How do you find the comet? Every astronomer will give different advice, but here is mine...
How do you find the comet? Every astronomer will give different advice, but here is mine...
0150 Universal Coordinated Time, Monday, October 29th.
The moon is coming over the horizon. At zenith, 2nd magnitude stars are visible in Cygnus. 4th magnitude Eta Cygni is not visible.
The comet is clearly visible with the naked eye. It is somewhat dimmer than Alpha Persei, or Mirfak. It is about the same brightness as third magnitude Delta Persei.
Clearly visible in the view finder of the 10 inch. Clearly a nebula or comet.
Through the 10 inch reflector, with 2" E=lux eyepiece. Clearly visible. Central coma is evenly distributed. Surrounding halo is also evenly distrubed. I see no mottling. No central nucleus. No texture. No streaks. One of the two stars is on the edge of the brighter central coma. The other is just beyond the edge of the bright coma and into the surrounding halo. I sense no color.
Through 12.5 eyepiece. I can now see not only the two stars I just described, but also a third star. With averted vision, I can barely make out a fourth. Of those first two stars, the one on the edge of the inner coma, is not so distinctly stellar, but has a hazy appearance.
Through the 12.5 and the 2x barlow, the comet fills at least half of the field of view. The comet is still very evenly distributed - no gaps, no streaks, no mottling. The one star within the edge of the central coma still looks fuzzy.
Through the 3.5 Quester, the most prominent stars are still clear. At high power, the comet fills up almost half of the FOV. If anything, the outer area does appear a little larger on the NE.
It is easy to find with the naked eye but has no sign of a tail.
With the unaided eye, it appears as a star, at least in my light-poluted back yard.
In a pair of binoculars, with 15x power, the "star" is clearly not a star. It appears fuzzy and bright.
Through a 3.5 Questar, the comet appears very bright. It almost looks like a bright eliptical galaxy. It has a shape of a planetary nebula or a globular cluster, but it is far brighter. There is no nucleus. No tail extends in one particular direction With averted vision, there is a brighter core with a dimmer halo. The halo is evenly distributed around the equally evenly distributed core. There is a distinct greenish color.
In a photograph taken with the 3.5 Questar, the comet does reveal a nucleus with a hint of a tail.
The lack of the traditional tail comes from the fact that we are looking straight into the comet, head on, as demonstrated in the computer simulation below.
You can see from this computer simulation that 17p/Holmes does not have a large orbit. Unlike many great comets, it does not go beyond Pluto, or even beyond Jupiter. It is currently moving away from the sun.
The brightness of the comet is due to a sudden "outburst." Comet outbursts happen from time to time, and Holmes has done this before. The outburst can be due to a sudden outgassing or a sudden release of particles from the comet. Holmes was discovered in November, 1892, and has had a similar brightening outburst in the year of its discovery. It has an orbit of 6.9 years, so it is possible to see this comet several times in one's lifetime.
Comet Holmes is easy to find with the naked eye. I took the image below with a Canon Rebel, with a 60 second exposure.
Here the comet formed a triangle with Delta and Alpha in Perseus (Alpha is also known as Mirfak). Each night this star-like comet should move.
The PSSG has moved to its new location - the Deerlick Astronomy Village. DAV is a unique planned community. One area has several lots that have been sold to individual astronomers who are building homes and observatories. The other area, Grier Field, is reserved for visitors.
DAV is located at longitude +N33° 33' 41.11", latitude -W82° 45' 47.30". It is in the middle of nowhere - making it a perfect dark site for folks from light-polluted Atlanta.
I've not been there before, and I wanted to evaluate the site and decide whether to take a week off work next year for the PSSG. It is a great site and I'll definitely take more time next year.
DAV is in Sharon (population 94), but the nearest town of any size is Crawfordville (shown above), which is the county seat of Taliaferro County (which I have learned, is pronouced Toliver). There are less than 3,000 in the entire county.
There are not many businesses open in the area - no Olive Garden, McDonalds, or (for those with T-Mobile) cell phone service. Nor are there any pay phones in the area.
We took I-20 most of the way. Even when we got off the interstate, we still didn't have any problem finding the isolated DAV. My son's GPS was a big help, but the instructions that are online are fine.
Not long before arriving at DAV, there is an interesting historical marker about Robert Grier, Astronomer. I understand that when the team of astronomers were developing a dark site for Georgia, they came across this and saw it as a sign -- well, not just a sign, but a SIGN. Look for it on your right after you leave Crawfordville.
There is a turn off onto an unpaved road, but the online instructions are clear, and the GPS was a perfect guide. To help, there were signs up for the Peach State Star Gaze pointing the way from this point onward.
The dirt road is in great shape for any size vehicle, and you don't have to travel very far. I doubt anyone would have difficulty on this road.
Before you know it, you reach the STAR GATE.
Yep, the developers found this star, bought it and put it on the gate. What could be more appropriate?
First stop - registration for the Peach State Star Gaze (I'd preregistered online).
The registration booth was easy to find.
They had a name tag for me and my son, and a packet that included a current issue of Sky and Telescope, a current issue of Astronomy magazine, and a few lists of deep sky objects for various levels. There was also information about Washington, Georgia, which is further north of DAV. We didn't go into Washington, but I understand that is where you would find the nearest ATM, hospital and lodging.
The folks helping with registration were great! Joanne gave us a run down on which way was north, east, south and west - where the RV's would be that would run generators, and where the electric power could be found. We didn't need any power, so we could camp wherever we desired.
We picked the middle of the field. If I was planning to stay longer, I think I would have camped closer to the tree line to get some shade.
We set up a 10 inch reflector, a Questar, a PST for solar observing, and over course the most important equipment for astronomical observations...
For food, there is Micki's Kitchen Concession. (Click here for the menu)
My son and I brought our own food -- a loaf of bread, ham, cheese, pretzels and an ice chest with soft drinks and water. Hey, when you are only staying over night, there's not a lot to plan.
Still Micki's is a great place for gathering together and chatting with folks - and my son recommends the Slushies.
They stay open until 1 AM, and the operators told me that if I needed anything after that, to just wake them up. During the night, they operate by red lighting to preserve dark-adapted vision.
As for the more important facilities, there are plenty of Port-A-Johns, and there is also a permanent shower/restroom house.
There are three units, each with a toilet, a sink and a shower. There is also a white light you can turn on once you are inside, or a red light to preserve dark-adapted vision.
The entire ground has been leveled out very well, so there is no problem walking in the dark without a flashlight.
My son and I ate supper and waited for the night sky -- but unfortunately the clouds rolled in. My son and I went to sleep shortly after 8 PM, but I woke up occasionally to get a peak at the sky. The skies were perfectly clear at 2:17 AM.
"Seeing" could have been better, especially in the eastern and southern areas where there were still some clouds, but for most of the sky, it was great.
So just how good is a dark site?
Here are two photos of Orion. The first was taken in my back yard at home, on the northern edge of the metro-Atlanta area. The camera is set so that the image shows exactly what my eye sees.
Just the bare outline of Orion is visible. However, the photo below shows Orion at the Deerlick Astronomy Village. Again, the setting on the camera duplicates what my eyes see.
I took a look at the Great Orion Nebula, M42. Great view. When I was younger, I could pick up several colors in the nebula, but I'm not as sensitive to that anymore. My camera picked up some of the colors. The nebula was much larger and showed more texture than when viewed in my backyard. The eye picked up more of the texture than the camera - due to the camera needing several minutes to capture the image, washing out some of the subtle texture the eye caught.
M79, a globular cluster, was still close to the horizon, and I never came back to it later in the evening.
The Crab Nebula, M1, was a bit of a challenge to find by memory.
These were good, familiar objects I used to test the settings on the computers on my telescopes and to compare with my backyard viewing.
I had set up an observing list, but it was based on my going to sleep around 1 AM, not waking up at 2:17 AM. I used some the lists suggested by the PSSG:
From their Lite List, I tried only one -- NGC 2264, an open cluster.
From the Intermediate List, NGC 1579, a nebula in Perius; NGC 1952 (which is the Crab Nebula, or M1); NGC 2158, an open cluster; Mars (which I've been photographing at home lately, as we are getting closer and closer to until December); NGC 2254, an open cluster, NGC 2392, a planetary nebula (which some people say looks like an eskimo - hence the nickname, "Eskimo Nebula").
From the Advanced List, NGC 1333, a nebula; and two galaxies - NGC 1600 and 1637.
Venus was very clear.
I observed 12 meteors between 2:17 and 4:55 AM (Eastern Time). Not a single one of them was very bright, but one left a trail. All were very swift. Most were seen after I was secured the telescopes for the night and laid down on the hammock, looking up.
In the morning, I took a little tour of the other side of the DAV. We were at Grier Field, which is a large open area except for the shower facilities, the registration building and the Atlanta Astronomy Club's building. The other side is the developed community of homes. There are a couple of nice homes, but most are small observatories.
Most of the observatories have roll-away roofs, so that the roof slides to the side, opening up the sky to those inside.
I saw only one domed observatory.
On April 20, 2007, the comet Encke had just dipped inside the orbit of Mercury, perilously close to the sun, when a solar eruption struck and literally tore the comet's tail off. This surely has happened to comets before, but for the first time in history a spacecraft was watching. NASA's STEREO-A probe recorded a fantastic movie of the collision.
The eruption that hit Encke was a CME or "coronal mass ejection." Sky watchers on Earth are familiar with CMEs because of the auroras they create when they occasionally hit our planet. CMEs are fast-moving and massive, packing billions of tons of solar gas and magnetism into billowing clouds traveling a million-plus miles per hour.
To read more, go to http://science.nasa.gov/headlines/y2007/01oct_encke.htm
Be sure to watch the movie of the comet's tail being blown away.