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Avani Soares

Location of Photo:

Canoas, Brazil

Date/Time of photo:

2022-11-05; 02:07 TU


C14 f/11 + ASI 290MM + IR pass 685


Normally, when we start astrophotography, our first target is the Moon. Our old Lua is generous because it works well even on the most modest instruments. A simple 60mm scope and a cell phone already allow for interesting photos. But shooting the moon in high resolution requires good apertures, proper collimation and a dedicated camera, and it can be difficult work if the photo is close to the terminator. But, in fact, it is the photos close to the terminator that reveal the good lunar photographers, as they require adequate control of light, both at the time of capture and in subsequent processing. In this photo we have Gassendi very close to the terminator, and with the sun at an extremely low angle, the relief of the floor stands out in a dazzling way. Its rhymes are usually very evident but with the sun low we can clearly see how irregular the floor of this remarkable crater is. Gassendi is one of the main lunar craters, with its 114 km in diameter, it is very old formed in the Nectariam period about 3.92 billion years ago. It is an impact crater with Fractured Interior (FFC), which was modified by volcanic action after its formation, probably huge lava flows gushed through the cracks in the floor, causing numerous stress fractures to form in its interior from the reservoirs. of lava, this made it quite shallow in relation to its diameter - just 2.8 km deep. When observed through spectroscopic analysis, the Gassendi crater has a "behavior" very different from any other lunar crater (Mikhail 1979). High-resolution studies performed in near-infrared light (Chevrel and Pinet 1990, 1992) indicated the presence of extrusive volcanic material (that is volcanic material that flows to the surface and then crystallizes) limited to the adjacent southern part of the Gassendi floor. the Mare Humorum mare. Interpretation of the data also suggested that major extrusive volcanism may have occurred in the eastern portion of the floor, as indicated by the significant presence of pyroxene, which corresponds to visible volcanic features. The western part of the crater floor, away from the geometric continuation of the western rim of Mare Humorum, is composed of rich upland material. The difference between the west and east sides of Gassendi with intensely fractured soil could be strongly linked to the early thermal history of Mare Humorum. I've already taken countless photos of Gassendi, but the result of this one with the sun very low really surprised me. A pleasant surprise, which shows that each photo is unique in itself and each moment is unrecoverable if we don't know how to take advantage of it. Text and photo: Avani Soares