Author Topic: Dark Halo Craters  (Read 55289 times)

Tom128

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Re: Dark Halo Craters
« Reply #15 on: June 25, 2010, 04:39:26 am »


ID: AMZ10014it
Latitude: -1.38331°
Longitude: 56.341°

Does crater upper right fit into dark halo parameters?




Geoff

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Re: Dark Halo Craters
« Reply #16 on: June 25, 2010, 08:24:29 am »


ID: AMZ10014it
Latitude: -1.38331°
Longitude: 56.341°

Does crater upper right fit into dark halo parameters?

Hi Tom

This looks more like a shallow impact crater to me. The impactor would have come in from the 2 o'clock position and the dark streak at this position is known as the "forbidden zone".
See this image of the week posting for more info (especially the reply by Katie Joy):
  http://forum.moonzoo.org/index.php?topic=202.0

Aliko

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Re: Dark Halo Craters
« Reply #17 on: June 25, 2010, 05:24:59 pm »

# ID: AMZ10013tj
# Latitude: 13.0503°
# Longitude: 62.1396°

Tom128

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Re: Dark Halo Craters
« Reply #18 on: June 25, 2010, 05:32:54 pm »
Thanks Geoff and Thomas. 

weezerd

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Re: Dark Halo Craters
« Reply #19 on: June 25, 2010, 09:12:44 pm »


000171654
Longitude: 333.894
Latitude: -8.37299


Well now that's really spooky!
I've increased the size because I just noticed the centre of the dark halo is a ghost of Buck's Fizz????
(or some other remnant from the 60s!!!)
« Last Edit: June 27, 2010, 04:38:55 pm by weezerd »

Aliko

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Re: Dark Halo Craters
« Reply #20 on: June 27, 2010, 11:24:13 am »

# ID: AMZ1001676
# Latitude: 21.0457°
# Longitude: 30.8841°

IreneAnt

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Re: Dark Halo Craters
« Reply #21 on: June 28, 2010, 12:47:42 am »
Irene: Tom128 found my original message for me and I modified my message here with the coords. 
Thanks DJ. I will have to spend some time looking at that one much more carefully.

Then I'm officially lost.  I figured if it wasn't consistent with a shadow it must be dark volcanic matter.  Back to the drawing board.
Thanks for the look-see, Geoff.
Just to clarify, there are 2 types of dark-haloed craters.
   1) volcanic vents that have dark halos of pyroclastic material that was emplaced around the vent when lava fountained from the vent.
   2) impact craters that have excavated dark mare materials from below a layer of light-coloured ejecta. Sometimes the buried mare material is patchy and so the dark halo can end up patchy too. The image I asked about (from the first quote in this post) was of this type.

Tom128

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Re: Dark Halo Craters
« Reply #22 on: June 28, 2010, 04:06:53 am »


 ID: AMZ10016pq
 Latitude: 20.7746°
 Longitude: 31.0279°


Tom128

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Re: Dark Halo Craters
« Reply #23 on: June 28, 2010, 04:16:58 am »


ID: AMZ10016lp
Latitude: 20.9887°
Longitude: 31.0009°



« Last Edit: June 28, 2010, 04:51:27 am by Tom128 »

Tom128

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Re: Dark Halo Craters
« Reply #24 on: June 29, 2010, 01:54:49 am »


ID: AMZ20002c4
Latitude: 48.7799°
Longitude: 3.02675°

level 2 zoom

Thomas and Irene, is this a halo?



Level 3 zoom

Looks pretty dark around the rim.

 

 Latitude: 49.2029°
 Longitude: 2.81395°

Couple more same strip.  Beginning to think they are faux halos.






« Last Edit: June 29, 2010, 02:03:50 am by Tom128 »

IreneAnt

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Re: Dark Halo Craters
« Reply #25 on: July 05, 2010, 05:46:24 pm »
Hey Tom128,

My first guess is that these are just shadows, because they occur on slopes that face away from the sun.

Thomas J

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Re: Dark Halo Craters
« Reply #26 on: July 05, 2010, 07:49:07 pm »
I agree with Irene, Tom128, they do look like shadows in these images. Please keep on looking, though, as there are a lot more out there to find. just post anything that you think could be one and we'll give you some feedback.

Thomas  :)

Tom128

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Re: Dark Halo Craters
« Reply #27 on: July 06, 2010, 12:47:46 am »
Thanks Irene and Thomas, any new information on this previous submission:




IreneAnt

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Re: Dark Halo Craters
« Reply #28 on: July 06, 2010, 09:02:01 pm »
Thanks Irene and Thomas, any new information on this previous submission:

Hey Tom128,

I have looked at this feature in the MoonZoo explorer and the original LROC strips (M106985205LC, M104627085LE, and M109345337LE). It's really hard to tell, but I think this is just shadows...?

Tom128

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Re: Dark Halo Craters
« Reply #29 on: July 06, 2010, 09:37:48 pm »
Thanks Irene,

I will look for features more in line with what you and Thomas have been sharing.