With its shrunken polar cap and its large apparent angular size, Mars is viewed here during Martian summer and while Earth nears opposition: where the Sun, Earth, and Mars all form a straight line.

Using the unique capabilities of telescopes specialized on cosmic gamma rays, scientists have measured the smallest apparent size of a star on the night sky to date. The measurements reveal the ...

Oda, M., Bradt, H., Garmire, G., Spada, G., Sreekantan, B. V., Gursky, H., Giacconi, R., Gorenstein, P., and Waters, J. R., Astrophys. J. Lett., 148, L5 (1967).