Asteroid Zelinda Occultation - 10 Sept 2007

Once again Vagelis many thanks for that very useful information and excellent advise and for taking the time out to reply. A lot of really good information to learn and make the most of, I just need to get out and practice!

Clear skies
Mike

I'm lost.

what occulted what?

Thanks for the detailed explanation Vagelis.

Hi Vagelis,

About 10 seconds was nice and long, the few that I got positive results (visually) were just a couple of seconds or so.

A few years back, I was lucky enough to become the first amateur in Ireland to observe an asteroid occultation.

What do you find to be the best timing source?

Video would seem the way to go, thanks for the notes,

John

(PJ: an asteroid occultatation is when an asteroid moves in front of a star, as the star is usually brighter than the asteroid the star "disappears")

John,
No time to answer now, I am just leaving home, I will be back on Tuesday!
See you PJ!

Hi John, and sory for the delay!
Good to hear that you have seen an occultation! Which one was it?
When I saw my first (of total 2) occultation last year, it was a visual observation, and I was told by experienced friends that I was very lucky that my first was visual and not CCD. Do you agree?

As for the timing source,

1. Best choice for visual observations it is just a radio controled clock which costs only 30-50 euros.
I have RMB899P Global Travel Clock (Oregon Scientifics) which I bought from "Clove Technology". And it is a perfectly accurate time source.
I tune it to Frankfurt atomic clock, DCF77, but you in Ireland can tune to the UK atomic clock: WSF-60.

2. An equal accuracy alternative would be a radio tuner, if there is a radio station that covers Ireland and broadcasts shortwave time signals.
Listen to this NIST Radio Station WWV sound file , which broadcasts in the USA ( tf.nist.gov/stations/wwv.html ).

3. Best choice for Video observations is a GPS Time inserter, or ...

4. ... a DCF Time Inserter (it takes time signal from DCF77, just like a radio controlled clock, eg RMB899P, but this is a video device, so it "prints" a DCF77 time stamp on video frames.

5. For Video observations, an alternative is to record the sound of the alarm of a radio controlled clock (eg RMB899P) in the audio track of the video.

In case 1, you have two options to use the Radio controlled clock:
a. To synchronise it with your stopwatch, or ...
b. ... set the alarm at the minute of the expected occultation or, better, minus 1 minute. Then you shout out loud, record your voice, and measure the start and end in respect with the alarm beeps.

I hope this is not too complicated!
Clear skies