Mars Gibbous

[cloudsweeper]

Not having been out much for a while, I grabbed the opportunity this morning at 3.20am.  Some stars were on show, but with patchy cloud around.  However, Mars was mostly clear at 28deg in the SE.  I aligned the 8SE on it.

I've seldom seen anything other than subtle albedo differences, but this time the noticeable feature was the slightly gibbous apparition of the Red Planet.  It became clear at x135, 169, but lacked sharpness at x185.  The limb in the western sky was somewhat darkened.

The effect is due to the closeness of Mars to Earth, occurring when the Sun and Earth are widely separated from the point of view from Mars.  

Well worth getting up for!

Doug.

[John]

Nice report Doug. I noticed that Mars was gibbous when I observed it a week or so ago. It's currently around 85% illuminated.

I could see dark features plus the southern polar cap quite clearly then. I hope we are are not in for a planet-wide martian dust storm again during this opposition !

 

 

[cloudsweeper]

1 hour ago, John said:

Nice report Doug. I noticed that Mars was gibbous when I observed it a week or so ago. It's currently around 85% illuminated.

 

 

Thanks John - Yes, it is an interesting effect.  (I noticed however than one "specialist" online stated that it is due to Mars falling within Earth's shadow.  The pitfalls of the Internet.......!)

Doug.

 

[Guest]

Just took a quick look at Mars with the 80mm Equinox (time 2.45 a.m.).I did see dark markings and polar cap. But what grabbed me was being able to notice the gibbous phase. I have never seen or noticed this before. Well chuffed indeed.

Promising for opposition.

[David Levi]

Thanks for the info about gibbous Mars. I observed it last week when it was quite low down in the gunk and dismissed the less than round observation as an atmospheric effect.