When you want to see the stars, find someplace dark
The solar system’s small stuff
Today Comet C/2011 L4 (Pan-STARRS) will pass through perihelion, its closest approach to the Sun. Take a good look now, given the 110,000 year orbital period, the comet will not be back anytime soon.
The comet should be visible as a 1st magnitude object 13° above the horizon at sunset and directly above the glow of the setting Sun. It will climb higher each evening after passing through perihelion. It will begin to fade as well, most likely dimming below 4th magnitude by the end of March.
Now for a truly awful comet image.
It had been wonderfully clear all afternoon. It was just as the sky darkened that trouble appeared, a band of high clouds sweeping in from the west. Noooo!
The comet appeared in the STi guide camera right on schedule, my coordinates less than half a degree off! Not bad with a manual telescope mount offsetting from the Sun. The clouds swept over the comet a few minutes later, just as the tail was beginning to appear in the darkening sky.
I did grab a few images from the guide camera and snap a few frames with the DSLR. The monochrome CCD on the guider managed slightly better shots despite a fairly bright sky. I managed a few more frames as an opening appeared a few minutes after that. It is still an awful image. The only reason I could tell it was the comet is that it remained centered as the clouds swept through the image. Take my word for it, the barely there spot at the center of the photo is the comet.
At least my vehicle is fixed, a new alternator in place. Try again tomorrow?
Today Comet C/2011 L4 (Pan-STARRS) will make its closest approach to Earth. Not that that is saying too much, close approach will be 1.09 AU or about 101,300,000 miles, just over the average distance from the Earth to the Sun. In contrast Comet C/2012 S1 (ISON) will approach us to closer than half that distance, about 0.42 AU or 39,000,000 miles from Earth on December 26th, 2013.
The comet should be visible as a 2nd magnitude object 7° above the horizon and a little south of the Sun at sunset. It will climb higher each evening, passing through perihelion, close approach to the Sun on March 10th.
Like so many other amateur astronomers, I am eagerly awaiting the appearance of Comet C/2011 L4 Pan-STARRS.
The comet was discovered in June of 2011, by the Pan-STARRS survey telescope atop Haleakala, Maui. The comet will pass closest to earth on March 5th, at a distance of 1.09 au. Perihelion, the comet’s closest approach to the Sun, occurs early on March 10th UT.
Initial predictions were quite optimistic with this comet, indicating a possible -1 magnitude for the comet. Reality seems to be somewhat more restrained, with a peak somewhere between magnitude one and two being more likely. Reports indicate that the comet has brightened to about 2nd magnitude, bright enough to be easily seen without optical aid.
Even more convenient, the comet will be well placed for observation this coming weekend. With new moon occurring on March 11th, this will be the prime weekend for a telescope outing. Amateur astronomers everywhere are already planing for this weekend. Our local club is no exception, expect a good crowd of telescopes to be at the Mauna Kea VIS this weekend. Myself? I will probably setup at the Substation site, just across the road from the VIS. The site offers a much better western horizon, which is blocked from the VIS by a line of pu’u, old cinder cones.
I will be taking photo gear, looking to get a decent photo of the comet. Stay tuned to Darker View to see the results if I meet with any success.
The latest orbital elements from the MPC
Another interesting opportunity will come on March 12th, when a slim crescent Moon will join the comet in the sky. A 1.4 day old moon, about 2% illuminated will be about 4° north (to the right) of the comet.
Another product of imaging earlier this week. Comet C/2012 K5 (LINEAR) is fading, but still bright enough to image. Right beside Orion it was well placed to target from my driveway. Just refreshing my comet hunting skills, getting ready for the show over the next few months as C/2011 L4 (PanSTARRS) comes into view.
While Comet 168P Hergenrother may be a bit of a mouthful, it is the proper designation for an interesting comet. Discovered in 1998, the comet is one of dozens that orbit in the inner solar system. Normally inconspicuous objects, these comets orbit quietly, objects that only astronomers love, or even know about. You would normally have needed a substantial telescope to see 168P, shining very dimly at magnitude 15.5 at it’s brightest. A community of amateur astronomers keeps tabs on these comets, occasionally photographing them, updating the orbits.
As the comet approached perihelion during the beginning of October, it became apparent that something had happened. Several observers were reporting that the comet had brightened. Suddenly the comet was far brighter, eventually reaching near 8th magnitude, over 500 times brighter than expected. We have seen this sort of thing before, a cometary breakup. Observations from several large telescopes, including Gemini North here on Mauna Kea, showed that the comet has split into at least four pieces.
When a breakup occurs it exposes a great deal of fresh material and debris, dramatically adding to the supply of dust and gas in the coma and creating a far brighter object. It is not the comet itself we see, that is fairly small. It is the coma and tail, the cloud of dust and gas that reflects the sunlight and gives a comet the synonymous appearance.
Comet 168P Hergenrother currently sports a small fan shaped tail, easily visible in the telescope. We enjoyed this classic comet shape in the telescopes last new moon at the Mauna Kea VIS. Setting up a telescope and CCD camera last night allowed me to photograph the comet, appearing much the same as it did a few weeks ago.
A new comet discovered earlier this week has caught the attention of the astronomy community. Comet C/2012 S1 (ISON) was discovered Tuesday by a telescope affiliated with ISON, the International Scientific Optical Observation Network. This is a network of mid-sized telescopes dedicated to surveillance of the near earth region of our solar system.
The reason this comet is intriguing is a combination of a large estimated size and an orbit that appears to provide both a close approach to the Sun and favorable viewing from the Earth.
The comet will approach the sun as close as 0.012 AU on November 28th, 2013, quite close indeed. The comet will also approach Earth as close as 0.4 AU (60 million kilometers or 37 million miles) on December 26th, 2013. As a result this comet could achieve a magnitude well into the negative numbers, brighter than most objects in the sky except the Sun or Moon.
This comet is in addition to comet C/2011 L4 (PanSTARRS), expected to be an unaided eye comet during the spring of 2013. If we get lucky 2013 will be a great year for comets.
As I have cautioned in the past, comet predictions are to be taken with a good amount of skepticism. This could be a spectacular comet, or this could be a mediocre comet, we will just have to wait and see. In the meantime pay attention to the light curve as it nears the Sun. As my friend David Levy observed… “Comets are like cats; they have tails, and they do precisely what they want.”
Currently passing through Usra Major, comet C/2009 P1 Garradd, is bright enough to appreciate in small telescopes. It is well placed for observation, well up in the sky through much of the night. At about magnitude 6.8 it is also bright enough to make an attractive photographic target.
I am not totally happy with the photo, I could have really used more time on target. Another issue, the exposures I used were a bit too long for this fast moving target, the coma is elongated in the frames. I will probably re-shoot the comet if I get a chance soon.
Finally, a night where… A) The sky is clear. B) The wind is not howling through the palm trees. C) I am not exhausted by working the summit. D) I do not have to get up early the next morning.
A + B + C + D = Astrophotography from the driveway!
The comet is nicely placed in Ursa Major, transiting late in the evening, available for several hours of exposures. And expose I did, with the auto-guider locked on the a dim star beside the comet, the shutter open for well over two hours. I was shooting my Canon 20Da and the AT6RC, a combination that framed the comet nicely.
It will take a while to get the resulting images processed. In the meantime I did a quick process on a set of images taken with the wide field/finder CCD camera. The results of which can be seen at the right. I also shot a few quick images of the M95 area with the CCD to capture SN2012aw.
I have been posting a lot of photos from others lately. Not something I do a lot of, I prefer to use my own shots. But when I get shots like this…
