|Ryukyu Astronomy Club Newsletter
|Volume 1, Issue 9||November 2002|
Next Club Meeting -
Conference Room B at the Camp Lester Naval Hospital
The October meeting of the Ryukyu Astronomy Club was held on the 12th in the Navy Hospital's Conference Center. There were 5 in attendance. Due to the relatively low attendance, we proceeded directly to our observing session. This month we ventured to a new location that seems to hold a lot of promise. Located on Zampa Cape, past Torii Station, we setup at the end of the parkway of the Avila Hotel. At our web site we will be posting a map to the location prior to this month's meeting. The site is huge and mostly protected from local lights. Additionally there is almost no traffic in the area, yet there is plenty of parking. The only notable disadvantage is lack of toilet facilities - a short drive is required to reach the hotel.
John O'Briant brought his computerized 3" scope and Mike Swanson brought his computerized 11" scope. Transparency was poor and reflected much light from a nearly first quarter Moon. Many objects were viewed, including:
Globular Cluster M30 - a nice compact GC well resolved in the 11" scope
Planetary Nebula NGC 7009 - the "Saturn Nebula" - very bright, but quite fuzzy, although the lobes resembling Saturn's rings were easily seen
Globular Cluster M2 - one of the most impressive GCs and quite a treat in both scopes
Globular Cluster M15 - another fine GC
Open Cluster NGC 7510 - a cute little cluster, easily overlooked
Asteroid Ceres 1 - easy enough to find, but still just a point of light
Uranus - an eerie greenish disk
Neptune - small and faint, blue in color
Open Cluster NGC 457 - a fine OC, better than many of the Messier clusters
The Double Cluster NGC 869/884 - though the fainter stars were washed out by the Moon, the Double Cluster is certainly one of the skies premier sights
While it will take a clear, moonless night to truly gauge the quality of this site, it looks like we found a winner. It most likely would take a much longer drive north to find a better site. Of course, November or December might be the perfect time for an all night star party at points far north…
to See This Month
Step outside on the next clear night and look directly overhead. Look for a large square consisting of 4 bright stars - the Great Square of Pegasus. The Square is one of the most prominent features in the autumn sky. With a star chart handy you can easily locate many of the treasures currently on display:
M31 - the Andromeda Galaxy - discussed in last month's newsletter, M31 is traveling through space with two smaller companions: M32 and M110. All three of these galaxies are visible in steadied binoculars under truly dark skies. A short focal length telescope is the best instrument for observing the trio.
The Double Cluster - NGC 869/884 - again, a short focal length telescope under dark skies is a great way to view these two open clusters. Astronomers recently determined that they truly are a pair, traveling through space together.
M45 - the Pleiades - also known as the Seven Sisters in the US and Europe or Subaru here in Japan, sharp eyes can make out 6 stars without optical aid. This open cluster is one of the nearest to earth and is truly spectacular in binoculars.
M34, M36, M37, M38 - great open clusters riding along the Milky Way.
For more objects of interest and the locations of those listed above, download the latest chart from www.skymaps.com or visit www.SkyandTelescope.com and customize the online star chart for Okinawa's general location of 128 degrees East longitude and 26 degrees North latitude.
Besides the constellations, we also refer to other imaginary boundaries in the sky. The horizon is the line where the land meets the sky. The zenith is the point directly overhead. The meridian is the line running from the northern horizon, up through the north celestial pole, overhead through the zenith, then down to the southern horizon. Thus it splits the sky into eastern and western halves. The celestial equator is a line that runs from east to west, directly above the Earth's equator. And finally, the ecliptic is a wavy line traveling north, then south of the celestial equator. The ecliptic is significant as the Sun, the Moon, and all the planets travel through our sky near to this line.
Similar to longitude and latitude used to pinpoint locations on the Earth, we use right ascension (RA) and declination (Dec) to pinpoint locations in the sky. Lines of right ascension run from the north celestial pole to the south celestial pole, similar to longitude on the Earth. Thus they meet or converge at the celestial poles. Lines of declination run east to west, parallel to one another, just like latitude.
We measure right ascension in hours, minutes and seconds. RA starts at 0h00m00s then goes clockwise around the north celestial pole until we come to 23h59m59s just before where we started. Thus there are 24 hours of right ascension. Declination is measured in degrees ( ° ), arcminutes ( ' ), and arcseconds ( " ). The declination of the celestial equator (right above the Earth's equator) is 0°00'00" (0 degrees), the declination of the north celestial pole is 90° and the declination of the south celestial pole is -90°. From this system we can give the coordinates for any object in the sky. For example, the coordinates for Rigel, a bright star in the constellation Orion, are RA 05h14m30s, Dec -08°12'06".
The line of right ascension directly above us at the meridian is known as local sidereal time (LST). Every hour, local sidereal time changes about one hour. In other words, if local sidereal time is currently 18h RA, in one hour LST will be 19h RA. Naturally this corresponds to the fact that the Earth rotates once every 24 hours. Sidereal rate is the rate that objects move across the sky - approximately one hour of right ascension for every hour of time here on Earth. Since the 360 degrees of the circle divided by 24 hours yields 15, this rate of motion corresponds to 15 degrees at the celestial equator.
Recipient of the RAC Messier Award
Mike Swanson is our first recipient of the Ryukyu Astronomy Club Messier Award! Visit Observation Awards at the RAC web site (www.nexstarsite.com/rac.htm) to read Mike's observation log.
As announced at the September general meeting, upon observing 70 of the 110 Messier objects, you will receive a certificate and your name will be posted on the club web site. After viewing all 110 objects you will receive an Expert level certificate and the web site will be updated to reflect your new status. All observations must be logged on or after February 23, 2002 and you must submit an electronic copy of your observations for each object. The required log format is available for download from our web site. Full details as well as a list of all 110 Messier objects are posted in the Observation Awards section of the RAC web site.
We are looking forward to conferring the next award!
for Articles for Future Newsletters
We are looking for short, one or two page articles for future newsletters. Choose a topic that interests you and do a little research. Perhaps exoplanets (planets in orbits around other stars) holds your curiosity or maybe supernovae. What about gamma ray bursts or perhaps the cosmic background radiation. It’s a big universe out there. Start your research at www.astronomy.com, www.skyandtelescope.com, seds.lpl.arizona.edu, and www.nasa.gov. Submit your articles to firstname.lastname@example.org for light editing and publication.
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