Keywords: Ina hrp219a.jpg The unique lunar feature Ina center within Lacus Felicitatis on the moon The feature was often called the 'D-Caldera' prior to http //planetarynames wr usgs gov/Feature/2680 formal naming in 1979 This is Figure 232 of Apollo Over the Moon NASA SP-362 1978 which has the following caption <br> The steep-walled but shallow D-shaped depression near the center of the photograph is apparently a unique feature It is located in a patch of mare on the foothills of the Montes Haemus west of Mare Serenitatis Measured along its straight side the depression is about 3 km wide It is situated atop a very gentle circular dome that appears to be somewhat smoother than the surrounding mare surface As is more clearly shown in the accompanying stereogram fig 233 the many bulbous structures on the floor give it a blisterlike appearance <br>The depression is believed to be volcanic probably a caldera El-Baz 1973b Figure 234 explains the probable sequence of events leading to the formation of this unusual structure -F E -B en wikipedia Apollo 17 Metric camera image AS17-M-1672 cropped to show Ina and surrounding terrain <br/> Immediate source NASA History Program Office http //history nasa gov/SP-362/contents htm Apollo Over the Moon A view from orbit NASA SP-362 1978 <br>Figure 228 http //history nasa gov/SP-362/hrp219a jpg hrp219 original 1972 published 1978 NASA<br/> PD-USGov Original upload log en wikipedia Ina+hrp219a jpg wikitable - 2014-04-02 04 18 700×724× 104920 bytes Jstuby The unique lunar feature Ina center within Lacus Felicitatis on the moon The feature was often called the 'D-Caldera' prior to http //planetarynames wr usgs gov/Feature/2680 formal naming in 1979 This is Figur Apollo 17 moon photography |