Lunar sodium tail

Lets brighten up peoples live with all those lovely pictures of the world around us!

Moderator: Montana

Post Reply
User avatar
KMH
Almost There...
Almost There...
Posts: 987
Joined: Sat Feb 22, 2014 4:45 pm
Has thanked: 641 times
Been thanked: 725 times

Lunar sodium tail

Post by KMH »

Back in May I posted pictures of Mercury's sodium tail. The moon has one too, thought to be mostly generated by micrometeorite impact. It is fainter than Mercury's, but can be easier to see at new moon. At this time, especially near astronomical midnight, we are looking down the long axis of the tail, increasing it's optical density considerably. Also, earth's gravity is thought to somewhat focus the tail, further aiding observation. It is still quite faint, but we were able to image it this weekend after several unsuccessful summer attempts. The anti-solar point at midnight is almost directly overhead here during winter, which helps a lot. Images were taken with a DSLR and 24mm lens, using a 10 nm bandpass sodium filter (589 nm). I should note that all the sodium vapor lamps around town don't really help this effort!
I attached two images. The first is from 12/3, about 2 hours before new moon. It is relatively unprocessed, and the spot can barely be seen between the Pleiades and the Hyades. It's big - about 2.5-3 degrees across. The second is much more processed (and hence noisy) in order to be able to better see the motion of the spot along the ecliptic between 12/3 and 12/4 (the latter being about 22 hours after new moon). Neither image will win awards but we're very happy with these as proof-of-principle images. We'll use what we learned from this and hopefully get better pictures in January. I may have to splurge on an imaging quality filter with narrower bandpass!


ps_dss_10min_ lunar_Na_120321_jsmall.jpg
ps_dss_10min_ lunar_Na_120321_jsmall.jpg (2.46 MiB) Viewed 1363 times
psflat lunar Na sidebyside jsmall.jpg
psflat lunar Na sidebyside jsmall.jpg (2.14 MiB) Viewed 1363 times


Tigger
Ohhhhhh My!
Ohhhhhh My!
Posts: 70
Joined: Tue Mar 23, 2021 8:27 pm
Been thanked: 98 times

Re: Lunar sodium tail

Post by Tigger »

Hi,

Thanks for sharing the images. I had no idea that the Moon had trail. You learn something new every day. Good luck in Jan, hope you have clear skies.

John


User avatar
Montana
Librarian
Librarian
Posts: 34558
Joined: Mon Oct 17, 2011 5:25 pm
Location: Cheshire, UK
Has thanked: 17648 times
Been thanked: 8787 times

Re: Lunar sodium tail

Post by Montana »

Wow! amazing images, I didn't know about this either :bow :hamster:

Could you add an annotated version to describe what we are seeing the images? I think I am looking at the right place but not sure. Also, why is there a halo, is this a 365 degree image?

Alexandra


User avatar
KMH
Almost There...
Almost There...
Posts: 987
Joined: Sat Feb 22, 2014 4:45 pm
Has thanked: 641 times
Been thanked: 725 times

Re: Lunar sodium tail

Post by KMH »

Thanks John and Alexandra!

Alexandra - there is severe vignetting since the clear aperture of our sodium filter is somewhat less than the lens aperture. The first image is pretty close to how it appeared on the camera screen. The second was extreme processed to better show night-to-night motion of the spot along the ecliptic (which helped us be confident that this was the sodium spot and not some artifact or cloud, since nothing was changed with the equipment setup (such as filter orientation)), but this also introduced LOTS of noise and a brightness gradient. I'll continue to work on the processing, and post another hopefully cleaner version that includes annotations.

I guess I should also have clarified that the tail is formed by radiation pressure, like a comet tail. The sodium has very strong resonant light scattering at 589 nm.

Kevin


User avatar
KMH
Almost There...
Almost There...
Posts: 987
Joined: Sat Feb 22, 2014 4:45 pm
Has thanked: 641 times
Been thanked: 725 times

Re: Lunar sodium tail

Post by KMH »

Here's an annotated version with less extreme processing. The line shows the ecliptic, and east is to the left. The circles indicate the shifting position of the spot along the ecliptic.

Kevin
psgreyraw_flat_dss_compare_120321_120421_small.jpg
psgreyraw_flat_dss_compare_120321_120421_small.jpg (1.24 MiB) Viewed 1318 times


User avatar
Montana
Librarian
Librarian
Posts: 34558
Joined: Mon Oct 17, 2011 5:25 pm
Location: Cheshire, UK
Has thanked: 17648 times
Been thanked: 8787 times

Re: Lunar sodium tail

Post by Montana »

:bow2 I understand now :bow

Alexandra


christian viladrich
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2150
Joined: Sun Jun 14, 2015 4:46 pm
Location: France
Has thanked: 1 time
Been thanked: 2712 times
Contact:

Re: Lunar sodium tail

Post by christian viladrich »

Amazing. Well done !!


Christian Viladrich
Co-author of "Planetary Astronomy"
http://planetary-astronomy.com/
Editor of "Solar Astronomy"
http://www.astronomiesolaire.com/
User avatar
pedro
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 12256
Joined: Sun May 01, 2016 8:26 pm
Location: Portugal
Has thanked: 14 times
Been thanked: 6573 times
Contact:

Re: Lunar sodium tail

Post by pedro »

fantastic post and images, well done


User avatar
marktownley
Librarian
Librarian
Posts: 42269
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20424 times
Been thanked: 10242 times
Contact:

Re: Lunar sodium tail

Post by marktownley »

Remarkable image!


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
Post Reply