Well, we’ve been clouded out for our last 2 attempts to see a lunar grazing occultation. Thanks to a great contact, I’ve been made aware of another occultation coming up on Nov 17 (thanks Brad). Will 3 times be the charm???
A regular occultation is when the moon passes in front of a star and blocks its light. A grazing occultation (GO) is special in that the edge of the moon passes in front of the star. By being properly positioned along the path, you can observe the star wink on and off as it passes behind lunar surface features such as mountains and valleys. Astronomers have used this method to determine dimensions of lunar features and the apparent diameter of the star.
The path of the next GO will be moving through our area at 8:50 pm on Nov 17 (18 Nov 1:50 UTC). It will pass close to Binbrook Conservation area which is one of our favourite viewing locations. However, it won’t be positioned quite as close to the path center as our last attempt. From our regular observing location, we would be barely within the 5km viewing path. This is far enough from the path center that we’d lose some of the effect and details. Therefore we may want to consider observing from a different location along the path. The star to be occulted is SAO 164750, which is a mag 7.8 star. Not visible to naked eyes, but should be easy with binoculars and small scopes.
I’ve added an image of the map with the graze path on it. We are still working out our plans on the actual location where we’ll set up to observe this occultation.
I’ve also provided a link to Google maps which shows the path. Be aware that this page may not load properly in all browsers. I find that I have generally had good results with Firefox. IE has generally been less successful. Your mileage may vary.
Grazing Path
Update: 12 Nov 2007
The current long range forecast (TWN) is calling for variable clouds, 20% POP, low temp of -3C, winds 20km/h from the west. Sunday is currently forecast to be clear – we may get lucky if the clearing trend arrives earlier than expected.
The moon will be about 40-45% illuminated. If I’m reading the charts correctly the occultation will begin in our area at around 20:47. The moon will be positioned 24 deg above the horizon and the azimuth will be 218 (SW) (This means we’ll want to be south of the city along the path for observing). The occultation appears it will occur on the sunlite side, at the SE edge of the moon.
We also have the opportunity to view Neptune which will be mag 7.9 nearby and we’ll be getting into the peak days of the Leonid meteor shower. (peak is expected Nov 18-19) So if the clearing breaks don’t allow us to see the occultation, we may have an opportunity to see some other things in the sky on Saturday night.
Observing location still to be determined. Stay tuned.
cheers
