Joshua Tree National Park

The Geminid Meteor Shower makes an appearance every December, typically between the 12th and 14th. Geminid is in reference to the constellation Gemini from which the meteor showers ten to originate. If you can find Orion, Gemini is close by.

2017 was a great year because the sky was dark from a new moon. You can see about 120 an hour at the peak. That seems like a lot but it’s about 2 per minute. Some are faint and some are out of the view of your camera.

My wife Liz and I went to Joshua Tree National Park to see the shower. I selected that location because it’s a pretty dark place and it’s also warm. Temperatures for the eight days we were there were typically in the 60s during the day and the 40s at night.

We had clouds on a couple of days, but the day before and the day of the peak were cloudless.

Arch Rock

All the images taken on this page were from the Arch Rock area near the White Tank campground. We visited the Arch Rock on three separate days.

I think they should rename the location to “Goose Arch”.

Feature Image Details

• Canon EOS 5D Mark IV
• Canon 11-24 F4.0 L lens at 13mm.

The feature image is a shot of alpenglow (after the sun had set but with golden light bouncing off the nearby mountains). I combined that with images taken a few hours later of the sky.

Beneath Arch Rock

The above images are the most complex I have taken, especially the one immediately above. Here is the process:

1. The image of the land is two separate images, one focused close, the other more distant, blended together. I used my Canon 11-24mm right at 11mm. The arch looks distant but it is no more than a few feet away. The top of the photograph is the arch looping back over my head.
2. There was a bit of alpenglow left. I added some fill light with a Dracast Camlux Max SB video LED light set to tungsten. I hand held the light with my arm stretched out and let the light brush the edge of the arch. The exposure was 30 seconds at ISO 640 at F16.
3. For the sky, I used a modified EOS 5D Mark IV. I had Spencer’s Camera replace the low-pass filter with one that allows the full spectrum of light to come in. This makes the camera useless for daytime photography without special filters. The advantage at night is the camera picks up an extra stop of light. That’s the difference between a 15-second shot and a 30-second shot.
4. The sky, minus the meteors, is a blend of eight images, 50 seconds each, taken back to back at ISO 3200, at F4.
5. Because the stars rotate, and because of camera noise, you just cannot take exposures beyond a certain length or the stars will look like streaks rather than points of light. The rule is E = 400/FL where E is maximum exposure time in seconds, 400 is a constant, and FL is the focal length of the lens in mm. With a 24 mm lens you can only shoot for 16.66 seconds. I round to the nearest 5 seconds, in this case, 15 seconds. At  11mm I could go 35 seconds.
6. I have an iOptron Skytracker Pro device that tracks the stars. With the Skytracker, one can double or triple the amount of time given by the E=400/FL formula. But you have to align the device to the North Star. However, I could not see the North Star as it was hidden by the arch. I estimated, knowing approximately where the North Star was. I added only an extra 15 seconds or so, making for a 50-second exposure.
7. Bear in mind that by tracking the stars, the land will now be blurry. That was the point of blending the two images of the land together rather than trying to do this all in one take.
8. I took eight images of the sky and made some basic adjustments in Lightroom. Next, I exported the images to Photoshop, opening them up as layers. Then I aligned the layers. To get align to work properly, you must first mask out the land or photoshop will attempt to align the images on the land, not the stars.  Next, I converted the layers into a smart object, then set the blend mode to median.  The point of this step is to reduce random noise. It also nicely eliminates any airplanes flying through. In eight images, only one of them will have a plane in the same spot. By telling Photoshop to use the median value of each pixel, blinking lights from passing planes vanish and random long-exposure noise is dramatically reduced.
9. Finally, I kept taking images every minute or so for a couple of hours hoping for meteors. I took eight of the brightest meteors and masked out everything else and put them about where I recall seeing them in relation to Orion.
10. For the verticle image above, I used 2 shots of the land, 8 images of the sky, and another 8 images of meteors blended together as described above. Equipment-wise, I used two EOS 5D Mark IV bodies, one of them was specially modified, Canon’s 11-24 F4.0 L lens, an iOptron Skytracker Pro, a Dracast Camlux Max SB Video LED light set to tungsten, and a Manfrotto 190 Tripod fitted with a Really Right Stuff BH-30 Ballhead and Panning Clamp.

Arch Rock at Sunset

The above image provides a bit of perspective on where I was situated for the complex image above.

Once again, I used the 11-24mm lens at 11mm. The image is a blend of exposures centered around 1/6 second,  at ISO 320, F16.

Equipment

Those interested in my equipment and recommendations can find it here: Mish’s Equipment List.

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Mike “Mish” Shedlock