British Astronomical Association
Supporting amateur astronomers since 1890

BAA Images Dominic Ford

Observation by Dominic Ford: Time-lapse video of Mars (2)

Uploaded by

Dominic Ford

Observer

Dominic Ford

Observed

2021 Jan 11 - 08:51

Uploaded

2021 Jan 11 - 08:56

Equipment
  • Watec 902H2 Ultimate
  • Pi Gazing
Exposure

Analogue video @ 25 fps, integrated for 1 minute

Location

Cambridge

Target name

Mars

Title

Time-lapse video of Mars (2)

About this image

This time-lapse video is a rather nice demonstration of Mars' motion over the course of its 2020 apparition.

My Pi Gazing meteor cameras take still images of the night sky every 4 minutes throughout the night (one minute exposures, integrated from analogue video), which allows me to make time-lapse videos with an interval of 23 hours and 56 minutes, at the same sidereal time each day. And because I leave my camera unattended for months at a time, I can make time-lapse videos over long periods from (almost) the same camera angle.

In this version of the video I've applied some background subtraction, keeping track of the mean brightness of each pixel over the past half hour, and subtracting that from each frame to eliminate some of the sky glow. This extends the limiting magnitude of the images to around mag 6. Both M31 and some fine structure in the Milky Way are visible in this version.

My camera points west and Mars was only just entering the field of view at dawn in late Aug, so I only just caught the beginning of Mars' retrograde (rightward) motion at the beginning of the video (on 9 Sept). You then see Mars track westward (rightward) in retrograde motion past opposition on 14 Oct, before doubling back on itself on 13 Nov as it returns to its usual eastward (leftward) motion.

I was hoping it would be possible to see the change in Mars' brightness over the course of the apparition, but that isn't particularly clear as the images are so saturated.

I should also clarify that the video isn't entirely smooth as I've removed some of the days when it was cloudy to make the video easier on the eyes.

There is an alternative version of this video, without background subtraction, here.

Files associated with this observation
Like this image