Asteroid Zelinda Occultation - 10 Sept 2007

Asteroid Zelinda Occultation - 10 Sept 2007
Diameter 127 km, Vmag=12.8
Star: TYC 0539-00499-1, Vmag=9.4

Video:

Prediction Map by Steve Preston: www.asteroidoccultations.com/2007_09/0910_654_8961_MapR.gif
Euraster Positive Report: www.euraster.net/results/2007/index.html#0910-654

Full Equipment Setup:
Meade LX50 10” SCT w focal reducer f/6.3
WATEC 902 H2 Ultimate 1/2" CCD Video Camera
Video Time Inserter: TIM-10 GPS Time-Inserter (ΑΜΕ)
GPS: Garmin GPS18LVC OEM Sensor
Radio Controlled Clock (DCF77): RMB899P Global Travel Clock.
Monitor: 10.5”
VCR: Thomson
... and A LOT of cables and wires!

Good video Vagelis.
Could you explain in a bit more detail how you recorded the video and inserted the time in it please?

Good video Vagelis.
Could you explain in a bit more detail how you recorded the video and inserted the time in it please?

Agree with that. I'd also like to hear of the history of your venture. It sounds to me like you were on a very close predicted path on the ground for this occultation... by the cheers, I mean.

Good video Vagelis.
Could you explain in a bit more detail how you recorded the video and inserted the time in it please?

Michael and Seanie,
The Watec 902 is a very sensitive CCD camera (0.0001 lux).
So if you put it on a 10 inch telescope you can record mag 12.5 stars in real time; that is stars twinkling at 50 fps.
The video output of the Watec is analog (composite video).
You pass this signal to a time inserting device, and then this device outputs the signal to a video monitor or a video recorder (VCR or MPEG).

The time inserting device (TIM-10 GPS Time-Inserter in my case www.astronik.de/produkte/gps/e_10167.html ) prints a time stamp in each video frame, so you have finally an output signal with a time stamp on it.
I have set up the time inserting device to print LOngitude (1st line) and LAtitude (2nd line) of the site, as well as the year, month, date, UT hour, min, sec and millisecs (3rd line).
The time inserting device, in order to produce a time stamp, gets either a GPS time signal through a GPS receiver (Garmin GPS18LVC OEM Sensor in my case psn.quake.net/gps/gps18.html ), or a DCF77 time signal through a DCF77 receiver.

So you finally have an analog video signal output with a millisecond precision UT Time stamp.

In my video I used both GPS time inserter (for video channel) plus I recorded the audio signals of the alarm sound of a DCF77 Radio controlled clock (for audio channel). Similarly, the first one of the quadruple beeps of the alarm marks the start of each second with millisecond accuracy.
Plus we can hear the voices of the observers.
I was observing the event through a TV monitor, while recording it, and the other 2 obserbers, Dimitris Kapetanakis and Kyriaki Tigani, were observing the occultation visually, through reflectors.
The star was occulted by asteroid Zelinda for 10.240 seconds.
We were very happy, the three of us, as you can hear!
A magical night.

Occultations of stars by asteroids are what I like most in astronomy.
Predictions of possible path and time do exist nowadays, eg astrosurf.com/eaon/ and www.asteroidoccultations.com/ but an occultation is always a LIVE event, which you never exactly know which fraction of which second it will take place, if it is even to take place or be visible from one's location.

Hey Vagelis i like it a lot, nice work.

thanx, Sirius!