During the night of 8/9 July 2010 asteroid 472 Roma with a diameter of about 50 km passed in front of Delta Ophiuchi, a naked eye star with a magnitude of 2.7.

Occultation path
Occultation path
Occultation path (PORTUGAL)

The occultation was visible along a path of about 50 km wide, crossing central Europe, Spain and Portugal.

Asteroids are generally too small to be resolved by ground-based observatories and asteroid occultations are extremely rare. Precise occultation timings recorded by observers along the path are invaluable for the determination of the asteroid shape and size.

A group of Portuguese Amateur Astronomers (APAA) were able to observe this rare event. The several groups were distributed along the occultation path:

1- Rui Gonçalves (team leader) & Juan Gonçalves (positive occultation) 38º 47' 56.0"N, 7º 39' 34.8"W
2- Pedro Ré & Carlos Saraiva (positive occultation) 38° 37' 1.3152"N, 8° 4' 50.0694"W
3- Luís Santo & António Silva + Rui Branco & Filipa Pimentel (positive occultation ?) 38° 30' 17.77"N, 7° 35' 44.35"W
4- João Cruz & Sérgio Bernardino (positive occultation) 38°59'19.74"N, 7°12'21.24"W

David Dunham (IOTA) organized part of these occultation observations in Spain and Portugal. Several observing teams were able to use portable setups provided by David to record the event.

Wide-field Chart
Finder Chart
Finder Chart

Imaging setup

Takahashi FS60C
QHY5 camera

  • Sensor Mitron MT9M001, 1/2 inch, BW
  • Effective Pixel: 1280x1024 1.3Mpixels
  • Pixel Size 5.2µm x 5.2µm
  • Peak QE 56%
  • USB2.0
  • 40 fps (with 400x400 ROI and 26 ms exp. time, can vary for other settings)
  • Uncompressed Video data
  • Built in Guide Port (standard 6 pin RJ12)
  • Mechanical interface M42x0.75 (T2)
  • Filter interface M28.5x0.5 Screw
  • Size 64mm diam x 33mm high
  • Weight 100 g
  • FS60C QHY5 camera (imaging setup)
    Imaging setup
    QHY5 rocks
    Will this thing work?



    FULL SIZE (LiMovie)

    Portuguese Team. From left to right: Luís Santo, Sérgio Bernardino, Rui Gonçalves, Carlos Saraiva, Pedro Ré, Juan Gonçalves, David W. Dunham, António Silva, João Cruz, David Dunham's wife (photo by Luís Santo).