C/2006 W3 Christensen

[martinastro]

This is the 2nd or 3rd lunation I have spent trying to see this comet and this time I succeeded. Sky cleared before dawn, I was up all night anyway so I immediately went outside. The sky was breathtaking, tans 9/10 with a slender crescent Moon low in the east mostly hidden by a convenient strip of cloud. I checked the alignment of the telrad then had a look at M42 to check focus and get the feel for the scope. The neb was phenomenal. I moved up to the flare, it too was bright with complex structure, I moved back down then picked up, for the first time, what I believe was a glimpse of the Horsehead nebula. I have never seen this before visually but I'm sure I did this morning. It's larger than it looks on images. After having a peek at M78 I decided to try for comet Christensen which was well placed in Cepheus.

I began a gentle slow search for through target area and within min's I found the comet at 05.08 BST. It was a faint hazy spot sitting among a sea of rich stars. It was an elliptical grey haze over 3' in dia at around mag +10.0. It got rapidly brighter towards the middle and had a stellar central condensation at centre. A faint ghostly outer coma surrounded this area. It was well condensed at D.C 6. With averted vision it was easy but direct version only showed the central region which could be missed at a causual glance. The coma is delicate and requires full dark adaption and a very trans sky. I made the above sketch quickly. This my 44th observed comet.

I spent over 1 hour searching for new comets after this until the sky was too bright. Picked up an anbundance of NGC and Messier galaxies in Canes, Coma, and Leo. Also caught M53 close to the Sun. It was a good session. 8.5" F/7 homemade reflector with SWA 32mm 2" occular.

[brianb]

Nice one, must have a go at imaging it ... if the sky ever clears for long enough to make an imaging run.

Now on 11th shower since dawn. At least there are gaps in the rain today.

[martinastro]

Thanks very much Brian. This comet is certainly calling for a camera to be turned in that direction. It's a small object though but well within range of a DSLR. Good luck with it and I hope you get that clear sky.

Observed W3 again this evening at 20.30, looks good, best seen with averted vision.

[martinastro]

Don't forget that comet Christensen is now very well placed after dark in Cepheus. Since a good clear night is forecast this would be a good time to track it down if you haven't seen it yet. It's not far west of Delta Cephei at mag +10.0 or so with a coma over 3' in diameter. A faint tail has been observed in larger instruments. The comet looks very green too. It's located near the zenith during the first few hours after dark. Can you pick it up with a DSLR?

Here's a chart from skyhound.

[Roman White]

My first observation of C/2006 W3...

June 19/20
2009 Jun.19.95 UT: m1=9.7, dia.=3', DC=6, no tail, 20x90B
[astronomical twilight, good transparency, Bortle class 5]

Quickly spotted it in Pegasus at 01:25 EEST (Jun.20) and observed until 02:10 EEST.
Small, faint, but well condensed.
Altitude 51^o. ML=11.5m

sketch

(the bright star close to the comet is TYC 2742-267-1, 7.5m)

P.S. Just to add:
Galaxy NGC 7331 (magnitude 9.5...10m - from different sources, dia. 11') was situated in 3 deg. SE, I observed it at the same time. The comet seemed to appear a bit brighter than the galaxy, though I didn't risk to use it for comet estimates.

[martinastro]

Congratulations Roman on catching Christensen. You are building up a nice tally of comets now, keep hunting down these beautiful objects. 

[markt]

Nice set of sketches both of you!  I'm with Brian here - if it remains clear for long enough i'm going to have a look for it...

[Roman White]

Thanks for the commets Martin and Mark.

During the period from Jun.22 to Jul.04 I observed this comet 6 more times.
Comet is situated in N part of Pegasus, in 2-3^о away from π Peg, therefore it was easy to find. Closer to morning twilight the comet rises at a great altitude (>60^o).

The weather was fine on those nights, ZNELM varied between 5.2-5.8m. Most of observations were done in the end of astronomical twilight. Magnitude estimates are based on 3-5 Tycho-2 stars each time.
Comet is small, moderately faint (in 20x90B) and well condensed.

June 21/22 - observed at 01:25-01:55 EEST.
2009 Jun.21.95 UT: m1=8.8, dia.=3', DC=6, no tail, 20x90B
[astronomical twilight, excellent transparency, Bortle class 5/6]
Altitude 52^о. ML=11.1m. Star TYC 2741-470-1 (10.7m) at the edge of the coma.

June 23/24 - observed at 01:45-02:20 EEST.
2009 Jun.23.97 UT: m1=9.3, dia.=3', DC=6, no tail, 20x90B
[astronomical twilight, good transparency, Bortle class 5/6]
Altitude 58^о. ML=11.2m.

June 30/01 - observed at 01:45-02:25 EEST.
2009 Jun.30.97 UT: m1=9.4, dia.=&2.5', DC=5/, no tail, 20x90B
[astronomical twilight, excellent transparency, Bortle class 5/6]
Altitude 65^о. ML=11.4m. Star TYC 2728-1471-1 (9.9m) at the edge of the coma.

July 01/02 - observed at 01:20-02:00 EEST.
2009 Jul.01.95 UT: m1=9.3, dia.=3'.5, DC=6, no tail, 20x90B
[astronomical twilight, excellent transparency, Bortle class 5/6]
Altitude 61^о. ML=12.0m. (*)

July 02/03 - observed at 02:15-02:52 EEST.
2009 Jul.02.99 UT: m1=9.2, dia.=4'.3, DC=6, no tail, 20x90B
[astronomical twilight, good transparency, Bortle class 5/6]
Altitude 69^о. ML=11.5m. (*)

* Some evidence of false nucleus was observed on Jul.01/02/03;
I confirmed it in 20cm refractor on Jul.02/03 (see below).

ICQ format:
IIIYYYYMnL YYYY MM DD.DD eM mm.m:r AAA.ATF/xxxx &dd.ddnDC &t.ttmANG ICQ XX*OBSXX
   2006W3  2009 06 19.95  S  9.7 TK  9.0B 5  20   3    6            ICQ XX KOSXX
   2006W3  2009 06 21.95  S  8.8 TK  9.0B 5  20   3    6            ICQ XX KOSXX
   2006W3  2009 06 23.97  S  9.3 TK  9.0B 5  20   3    6            ICQ XX KOSXX
   2006W3  2009 06 30.97  S  9.4 TK  9.0B 5  20 & 2.5  5/           ICQ XX KOSXX
   2006W3  2009 07 01.95  S  9.3 TK  9.0B 5  20   3.5  6            ICQ XX KOSXX
   2006W3  2009 07 02.99  S  9.2 TK  9.0B 5  20   4.3  6            ICQ XX KOSXX

I will also add some sketches later.

[brianb]

Excellent report! Must get a look, the troiuble is that the nights are so short at the moment!

[Roman White]

Hi Roman
Great job on those comet observations!
(...)
Martin

Thanks Brian and Martin. 

the troiuble is that the nights are so short at the moment!

Oh, I see, you are just out from all-night nautical twilight at your latitude. The comet worth to have a look indeed - it reachs perihelion tomorrow, and I hope it will look a bit better closer to August when the closest approach (2.13 AU) will occure. And it is currently the brightest comet, if do not mention C/2008Q3. The last one by the way is visible in my skies, but very low, maybe I will try a search in the nearest time (as the Moon goes away and the comet rises a bit higher - at least 10 deg.)

And I also worry about the full Moon which already crawls into the morning skies... Maybe I will make a look at the comet tonight at moonset (if only the sky will clear - currently it's partly cloudy).

[Roman White]

Observed the comet at Poltava gravimetric observatory with 200mm refractor on July 02/03 (00:20-01:00 EEST).

Good sky transparency, city light pollution (Bortle class 7 or so). ZNELM>~5.0.

Tried a look at 70x and next at 150x. Coma was enough large, well condensed, with faint nearly stellar condensation (circa 12.0m) in the centre.
As it was high in the sky, the magnitude limit was 13.1m, I'm quite excited with that.

Estimates (Jul.02.91UT):
Dia.~3.5', DC=6, m1=(9.2)*
*magnitude estimate done 2 hours later in 20x90B (see above)
Sketch

2 closest stars are GSC2.3 N2W7000241 (11.9m), GSC2.3 N2W7000236 (12.7m)

[martinastro]

Excellent comet observation Roman!. The view through the observatory's 200mm refractor must have been wonderful, I can only imagine the view of a comet through a high contrast glass like that. Wonderful sketch also, I can tell you have had a great time with this comet. Thanks for the latest visual info, the sky is getting a little bit darker here now so I might have a go for it once the Moon wanes a little more. Cheers.

[Roman White]

Cheers Martin. Thanks for the comments.
I will be hunting it again with my binos since tomorrow, I only hope that the weather will keep being fair, at least at night.

[Roman White]

I am back on observing this comet, tonight I observed it for the second night in a row and for the 9th time in total.
It looks pretty good while situated in Cygnus. 

I will report the observation later. Very unfortunately, my Windows had crushed a few days ago and I can't operate with my PC at the moment...  

[martinastro]

My last obsv of this comet was in Oct 2008 but last night I decided to have another look at it. It was perfectly placed in Cygnus below the zenith and looked nice among a Sea of stars. Comet was fairly bright, a probably binocular object, and well condensed at D.C: 6 with a 4' coma sporting a bright central condensation and stellar false nucleus. Could see the Veil Neb a few degrees above it.