Frustrations of astrophotography

Astrophotography can be frustrating.

Right now, from the Earth’s perspective, Jupiter, Saturn and Mars appear close together in the sky. This conjunction is quite a pretty sight, although you have to get up early in the morning to see it, as it’s fairly low in the East.

From my latitude (38° South), Jupiter is out on its own, blazing away higher than the others. Saturn and Mars are closer to each other, with Saturn slightly higher. Mars itself is clearly redder, but is similar in brightness to Saturn. The whole conjunction is wedged in between the constellations of Sagittarius and Capricorn. 

My back yard faces East, but it’s up a hill and there are some tall trees blocking the view. Last night I woke up at about 3am so I thought I’d give it a whirl anyway. As it was a very wide field I decided to use my DSLR with a 70mm lens, which gave me the right sized view. I grabbed the tripod and stumbled out into the darkness.

Jupiter was blazing brightly, but it was through a tree. Mars and Saturn were in the lower branches. I took a photo, waited for the planets to rise a bit, and relocated slightly.

I was soon able to get a better shot, although there was still foliage in the frame. After waiting a little more, and framing to allow the planets to rise without drifting out of shot, I set the camera to take 100 six second exposures. I planned to stack these for the final image.

The process was going to take about 15 minutes, so I retreated inside. It was cold and had been raining and I kept stepping on snails, which was pleasant for neither me nor the snails.

I got back, and had a look at the back of the camera. There was a small smear around the image of Jupiter. Dew! How could I have made such a rookie mistake? Had I have thought about it, I could have put one of my heater straps around the lens to keep the dew at bay. 

You can see the final photo, a well as an annotated version. The dew halos are still pretty bad, but so is light pollution. You live and learn - I'll try to do better next time.