The observatory logo, the first image analysed from the 1990 February 9 lunar eclipse
In 1966, NASA released a photograph taken by Lunar Orbiter 2 of a region on the western edge of the Sea of Tranquility that showed several objects casting unusually long shadows. A few scientists at the time speculated that the shadows were too elongated to be cast by common lunar boulders or ridges. Among them was William Blair, reportedly of the Boeing Institute of of Biotechnology. Blair noted that the objects casting these shadows appeared to be arranged in a subtly regular fashion that, together with the seemingly anomalous height of the objects, suggested an artificial origin.
These objects came to be known as the Blair Cuspids
This is the area studied by video imaging to produce surface
contours in the Blair Cuspids at 15.5oE and
5.1oN . The map is credited to Hamlyn Atlas of the
Moon by Antonín Rükl Director of Prague Planetarium
ISBN 0 600 57190 4, 1990. The Cuspids are a little E of and near to
crater B which is N of and near the feature Cayley.
Instrumentation
The Calwell Lunar Observatory is equipped with a 150 mm Newtonian reflector at f/7.3, a light control diaphragm and a monochrome CCD video camera with 650 lines horizontal definition.
The video images were captured by a Macintosh IIci computer and QuickImage 24 frame grabber with the images enhanced by the National Institute of Health Image version 1.58 software to obtain 3D surface contours and profile plots from each image. The telescope is equatorially mounted and quartz driven with slow motion remote control in both axes. A simple image intensifier is used to obtain images at 350 magnification, which can be captured on-line or by a 300 line video recorder for later analysis. The software contours are increased 7 to 8 fold to around 2,500 magnification.
Images from Lunascan
A Clementine image of the Cuspids has been received from Lunascan which illustrates the long shadows from five features, as shown below:
Images
Two observations were made to locate the area of the Blair Cuspids using data provided by the Lunascan team. These were conducted on 1997 February 18 from 11h 42m (UT) and on 1997 February 25 from 12h 30m (UT).
The camera CCD face was slightly contaminated on the first run but a typical image from the second run is shown in Figure 1 below where the Blair Cuspids are within the marked square now correctly shown, thanks are due to Lan Fleming:
Further observations
A third observation was conducted on 1997 February 28 when the moon was at an local altitude of 27.5 o, was 20 days old and at 68 % illumination, so as to obtain images near the local lunar sun set. Unfortunately the observations were a little late as the Cuspids were in shadow and just below the lunar terminator as shown in the image at Figure 4.
In the upper right corner are the craters Godin and Agrippa with the Cuspids in shadow just below the terminator. The lightened image shown in Figure 5 does not reveal any improvements in detail.
Conclusions
The Blair Cuspids are in an area of just 0.3 arc seconds (Lan Fleming, 1997 Feb 24) and cast long shadows when the Sun is at 2 degrees elevation, much later in this lunation than the first series of exposed image discussed above. Subsequent imaging has produced improved results as shown in figure 4, which includes the Cuspids area which unfortunately was just below the terminator and in shadow.
These observations have identified the location of the Cuspids for further study perhaps with much larger apertures and with illumination conditions at an optimum.
Acknowledgments
I am indebted to the Lunascan team, especially Francis Ridge for the initial information and to Lan Fleming for his helpful comments and exact location of the Blair Cuspids Area.
References
e-mail: slk@world.evansville.net
image: LO261H3.PICT as an attachment from Lunascan.