[DaveGee (Dave Gault)]

22nd June 2008 - 19:06 to 19:23 Universal Time (UT)

On the morning of the 23rd June 2008 (local time) Pluto and Charon will occult 2UCAC 25370733, a mag. 12.4 star in NW Sagittarius.

Observers from the Eastern Australian Coast and Indonesia to Madagascar and South Africa are encouraged to observe the events.

The goal is to measure the rate of dimming of the star as the planet and the atmosphere absorb the light. From this, the pressure and temperature can be calculated. This will contribute to ongoing studies undertaken by researchers at Observatorire de Paris and Southwest Research Institute and Lowell Observatory. These researchers will welcome all observations.

Typically an observer with a 8" scope or bigger would take intergrations as fast as your equipment will allow, ideally one or two per second or better. For the event in 2006 I used my 10"f5 and a Meade Deep Sky Imager (pro). For this event, I'm planning on using two scopes, an 8" SCT with the DSIpro and my 10" Newt with the Watec WAT-120N intergrating video camera.

Both Pluto and the Target Star will be in the FOV of this equipment from the 17th to the 27th so you will have plenty of opportunity to practice finding and observing. You will need images of the pair well separated anyway for accurate photometry, so start the observing project early.

Visual Observers should attempt the observation as well. When Pluto or Charon occult the star, there will be a 1.7 magnitude drop in brightness which should be easily detected. OK, you probably won't be able to detect the thermal layer in the atmosphere but your observation will aid in determining the actual path limits due to your geographic location and timing data. Besides, you can boast that you are among the first to visually observe an occultation of a Kuiper Belt Object.

Below are the latest path predictions for both events.

If you know of an observer near the path prediction for either event, please forward this message to them.

Any questions? I'm happy to help. Just ask here or direct an email to... (dave4gee "at" yahoo.com.au) "at" = @)