mars from saturday 6th March 2010

[chrisrnuttall]

a cool, very clear and dark night, frost on the telescope but not on the lawn. seeing a little below average, but variable with fleeting steady spells.

I used the dark red filter to record the majority of the dark areas, but it was hard work and the image frequently became blurred or jumped about, so then tried the light red, which gave a crisper image but with lower contrast and i was able to glipmse erythraeums knobbles including margarifiter sinus and Juventae fons, and also solis lacus and aurorea sinus later on.

Also used no filter to look at the over all colours on the disc, and a dark blue to check for other clouds.

sinus meridiani showed little detail before rolling over the limb, there were two brighter arcs to its south on the limb, next to erythraeum, i think one is argyre.

For the first time i saw a notch in the polar cap, it appeared to be an extension of mare acidalium, and was very dark.

Bright white clouds seemed to form on the eastern limb as i observed ( or maybe i didn't notice them at first), the equator seemed bright again, more so in the chryse area, and the western limb had white/blue-ish mist over it.

I have also attached the page from my note book after seeing Andrew's 'Entry from last night's journal'. I thought it was a nice idea.

Chris

[DarkerSky]

Nice one Chris. You're picking up on a good bit of detail. Great to have cross-reference on the darker notch into the NPC.

[Andrew*]

Brilliant work - amazing detail.

Nice to see the journal page too! You take brilliantly detailed notes, unlike my eccentric scribbles!

Andrew

[dweller25]

Thats an excellent observation and very nicely drawn too.

[Paul G. Abel]

Absolutely stunning Chris! Your view of Acidalium and Mare Erythraeum tallies nicely with mine!

Best wishes,

-Paul.

[chrisrnuttall]

Paul

I just opened the two drawings in separate windows next to each other, its' quite good fun to compare them, we've got exactly the same features, but an hour apart.

I am interested to see you have rendered the equator quite pale and bright too, any ideas what causes this (clouds clearly but why at the equator? sunlight acting on the atmosphere?)

Incidentally i thought i saw the feature to the right of niciliacus looking forked as you drew it, but the seeing was so poor i couldnt be certain.

[Paul G. Abel]

Hi Chris,

It is more than fun to compare observations; it is essential!!! I'm glad we compare well, always reassuring to know we're all going in the right direction!

Now, for this apparition, a bright equatorial cloud is very common. I think Richard McKim discusses it in the report here http://www.britastro.org/mars/images/mars1995.pdf

I think the cloud activity maybe the result of the sublimating npc.

Have you been looking at Saturn?

-Paul

[chrisrnuttall]

Thanks for that link Paul, i will enjoy reading that report it looks like there is loads of good info in there, i find observing much more rewarding when you know about the object in the eyepiece!

I have only looked at saturn once this aparition, and it was over next door's house, lower than mars and decidedly blurry. I thought the disc seemed much more subdued than i have ever seen it, (which i think is now 11 years).

I will be observing saturn more in the coming weeks since my view of the western half of the sky is unobstructed, but an object to the east of the meridian is pretty much out of bounds for me, and i have two young kids and a job involving long hours, so getting to bed at a sensible hour is paramount!

I was surprised to see in your recent sketch that it is possible to observe a shaddow transit of a moon other than titan on saturn. I tried to see Dione in April of last year, but the seeing was not great like i remember it being when saturn was really high a few years ago, and i detected no sign of it. I will have to try again if there is another transit.

I am hoping to exploit my western horizon by continuing with mars until it is tiny, i find the seasonal chages fascinating.

[Paul G. Abel]

Hi Chris,

The drawing I made of Dione suggests it was an easy affair when it was incredibly difficult and I was, quite frankly on the limit of what I can do! I used averted vision to get both the shadow and Dione, although I am awaiting confirmation to make sure I did see Dione!

I got a few satellite transits last year but the seeing had to be good; misty nights are ideal. I have to admit that in average seeing, when there were transits of Saturn's satellites I couldn't see them in those conditions. In Leicester we often get misty nights (not sure why, the river soar is small and a few miles away!)

I did try of Mars' moons by blocking out Mars but I was unsuccessful! Do post your Saturn obs so we can compare!

[chrisrnuttall]

Paul

I will post them.

misty nights here too near york, but saturn is lower every year now. Could try Austrailia, I've heard it's lovely!

[bish]

You've managed to eek out every bit of detail you can with an 8" scope by the looks of it and produced a excellent sketch. Great stuff - shows what can be done.

[chrisrnuttall]

thanks Bish

i don't think there was much left that i could have got on the night. There is pretty much an hour and a half of solid staring in the sketch, i find it hard to do it any quicker!