The “terminator” in this case is not some sci-fi sounding robotic killer. Instead, it is the line that marks the sunlit from the dark part of the moon. As it moves across the moon’s surface each month it has a dramatic effect on what is visible.
Here, for example, is Tycho crater, taken on 11 April.
Tycho is the centre of the large “splash” in the middle of this photo. Large rays of ejected material, resulting from the impact that caused the crater, are clearly visible, extending over a thousand miles in all directions.
Yet when we look at the same crater a few days earlier, the scene is completely different.
Tycho is more to the left in this picture. The rays are much less pronounced, with some of them barely visible. Instead, the crater walls and central mount are much clearer. These two photos barely even look like the same moon.
As I’ve pointed out before, even over a single night, the terminator moves visibly across the moon’s surface. It is this constant interplay of light and shadow that makes photographing the moon so endlessly fascinating.
It’s been a splendid couple of weeks for moon pics. And unusually for my part of the world, there’s even be a few clear skies.
I’ll start off with the phases of the moon, beginning with first quarter on 6 Jan, all the way through to the full moon on 13 Jan. There were still a couple of cloudy nights, so it isn’t a complete record. I also haven’t got the scale and illumination quite right, so don’t pay too much attention to that. The first two photos on the top left are from consecutive nights and give a good, clear indication of how much the phase changes in a single day. These were all taken with my main 6″ telescope and the Panasonic Lumix GF7 camera.
The moon’s been doing a regular tour of the night sky, starting on 4th Jan by visiting Venus. Sadly, I didn’t get a picture of this one, so you’ll have to rely on the BBC for that.
On the 9 Jan it was the turn of the Pleiades star cluster, better known as the Seven Sisters, to receive a visit from the moon.
The photo above is really a composite of two photos taken a few seconds apart with very different exposures. The moon is much, much brighter than the brightest stars. A single image tends to either grossly over expose the moon, or make the stars invisible. Here’s what a single exposure from a few minutes later looked like.
Both the above images taken with the GF7 and a Carl Zeiss 135mm lens.
Next up on the grand tour was Jupiter. Once again, I needed to combine two separate images. Even Jupiter is no match for the brightness of the moon.
The inset on this image is a crop of Jupiter from the same photo, showing a close up of some of the Galilean moons. GF7 + Carl Zeiss again.
Finally, on the morning of 14 Jan, there was a lunar occultation of Mars, where the planet passed behind the moon. This wasn’t fully visible in the UK. Here, the moon just edged closer and closer to Mars, but never actually obscured it. For an excellent description of why occultations are important, especially when it’s a full moon, see this post by Matt Strassler.
I was in my back garden until about 3.30 am. The closest approach wasn’t until about 4.30, but I was just getting too cold and too tired to wait up longer. So this was one of the final pictures that I took.
Taken with my 6″ scope and the GF7. It’s been cropped and I’ve slightly increased the brightness and colour saturation of Mars, but otherwise it’s a single image from the camera. I was reasonably chuffed with this. Then I saw this totally amazing image on Astronomy Picture of the Day.
The few clear nights recently have been dominated by a near full moon. You know what that means by now, more moon pics!
I’ve highlighted the Mare Crisium (“Sea of Crises” – who came up with these names?) on this full moon from the night of 15th Dec. It’s the dark patch on the top right of the red rectangle.
I wouldn’t think close ups during a full moon would be that interesting. But a few days later, with the shadows beginning to grow on the surface, zooming in is a bit more fun. Here’s a close up of Mare Crisium from 17th Dec. I’ve tried to up the contrast a bit and bring out a bit of detail. Hopefully not too much. If you exaggerate the detail too much then the picture stops looking natural and it becomes very obvious that it’s been manipulated.
Fans of Star Trek: the Next Generation might be interested to know that one of the craters in Mare Crisium is named Picard. Not, it has to be said, after Jean Luc Picard, the captain of the Enterprise, but another Jean Picard, the 17th century French astronomer.
To give you a sense of scale. Picard crater is 23 km across. So about the size of a large town or city. The whole Mare Crisium is about 550 km across – roughly the size of England.
Three days later, on the morning of 20th Dec, Mare Crisium had disappeared into the shadows. The terminator between night and day had moved west. I’ve highlighted the area with the yellow rectangle.
The closeup from that night is centered on the large crater Theophilus between Mare Tranquillitatus to the north and Mare Nectaris to the south.
None of these pictures are likely to win any prizes. But bear in mind they’re taken with a relatively cheap (by astronomy standards) 6″, entry level telescope, and a second hand mirrorless camera. Neither of which are designed for astrophotography. I’m still trying to see just how far I can push such modest equipment. I suspect the real limit is my location in the heavily light polluted Southend-on-Sea.
Any dark skies next week should be mostly moon free. So I have to start planning what to look at.
And if you managed to get this far, Happy Winter Solstice!
Unfortunately, my best effort last night didn’t even come close.
The winning image is of a small section to the top right of my photo. Still, undeterred, there are a few things I could do to try and improve things.
Better telescope, better camera, better lenses. These all cost money. In some cases, serious amounts of money.
Move to a better climate. This is my favourite solution. There are people who can actually plan what and when they’re going to photograph. They have regular clear skies and low light pollution. In my case, it’s more a matter of waking up at midnight, sticking my head out of the window, and if it’s a clear sky, hurriedly getting dressed and dashing out into the back garden to see what I can capture before the clouds roll in again.
Don’t photograph the full moon. The above photograph has very low contrast because it’s a full moon. The winning photograph was taken when the sun was casting beautiful shadows across the craters and mountains of Sinus Iridium.
Try stacking photos. This was a single image. It might be worth taking a few dozen and try stacking the results. Might be worth a go.
The movement of comet Tsuchinshan–ATLAS is quite obvious from night to night. Here are a couple of images taken last night and the night before.
The comet’s now well on its lonely, icy way back to the Oort cloud.
I was hoping to do a fancy picture with the two images merged, but the program I was trying to use kept crashing. So you’re stuck with side by side images for now,
I also tried to get some telescope images last night, but neither the telescope nor the camera would cooperate. The telescope refused to save its alignment, so tended to wander off all over the place. The camera’s focus assist also decided to show a blank screen, so it was nearly impossible to get a good focus. It’s live update screen was also taking ages to update, when I need it to operate in real time. As a result, most of last night’s close ups weren’t very good.
There are days when every bit of technology I touch just seems to break.
Platitude of the Day 