IPB

Welcome Guest ( Log In | Register )

48 Pages V  « < 46 47 48  
Reply to this topicStart new topic
Akatsuki Venus Climate Orbiter
JRehling
post Jan 17 2018, 10:08 PM
Post #706


Senior Member
****

Group: Members
Posts: 2049
Joined: 20-April 05
Member No.: 321



These are wonderful. A similar palette is being used by many amateurs making IR/UV images at much lower resolution.
Go to the top of the page
 
+Quote Post
jccwrt
post Jan 18 2018, 03:00 AM
Post #707


Member
***

Group: Members
Posts: 199
Joined: 4-October 14
Member No.: 7273



A couple of attempts to merge the sunlit cloud deck imaged in near-UV and near-IR with nighttime thermal data taken at the 2.26 micron wavelength, which appear to be the least overexposed of the 2 micron camera images. The two sets of images were taken up to 2 hours apart, so the geolocation of these images probably isn't super accurate but should be fairly representative. I've also added a heat colormap to colorize the thermal infrared data - the scale doesn't correspond to specific temperatures or anything, it's just there to enhance some of the detail present in those images while also emphasizing that it's thermal data.





Go to the top of the page
 
+Quote Post
JRehling
post Jan 18 2018, 04:43 PM
Post #708


Senior Member
****

Group: Members
Posts: 2049
Joined: 20-April 05
Member No.: 321



Nice display of IR! It certainly gives the impression that we should not touch Venus without protective gloves.

It's hard to tell from just a couple of images, but I'd like to see a global average of limb darkening. There should be some limb darkening but in any single image, the regional variations are a bigger factor.
Go to the top of the page
 
+Quote Post
scalbers
post Jan 18 2018, 08:39 PM
Post #709


Senior Member
****

Group: Members
Posts: 1297
Joined: 5-March 05
From: Boulder, CO
Member No.: 184



I would guess the limb darkening has an interesting dependence on phase angle and location along the limb. A fun simulation project as well.


--------------------
Go to the top of the page
 
+Quote Post
scalbers
post Mar 8 2018, 06:04 PM
Post #710


Senior Member
****

Group: Members
Posts: 1297
Joined: 5-March 05
From: Boulder, CO
Member No.: 184



I'm curious whether any of the recent data or images would show how much limb darkening Venus exhibits at a low phase angle (fully lit). Is it possible to assess this with an image using only visible wavelengths?


--------------------
Go to the top of the page
 
+Quote Post
JRehling
post Mar 9 2018, 08:54 AM
Post #711


Senior Member
****

Group: Members
Posts: 2049
Joined: 20-April 05
Member No.: 321



QUOTE (scalbers @ Mar 8 2018, 11:04 AM) *
I'm curious whether any of the recent data or images would show how much limb darkening Venus exhibits at a low phase angle (fully lit). Is it possible to assess this with an image using only visible wavelengths?


That's an issue that I would love to see addressed. It certainly seems in all images that I've seen that this has at least some difference, though subtle, across the visible spectrum.

Venus Express imaged a glory on Venus, which implies that such a thing is perhaps in their data, unless the whole disk was not imaged. I haven't seen any such image that captures such a wide view.

Over the last few months I've been extremely eager to get a terrestrial photo of Venus at its fullest. I captured an image just four days ago with Venus at a phase angle of 18.5. (And immediately thereafter, an image of Mercury.) I wish it'd been less, and/or that the quality were higher, but weather has not been helping me out. I've seen few terrestrial images of a relatively "full" Venus in color. Perhaps what you are looking for can be approximated with this or a better terrestrial image.

Attached Image
Go to the top of the page
 
+Quote Post
vikingmars
post Mar 9 2018, 12:04 PM
Post #712


Member
***

Group: Members
Posts: 835
Joined: 19-February 05
From: Close to Meudon Observatory in France
Member No.: 172



QUOTE (jccwrt @ Jan 18 2018, 04:00 AM) *
A couple of attempts to merge the sunlit cloud deck imaged in near-UV and near-IR with nighttime thermal data taken at the 2.26 micron wavelength, which appear to be the least overexposed of the 2 micron camera images. The two sets of images were taken up to 2 hours apart, so the geolocation of these images probably isn't super accurate but should be fairly representative. I've also added a heat colormap to colorize the thermal infrared data - the scale doesn't correspond to specific temperatures or anything, it's just there to enhance some of the detail present in those images while also emphasizing that it's thermal data.


How nice ! Thanks very much jccwrt (and also to Ant103) : I'm feeling the heat too smile.gif
Go to the top of the page
 
+Quote Post
scalbers
post Mar 9 2018, 04:34 PM
Post #713


Senior Member
****

Group: Members
Posts: 1297
Joined: 5-March 05
From: Boulder, CO
Member No.: 184



Indeed now's a good time to get low phase angle images from Earth as JRehling did 2 posts up. I found this reasonably low phase angle view from MESSENGER (sorry this isn't Akatsuki) posted at The Planetary Society and processed by ugordan. Looks like there's some darkening even on the brighter limb. Interesting to see also how the subtle details look with the visually realistic processing.

http://www.planetary.org/multimedia/space-...01387b94_o.html


--------------------
Go to the top of the page
 
+Quote Post

48 Pages V  « < 46 47 48
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 24th April 2018 - 06:38 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.