Ten Years of NAC Imaging: Fun Visualization!

This week the LROC team looked back on ten years of lunar exploration at the Planetary Data Workshop, in Flagstaff, AZ. For this presentation, two 80+ GiB montages were created from NAC images collected from first light on 30 June 2009 until 17 June 2019. During a talk one can only give a small glimpse into the entire image, so we are posting the two images here allowing anyone to explore this fun visual and get a sense of just how large is the LROC dataset.

Zoomed out, the first montage looks like a cropped area of a NAC image. Zoom in and you will find it is made up of 1,210,000 squares of the Moon. The montage is composed of tiles cut from NAC pyramidal TIFF browse images; these tiles are roughly 1/4 the width of the NAC image and are subsampled to 256 pixels square. The tiles are arranged to make a 281,600 pixel square image resembling a Plato area image that appeared in an earlier LROC post, visit The West Side of Plato Crater.

Zoomed out the second montage looks like static from an analog TV. However, it is composed of 1,340,515 squares cropped from the center of NAC images, just like the first montage. This one is a little bigger because it includes a square from every NAC with a data quality ID of 0, > 1000 lines, a slew angle < 10° and an incidence angle < 85°. Even with those conditions, nearly 10 years of imaging resulted in an extremely large collection of NACs. The NAC tiles were placed in the montage in time order resulting in its distinctive appearance. The thin, dark bands across the image represent equatorial terminator crossing while the wider dark bands are centered at noon surface time. With the Sun directly overhead, high albedo areas stand out in high contrast. Due to the way LRO's orbit precesses around the Moon, each beta cycle (dawn to dusk terminator crossings) lasts 6 months. Count up the thin dark lines in the image, and you'll see all 20 beta cycles! This montage is 298,506 x 299,022 pixels in size, so zoom way in and explore the Moon from the earliest LROC NAC images (at the top) to the most recent LROC NAC images (at the bottom).