Photographer Brennan Gilmore has used Jupiter’s closest position to Earth over the past 59 years, capturing a photo of the gas giant along with its four Galilean moons above a barn roof.
The photo shows Jupiter and its moons, left to right, Ganymede, Europa, Io and Callisto, and was taken on Monday September 16 near Charlottesville, Virginia. The photo was made possible because Jupiter was in opposition, meaning Earth was directly between Jupiter and the Sun, combined with the fact that the gas giant was as close to Earth as it has been in 59 years and as close as it will be will last until the year 2139. The result is that Jupiter’s angular size in the sky and the planet’s brightness were both extremely increased.
“Jupiter rises above the central barn of Carter’s Mountain Orchard, a popular spot in the Charlottesville area that dominates the eastern horizon high above the city. This ridge location makes it particularly attractive as a foreground for sunrise and moonrise shots – and I’ve photographed a full moon there before,” says Gilmore PetaPixels.
“Increasing the ridge line by four to five degrees means that sky objects have a higher degree of clarity/less distortion than when they rise right up the horizon because you’re photographing through less air mass.”
Gilmore says he planned this shoot using two apps that he says are central to his astrophotography: Planit Pro and Stellarium.
“I used Stellarium to confirm the field of view – that I would be able to capture all the moons in the frame,” he says. “And PlanitPro helped me narrow down the exact location I would need to be shooting from to capture Jupiter over the building. I used a third app, Atomic Clock, to ensure my time is in sync with those apps’ ephemeris.”
Gilmore says that to get the extremely forced perspective he wanted, he used the largest lens — or optical tube assembly (OTA) — he owns: a Celestron EdgeHD 9.25″ Schmidt-Cassegrain telescope
“This OTA is made for the optical needs of astrophotography and I typically use it for deep sky and planetary astrophotography. For this shot, instead of using a cooled astrocamera and filter wheel, I shot with a Sony Alpha 7R III connected to the telescope via a specially adjustable camera ring that allowed me to get the precise back-focus I needed.” he explains.
“I also used a remote shutter release and shot with the silent shutter as even the slightest shake at a 2350mm focal length can cause noticeable blur in the images. The camera and scope sat on top of a Sky-Watcher EQ6r-pro mount, although I only used it as a heavy-duty tripod as I wasn’t tracking the sky, I was shooting from a static position.”
Gilmore says he tried several possible locations for the shot he was hoping to get, but unfortunately most of the ranges didn’t work to line up accurately with the target building.
“Either there were trees blocking the view or it was private residences – one homeowner, when I asked permission to photograph from his property, said, ‘Hell no!’ Eventually I found a construction site along the needed axis and luckily at 6:30 p.m. no one was there when I showed up,” he says.
“After setting up all the gear, I adjusted the focus as the temperature dropped. The large mirror and glass objective in the tube reacts very sensitively to temperature fluctuations. Clouds loomed ominously above me and I worried that the horizon might be obscured at the right moment. Luckily, the area of the sky that I photographed remained clear,” Gilmore continues.
“When the time came, I didn’t see Jupiter at first – there’s always some slight variation from the apps to what you see – but I was thrilled to soon see a bright light emerging from the trees, just where.” I wanted to frame it. I quickly snapped several images, adjusting ISO and exposure to try and get as slow a shutter speed as possible to ‘freeze’ the image as air turbulence would severely distort the focus and shape of the planet and its moons. Because Jupiter was so low and the light penetrated so much air mass, there is noticeable color distortion at the edges of the planet and the moons – this is due to the differential refraction of different wavelengths of light.”
Gilmore says that because of the focal length, the planet passed through the image in just over a minute, and the time that Jupiter and the moons were all visible was only about 30 seconds.
“Luckily, thanks to careful advance planning, I was positioned exactly where I needed to be and was able to capture a unique shot on the day Jupiter is closest to Earth in my life,” he says.
Gilmore adds that he was hoping to get a closer planetary image of Jupiter that night, but clouds obscured the sky shortly after he snapped the image of the gas giant and its moons.
To see more from Gilmore, be sure to visit his website and follow him on Instagram.