Observing Lunar Occultations

This post deals with the observations of Lunar Occultations –

Recording exact time of the occultation – eyes method:

We would require at least two stopwatches.  One of this has to be accurately synchronized with a standard time.

Two Smart or Android phones.  On one phone you should install a GPS or atomic clock time app.  There are quit a few apps available.  One such phone is good for more than one observers.

Use the other phone as a stopwatch.

First check and set the time accurately on your phone with GPS or Atomic Time app.

Now we simply wait for the event to take place. Keep your eyes glued to the star and a finger ready to start the stopwatch.

The moment you see the event taking place i.e. the star vanishing – start the stopwatch.

Now stop the stopwatch at some fix time display by the GPS time watch. The difference between the two will give you the time of occultation.


A – GPS clock time when the stopwatch was stopped   22:28:00

B – Time in the stopwatch   00:02:08.37

The time of occultation = A – B = (22:28:00 – 00:01:02:37) =    22:27:57.63

Simple isn’t it.  You must also provide the exact location of your. You can get the location of your observing site from http://wikimapia.org/

See this map below.  We identified the location of our telescope on the map. Then using cursor keys we centered it on + mark of the map. You can see this in the right side of the map (which is cropped). We can read the coordinates as

Latitude  18 deg 59 min 21.3s N and Longitude 72d 48m 55.4s E





About skytonight

I am the present Director of Nehru Planetarium of Nehru Centre Mumbai, India I like to talk about astronomy and sky observations to general public.
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