part of the image. I think Joe uses Noise Ninja (is that it, Joe?) to remove noise. However, I tried it on my images, and it didn't really seem to help much. Joe, if you want, I can send you an original TIFF and see what you can do with it.

[Chicago Astronomer - Astro Joe]

Robb,

Semd me the original please.

[RobbW]

Hmm, I gotta figure out how to do that for you, Joe. The original RAW file is 10MB, but do you work with RAW? I always convert my RAW to TIFF, but it is even bigger at 56MB. I can send you a high quality JPG, but it will be compressed and will have lost some of its detail. Your pick!

[Chicago Astronomer - Astro Joe]

Robb...

Send me the Jpeg.

Let's see what happens.

[Chicago Astronomer - Astro Joe]

robb,

No dice.

The pics you sent have the noise too embedded in them.

But cool you captured Hartley.

[patrickm]

Comet 103P/Hartley can kiss my fraking a$$! All attempts by me, INCLUDING BINOCULARS at 5-6:15AM yesterday with the Moon already set, have failed. I give it the astrofinger.

...but will try again tonight once we get settled cuz that's how I am.

[Chicago Astronomer - Astro Joe]

Been watching the live NASA tv feed all morning on the close approach of the EPOXI mission to Comet Hartley...

Very cool.

First close-up raw images show a peanut shaped object, with enough gravity to hold on to what looks like boulders on the surface.

Having observed the comet first hand in the C11 makes it a bit more meaningful and personal...

Geek.

[Paulie pchris00]

Here's a nice animation by Emily Lakdawalla of the Planetary Society.

www.planetary.org/blog/article/00002758/

[hillimolly]

Paulie, That is way cool to see.