Observation by Chris Hooker: Mercury's sodium tail, 24th April 2022
Uploaded by
Chris Hooker
Observer
Chris Hooker
Observed
2022 Apr 24 - 21:30
Uploaded
2022 Apr 27 - 20:05
Objects
Mercury
Equipment
- 300mm F/4 Pentacon lens with 0.5x re-imager
- Knight Optical sodium D-line filter
Exposure
Stack of 15 frames of 30 seconds @ F/2
Location
Near Didcot, Oxfordshire
Target name
Mercury
Title
Mercury's sodium tail, 24th April 2022
About this image
Protons in the solar wind sputter light atoms out of rocks on Mercury’s surface to form a very tenuous exosphere around the planet. Material in the exosphere can be accelerated away from Mercury by solar radiation pressure to form a tail such as seen in this image, which was taken using a 3nm bandwidth filter transmitting the yellow D lines of sodium at 589.0 and 589.6 nm. The bright spot at the start of the tail is Mercury itself, attenuated by the strip of blocking filter. The two bright stars on the left-hand side of the image are 0.4 degrees apart, and the angular extent of the tail is about the same, which makes the physical length of the visible part of the tail roughly 1 million kilometres.
This image is a stack of 15 30-second exposures. The gamma has been greatly enhanced to increase the contrast of the tail.
Files associated with this observation
Like this image
Jeremy Shears,
Nick Hewitt,
Grant Privett,
Les Dickens,
Dominic Ford,
Mike Harlow,
Paul Whitmarsh,
David Basey,
Bill Leatherbarrow,
Richard Sargent,
Alan Thomas,
Paul G. Abel,
Peter Tickner,
James Weightman,
Robin Leadbeater,
Callum Wingrove,
Gerard Cauchi,
Dr Paul Leyland,
Philip Masding,
Ron Johnson,
Chris Dole,
Martin Lewis,
Steve Knight,
Nick James,
Richard Miles,
Mel Gigg
Comments
Thanks, Mike.
Another link with a nice movie from Messenger data is here:
https://spaceweatherarchive.com/2021/05/10/the-sodium-tail-of-mercury/
Chris
Great work Chris. I had no idea you could image this phenomenon with amateur equipment. Another one to add to the list of extreme planetary imaging challenges.
Martin
Thanks, Martin.
This was my fourth attempt over the last couple of years. However, I may have been making things more complicated than necessary: Nick James posted a couple of images of the tail that he took earlier this week from La Palma, without either an occulting block or a sodium filter. Not sure that would be possible from the UK, though!
Cheers,
Chris
Chris - I did have the advantage of being above 1000m on a mountain with stunningly transparent skies. It does show that it is possible to get it without a filter although I would doubt it is possible from anywhere in the UK.
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