The opposition of Mars, 2014: Part I

2021 February 2

Richard McKim

Introduction

This report describes BAA observations of Mars during the period 2013 July to 2015 April, covering the very end of Martian Year (MY) 31 and most of MY 32.¹

Mars came to opposition in Virgo on 2014 Apr 8 at 21h UT (at areocentric longitude (Ls) 114°, in early northern summer) at declination –5° and with a diameter (D) of 15.1 arcseconds (″), a little larger than in 2012. Closest approach (D = 15.2″) occurred on Apr 14, and for UK observers the higher diameter did not compensate for the much reduced altitude. The planet’s diameter was 6″ or greater between 2013 Dec 12 and 2014 Oct 6. The latitude of the centre of the disc at opposition (D_e) equalled +21.4°, favouring observation of the northern hemisphere; it remained positive until 2014 late October. Key dates are listed in Table 1.

The Director received 6,317 observations (5,759 images and 558 drawings) from 102 observers (Table 2). Excellent coverage from 2013 Jul 27 (D = 3.9″) until 2015 Apr 15 (D = 3.9″) corresponded to Ls = 358° through 0° to 326°, or 91% of a continuous span in Ls. Images spanned 2013 Jul 27 (Kardasis) to 2015 Apr 13 (Foster), and visual records 2013 Aug 13 (Gray) to 2015 Apr 15 (Adamoli). The distribution by month (days observed/days possible) was: 2013 Jul 1/31, Aug 5/31, Sep 20/30, Oct 29/31, Nov 22/30, Dec 22/31, 2014 Jan 23/31, Feb 27/28, Mar 31/31, Apr 30/30, May 31/31, Jun 30/30, Jul 30/31, Aug 29/31, Sep 25/30, Oct 21/31, Nov 12/30, Dec 7/31, 2015 Jan 11/31, Feb 11/28, Mar 9/31, Apr 4/30.

We were well-supported by observers in Australia and (for the first time in many years) South Africa. From the latter country, Clyde Foster made full use of advantages conferred by low latitude (25.8°S) and high altitude (1,475m) to study the planet in the evening twilight for many months after opposition. Supported by the visual work of Gianluigi Adamoli, Foster’s images proved the absence of an encircling dust storm. Paul Maxson again obtained the largest number of images (871) on 178 dates, with much valuable early morning work. Yukio Morita and Maurice Valimberti each supplied over 500 images. In the UK, despite the lower altitude, high resolution was achieved by our observers, in particular by Martin Lewis and David Tyler. Damian Peach made another successful expedition to Barbados in April. The Director secured 55 drawings. This was the final Mars apparition observed by Don Parker,² and Masatsugu Minami.

The following are seasonally comparable oppositions covered by the BAA: 1903 (Ls = 103° at opposition),³ 1920 (127°),⁴ 1935 (111°),⁵ 1950 (097°),⁶ 1952 (136°),⁷ 1967 (121°),⁸ 1982 (105°),⁹ and 1999 (129°).¹⁰ Short interim reports were produced,^11–13 together with a preview of what might be observed.¹⁴ Other organisations maintained online image galleries,¹ but none produced final analyses. Schmude has discussed some of the Mars Reconnaissance Orbiter images.¹⁵

Throughout the apparition NASA’s Mars Odyssey (arrived 2001) and Mars Reconnaissance Orbiter (MRO, 2006) remained active in orbit, as did ESA’s Mars Express (2003) probe. The NASA rovers Opportunity (2004) and Curiosity (2012) were still at work on the surface. This select group of spacecraft at Mars was enlarged by the post-opposition arrival of NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft on 2014 Sep 21,16 and India’s Mars Orbiter Mission (MOM) spacecraft Mangalyaan on Sep 24.¹⁷ China also had a Mars mission at the planning stage.

Surface features

General

The albedo features were mapped by T. Kumamori (Figure 1) and M. R. Lewis. Though Figure 1 is less detailed than our 2012 chart, it confirms that there were no major changes since then. D. A. Peach created an impressive ‘animated globe’ video, covering a wide longitude range. The 2010 and 2012 oppositions also showed hardly any albedo feature variations (the last planet-encircling dust storm having occurred in 2007). We again refer mostly to telescopic names from Ebisawa’s general map, readily available at the Section’s website.

Region I: long. 250–010°

See Figures 1 & 2. Syrtis Major continued to be broad, and blunted to the north, with Nepenthes invisible. The dark spot in Huygens was well visible.

(Login or click above to view the full illustrated article in PDF format)