OR: Joshua Tree comets and a supernova

Here is Jane's observing report from this past weekend -- Four comets and
a supernova.

Mojo
--
Morris Jones *
Monrovia, CA

http://www.whiteoaks.com

---------- Forwarded message ----------
Date: Mon, 11 Oct 2004 21:58:04 -0700
From: Jane Houston Jones
Subject: Observing comets (and a few other things) at Joshua Tree

With cooler temperatures in the desert at long last, we brought our two
reflector telescopes to an Octoberfest star party at a friend's house
near the entrance to Joshua Tree National Park in Southern California
October 9th, 2004. When we arrived, piles of saucer-shaped lenticular
clouds hung in the air over the undulating hills and a jumble of craggy
rounded rock formations formed our southern observing horizon.

The rocks themselves were worth the drive. Molton liquid, heated by the
movement of earth's crust, oozed upward and cooled while still below the
surface millions of years ago. These intrusions of granitic rock
developed a system of rectangular joints. Some oriented horizontally,
some oriented vertically, and some overlayed the others at high angles.
This system of joints developed rectangular blocks, and over millions
of years water percolated down through the joint fractures, loosened
mineral grains and rectangular stones weathered to spheres. Ancient
flash floods washed away the ground surface and the huge boulders
settled one on top of another creating the rockpiles we see today.

After an Octoberfest's-worth of beer and six varieties of sausages, red
cabbage, onion bread and potato salad were consumed, we watched the
shadow of the earth darken the valleys and eastern horizon, and prepared
for a night of observing. First we held an old fashioned star party for
about 20 friends and neighbors of our hosts. It was windy and the high
clouds offered tantalizing sucker holes, which didn't dampen the
enjoyment of the crowd, at least the crowd at our two sturdy Litebox
reflectors. We offered views of Pluto, Uranus, some Milky Way wonders,
and selections from the observing lists below for several hours until
the guests drifted off homeward or conversation bound.

Hoping for an after midnight comet viewing clear sky, I took a disco nap
and woke up at midnight to a clear windless night. The seeing wasn't
great, but the sickly greenish glow of a neighbors mercury vapor
spotlight had mercifully timed out. It was almost comet time!

While waiting for prime comet time, and continuing while Mojo was
finding the comets in his 14.5 inch Litebox reflector, I hunted
hopelessly for several fall Hickson galaxy clusters in my 17.5-inch
reflector. The seeing wouldn't support the 200x magnification I needed
for confirmation of these faint galaxies, although I may have seen a few
galaxy blobs in amongst the star blobs. I'll try Hickson galaxy clusters
3, 4, 6, 9, 15 and 16 again next week at another Joshua Tree location -
a location we discovered while completing a Messier Marathon with comet
discover Don Machholz this past March 2004.

We first aimed our telescope at SN2004et, a type II supernova in mag.
8.9 NGC6946, a spiral galaxy in Cepheus, near the border with Cygnus.
R.A. = 20h 35m 25.4s, Decl. = +60o 07' 17.6". The time of our
observation was 1:45 a.m. 10/10/04 (08:45 UT) 10/10/04. NGC6946 was
discovered in 1798 by William Herschel and eight supernovae have now
been detected in this galaxy since 1917. It is leading the supernova
statistics, with more supernovae more than follow-up galaxy M83
http://www.seds.org/messier/m/m083.html. SN2004et was discovered
September 27, 2004 by Italian observer Stefano Moretti during a full
moon.We used the AAVSO chart to find the supernova and also to estimate
the magnitude. The chart, with its hand drawn galaxy spiral arms, also
shows the location of SN1980. The supernova is located 4.1' E and 1.9' S
of the galaxy nucleus, just west of a pair of mag 13.9 and 13.6 stars.
Mojo estimated the magnitude to be 12.6 and I estimated it to be 12.9,
using a nearby mag. 12.7 star and the fainter mag 13 stars for
comparison. Try it for yourselves!

Then we settled in for some morning comet hunting.

First up Comet 88P/Howell. This comet was supposed to be mag. 13.37,
coma diameter 1.5' R.A. = 02h 20m 48.3s, Decl. = +10o 06' 22" at 01:49
a.m. We looked for it at 1:55 a.m. (08:55 UT) and detected a small
glow, more of a lumpy darkness kind of glow with averted vision. This
was on the limit of the night's conditions.

2:10 a.m. (09:10 UT) Comet C/2004 Q2 (Machholz) Don's comet was a
beauty! Congratulation to local California comet discoverer Don
Machholz for his 10th comet! It should brighten over the next month or
two! Right now, it's mag 9.14, and located in Eridanus. Coma diameter
3.7" R.A. = 05h 03m 26.1s, Decl. = -27o 34' 03" . We saw the bright
nucleus and halo, but not much of a discernable tail. I tried it in my
17.5-incher, after Mojo located it in his 14.5 incher and I could at
least see the direction of the tail with the additional aperture.

2:24 a.m. (09:24 UT) Comet 78/P Gehrels mag 11.67, coma diameter 2.8'
near the Pleiades and Aldebaran in the morning sky. Smaller than Q2
Machholz, this comet had a more visible tail.

Our fourth and last comet was the most fun observation of the evening,
following on the celebratory nature of observing Q2 Machholz. C/2004
Q1(Tucker) is a mag 11.5 comet we observed at 2:33 a.m. (09:33), coma
diameter 1.7' comet located R.A. = 01h 48m 52.5s, Decl. = +21o 55' 09".
The comet was easily seen, but the additional treat was spotting two
galaxies in the same field of view. NGC678 and NGC680, a pair of nearly
edge-on spiral and elipitcal galaxies that were an interesting find
themselves! NGC 678 was a sliver of light which glows at 12.2
magnitude. Nearby NGC 680 is slightly brighter, 11.9 mag. and being
eliptical, was nearly the same size (but a little larger) that the
comet. A small nudge of the eyepiece would have revealed 5 additional
galaxies in the 13-14 magnitude range had the seeing been better.

The wind had picked up, and the temperature was decreasing. Moonrise was
at 3:12 a.m. but it took an additional 10 minutes for the 26 day old
waning crescent to rise over the nearby Copper Mountain. First we saw
the two "horns" appear, and soon the earthshine was cradled in a sliver
of moon like a smile. We packed up the telescopes, and enjoyed sleeping
in our friend's trailer for a few hours before heading for home two
hours away.

Scary Halloween observing list: http://ephemeris.sjaa.net/0110/b.html

Caroline Herschel objects:
http://www.seds.org/messier/xtra/similar/cher.html

Supernova 2004et http://www.astrosurf.com/snweb2/2004/04et/04etHome.htm

AAVSO chart for SN2004et:
http://www.aavso.org/cgi-bin/shrinkw.../NGC6946-E.GIF

Limiting magnitude charts: http://nineplanets.org/lm/rjm.html

Don Machholz's 8/27/2004 comet discovery:
http://ephemeris.sjaa.net/0410/b.html

Date October 9 p.m. to October 10 a.m., 2004
Location: near Joshua Tree, CA
Altitude: 3,500 feet
Latitude: 34° N
Longitude: 116° W
Temperature 86° at sunset, 56° at 2:30 a.m.
Humidity 23% at sunset, 47% at 2:30 a.m.
Seeing: soft to poor 2/5, Limiting magnitude using area 8
alpha-beta-zeta Tau, LM 6.4 (17 stars)
Comet location, size, magnitude and finder charts: SkyTools v2.2
Equipment: two LITEBOX reflectors: 14.5-inch f/4.8 at 94X and 17.5-inch
f/4.5 at 125 to 222X with 80mm short tube finder running from 16x to 30x.

Jane

--
Jane Houston Jones
34.2048N 118.1732W, 637.0 feet

http://www.whiteoaks.com

--
Morris Jones *
Monrovia, CA

http://www.whiteoaks.com