A recently discovered comet is now shining brightly in the morning sky. Comet C/2020 F3 (NEOWISE) was first spotted March 27, 2020, by NASA’s NEOWISE space-borne telescope. The comet passed inside Mercury’s orbit on 03 July 2020 and quickly brightened as it as heated by the intensity of the Sun.
The comet has been rising around the start of Astronomical Twilight when the eastern horizon is just beginning to brighten. Within about 45 minutes to an hour—or shortly after the start of Nautical Twilight—the morning sky has become bright enough to make observation difficult.
The image above was taken as the comet rose above Grand Canyon. Also visible in the image are the planet Venus, the bright star Aldebaran, and the Hyades and Pleiades star clusters.
By the third week middle of July the comet will shift from the morning sky into the evening twilight sky. Again, there will be a short window of time in which it is easily observed but viewing the evening is far easier than the morning.
Although it’s fun to photograph the Full Moon, I actually prefer photographing a thin crescent Moon, usually just a day or two after the New Moon. The thin crescent is brightly lit while the remainder is softly lit by light reflected by Earth, hence known as Earthshine. It’s also known as DaVinci Glow. As well, the Moon does not overwhelm the night sky so that stars can also be in the photograph.
During late Spring and into early Summer the crescent Moon sets in the west-northwest and this makes it a good target for shooting at Upper Lake Mary. The long and narrow lake is aligned WNW–ESE so that the Moon casts a brilliant reflection that can run the length of the lake.
I’ve shot this several times over the last few years but never tire of it. All it requires is enough of a gap in the clouds for the Moon to shine and for light winds so that the lake surface is relatively smooth.
During the first few days of April 2020 the planet Venus moved towards and then through the Pleiades star cluster. Venus and Pleiades have a conjunction every year but every eight years the conjunction is at its closest. This year, Venus moved right through the star cluster.
I shot images of Venus and Pleiades on three nights: 01 April, 03 April, and 05 April. Venus and Pleiades were closest on the night of 03 April. I then did a composite image of the three nights showing the progression of Venus past the star cluster. These were all shot at 8 seconds, ƒ/4, 180mm, and ISO 800.
Additionally, I overlaid another image taken 13 February 2020. This is a stacked composite with 11 images shot at 120 seconds, ƒ/4, 180mm, and ISO 1600. The images were stacked using Starry Sky Stacker. The stack was then post-processed using rnc_color_stretch. This composite image was used because it shows the nebulosity and color within the Pleiades better than the shorter exposures captured that show the motion of Venus.
The image above shows the composite from the three nights without the additional layer showing the nebulosity.
The past few weeks have offered numerous opportunities for photographing objects in the twilight and night sky.
Above is a photograph showing the planets Venus (visible near the top of the image) and Mercury (located just below the center of the image). The glow of evening twilight on the horizon is reflected in the shallow waters of Mormon Lake.
Taken later on the same evening is a photograph showing four planets and an asteroid in a single frame. This was taken with a 24mm focal length lens to capture these solar system objects (SSO). I did this as a fun test to see if a wide-angle lens was able to capture these dim and distant SSOs. From top to bottom are the asteroid Vesta, Uranus, Venus, Neptune, and Mercury.
Zoomed-in crops (below) show the dimmer objects that are in the image above.
Before leaving that night I did a final wide-angle shot of the southeastern sky which included the constellation Orion as well as a portion of the winter Milky Way.
The following night I was out again to test my recently purchased Nikon 180mm ƒ/2.8 ED AIS manual focus lens. A few previous tests have shown that star images are pretty good at an aperture of ƒ/2.8 but much better at ƒ/4. At ƒ/2.8 there is just a hint of star spikes; at ƒ/4 they are quite prominent. This is a stacked sequence of images of the Pleiades star cluster. Image stacking was done with Starry Sky Stacker; histogram stretching was done with rnc-color-stretch.
On 18 February there was a Lunar occultation of the planet Mars. I had planned to get up early and drive to a dark location but an alarm failure meant I barely had time to get up and set up the gear on the rear deck of the house to start the sequence. Luckily, Flagstaff is a Dark Sky City and it was dark enough to get the shots. This is a sequence from just a few minutes before the Moon moved in front of Mars followed by a longer sequence after it reappeared.
Finally, Comet C/2019 Y4 (ATLAS) is in the northern sky making it an easy target—except that it is still very dim with a magnitude of about +12 at the time of this image. The still image is a stack of 49 images each 120 seconds duration at ISO 1600, 180mm, and ƒ/2.8. As noted above this lens is pretty good at ƒ/2.8 but better at ƒ/4. Because the comet is so dim I wanted the maximum light gathering ability so settled for an aperture of ƒ/2.8. Also in the image is M97 (“Owl Nebula”) and M108 (“Surfboard Galaxy”). The star Merak is part of the “Big Dipper.”
Also, there is an animation—made from the same images—showing the movement of the comet over a period of just under 2 hours.
In late January, the easily visible planet Venus was located in the same part of the evening sky as the dimmer and distant planet Neptune. I’ve never tried to photograph Neptune but this pairing of the planets was a good reason to do so.
The first attempt was taken on the evening of 27 January (shown below) and I was limited to very short exposures as I was using a standard tripod. The second attempt was the following night from a better location and, more importantly, I was using my equatorial mount star tracker so that I could follow the stars (or planets) for longer exposures.
The image at the top is the second attempt. High, thin cirrus clouds were beginning to move in from the west and I was hoping that the clouds might make some of the stars more colorful. What I got was an amazing corona surrounding the very bright planet Venus while stars and the dimmer Neptune appeared relatively unchanged.
The image above is from the first night of shooting and shows diffraction spikes around Venus. Examing these two images you can easily see how far Venus has moved in one night by comparing the position of Phi Aquarii (φ-Aqr).