Sunrise over Theophilus

    The images below were obtained on 22 June 2004 Pacific Daylight Time at prime focus of my Takahashi FS-102 using a Philips ToUcam Pro with an IR blocking filter. The imaging session spanned approximately 8 hours from about 3:15pm to 11:20pm at Hidden Hills Observatory, the dark sky site of the Tri-Valley Stargazers. Five minute videos (captured at 2 frames/second) were obtained every 10 minutes, resulting in 48 videos over the 8 hour session. Eight of the images were rejected from use in the movie because they were too out of focus.
    Theophilus lies at the western edge of Mare Nectaris, located in the mid-upper right of the movie below, and the near center of the Eastern Hemisphere image below. This crater is 110km in diameter, and it is one of the deepest craters on the Moon at 4.1km. It is a Tycho class crater which means it is characterized by "terraced walls, a flat floor, and broad central peaks" (p. 113, The Modern Moon: A Personal View, Charles Wood, Sky Publishing Corporation). Fracastorius lies at the southern edge of Mare Nectaris. You'll notice that it's northern rim has all but disappeared. It is believed that lava that filled Mare Nectaris caused subsidence due to its massive weight, with the result that Fracastorius tilted toward the center of Mare Nectaris. Subsequent lava flows buried its northern rim. Further south is Piccolomini (I just love that name, and just about anything Italian by the way), which lies at the eastern edge of the Altai Scarp. These features change dramatically in the time lapse movie below.
    Northeast of Mare Nectaris is Mare Fecuditatis, as seen in the Eastern Hemisphere image below. While bland in comparison to Mare Nectaris, it has one of the coolest features on the Moon (in my opinion), the craters Messier and Messier A. These craters are located in the northwest quadrant of Mare Fecuditatis. They appear as two black features (dots for the most part), with Messier (the eastern most of the pair) being 14 x 6km in size, and Messier A being about 13km in diameter. What distinguishes them is their tri-lobed bright rays. As you might have guessed, the elongation of Messier is because its progenitor impacted from the east at a very shallow angle, estimated to be 1-5 degrees (p. 94, The Modern Moon: A Personal View, Charles Wood, Sky Publishing Corporation). Perpendicular to the direction of impact two broad bright rays extend approximately to the north and south. The northern ray is broader and longer than that to the south. Messier A is a secondary impact with a bright ray that extends downrange to the west. If you look closely, you'll notice that this ray actually bifurcates into two rays. These are a few of the many interesting features that make the Moon a gem, which is all to often overlooked. I strongly recommend "The Modern Moon: A Personal View" by Charles Wood, Sky Publishing Corporation which gives a grand tour of our nearest neighbor.

The videos were processed using RegiStax 2 and in each case the best 200 frames were averaged to yield a single image that was then incorporated into the movie above. Final image processing was performed using Paint Shop Pro. All images were converted to black and white, and a variety of techniques were applied in an attempt to produce consistent "color" saturation across all images. This was especially challenging as the images were obtained under direct sunlight, twilight, and nighttime conditions. Focus changed dramatically during the day, especially in the late afternoon as the ambient temperature changed rapidly. The lesson learned is that the focus needs to be adjusted every 20 minutes or so. 8 of the images were rejected from use in the movie because they were too out of focus. Daylight exposures were at 1/250 second, while those at the end of the session were 1/50 second. The exposure time was changed based on the visibility of craters etc. in the ToUcam interface. However, once processed, most of the daylight images were too dark and had less contrast than the nighttime images. However, the evening images tended to be overexposed near the eastern limb. Next time I may settle on a single shutter speed (1/100 second) and find out if the final product is more uniform. The movie is a cropped version of the original 640x480 webcam format. Basics of the steps involved at getting consistent "color" saturation for the above movie are indicated below. The images at the end of the session tended to be brighter than those obtained early on, and as such the sunrise highlights were better defined. As a consequence I increased the brightness of the early images, which in some case didn't result in the best overall quality.

Raw Image (31kb) The is a RegiStax 2 processed image based on the best 200 frames of the 5-minute video. 22 June 2004, 22:22UT
Initial Processed Image (45kb) Using Paint Shop Pro this image was converted to b/w. The histogram of brightness values exhibited a very strong peak. I adjusted the low pixel value to the edge of the histogram peak. This contrast adjustment was stronger than a simple "stretch." 22 June 2004, 22:22UT
Cropped Processed Image (12kb) Cropped from the image immediately above, this frame was dark compared to the nighttime images, and it did not have as much contrast. 22 June 2004, 22:22UT
Final Processed Image (21kb) Here the brightness was increased, the midtones were expanded, and gamma was set to 1.2. 22 June 2004, 22:22UT

Sunrise over Theophilus: The Movie (2.3mb) Nominally, the frames are separated by 10 minutes, but because of poor image quality, mainly due to poor focus, some frames are missing. The highlights include sunrise over the western rim of Theophilus, and the subsequent emergence of two of its central peaks. Enjoy the sunlight creeping west along the Altai Scarp, and don't miss the shadow receding across the floor of Piccolomini. 22-23 June 2004, 22:22-06:17UT
The Eastern Hemisphere (50kb) This is a full frame image with labels of some of the major features. 23 June 2004, 04:27UT
The Eastern Hemisphere (40kb) The image immediately above, but without the feature labels. 23 June 2004, 04:27UT