It’s interesting to see how far sensor technology has come in the past generation or two. On the night of January 6, the sky was clear (but not photometric) after a very stretch of iffy weather. Walking to the house, I admired the majestic Orion riding high in the southern sky. I wondered, “Have DSLRs become capable of photographing the night sky handheld?” Orion, being full of bright stars would be my test case. Here is the result using a fast lens and ISO 32,000. Can you spot Orion at the upper right and α Canis Majoris (Sirius), at the bottom?
For comparison, here is a 10-second exposure at a lower sensitivity (ISO 3,200 rather than ISO 32,000) with the camera on a tripod without tracking. Most notable to me is that faint wisps of cloud appear here and there, showing that the night was not actually “perfectly” clear (termed “photometric”). The image shows the Great Orion Nebula (M42) in Orion’s sword and also the Rosette Nebula as a diffuse smudge far left of Orion’s sword. Notice the bright red giant star α Orionis (Betelgeuse) in Orion’s upper left armpit. That’s my house at the bottom.
Finally, here is a 15-second exposure, unguided, adjusted to include the Pleiades cluster at the upper right. Look carefully and you will see the Pleiades enveloped in the bluish glow of nebulosity enveloping the cluster and illuminated by its hot B-type stars. Sirius is the bright star near the bottom. The Milky Way is visible stretching vertically, left of Orion. Again, notice the faint reddish patches of cloud near the center and horizontally along the bottom — definitely not a photometric night!
