Prepping for Perseids

August 11, 2016   15/2.8, Astronomy

I spent two hours last night with the Nikon practicing for tonight's Perseid shower. Actually much of the time was spent on the couch, drinking wine, as the camera's interval timer does the grunt work. I didn't expect to catch much in the way of meteors, it was more about getting the exposure right and the interval timer working, so I was pleased to find two of sixty shots show what look like faint meteors. Study the upper left of the shot below and you'll see it, though maybe not on a phone.

Taking a photo of a meteor is different from your typical photo. A wide fast lens is good for this so I used both a 20/2.8 and a 15/2.8. I much prefer the fisheye but I know some people hate the distortion. The camera's settings were as follows:

  • Manual focus
  • Focus lens on infinity
  • 30 second shutter
  • ISO at 1250, maybe more
  • Matrix exposure
  • Long exposure noise reduction (LENR) set to ON (Shooting Menu)

Why these settings? Thirty seconds is long enough to get a nice streak but not so long as to get star trails. The matrix exposure setting is Nikon-speak for whatever is the camera's smartest exposure algorithms. ISO? Well, I'm still experimenting. It's 1250 here. And set LENR to ON so that the camera takes a second shot each time, for the same exposure length, but with the shutter closed. Then the camera subtracts the second from the first, thereby removing some noise. Note this more than doubles the time for a shot as the camera has to perform the calculations and write the image file or files to the card.

Next, place the camera on a tripod and position it to get a broad swath of night sky.

Finally, set up the camera to automatically take a series of photos. The interval timer needs to know how many photos to take and the time between each photo. For example, say you've an hour before you go to bed and so you want the camera to shoot for sixty minutes. A thirty second exposure takes the camera no less than sixty seconds (remember the LENR?) so we can take at most sixty shots per hour. A little less actually. I add a generous 15-second cushion between each shot making the interval 1 min 15 seconds for a 30-second exposure.

Now that we've the interval length and number of intervals go to the Nikon's interval timer. This is a powerful feature but it's a bit awkward to use. Here is the path I use through the timer's menus:

  • Shooting Menu
  • Interval timer shooting
  • Select Now then press right arrow
  • 00 Hr 01 min 15 sec (right arrow moves through)
  • 060 intervals x 1 shot per interval = 0060 shots
  • Select On and press the OK button

While the Nikon was busy I spent some time with the Fuji X-pro2, shooting the sky with the 16mm, and I found it has a similar interval timer, though it can only do one shot per interval.

I am listening to Trouble by Jose James.

Perseid meteor