My photos of the lunar eclipse did not turn out well when the moon was reaching totality: basically, underexposed because the moon was (nearly) gone! I recall from earlier shots that 1/125 second was about as slow as would work, due to motion blur from atmospheric effects and the moon’s motion. So I left it at 1/125 with maximum aperture (f/5.6), and increased the ISO as the moon disappeared.
However, I integrated 12 exposures taken as a burst, giving essentially 12/125 or about 0.1 second. Even though the exposures were made within the space of 2 seconds, each one showed the image in a different position, which illustrates why a longer exposure is blurry. By chopping it into separate short exposures I was able to manually align the separate images.
This simply adds the pixel sample values together. Dedicated software, such as used with astronomical instruments, would do better at removing the random noise as part of the process. I did noise reduction on the combined exposure.
Yes, the sky really is purple. There was a visible haze here, and later clouds were visible over the moon. I calibrated the white balance on an exposure of the normal full moon taken just after the eclipse ended, setting that to neutral grey. The same profile was applied here, so the red tone is visible and accurate.
The last bit of direct light was just touching the limb, and that is pure white and overexposed in this image. By eye, the area between the white tip and the red blush did appear more turquoise (blue/green), but that’s a perceptual illusion due to the fact that it’s simply less red than the neighboring region. These colors did not show up in the true-color photo. I suspect that the dark colors next to a full-sunlight bright spot affects the eye differently than the camera sensor.
Also notice how the upper-right blends into the same shade as the surrounding sky. That’s how dark it appears: only just an ember separating itself from the empty haze.
The picture loses something in the JPEG compression, and the sRGB color space is disappointing after viewing it in Photoshop in the full gamut available to my monitor. But you get the general idea.