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Amateur Ground-based support of the Venus BepiColombo and Parker Solar Probe flybys


The BepiColombo flybys: 15 October 2020, 10 August 2021

The European-Japanese joint mission BepiColombo (ESA/JAXA) will arrive to Mercury on December 2025 after an interplanetary trajectory in which it will perform two flybys of Venus on 15 October 2020 (03:58 UT, the exact time may vary) and 10 August 2021. The flybys will be a unique opportunity to study Venus from a multiple perspective. During the flybys BepiColombo will obtain observations of Venus in coordination with the Japanese Akatsuki mission (JAXA), currently in an equatorial orbit around the planet. In addition, a large ground-based campaign to observe Venus has been organized not only during the flyby, but also in August 2020, when Venus reaches its maximum elongation (45 deg), with an apparent size from Earth of 23-24 arcsec.

Amateur support

Venus observed from Pic du Midi Venus observed from Pic du Midi

We are seeking context observations of Venus provided by amateur astronomers to enhance the scientific return of the BepiColombo flyby in October 15, 2020. To that end, we encourage amateur observers to observe Venus in mid-July, late August and mid-October 2020. Observations around 11 July 2020 will be used to support the analysis of data acquired during the 3rd flyby of Venus by the Parker Solar Probe (NASA) on 11 July 2020.

Images on the right show Venus observed from the Pic du Midi 1.05m telescope by a group of amateur astronomers in 2017 and processed by D. Peach. Observations obtained also in smaller telescopes with similar techniques (fast cameras) have a high potential to study the atmospheric activity visible in Venus clouds.


We expect that observations provided by a large group of collaborators from different locations on Earth will be able to cover Venus atmosphere and study its atmospheric superrotation as it was done prior to the Akatsuki orbit insertion in 2015 (Sanchez-Lavega et al. ApJL, 2016). Amateur observations of Venus in 2007 were also analyzed in the context of the MESSENGER flyby ( Peralta et al. GRL, 2017). A recent study combining observations obtained by the Akatsuki mission, professional telescopes and observations provided by amateur astronomers was published recently and shows the value of amateur images in combination with spacecraft data (Peralta et al. GRL, 2019).

Observations of Venus surface are also welcome. We expect that the large number of observations obtained by different teams around the BepiColombo flyby in combination with the ground-based amateur campaign will produce a unique set of observations of Venus. Initial results from the August 2020 observations will be presented at the EPSC2020 conference.

Venus observed from Pic du Midi

Observation windows

Observation windows of Venus are discussed in this publication:

Amateur observations in the following windows are desired:

Cloud contrast is strongest in UV, strong in Vio, very weak in blue, and weak (but with real feature) in wavelengths above 700 nm. The contrast in RGB images of the Venus' clouds is extremely low. However, on occasion, images taken with a green filter have proved useful in the study of intermediate clouds.

Examples of observations in these wavelengths are given in the figure on the right composed from observations available in the PVOL database and acquired by T. Olivetti, N. MacNeill, M. Kardasis and M. Lewis. The images have been edited for the purpose of fitting them in a single figure.
Venus lower clouds, Sebastian Voltmer

Lower clouds:

Some observers may have access to cameras operating at wavelengths beyond 1.0 microns. These cameras can also observe the lower clouds of Venus through the infrared radiation that escapes from the planet through holes of lower cloud content at an altitude of about 50 km above the surface. The image of the right was kindly sent by Dr. Sebastian Voltmer and is a demonstration of this capability using a Ninox 640 II SWIR camera from Raptor Photonics and a Baader prototype Sloan-Z filter using a C11 telescope. Details of this unusual amateur observation are below.