Late 'night' Phoenix Observations. |
Late 'night' Phoenix Observations. |
Jul 12 2008, 08:55 PM
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#1
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Junior Member Group: Members Posts: 47 Joined: 27-June 08 From: Ashford, Kent, United Kingdom. Member No.: 4244 |
Hi everyone.
Phoenix on Sol 46 have returned images of the Sun above the Northern Horizon, just before midnight. Sun 11:14 PM local time. Sun 11:16 PM local time. Sun 11:26 PM local time. Andrew Brown. -------------------- "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.
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Jul 13 2008, 07:57 AM
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#2
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Member Group: Members Posts: 646 Joined: 23-December 05 From: Forest of Dean Member No.: 617 |
Thanks Stu and all, that's a keeper. I love such simple, almost abstract images where the power comes from the context.
At some point as the season changes there will be prolonged semi-sunsets, hopefully the CCD bleed problem will be mitigated somewhat - I'd love to see something like the Oppy "sunset at Meridiani" image, or even a simulated multiple exposures shot compiled over many days -- something like, say, http://www.eaglestation.com/sunsets/620-2197.jpg .(That's just a random pick from a quick google.) -------------------- --
Viva software libre! |
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Jul 13 2008, 08:25 PM
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#3
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Junior Member Group: Members Posts: 47 Joined: 27-June 08 From: Ashford, Kent, United Kingdom. Member No.: 4244 |
Hi imipak, what you suggested with the Midnight Sun montage you linked to, is exactly what I have already suggested to the Phoenix team.
Thought this may be interesting to share. Changing illumination during half a sol 46 - 47 from the RAC, local time, Scandia Colles. 12:09 Hrs Sol 46. 19:25 Hrs Sol 46. 20:45 Hrs Sol 46. 22:36 Hrs Sol 46. 23:20 Hrs Sol 46. 00:06 Hrs Sol 47. 00:58 Hrs Sol 47. Andrew Brown. -------------------- "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.
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Jul 15 2008, 04:08 AM
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#4
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Member Group: Members Posts: 150 Joined: 3-June 08 From: McLean, VA Member No.: 4177 |
Thought this may be interesting to share. Changing illumination during half a sol 46 - 47 from the RAC, local time, Scandia Colles. I really don't understand why the shadows, which are very distinct during the day, should be so washed out at midnight. Is the sky that much more lit up by a low sun? Is there a good deal of backfill lighting by the midnight facing surfaces of Phoenix... (no). Very odd and disturbing for a guy who has been trying to paint that scene for the last month (with little success). Paul |
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Jul 15 2008, 03:38 PM
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#5
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
I really don't understand why the shadows, which are very distinct during the day, should be so washed out at midnight. I noticed that too. The ratio of scattered light (via the sky) to direct sunlight is much higher when the sun is close to the horizon, because the air is so dusty, and low sunlight must pass through lots of dust. Think of the dust storm last year - there was so much dust that shadows became much less distinct for the rovers, even at midday. On earth you can see the same effect, but it's less noticable on clear days because on earth more of the scattered light is from air molecules than dust. Think of a smoggy or smoky day on earth. |
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Jul 15 2008, 04:14 PM
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#6
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Member Group: Members Posts: 150 Joined: 3-June 08 From: McLean, VA Member No.: 4177 |
Okay, that makes sense. I would have thought it would have been like the Opportunity low sun anyway - perhaps even more pronounced. The midnight shots are maybe a little more exposed, but I don't think so much that it would wash out a shadow line completely, especially since the lit parts aren't blown out. The anti-sun sky must be bright too then!
Paul |
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Jul 16 2008, 03:05 AM
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#7
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Member Group: Members Posts: 150 Joined: 3-June 08 From: McLean, VA Member No.: 4177 |
I'm trying to suss out the anti-sun sky near midnight and I'm not sure if I'm interpreting some of the 'blocky' SSI pics right. From Mark's site, SOL 49, this is a view straight at the sun at 1:00am. This was taken about a half hour later about 20 degrees east of anti-sun. To my eye, the at-sun shot gross variations in value compare reasonably well with the high rez pic gradations taken earlier. It's filter was L3 450.8 (solar/dust). The second picture, taken through the L5 887.0 filter (solar/dust+water), seems to indicate that the sky brightens as elevation >increases<. At least me looking at a 'lego block tower' shot with fredk's take on the lack of shadows in the RAC midnight pics in my head, makes me think that's what I'm looking at. Is the data too skimpy? (What, 15 pixels ...?) Anybody see what I'm seeing? Should I read up on filters?
Paul |
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Jul 19 2008, 04:10 PM
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#8
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Junior Member Group: Members Posts: 47 Joined: 27-June 08 From: Ashford, Kent, United Kingdom. Member No.: 4244 |
Hi all,
I have worked on this image, with contrast & a little cropping, centreing the Due North point. Looking Due North @ 11:09 PM / 23:09 local time in Scandia Colles. North Pole is approx 1,303 KM / 809 miles straight up the centre. Sun is off to the left. Andrew Brown. -------------------- "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.
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