Posted January 28th, 2019

Eclipse Unveiled

It is very unlikely that this is the best photo you have seen of the super blood moon of January 20th. However, the circumstances under which I captured it make it notable enough that I decided it is worthy of presentation. You see, the evening of January 20th was overcast here. The cloud was thin enough that prior to total eclipse the moon did shine through, but it was a hazy, featureless blob. The photos I took at that stage were far too lacking in definition to be usable. When totality was reached, the blood moon was competely invisible to the eye, but I continued to follow its path with my camera. Using ridiculously extreme exposure settings, I discovered I was able to pull it out of the murk. Red light scatters less than the shorter wavelengths included in white light, and my images showed surprisingly good definition. The image I present here, photographed just after the eclipse exited totality, was a 40 second exposure at f/6.3 and ISO 6400! Comparing this to exposures used for this subject by other photographers who were under clear skies, I estimate that the cloud cover had the effect of a 6-stop neutral density filter. Of course, this long of an exposure with a 500mm focal length would be heavily blurred by the rotation of the earth without a tracking system. I do not own a tracking mount, but my Pentax camera has a feature called “Astrotracer” that attempts to mimic an equatorial mount by moving the sensor during exposure. It does not always work perfectly, especially when exposure times are pushed towards the high end of its capability, which is limited by the available range of sensor movement. But I must have had it calibrated especially well on this occasion because it performed admirably right at the exposure time limit that it could offer in this situation. The ability of a modern advanced digital camera like my K-1 to show me things that I cannot see with my naked eye is a major inspiration for night photography, and it is very satisfying to have achieved this image in seemingly impossible conditions. I should note that this rendering of the image involved some fairly heavy post processing adjustments in Lightroom, particularly with the dehaze and black point controls.
Pentax K-1, Sigma 150-500mm f/5-6.3 APO DG OS HSM @ 500mm, 40 sec @ f/6.3, ISO 6400