OT: imaging the close flyby of Amor asteroid (3122) Florence

On 1 September 2017 near 12:06 UT the Amor class Near Earth Asteroid (3122) Florence made a relatively close approach to Earth. The nominal pass distance, 0.047 AU or about 18 Lunar distances, was a safe distance. It does not often come this close: the asteroid had last been about similarly close in 1930, and will not be really close again until 2057.

(3122) Florence is one of the more rare larger NEA's. It is about 5 km in diameter and currently has a theoretical MOID (Minimum Orbit Intersection Distance) of 0.044 AU, only slightly less than the pass this year.

While this is a safe distance for now, orbital disturbances in the (distant) future could bring it closer, and the size of the object is such that it would be of future impact concern. It is therefore on the PHA list, where PHA stand for "Potentially Hazardous Asteroid" (for some reason, I always make "Potentially Hostile Asteroid" of this in my mind, probably because of the similar "Potentially Hostile Aircraft").

(3122) Florence became quite bright during this close pass, and was visible in binoculars at a maximum brightness of about magnitude +8.7 just before the moment of closest approach.

About 1.5 days after the moment of closest approach, near local midnight of September 2-3, I imaged the fast moving asteroid from Leiden with my Celestron C6 telescope. It was about mag +9.1 at that time. The movie above, and the stacked image below, was made from 87 images (each an exposure of 10 seconds with a 5 second interval) taken over a 17-minute period between 22:31:32 - 22:48:47 UT (Sep 2).

The asteroid was at a distance of 0.048 AU at that time and moving fast through Delphinus, at an angular speed of about 22".5 per minute.

The equipment used was a Celestron C6 (15 cm) Schmidt Cassegrain telescope with F6.3 focal reducer, and a Canon EOS 60D DSLR at ISO 3200 in the prime focus of the telescope.

(the satellite that can also be seen zipping past in the movie, is a Russian GLONASS, Kosmos 2425)

stack of 87 images taken over a 17-minute time interval
(click image to enlarge)

OT: more imagery of the earthgrazing asteroid 2011 MD

Like yesterday, I used the 0.61-meter F/10 Cassegrain of Sierra Stars Observatory (G68) in California again to image the earthgrazing asteroid 2011 MD, this time a few hours after closest approach.

Below animated GIF was made from three 30 second exposures, spaced 30 seconds, starting at 09:35:01 UTC (28 June).

OT: Close Encounters of a Rocky Kind (2011 MD)

Today, a small asteroid, 2011 MD, made a very close pass by the earth, coming to within a distance of 12,400 km at about 13:30 UTC (June 27). That is well within the distance of geostationary satellites, and even within the distance of GPS satellites in MEO!

This morning, some 5 hours before closest approach, I used the 0.61-meter F/10 Cassegrain of Sierra Stars Observatory (G68) in California, to capture this PHA earthgrazer.

click image to enlarge

This image is a 30 second CCD exposure taken between 08:32:00 and 08:32:30 UTC (June 27, 2011). In these 30 seconds, the fast moving object left a notable bright trail on the image. Star field is in Serpens, image center approximately RA 15h35m57s, dec. +19.441 degrees.

UPDATE: more of my 2011 MD imagery shot on the 28th here.