British Astronomical Association
Supporting amateur astronomers since 1890

BAA Images Paul Leyland

Observation by Paul Leyland: Elara (Jupiter-VII)

Uploaded by

Paul Leyland


Paul Leyland


2019 Jun 20 - 01:00


2019 Oct 08 - 10:53



  • 0.4m Dilworth-Relay
  • SBIG-8 with AO-7 autoguider
  • No filter

1x10s+ 10x60s around 02:45UT and 18x30s around 04:05UT


Tacande Observatory

Target name

Elara (Jupiter-VII)


Elara (Jupiter-VII)

About this image

The right image shows Elara at 02:42 UT; it's a stack of 11 images centred on the satellite. By 04:04UT Elara had moved very close to the V=16.45 star UCAC4 336-092391 and wasn't resolved. However, the addition V=16.6 Elara approximately doubled the brightness and this effect is easily visible when one compares the appearance of the line of four relatively bright stars in each image. The faint object visible in the left image at the position where Elara had been almost two hours earlier is a real star. It is 4115201409792784512 in theĀ Gaia-DR2 catalogue where it is recorded as being of magnitude 18.37. Precision astrometry in such a crowded field would be challenging.

My thanks to Nick James who taught me to make two sets of tracked stacks. It was fortunate that in this instance the images fell naturally into two sets each of short duration and well separated in time.

Files associated with this observation
Like this image
Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of work by third parties is expressly forbidden without the consent of the copyright holder. By submitting images to this online gallery, you grant the BAA permission to reproduce them in any of our publications.