Lunar eclipse, 26 May 2021

Lunar eclipse, 26 May 2021

If you're reading this, the eclipse will be long in the past. Don't worry, there will be more soon - a lunar eclipse isn't a very rare event.

The lunar eclipse is on Wednesday!

On the evening, the Moon rises before entering the Earth's shadow.

Because the shadow isn't a sharp line, the start of the eclipse is a bit vague. I'm saying that it begins at about 7:45, although you may have noticed some dimming on one side for some time.

The mid-point is something we can be pretty certain of - it's at about 9:15pm. At this point, the Moon will be bathed in red. Why?

If you were on the Moon, looking up, you'd see a solar eclipse, with the Sun behind the Earth. But more than that, the Earth would look like a circular sunset. Blue light is scattered by the Earth's atmosphere. Just the red light gets through.

My photo here is from a few years ago. This is how I did it - have a go yourself!

Shortly before the beginning of the eclipse, when the Moon was very full, but before any shadow fell on it, I took a large number of photos with my birdwatching lens. I didn't use my scope. Because of the amount of light being cast on the Moon, my exposures were very short, like 1/1000s.

At the mid-point, I took a single photo of the Moon. This was a much longer exposure, from memory about four seconds.

I watched the rest of the eclipse with my eyes. Don't forget to do this.

Next morning, I processed the images. I stacked the first set of images in AutoStakkert and sharpened them using Registax. I've described this process before. I saved this image as monochrome - I wasn't interested in colour at all, just the sharp surface detail.

I didn't do much with the four-second totality image at all. I was simply looking for the red colour.

I arranged the images on top of each other in Photoshop, with the sharp monochrome one on top and then set it to blend as a luminance layer. That took all the sharp details and displayed them with the colour of the totality image.

I confess it's cheating.

The ASV's live event is booked out, but they're streaming it on YouTube and Facebook. Tune in for more comments from Mark and others.