Imax=16000 (1s)	Imax=2000 (5s)	Imax=1000 (5s)	Imax=500 (5s)

Imax=200	Imax=100	Imax=50	Imax=20

Imax=10	Imax=5	Imax=2	Imax=1

Nonlinear	Nonlinear

SBIG ST-4K, 1800s exposure at 300s, 9/22/17 Whisper Canyon, CA

Here was another attempt to capture the full range of features visible in the Orion Nebula. The scaled images above were made by combining 21 images with 1s exposure, 15 images with 5s exposure, or 6 images with 300s exposure, the last exposure happening as the sky was just starting to brighten before dawn. The first image shows the main stars, including the trapezium. In the next few images, which show the bright core of the nebula, a bright red shelf appears, with a dark protrusion in front of it (just above a bright star). I am not able to see this feature visually, perhaps because our eyes are not very sensitive to hydrogen-alpha emission, and we see mainly the oxygen-III emission, which appears blue with this camera. I think the images out to Imax=20 show roughly the extent of the nebula that can be seen visually. The third row maintains linear scaling, showing the fainter features at the periphery of the nebula, while saturating the center. The bottom row shows two nonlinear scaling methods, applied after replacing the saturated pixels from the 300s exposures with values taken from the 5s exposures. The image on the left used a histogram equalization method, and the image on the right used a logarithmic scaling. Both methods maintain the hue at each location, applying the nonlinear scaling to the intensity only. These methods drastically change the appearance, but allow textural features to be followed over the entire field of view.

Imax=350	Imax=15	Imax=2	Nonlinear

SBIG ST-4K, 1080s total exposure 10/3/13 Lake San Antonio, CA

This is another attempt at the Orion Nebula, using the new camera. Compared with the previous image, the focus is not as good, but a much larger area of the nebula is visible due to the larger sensor area and deeper exposure.

Imax=1500	Imax=1000	Imax=500	Imax=250	Imax=150

Starshoot DSCI, 33 exposures, 10s each 9/26/08 Lake San Antonio, CA

As with M31, this object presents a huge range of brightnesses, so 5 different intensity scalings are shown here. Such beautiful colors!

Orion

Pentax 35mm camera, Fall 1990, Scottsdale, AZ

This color photograph of Orion was obtained by pointing a 35mm camera directly at the sky. The pink color of the Orion Nebula can be seen.