SpaceX SXM-8 Night Launch
Another awesome Space Coast night launch! SpaceX launched a Sirius XM Radio satellite into orbit. The SXM-8 was sent to replace SXM-7, launched last year. SXM-7, also launched by SpaceX, was successfully placed into orbit but was D.O.A. and was unable to be revived. SpaceX successfully placed SXM-8 into orbit. It will be several days until the health of SXM-8 will be known.
Usually when I do a streak photo of a night launch, I like to get the arc. As a rocket launches, it ascends into the sky. When it reaches altitude it levels off and continues to fly. Due to the curvature of the earth, from the ground, it almost looks like the rocket is coming back down. During a long exposure night photo, you are actually photographing the light from the rocket engines. This makes a streak in the sky, due to the curvature of the earth the streak makes an arc in the sky.
Now, to work out the exposure. A typical rocket takes 3-3.5 minutes to reach orbit. I usually use 3 minutes for my shutter speed for testing my exposure. In real time I will hold the shutter open until I can no longer see the rocket. To work out the f-stop, I do a series of test exposures at different f-stops. The amount of lighting on the foreground will determine the proper f-stop. When the foreground is exposed properly with a 3 minute shutter speed, that’s the correct f-stop. In this case it was f-16.
This launch had two issues. The first was trajectory, the rocket was flying due east. From Titusville it was flying directly away from the camera. So no arc, it would look like it was just going straight up. The second issue was cloud cover. Shortly after launch the rocket was going to go behind the clouds. Once again no arc, no matter what direction it was flying. Normally I use the widest angle lens I have, my 24-70mm at 24mm. Knowing the rocket was going to go behind the clouds shortly after launch, I zoomed in to compress the scene. This sort of, solved both issues to make a pleasing image. Also because the rocket was going behind the clouds, it wouldn’t be visible for the full 3 minutes. To make the exposure correct I still needed to keep the shutter open for the full 3 minutes. In this case I actually opened the shutter 1 minute before liftoff.
I photographed this launch from the newly renovated Rotary Riverside Park along US 1 in Titusville. The park had been destroyed by a hurricane a few years ago. It had just been reopened a few days earlier.
roy thoman photography 