Shooting the Moon with a Smartphone
I bought my first smartphone, the HTC One, a few months ago. I hadn’t thought about using the phone’s camera for astrophotography until the ALCON 2013 Conference when I tried shooting the Sun through the eyepiece of solar telescope which had been set up for conference participants during a lunch break. I managed to get two decent frames out of a couple of dozen frustrating tries by hand-holding the phone over the eyepiece. The results and disappointment were much worse this summer when I tried to take a photo of the Moon by hand-holding the phone over an eyepiece. I knew this was not going to work out.
Then I saw an ad for the Orion Steady Pix Universal Adapter for Smartphones (let’s shorten that to “Orion Smartphone Adapter” for this article) and decided to give it a try. Mine arrived in early September and I used it for the first time the night of September 14th-15th. Being somewhat clumsy, I initially had a lot of trouble trying to set it up so that the phone would be directly over and aligned with the eyepiece…and stable. I tried first with the 80mm refractor with a helical focuser that is piggy-backed on my C11. After numerous attempts, I gave up in frustration. I then tried clamping the phone and adapter to a 9mm orthoscopic eyepiece and using it with my C11, which also has the benefit of a JMI feather-touch type of focuser (very smooth). I managed to get the camera over the eyepiece and stable after only a few tries. I did not use the zoom function on the HTC One’s camera and found that the camera’s chip is not large enough to capture the entire field. But I did get some decent photos. I selected the best and cropped and edited them in Photoshop Elements 9. I was shooting through thin cirrus clouds that night, which contributed to a slight spurious color cast, so I converted the photo to black & white. Here’s the resulting image of the smooth-floored crater Plato, the lunar Alps with the Alpine Valley and the bulls-eye crater Cassini at the bottom of the frame. I want to again mention that this is a single frame; I did not take videos and did not stack and process anything in Registax.
The Plato image is not as good or detailed as I’ve been able to get with my Celestron Neximage 5 Solar System Camera, but I was encouraged enough to try again. After all, the HTC One and Orion Smartphone Adapter are easier carry around than the Neximage 5 camera and my wife’s laptop computer and there’s no complicated software to operate with the phone. I tried the Orion Smartphone Adapter again the night of September 20th-21st and was able to set up easier and faster than the first time. This time I also used the smartphone’s digital zoom to adjust the view to the main features I wanted to capture. I took a few to several frames of each feature and uploaded them to my computer the next day. I selected the best frame for each and adjusted the brightness, contrast and sharpness in Photoshop Elements 9. Here are a few of the results:
Cleomedes is the large (126 km), smooth-floored crater above the north shore of Mare Crisium at the bottom of the frame. In a line above Cleomedes are the craters Burckhardt (57 km) and Geminus (86 km) at the top right of the frame. Cleomedes has some small, newer craters on its floor and all three craters show small central peaks.
Endymion is the large (125 km), smooth-floored crater near the Moon’s terminator at the top of the frame. It has high, prominent walls and its floor is not marred by any fresh craterlets. Atlas (87 km) is below Endymion. It is interesting for its ring of central mountain peaks and two prominent patches of dark material on its floor. Hercules (69 km) lies to the right of Atlas and has a fairly large craterlet on its floor.
The crater Petavius (177 km) is a popular target for lunar observers for its large size, large complex of high central peaks and, most notably, for its prominent rille connecting its central peak complex with its southwest wall (lower right wall in this image). If you look closely, you can see a much smaller, thinner rille going north (up) from the central peaks. Petavius also has a dark patch at the base of its north wall.
Langrenus (132 km) is the large, fresh looking crater near the top of the frame. Its high, terraced eastern wall is brightly lit by the setting sun, as is its prominent central peak. To the left beyond Langrenus lies the Moon’s terminator and to the right (west) lies Mare Fecunditatis. Below Langrenus lies the older, much eroded crater Vendelinus (147 km). Its walls are much lower than those of Petavius and partially obliterated by newer craters while its floor is filled with mare lavas.
All of these September 15th images were taken less than two days after the full Moon, so the terminator where night is falling is in the east to the left and the Sun is shining as it descends in the west to the right.
Jay Albert, Lake Worth, FL