When you want to see the stars, find someplace dark
Sunday night I shot a wide-field image of the comet as it passed near the Pleiades star cluster. I am somewhat disappointed by the image. The skies over Waikoloa are just not conducive to wide-field imaging. And with a couple scheduled mountain days I did not have the option to take the gear up to where conditions are better. Not and get any sleep. Still, it is not a total disaster…
The first good night for comet imaging since the moonlight has departed the evening sky. If is wasn’t clouds it was heavy haze and vog. With a good Saturday night I set up the ‘scope in the driveway and shot for a couple hours on comet C/2014 Q2 Lovejoy.
This is not a properly processed shot, rather just a quick stack of the longer exposures. The real image will be a few days before I can get about to processing it. Still, a lot of interesting detail in the tail…
Back on August 17th, Australian amateur astronomer Terry Lovejoy disocvered a very nice Christmas gift for us all to enjoy… A bright comet that we have now unwrapped and are able to enjoy through the new year.
Comet C/2014 Q2 Lovejoy is currently passing through perihelion. While closest to the Sun and the Earth it will be at its brightest during the first couple weeks of January. For northern hemisphere observers the comet is currently low in the southern sky and getting brighter each day.
The comet passes through perihelion on January 30th of 2015. For earthbound observers it will be at its brightest during the first weeks of January, reaching near 4th magnitude. It is currently visible around 5th magnitude in the faint constellation of Columba south of Orion. It has been visible without optical aid for a few weeks, as long as you have access to a dark sky and know where to look. As it brightens it will be easily visible, even rather obvious. With binoculars the view will be even better, a bright fuzzball with a wispy tail.
The next thing you may note about the orbital diagram is that the comet has a high inclination to the ecliptic. Currently approaching from underneath the plane of the solar system, the comet will exit north of our Sun. The practical side of this, is that over the next few weeks the comet will move northwards across the sky, rising higher each night. While our friends down south have been enjoying nice views of the comet approaching perihelion, it is northern hemisphere observers that will be able to best view the comet after perihelion.
One issue will be the bright Moon. Currently a waxing half phase, the Moon will be full on January 4th. This will make spotting the comet much more difficult and completely drown out the faint tail. By 9th or 10th the Moon will have waned enough to make comet viewing much more successful.
As January fades, so will comet C/2014 Q2. By the end of the month the comet will slip below unaided eye visibility, while staying within reach of binoculars through April or so. Sky watchers will be able to follow the comet for months betond that with the aid of a telescope. Enjoy the comet while you can, 8,000 years will pass before this comet returns to the inner solar system.
The first real product of Saturday’s imaging session on Mauna Kea. Processing comet images is a challenge (actually I am using far less correct language while I work on it). The problem is that comets move rapidly against the star field. This creates all sorts of issues when attempting to assemble a final image.
The single frame shown here is he product of 28 light frames and thirty calibration frames. The light frames used in this image were each 4 minutes long, accounting for nearly two hours of exposure total. There were a few more, but a few had to be discarded due to wind-shake of the telescope during the exposure.
The image below is processed to align on the comet as it moves against the background stars. During the two hours of exposures the comet moved appreciably. The stars are somewhat suppressed by using a sigma reject combine, but they are still there. Processing like this allows the details in the tail to be seen.
With a set of images running for two hours taken without interruption other things can be done. One possibility is that these images can be animated, leading to another interesting product… Up next!
It has been a while since the last good photographic comet. Since comet ISON disintegrated at perihelion a year ago, we have had few opportunities to get a really nice comet photo. It is the surprise of comet C/2014 Q2 Lovejoy that changed this.
Better yet… The comet is well placed for photography in the late evening and early morning sky. While fellow sky watchers on the south side of our planet have been enjoying the comet as it has brightened, for most northern hemisphere observers it is still rather low. In the past couple weeks it has moved far enough north that it is now nicely positioned to observe from Hawaiʻi. I have been following the comet for a while, catching it in binoculars from the house. We showed it to students of Paʻauilo Elementary in club telescopes as they camped out at the Kilohana Girl Scout Camp earlier this week.
Unfortunately it is still low enough that my neighbor’s trees prevent me from photographing it from the driveway. Thus I took the opportunity to pack up the ‘scope and head for Hale Pohaku and the Mauna Kea Visitor Information Station for a night of photography.
The Mauna Kea VIS is busier than ever, the numbers of tourists coming to this free show just continued to increase. Parking is now a major issue, with even the lower gravel lots full of visitor vehicles. Fortunately, with some discussion and name dropping, the rangers allowed me and my vehicle past the barricades into the main lot so I could set up just off the patio. I would be entertaining guests at the telescope and answering questions all evening, becoming part of the show.
I had set the alarm clock for 0230 to get up with plenty of time to setup and take comet photos. What greeted me was a sheet of cloud, an all to familiar sight lately. I did not reset the alarm and went back to sleep. A couple hours later I found myself lying awake again, realizing I would probably not fall back to sleep I got up to look outside. To my surprise Orion shown brightly over the street.
Is there enough time to setup and shoot before dawn?
I rushed the alignment, hoping to setup in less than half an hour. Things did not go smoothly… The EOS utility in the computer did not recognize the 6D, I need to update the drivers. A thin cloud stubbornly sat in front of Polaris, I think I got the polar alignment, the star was very dim on the polar ‘scope. Even when exposures seemed to be going smoothly I they were not. I find out later the auto-guider had moved itself to a hot pixel, probably when a bit of cloud passed through. In the rush I did not get a dark frame for the guider, most of the frames show small guide errors.
One not so bad bit of serendipity… The Hubble Space Telescope went right through one of the frames.
Despite all I did get an image of the comet. It should have been better, rushing astrophotography is not a good plan…
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…
I did attempt to see comet C/2011 W3 Lovejoy in the daylight. I actually tried several times. Once on the morning of the 15th and a couple more times on the morning of the 16th after I heard that the comet had survived perihelion passage. Neither time did I see the comet with an unaided eye.
On the 15th I was not surprised I could not see it. I was in Waimea where there was a lot of low altitude haze and a lot of glare around the Sun. On the 16th I had a much better chance using the clean high altitude air of the summit of Mauna Kea. But still, no comet seen even though it should be just over four degrees from the Sun. This is about the same separation that had allowed me to see comet McNaught in early 2007.
Just to be certain I set the camera on a tripod, placed it just inside the shadow of the Keck 1 dome, and blazed away. Examining the photos on the camera display likewise revealed no trace of the comet, but there were some interesting spots of light.
It was not until I sat down and really analyzed the raw frames that I found something. Using some astronomy software, I calculated the position of the comet when the shots were taken and the field of view of the camera. And lo! There it was, a small spot with a trace of tail. It showed up best in the green channel, and not at all in the blue thanks to Rayleigh scattering in our atmosphere. Stacking nine of ten frames and processing the heck out of the frames does allow you to clearly see the comet…
Will Comet C/2011 W3 Lovejoy be visible in the daytime? This is the morning to find out. Look about 2° below the rising Sun once it is well up in the clear sky for a small white object. Two degrees is four times the Sun’s width in the sky.
I have seen one other daytime comet in my life, C2006/P1 McNaught back in January of 2007. That time the comet was about 5° from the Sun, over twice as far away from the glare. The photo at the right should give an idea of what to look for today. Remember to shield your eyes from the Sun’s glare by positioning yourself to put the Sun behind some object like a wall or streetlight. There is no guarantee that Lovejoy will be at all visible, but it is worth taking a look this morning.
The rumor is running around the various astronomy sites and listservers that Comet C/2011 W3 Lovejoy might be daytime visible. Will it be? That is a very qualified maybe.
It becomes a valid question to ask if comet Lovejoy will even survive perihelion transit.
Passing that close to the Sun will mean that the volatile elements of the comet will be streaming off the comet at a fantastic rate, enough to dramatically brighten the comet. Below you will find the ephemeris for perihelion on Dec 16th (Dec 15th HST) from the Minor Planet Center. As you can note, the predicted magnitude is -8! This is bright enough to be seen in broad daylight. Thus the possibility of a daytime comet.
The catch is that the comet will be quite close to the Sun. Within 2° as the Sun and comet rise on the morning of the 15th here in Hawai’i. For observers in the islands the best chance to look is on the morning of the 15th, as perihelion will occur in the afternoon as the comet passed behind the Sun from our point of view.
Will it be visible? Maybe. It depends on the accuracy of the magnitude estimates, which are uncertain to say the least. It could be substantially dimmer, or even substantially brighter than forecast under such conditions. The proximity to the Sun also complicates the issue. It is worth a look, seeing a daytime comet is highly unusual.
If you do look please take a few simple precautions… Do NOT use any sort of optical aid this close to the Sun, the risk of permanent eye damage is too great. If it is bright enough the comet should be a naked eye object. It will greatly help to position yourself to put the Sun just behind some obstruction. A building, a streetlight, anything to block the Sun’s glare and aid in picking out the comet. On the morning of the 15th the comet will rise 2° behind the Sun, thus 2° lower in the sky.
Give it a try!