Grazing Occultation of Aldebaran
29 July 2016
(9:50 – 10:50 UT)
This event was videotaped by MANY observers!!
If you have any observations, please let us know!!
Email basic information
(who you are, where you observed from, type of observation you made)
to Brad Timerson.
We will proceed from there with what else we need for a proper analysis.
This map is from David Dunham’s article about this event on p. 51 of the August issue of Sky and Telescope.
General Information for Observing Lunar Grazing Occultations
If you plan to set up only one station, or if you just want more detail of you observing sites (such as using the Google Map Street View feature to actually look at potential sites), you should use the interactive Google Map; for it, just click on the item in the “Google Map” column, the second from the right side. But before that, click on the predicted “Graze Profile” to the left of the Google Map; it shows the profile of the Moon’s edge with time relative to central graze in the horizontal direction, and distance in kilometers north or south (measured perpendicularly to the northern limit line, shown in light green on the Google Maps) in the vertical direction. A horizontal line drawn across the profile at the distance of the observing site from the limit line will show the events that can be expected, where the line intersects the profile. Gray bars on the left side of the profile indicate the number of events that can be expected; for one station, select a site at a distance where the gray bar is longest (extends farthest to the right). This distance (in kilometers) should be within the range of the two “Offsets” given in the last (right-most) column, but CAUTION, since the graze will occur in a low part of the Moon, the graze zone is entirely south of the green northern limit line (from which, therefore, no occultation will occur) – on the profile, the distance values are then negative, but for the offset values for the Google Map, they must have the OPPOSITE sign (always positive for this graze); sorry for the confusion, that’s just the convention used by the program used to generate the Google Map “.htm” file.
If the elevation above sea level of your planned observing site is more than 30m (but within 50m is probably OK) of the elevation value for the static map (it’s also the elevation value for the interactive Google Map), then you should send a message to IOTA member Brad Timerson at email@example.com asking for an .htm file for the elevation above sea level of your planned site, specifying in that message the elevation, and approximately where the observing site will be located, preferably by longitude and latitude. If you have IOTA’s free Occult 4 software, you can generate the google map file yourself after generating the graze path data from the lunar occultations menu grazing occultations page.