Firstly, after I had set up my 15" dob beside my apartment block and collimated my scope for a quick look at Mars, a sudden deluge of water rained down on me. Two neighbours beside me did not get wet but they witnessed the downpour. Apparently someone upstairs has a habit of throwing water out of the window and I happened to pick the wrong spot to set up my scope.
So they helped me to carry and shift the scope to a safer location at the back of the block, right at the edge of the road kerb - see photo below! I re-collimated the dob and showed 9 neighbours and passerbys who were delighted by the views of the crescent Moon and Mars.
After 11:15pm, the passerbys and neighbours left and I was able to spend some private time to observe Mars. I had a magnificent view of Mars! Image was sharp and steady at 438x using the Leica ASPH Zoom with Zeiss 2x barlow, and 523x using the Ethos 3.7mm on my home-built 15" f/4.5 dob with ZOC mirror. Paracorr II was in use but I did not bring any filter. I didn't bring my equatorial platform, so I was observing just by drifting the object from edge to edge. Over here in Singapore, we usually have steady seeing and I usually observe planets at 400-600x on the 15" dob. Two years ago, I managed to observe Mars sharp and steady at 750x on this same dob.
I was delighted to observe two of the Tharsis Mons as distinct dark discs, so I did a quick pre-sketch on the back of an envelope at 11:43pm. Later after midnight, the third of the Tharsis Mons (ie, Arsia Mons) and Olympus Mons were clearly visible at the preceding limb, and I did a second pre-sketch at 00:26am. Asia Mons seems to be slightly closer to Tharsis Montes (the middle Mons) than Tharsis Montes to Ascraeus Mons, perhaps due to forshortening effect at the preceding limb. The first two Mons were seen distinctly as dark disk spots (almost like Jovian moon shadows), while Arsia Mons was a little indistinct and smeared. Olympus Mons was a faint and extended object in comparison to the three Tharsis Mons.
After my observation, I took a look at the condition of my primary mirror and it was littered with droplets of murky water - see photo below. Also the light shield at the rear of the primary mirror had fallen off while we carried the dob, so I was quite happy that I still had an excellent observation of Mars despite these handicaps. I told my wife I will only be observing for 15 mins but I ended up spending more than 1.5 hours!
