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Mars (and moon) last night 5 March 2012.

Moonshane

By Moonshane
in Observing - Planetary

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Moonshane

Moonshane

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I had only two targets last night, Mars and the moon.

As I drove home the sky was very clear and although the seeing did not look superb I decided to have a go with my 16" f4 scope which for lunar/doubles and planets I mask down to provide an unobstructed 6.7" at f11. This usually provides me with a slightly darker, more contrasty and better defined view than the full aperture most of the time. For those rare nights of wonderful seeing, I will find the full aperture useful but that will be a rare event.

After set up and collimation I then went in for something to eat and waited for thermal equilibirium having taken the scope from a balmy house to the cool garden. This took surprisingly little time and with the fan running I could observe the moon at low power quite happily.

The moon was more than 50% illuminated and I was to observe Mars too so as usual I put the 2" Baader Neodymium filter in the 2" - 1.25" adapter so I could change eyepieces without having to change the filter over all the time - I can be clumsy in the dark. This I then put into the Paracorr which lives in the focuser of this scope giving an effective focal length of 1840mm.

One advantage of this focal length is that it allows the use of long focal length eyeieces to achieve half decent magnification. the 32mm plossl (58x) provided a superb image of the full waxing gibbous phase of the moon which sat nicely in the field with a good deal of space around it. The detail visible at this magnification is staggering and in truth not much less than when you up the power. The filter provides excellent contrast and a really 'natural' grey image. I took the time to look around the terminator edge and toured some of my favourite features using different magnifications. One thing that surprised me initially was that using a 32mm plossl in a f4 scope should have created a massive exit pupil (8mm) and that this should have made the secondary obvious at the eyepiece - after a few seconds I quickly remembered that I was not using the full aperture but the unobstructed refractor like 6.7" - no wonder! Doh!

The area around the crater Aristarchus is truly sensational when lit as it was and the large volcanic dome, Mons Rumker, like a big dob of plaster. One advantage of lower power viewing at this pahase is that the crater rays from e.g. Tycho are seen in context - and they are massive! i could not resist the oppoerunity to use my 6-3mm Nagler soom and just let the moon pass through the eyepiece. At 6mm (306x) the view was great and even at 3mm (612x!!) the view was usable, albeit no extra detail really seen. Not bad for a 6.7" scope!

With Mars a little higher now I turned my attention to that for the rest of the night. I tried lots of different magnifications and eventually settled on my 8mm Radian giving 230x. This provided the most steady view in fairly average seeing and allowed numerous features (no ideas of the names of most Mars features) to be observed. I could see the northern ice cap and surrounding collar of dark material very clearly and in the centre of the orange disk, three small but distinct areas of dark patches. At the other end of the planet, the south pole did seem visible to me as a pale brownish streak but perhaps I was seeing things as this is not seemingly visible in photos. However, what was clear was the dark greenish marking similar to that at the north pole. i could not make out Syrtis Major as I had done on previous nights.

One particularly interesting feature was a pale, roundish area near the eastern limb and about '10 past the hour'. I have no idea what this is but it shows well on the image in this thread which is a good representation of what I was seeing.

http://stargazerslounge.com/imaging-planetary/179043-mars-march-5th-5x-powermate-2x-barlow.html

All in all a great night's observing and brilliant to be under the stars (or the planets I suppose!) again for a while.

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Ags

Ags

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Your description of Mars on the 5th matches closely what I saw on the 4th with my 100mm mak, including the markings near the south pole which I also observed. (Of course, Mars is quite similar from night to night as it has a 24.5 hour day). But I have not been able to make out any sign of cloud formations - that must be beyond my scope. Hopefully I will have another chance again tonight... :-)

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spaceboy

spaceboy

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It is interesting to hear of these clouds. Would they resemble a light patch similar to the iced over pole ? I have several times seen what I had thought to be a second pole yet checking images on the net there is only one ice cap. Is there a chance that it is cloud I am seeing or at least the reflection of light off the cloud??

Great report BTW Shane. Have you tried out the 6" OO yet ? and how dose it compare to the stopped down 16" ?

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bish

bish

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One particularly interesting feature was a pale, roundish area near the eastern limb and about '10 past the hour'. I have no idea what this is but it shows well on the image in this thread which is a good representation of what I was seeing.

http://stargazerslounge.com/imaging-planetary/179043-mars-march-5th-5x-powermate-2x-barlow.html

All in all a great night's observing and brilliant to be under the stars (or the planets I suppose!) again for a while.

That is very much how I saw it a few nights ago. I was sure I could see a large light patch, but the seeing didn't stay good for long enough to have a really good look at it, just glimpses that it was there.

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