Observing Report 21st January 2011 - Lunar 100 (mainly)

Moonshane · January 24, 2011

Observing Report 21st January 2011

Location Cheshire, England Latitude: (53°N) Longitude: (2°W)

Equipment – f5.3 300mm Orion Optics UK Dobsonian, Televue and Baader Genuine Ortho eyepieces

Main Target: Lunar 100 List

After a successful night on the Lunar 100 on 16th of January, I followed this up this evening with a further evening of mainly lunar observations. With the Luna so bright and almost full, this is about all you can do anyway! As always, I like to add another object to my list and did so with Sabine & Ritter late in the session, taking my overall tally to 66 from the 100 list.

The main eyepieces used were my 9mm University Optics Orthoscopic (178x) and my Televue Nagler 6-3mm zoom (267x-533x) with occasional use of my 7mm BGO (228x). The zoom was mainly used at the 6mm end but occasionally the seeing was good enough to use with a little more magnification (300x+). Using my two scopes on the same target, I found that although there was possibly more contrast with the 6” f11, the 12” f5.3 just edged it on detail visible with the additional resolution that comes with aperture. The more stable platform of the heavier and lower OTA also makes this a much more enjoyable scope to use; there is almost no vibration even at high magnifications. I expect that my view might change on this once I complete my equatorial platform for the 6” (I may also make one for the 12”) given the benefits that tracking objects, without the need to constantly to move the scope, will bring.

I am following the East Valley Astronomy http://www.eastvalleyastronomy.org/obs-lists-pdf/OTL100.pdf daily lists for the moon and we were on Day 16 according to an online source. Tonight there were 15 targets including my new target as mentioned above. So I looked at just these objects rather than adopting my usual approach of looking for those objects on days either side of the date on which I observe. I am finding the book Moon, Mars and Venus by Antonin Rukl to be a real bargain and absolutely excellent for ‘crater hopping’ to more difficult Lunar 100 objects. You can also often use the position of other more defined craters to confirm the position of your main target where this is proving tough to locate.

10 Mare Crisium - success

When fully illuminated, this area of the moon forms a large, and apparently flat, oval shaped basin, visible with the naked eye at around the two o’clock position. Tonight it was about half visible and as a result, was beautifully framed by the mountainous walls. Plenty of surface wrinkles were highlighted by the strong side lighting. I noted eight main craters on the basin floor including Pierce and Pierce B, Picard, Yerkes and Lick.

12 Proclus - success

This is an interesting crater and in this light appeared almost caldera-like. It is very bright with a lot of white material within the walls and with a large ray off to the left.

16 Petavius - success

This is a large crater and no real detail could be seen due to the phase of the moon. Only the huge central peak was visible, the rest of the area being inside the shadow beyond the terminator.

25 Messier and Messier A – success

These ‘twin’ craters are easily found even when the moon is full. As always the similic sideways glance of those ‘robot eyes’ makes me chuckle.

31 Taruntius - success

This crater was well lit and as a result, the central peak seemed quite low and small; dare I say somewhat nipple-like. I managed to pick out good detail in the concentric rings within the main crater wall.

40 Janssen Rille - success

The view tonight was even better than previously and I now wonder how I have not been able to see this feature before 16/1/11. This is a huge crater and with many details including the very clear rilles. This area could be studied for a long time.

56 Mare Australis – fail