Comet C/2014 Q2 Lovejoy is still visible in the sky in the constellation Cassiopeia. It is not as bright as it was a few months ago but can still be seen with a pair of binoculars. It is probably best viewed in the evening as Cassiopeia moves lower in the sky overnight and in the early morning hours. This makes it more difficult to see as there is more atmospheric attenuation at these lower elevation angles.
Sky map for locating Comet Lovejoy (03/22/2015) using the free and open source Stellarium planetarium software.
Using my recently acquired iOptron Skytracker for tracking night sky objects I took numerous exposures totaling 14 minutes (9x60s@iso1600; 10x30s@iso3200). These were then stacked in Deep Sky Stacker (DSS), a very good and free program designed for astrophotography.
Comet C/2014 Q2 Lovejoy on 03/16/2015. A faint tail can be seen extending to the upper right.
The resulting image was then post-processed using the Astronomy Tools v1.6 actions in Photoshop.
As mentioned in a previous post, I now have a tracker mounted on my tripod (iOptron SkyTracker). With this gadget, I can take longer exposures of the night sky without star trails. Exposures of 30 to 120 seconds typically give me the best results. Shorter exposures don’t gather enough light and the longer exposures may show a hint of star trails.
There was an evening a bit over a week ago with mostly clear skies. Very thin cirrus clouds were moving across the area. I was unable to see them while photographing but inspection of satellite imagery at the time showed that there was some high-altitude moisture moving across the area. The result? The thin clouds produced a faint glow around the brighter stars in the constellation Orion. I like the result.
Comet Lovejoy (known formally as C/2014 Q2) continues to put on an impressive show for sky watchers. In December it began to climb upwards from the southern horizon towards Orion, then passing to its west and climbing higher. In mid-January it was nearly overhead in the evening sky as it passed near Taurus and Pleiades. Many astrophotographers have taken advantage of this setting and there have been some beautiful photographs posted at various web sites.
To best capture the delicate details of the comet—and especially its tail—a tracking device is needed to guide your camera or telescope so that it matches the motion of the stars across the sky. This allows longer exposures without the stars streaking or creating star trails. Without a tracking device, exposure time is limited. This limitation can be partially overcome by taking numerous short exposure images and stacking them using any of the many applications available. Still, the laws of physics and the engineering of camera sensors will result in better images if you have, say, five 30-second exposures than thirty 5-second exposures—even though both are 150 seconds total exposure.
From the DeepSkyStacker pages on the theory of stacking:
Are 100 x 1 minute and 10×10 minutes giving the same result? Yes when considering the SNR but definitely No when considering the final result. The difference between a 10-minutes exposure and a 1-minute exposure is that the SNR in the 10-minutes exposure is 3.16 higher than in 1-minute exposure.
Thus you will get the same SNR if you combine 10 light frames of 10 minutes or 100 light frames of 1 minute. However you will probably not have the same signal (the interesting part). Simply put you will only get a signal if your exposure is long enough to catch some photons on most of the light frames so that the signal is not considered as noise.
For example for a very faint nebula you might get a few photons every 10 minutes. If you are using 10 minutes exposures, you will have captured photons on each of your light frames and when combined the signal will be strong. If you are using 1 minute exposures you will capture photons only for some of your light frames and when combined the photons will be considered as noise since they are not in most of the light frames.
Since I don’t have a tracker (at least, not yet), I have no choice but to stack short-exposure images of the comet. Here are a few images of Comet C/2014 Q2 Lovejoy taken on several different nights. The quality of the images varies depending on how much light pollution was captured in the image, whether there was moonlight, and how clear the sky was.
Comet C/2014 Q2 Lovejoy and Pleiades: 19 January 2015.Comet C/2014 Q2 Lovejoy: 08 January 2015Comet C/2014 Q2 Lovejoy: 27 December 2014
Comet C/2014 Q2 Lovejoy and Orion above Cathedral Rock, Sedona, Arizona: 28 December 2014
There’s still plenty of time this winter to venture outside with a pair of binoculars and gaze at the comet. Here is a link to a sky chart provided by Sky and Telescope for the month of January. For February and beyond, try this chart hosted by UniverseToday.
Although it is still a few days until the peak of the Perseid meteor shower, the combination of exceptionally clear skies and a waxing moon illuminating the interior of the Grand Canyon was too good to ignore. So we headed up to the South Rim arriving shortly after dark. Most folks had already left so we had the spot mostly to ourselves for the evening.
The wind was blowing a gentle breeze which kept bugs away. The evening temperature was comfortable—if not exactly warm. So we lay back on the rocks at the very edge of the canyon staring up at the stars and watched as a few meteors arced across the sky. This many days before the peak of the shower results in only a few Perseids per hour (compared to the maximum rate of up to a hundred per hour) but there were also “sporadics” (i.e., a meteor which is not associated with one of the regularly recurring meteor showers) to light up the sky.
Meteors above the Grand Canyon.
This is a composite of two images taken a few minutes apart. There are two meteors visible: a Perseid in the constellation Cassiopeia and a very bright sporadic closer to the horizon.
The hourly rate should increase over the next few nights but the nearly full moon will make it difficult to see any but the brightest.
With exceptionally clear and dark skies it was a good time to capture an image of the zodiacal light. Here is what Wikipedia has to say about this astronomical phenomenon.
Zodiacal light is a faint, roughly triangular, diffuse white glow seen in the night sky that appears to extend up from the vicinity of the Sun along the ecliptic or zodiac. It is best seen just after sunset and before sunrise in spring and autumn when the zodiac is at a steep angle to the horizon. Caused by sunlight scattered by space dust in the zodiacal cloud, it is so faint that either moonlight or light pollution renders it invisible.
With no moon and Flagstaff’s dark skies, it’s pretty easy to see the zodiacal light.
Zodiacal light seen over the Kachina Wetlands near Flagstaff, Arizona.
In 1958, Flagstaff pioneered the world’s first lighting ordinance designed to preserve the night for astronomy. Since 1958, Flagstaff astronomers have mostly relied on quiet, friendly diplomacy to protect the night sky…
Flagstaff’s dry, clear skies and dark, cloudless nights drew Percival Lowell to town in 1894. The townspeople deeded the eccentric, wealthy Bostoner a pine-clad knoll atop the mesa immediately west of town as an observatory site, and built him a wagon road to reach it. The area became known as Mars Hill because of Lowell’s famous passion for the red planet.
An exposure of 30s, ISO3200, f/4 was enough to bring out the details of the white glow as well as its reflection in the waters of the Kachina Wetlands. At the top of the image is the bright planet Jupiter.
