[Launch Alert] Launch on Schedule

[Launch Alert]

Thursday morning's launch of an Atlas V rocket from Vandenberg AFB remains on schedule. Liftoff is slated for 05:49 PDT, the presumed start of an undisclosed launch window. Following liftoff, the Atlas will rise vertically for several seconds and then probably begin a gradual turn towards the south.

During the early portion of the launch, the Atlas will probably resemble a moving orange or red light. As the rocket heads downrange, its color should likely gradually change to white. Near the end of the first stage burn, the exhaust of the Atlas will expand and form a "diamond ring" consisting of a white arc with a bright "star" (the rocket) on the edge of the arc.

If you have suitable equipment, you may want to try to photograph the diamond ring. The suggested equipment is:

- Digital SLR
- 100 mm lens
- Tripod
- Cable release

I estimate the correct exposure to be 1/4 second at f/4 and ISO 1600. However, I would suggest using shutter speeds of 1, 1/2, 1/4, and 1/8 second to improve your chances of getting a usable image.

There is a one-in-three chance that the rocket will climb into sunlight during the first stage burn. In that case, the rocket's exhaust plume could be brighter.

Webcasts of the launch should be available from the following web sites:

  https://spaceflightnow.com/

  http://www.ulalaunch.com/

  https://www.nasa.gov/multimedia/nasatv/

Because of my schedule, I will not be able to answer questions regarding this launch. For information about viewing Vandenberg AFB launches, go to:

  http://www.spacearchive.info/vafbview.htm

For information about photographing Vandenberg launches, go to:

  http://www.spacearchive.info/vafbphoto.htm