The Astronomy Help Center: handy & Informational Articles

GPS Rollover problems with Celestron Hand Controllers

Some GPS receivers may malfunction on or after 6 April 2019 due to the GPS Week Rollover.

This is a known issue caused by the way that GPS used to handle the week element of the navigation signal. GPS used a 10 bit field to encode the week number in each GPS time message. This means that a maximum of 1024 weeks could be handled. This period is called an epoch. At the end of each epoch, the receiver resets the week number to zero and starts counting again.

The current epoch started on 1 August 1999. The next GPS rollover is 6 April 2019 when the receiver will revert to week number zero and start counting up to 1023 again.

How to Collimate your Optics Using a Laser Collimator

  • Posted on
  • By Howie Glatter
How to Collimate your Optics Using a Laser Collimator

Collimation of a telescope's optics is a critical bit of maintenance that should be checked as often as possible. To maximize the performance of your optical instrument you need to ensure that the optics are properly aligned at all times. Today, the easiest and quiclkest method of collimationis with a laser collimator. Here is an informative article from the late great wizard of collimation , Howie Glatter, who will explain the entire process for each different type of telescope.