Moon mosaic - with a difference

2 December 2019

I spotted this photo on the Sky-Watcher Facebook page the other day and immediately realised it was something special.

The Moon is everyone's first target. In fact, some people end up specialising in lunar photos, there's just so much detail. What's more, the angle of the light changes constantly, so the views change every night, increasing the fascination.

But while a full Moon shows the whole disc, having the light right behind us flattens a lot of the detail. It all really comes out when the light is on an angle. The craters reveal their shadows, highlighting the 3-D effect.

Jacob uses a Sky-Watcher 8” go-to Dobsonian (www.opticscentral.com.au/skywatcher-8-go-to-computerised-dobsonian-telescope.html) he got from BinoCentral in Perth. He uses a Nikon D7500 and a 3x Barlow to take lunar photos. The magnification that this gives him means he can't get the whole face of the Moon. Instead, he has to make mosaics, and fit them together on his computer afterwards.

Earlier this year, Jacob realised that he didn't have to use images taken on the same night. Instead, he took images of parts of the Moon where the angle was just right. These areas are not too close to the terminator (where the shadows were too long), but not too far either (where the shadows were too short). He then stitched the photos together, which was complicated due to "libration" (the way the Moon seems to wobble on its axis).

Jacob took three months to get the 117 images he used to make up the finished version. Of course, he took a lot more, ditching the ones that weren't up to scratch. He used Photoshop to align them and adjust the lighting, but he says if he had his time over he'd investigate Microsoft ICE as a stitching program.

For the detail-minded, Jacob used UHD video grabs of around 2000 frames from his Nikon, pre-processed them in PIPP and stacked and sharpened them in Registax before importing them into Photoshop.

It's a fantastic idea, and brilliantly executed. Amazing work, Jacob!