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[wwpierre]

Koff...koff.....

Wow, it's dusty in here.

The last few nights I have been observing the passage of Comet Gerradd from the vicinity of Messier 15 toward the constellation Delfinius. I have observed it with my new Vixen 80 and my 8" short newt. I am observing from the yellow zone. You can read about it here.

[Chicago Astronomer - Astro Joe]

WW...

Excellent.

We had the opportunity to catch the comet under the very light polluted skies of Chicago recently with different scopes...

astronomer.proboards.com/index.cgi?board=Observations&action=display&thread=3331

(You can also catch the 90mm Meade that was discussed at the other forum we met at.)

No tail yet from here...but we intend to follow it's progress.

[Paulie pchris00]

No images of the comet, but we found it last night on Chicago's north side, under horrendous lighting. Might as well have been looking for it in daylight.

astronomer.proboards.com/index.cgi?action=display&board=Observations&thread=3344&page=1#13390

[patrickm]

Aug 10, 2011 14:12:26 GMT -6 Paulie pchris00 said:

Might as well have been looking for it in daylight.

Ain't that the truth!!

[wwpierre]

I feel for you guys.

[wwpierre]

Now that the moon is waning, I felt it was again time to check on Garradd before the moon rose over the Chief and make sure it wasn't deviating from it's designated path. I chucked my 30mm Siebert Ultra in my G-8N and sent it to M71, a globular cluster in Sagitta. From there, I star hopped to HIP 100276 and found the comet between that star and HIP 100807.

My sky conditions were about average for my site. I could barely make out the handle of the big dipper. The nucleus of the comet was visible with averted vision, and the coma was elongated.

[Paulie pchris00]

Friday night I also starhopped to the comet, but I started at Sualocin (Alpha Delphinus). From there the next bright star up in my finder scope was HIP 100807, and also found it roughly in a line two-thirds of the way to HIP 100276. (Thanks, btw, for forcing me to look up these two star numbers, using both Redshift and Cartes du Ciel to verify.) Next Friday, starting at M71 you won't have to starhop to find the comet. It will be right there!

[wwpierre]

Yeah, looking forward to that. Last night was a wash. I have a waterfront trail running through my front yard, and right through my "observatory". Although I observe almost every opportunity, I particularly set up on clear Saturdays, and have posted on bulletin boards all over town inviting the public to "Saturday Stars". Last night I was too busy showing the sky to passers-by to find the comet. Then the clouds rolled in around 11. I had my Burgess refractor on my CG5-GT, my Orion 5" Cat on my motorized EQ3-2, and my 90mm Astrostar all set up. I was as busy as a cat in a room full of rocking chairs.

[patrickm]

Holy Moses! That's a lotta scope for one person. Exhausting fun!

[atomant]

Well, Accuweather was a bit off this weekend.
But still able to head over to dark skies in Utica, IL to catch two fuzzy balls, C/2009 P1 Comet Garradd and M71 glob.
As we head to the Labor Day weekend, be sure to catch the comet flying by the Coathanger!

This little harbinger of death can really move...

used my lil celestron 80mm f/5 shorty achro, 25sec, iso3200, 400mm


closer inspection with AT6RC, 120sec, iso3200, 1350mm
hmm, hint of tail?


the following nite, 90sec, iso3200, 1350mm

a few hours later...

zipping away from sagitta, 98sec, iso3200, 1350mm

Not sure I'll catch this lil sucker as it approaches M92 in Hercules in 2012.

[Centaur]

I’ve created graphics related to Comet C/2009 P1 (Garradd). They can be seen at www.CurtRenz.com/comets

The first is a view from north of the solar system showing comet passing through our neighborhood. The image is parallel to the ecliptic (Earth’s orbital) plane. Keep in mind that the comet’s orbital plane is inclined to the ecliptic by 106° (or 74° but retrograde) so the comet’s graphical image should be imagined as being much closer than that of the Earth. The other two graphics are mappings of the comet in equatorial coordinates of the current date (not 2000.0).

Based on the current JPL orbital solution, I calculate that the comet should reach perihelion (closest to Sun) of 1.551 AU on 2011 DEC 23. Its peak brilliance at magnitude +8.7 should occur around 2012 FEB 23, and perigee (closest to Earth) of 1.266 AU should be achieved on 2012 MAR 05.

[atomant]

Curt, your charts provide a cool perspective on this lil fella!
Thanks

[patrickm]

COOL charts!
SkySafari says it's at 8.1 now. Confused!

[Paulie pchris00]

Okay, it looks like we're going to lose it to the glare of the Sun in late November/early December, then pick it up for some good viewing again by mid-late January? A double dip comet? I like this little iceball more each day!

[Centaur]

Aug 31, 2011 10:26:12 GMT -6 patrickm said:

COOL charts!
SkySafari says it's at 8.1 now. Confused!

Thanks, Atomant & Patrick. As was the case with Comet Elenin a few months ago, NASA/JPL and the IAU provide disparate predictions for Comet Garradd's brightness. I use data from the former for my charts. More recently the two sources have come close to agreement regarding Comet Elenin. Although the apparent disintegration of Elenin could make both of their brightness forecasts mute. Currently NASA/JPL predicts a peak magnitude for Garradd of +8.7 and the IAU forecasts +7.0. I imagine they will eventually come closer to agreement.

[wwpierre]

Update: I found it again on the 19th. I went to the Coathanger, dropped down a bit, to the "hook". From there it was a simple star-hop, using only the R/A control. I judge that it has changed little in brightness.