Mars Opposition Photos from the Past

by John Church

Left Picture: August 18, 1971         Right Picture: Oct. 11, 1973
Edmund 4-inch refractor            Hastings-Byrne 6¼ inch refractor
Angular diameter 24.7 arcsec           Angular diameter 21.4 arcsec
Central Meridian 10º              Central Meridian 328º
                       Published in Sky & Telescope, March 1979

Back in the 1970’s I did not have today’s superb electronics, charge-coupled devices, and so on. All I had was fine-grain film, a home darkroom, and advice about special developing techniques from an advanced amateur photographer and a professional at work. Plus some good refractors. I still have my Edmund 4-inch which I occasionally use at home. I was lucky to have had custody of our fine Hastings-Byrne refractor from 1972 until it was installed at our Washington Crossing observatory soon after we had finished building it in the late 1970s.

Mars is a superb object at a good opposition when there isn’t a major dust storm, such as the one two years ago. We are having an excellent view at present and many surface features are visible. In my August 1971 photo, the prominent feature Syrtis Major had just rotated out of view to the east. Mare Serpentis extends upwards towards the south polar cap. Sinus Meridiani, at 0 degrees Martian longitude, had rotated slightly east of center. The south polar cap is prominent. The extensive dark area to the upper right is Mare Erythraeum.

In my October 1973 photo, Syrtis Major is the large dark area, with Mare Serpentis again extending upwards to the right. Sinus Meridiani is the rightmost small dark area. The south polar cap has shrunk considerably with the advance of summer in Mars’ southern hemisphere. We can also see a small change in the apparent tilt of Mars as seen from Earth. At the present opposition, the south polar cap is also quite small but still readily visible in our telescopes at the observatory.

Technology has advanced tremendously since the age of film. Our talented club astrophotographers are producing wonderful images of Mars and other objects with their fine equipment and techniques. I look forward every month to seeing the results of their extraordinary work in the pages of Sidereal Times.

This entry was posted in November 2020, Sidereal Times and tagged , . Bookmark the permalink.

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