A typical procedure in astrophotography involves mounting a camera on a stable platform like a tripod so it doesn’t move during exposures. Some people have motorized platforms that allow the camera to move and track the subject for long exposures of several minutes. I was curious how an image would look for a camera mounted on strings that allowed it to swing forward-backward and left-right at the same time during an exposure. Years ago, this image appeared in a magazine. I kept it and thought of trying it someday.Continue reading
Jupiter rose over the tree across the street a few minutes after 9 pm. With camera on a tripod and on full zoom, the intervalometer was set for 1 minute intervals of 10 exposures. The camera was set to ISO 800 and ¼ second. I hoped for just enough exposure to barely reveal the moons and not overexpose Jupiter too much. Europa was barely visible left of Jupiter. Ganymede and Callisto farther to the right. Smoke haze from western state forest fires dimmed the sky. After the exposures, Pixelmator Pro was used to layer them in this image.
I was inspired by a recent post in the blog Cosmic Focus by fellow amateur astronomy Ggreybeard in Australia. He put his DSLR camera on a tripod facing north and attached an intervalometer. The result was a series of 100 images each 45 sec long stitched together showing the star trails across the northern sky. I encourage you to go visit his blog to see the beautiful image.
I noticed Ursa Major and Minor, the Big and Little Dippers to most people, in the northwest sky in recent summer evenings when I was out with my telescope or binoculars. That post by Ggreybeard made me want to try the same thing. I decided to try to get the star trails using two different camera setups.
My iPad has the app NightCap Camera on it. It can capture many varied low-light scenes including one called Light Trails. I set the iPad on a stable base and started the exposure. It lasted for 1 h 7 m 46 s. Some scattered clouds glided in that were lit up by ground lighting. Airplanes flew over in various directions with blinking lights. The resulting image showed it all. I added some yellow lines highlighting Ursa Major and Ursa Minor as well as Polaris the North Star. It was a messy yet interesting image.Continue reading
Comet C/2020 M3 (ATLAS) was discovered on 27 June 2020. The acronym ATLAS stands for Asteroid Terrestrial-Impact Last Alert System, based on the Hawaiian islands. Two telescopes of the robotic early warning system are designed to detect smaller near-Earth objects a few weeks to days before they might impact Earth. Since 2017, the scopes survey one quarter of the observable sky four times each clear night. The system is NASA funded and operated by the University of Hawaii.
Orbits near the Earth of objects larger than 1 km are well-known. Most are well documented and predicted years in advance of their close approaches to Earth. Objects down to 140 meters in size are harder to see. It is estimated ⅓ of them have been found. None of those found so far are predicted to threaten Earth in the next century.
Smaller objects less than 140 meters are detected only when they are much closer to Earth. Late discovery means there is the greater potential for a locally catastrophic collision with little warning time if they are on a collision course. ATLAS looks for these smaller objects. Comet C/2020 M3 (ATLAS) was discovered by this system.
The comet became a popular object for amateur astronomers to image. By November 2020 it was nearing the Orion constellation. This image on 6 Nov 2020 was by José J. Chambó at his web site Cometografia.es. I thought it would be interesting to image this comet several times as it passed through Orion.
Centaurus-A is located in the southern hemisphere skies. I have never seen it from my location 42˚ north latitude. It rises only 5˚ above my southern horizon in early December. I’m certain it is very familiar to my blogger friend Roger in Australia. It is the 5th brightest galaxy and easily viewed by amateurs. It contains a black hole of 55 million solar masses ejecting jets of x-ray and radio wavelengths. Models suggest the galaxy collided with another smaller galaxy in the past leading to areas of star formation in the resulting complex structure. I enjoyed combining 3 greyscale Hubble images into this composite. In the center are several newly formed bluish stars. The dark areas are dust blocking the passage of light.