Jump to content
  • Join the online East Midlands astronomy club today!

    With active forums, two dark sites and a knowledgeable membership, East Midlands Stargazers has something for everyone.

Mars White Albedo Feature

Recommended Posts

4 hours ago, Sunny Phil said:

Did you get any of these images with your ED72?

No, they're all screenshots from various software. The second picture, which is mirror-reversed, is from SN8 and I added the white albedo feature with Photoshop. The last picture is from Nasa and public domain. I've observed Mars since with the 72ED at 190x and 210x with Baader Neodymium and Semi APO filters. The transparency wasn't good and Mars was much lower. The southern pole looks a bit yellow even without a filter.  The white albedo feature in the north was still there. Others have also seen it.

Link to post
Share on other sites

I want to set my EQ5 up soon, I usually leave it at the northern end of my garden covered with a tarpaulin. In this way I only have to carry the 150mm Newtonian OTA out to it when I want an observing session.




I'm partially paralysed on the entire right side of my body, so my smaller scopes get out more often lol. I've seen small white albedo features on Mars in previous opposition years, but this is big enough to see with a 72mm refractor.  I've seen it with my 80ED DS Pro and my 102mm ED doublet. I automatically assumed it was cloud. 




I'm leaning towards the idea of sunlight reflecting off a large flat plain of some description.




Maybe not unlike something similar to the Indus Vallis area. The southern pole is easily visible this opposition year. In years past I've often struggled to see either pole and occasionally needed filters. The angle of sunlight must be making the pole more visible, and doing the same for the white albedo feature.

Edited by Nightspore
Link to post
Share on other sites
  • 3 weeks later...

After some research I'm fairly certain that the white 'cloud' feature I've been regularly observing on Mars is a manifestation of the Northern Polar Hood.


"The ice cap in the north is of a lower altitude (base at -5000 m, top at -2000 m) than the one in the south (base at 1000 m, top at 3500 m).[21][22] It is also warmer, so all the frozen carbon dioxide disappears each summer.[23] The part of the cap that survives the summer is called the north residual cap and is made of water ice. This water ice is believed to be as much as three kilometres thick. The much thinner seasonal cap starts to form in the late summer to early fall when a variety of clouds form. Called the polar hood, the clouds drop precipitation which thickens the cap." ~ Wikipedia


The image below is a screenshot from Stellarium, edited, mirror reversed, and re-oriented in the Glimpse Image Editor.




Although much bigger and more defined than I've been seeing through the eyepiece (for clarity), this is an approximation to what I saw on 19/9/20 roughly at transit. I've tinted the southern pole with yellow as it appears this way to me (even unfiltered) and I've added an approximation of the Northern Polar Hood.


Edited by Nightspore
Gremlins with attitude
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.