Observation by Alex Pratt: (987) Wallia occults UCAC4 595-021823

Uploaded by

Alex Pratt

Observer

Alex Pratt

Observed

2024 Mar 30 - 23:44

Uploaded

2024 May 22 - 21:50

Objects

987 Wallia
Lightcurve

Equipment

C11 f/10 and f/3.3 focal reducer
QHY174M-GPS camera
SharpCap Pro (recording)
Tangra and AOTA (reduction)

Exposure

0.150 s

Location

Leeds, West Yorkshire (Bortle 7)

Target name

(987) Wallia occults UCAC4 595-021823

Title

(987) Wallia occults UCAC4 595-021823

About this image

The mag. 16 asteroid (987) Wallia was predicted to occult a mag. 11.5 star for up to 2.4 seconds. I was close to the centreline and successfully recorded a dip of 2.48 seconds' duration. The video is available here:

It was also observed by Karim Saci (Dunkerque, France) who recorded a 2.09 seconds dip. The lower graphic (by Tim Haymes, from SODIS data) shows our chords across (987) Wallia and an overlayed fitted ellipse of dimensions 55.5 km x 49 km.

Files associated with this observation

(319)_Wallia_20240330_ ARP.png (588.1 kB)

Like this image

Gerard Cauchi, Jeremy Shears, Robin Leadbeater, Tim Haymes, Dr Paul Leyland

Comments

Alex Pratt, 2024 May 22 - 22:03 UTC

Apologies, the online video is jittery and of poorer quality than the same MP4 on my laptop. I'll try to improve it.

Alex Pratt, 2024 May 22 - 23:02 UTC

Recreated the video as WMV. Its quality at the above link is degraded. Pity we can't attach more files to an observation; it's only 1 MB in size.

Tim Haymes, 2024 May 26 - 13:14 UTC

Illustrates how two or more observed chords can begin to reveal a profile. The vertical scale marker is 20 milli-arc-seconds. Occult4 prediction gave a diameter of 54Km (21 mas).

Nicely observed Alex and Karim.

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