Observing Report 20th September 2010 - Lunar 100 List

[Moonshane]

Observing Report 20th September 2010 (and it’s taken me so long to write this report 21st September 2010!)

Location Stockport, England

Equipment – f11 150mm Orion Optics UK Dobsonian

Main Target: Lunar 100 List

I recently came across a http://stargazerslounge.com/observing-lunar-solar/114080-useful-lunar-100-list.html and was keen to try this out and also use my newly acquired OO UK planetary dob. It was slightly frustrating again as I have not yet got the parts back from drilling and tapping for my home made friction brake (I’ll upload a thread when I get it back). As a result, for all my eyepieces other than my 11mm plossl, I have to, literally, hand-hold the tube to prevent it sagging. As a result all of the observations were made with my 11mm Televue Plossl at 145x.

As it was ‘moon day 12’ (I think!!) – is day one the new moon or is this the next day?? – I decided to work on the Day 11 and Day 12 targets in the above link as I presumed that many of them would be visible. With one exception I saw all of the 13 targets for these two days, of which six were new additions to the list for me. These are asterisked below.

20th September 2010

Moon Day 11 List

11 – Aristarchus – success – This is a really obvious feature on the moon and even when seeing is poor and cloud rolling in you can still see this crater. It’s one of the few craters visible in ‘Earthshine’ when the new moon is out and / or this area is in shadow. It’s in the outer edge at around 10 o’clock. The whole area around this crater, Herodotus and Schroter’s Valley (see below) is known as the Aristarchus Plateau and really interesting section of the lunar surface. The crater itself is beautiful bright white, with darker lines forming a stripy pattern inside.

17 – Schroter’s Valley – success – This is the largest rille on the moon and is most impressive. It cannot be missed assuming you have the right area. The start of the rille is a widened area known as the ‘snake’ or ‘cobra head’ which is a really appropriate name.

22 – Aristarchus Plateau – success – As mentioned above this is an raised area of volcanic activity and close up photos reveal many features of interest. It surrounds Aristarchus and Schroter’s Valley.

39 – Schickard* – success – The first time I have seen this crater and I have to say that when finding new features on the moon, my book ‘Moon, Mars and Venus’ by Antonin Rukl is absolutely superb . http://stargazerslounge.com/equipment-reviews/103116-book-review-moon-mars-venus-antonin-rukl.html The lunar maps are so detailed you can easily find all the other craters and features around the target and this confirms that you have the right crater, which can sometimes be difficult in the denser areas. The advantage with a Newtonian design is also that the view is simply upside down and this means you can just look at the book upside down for the same view. I find this much easier than the back to front inversion of the refractor when seeking out finer details; another reason I settled on dobsonians. Schickard is an excellent crater, actually a walled plain, with a dark floor bisected by a slightly raised paler area. The identification was confirmed by the craters Lehman, Schickard E and also Inghirami which were all position per Rukl. Secondary craters were present on the crater floor.

42 – Marius Hills – success – I really like this feature and have seen it several times before. It consists of various little ‘pimples’ and domes all from volcanic activity; the light angle has to be just right to see this at its best and it was tonight with my previous description of ‘peppercorns packed into ladies tights’ again springing to mind – think about it and you’ll know what this feature resembles.

44 – Mersenius* – success – Not seen this interesting crater previously. It is quite a large feature (82km long) and really does have an obviously domed floor, punctuated by smaller craters. Again the angle of light helped with this. The position confirmed by the proximity of Rupes Liebig, an impressive series of rilles one of which passes through Mersenius F and G which were also noted.

57 – Reiner Gamma – success – this is a slightly weird feature being a fish-shaped pale area of flat landscape, just ‘outside’ the large Crater, Reiner.

86 – Prinz Rilles (Rimae Prinz) – failure – I tried to see these rilles near the remains of this crater quite close to Aristarchus but had no success. The seeing did not help me and neither did the unstable scope which at higher magnifications has to be hand held to prevent sag – I have now resolved this thankfully see http://stargazerslounge.com/diy-astronomer/115026-ongoing-mods-my-orion-optics-uk-6-f11-planetary-dobsonian.html and will try again sometime with better seeing conditions and when the feature is closer to the terminator.

91 – De Gasparis Rilles (Rimae De Gasparis)* – success – again not seen to their full extent but I could clearly see the main rilles crossing the crater and will follow up this sighting under better conditions.

Moon Day 12 List

37 – Bailly* – success (I think) – The terminator was right on this feature and I could see the bright white crater wall of Bailly B and then the shape of a larger crater which I took to be Bailly to the correct side of the bright wall. Can anyone please confirm if I was looking at the right feature or is it a basin visible when the terminator reveals more of this area?

43 – Wargentin* – yes – No doubt about this one. The middle of the crater was again right on the terminator which moved a little as I was watching this feature. There was an obvious fold right up the middle of the crater, like a huge ridge on the dark floor – really quite impressive. Craters Nasmyth and Phocylides were seen nearby to confirm I was in the right spot.

62 – Rumker Hills (Mons Rumker) – success – this is a large blob of volcanic material which is really quite impressive when seen in the high contrast conditions seen tonight.

77 – Sirsalis Rille (Rima Sirsalis)* - success (eventually) – really quite a difficult feature to see tonight for some reason but eventually located using many of the guideposts nearby. The shadows of the terminator often make some bizarre shapes and tonight’s most strange was the shape made by Sirsalis itself. To my ‘crazy eyes’ it looked like a screaming spoon and I have tried to recreate roughly what I saw by cheekily extracting an image from Rukl’s plate of this area. The black line indicates roughly the terminator and to the right is shadow. Spoon = two ‘eyes’ at the top and ‘spoon handle’ at the bottom. I saw this feature a lot more clearly the following night.

21st September 2010

Moon Day 13 List

36 Grimaldi basin* - success – this is a superb crater and really quite prominent and with a flooded basin which is very flat and dark. Superb.

52 Cruger* - success – This is another prominent crater, a lot smaller than Grimaldi but again with a very dark crater floor. Nearby are the craters of Darwin and Lamarck, both people of whom I am a great admirer for their views on evolution – not that the latter got it right but was brave enough to make a stand for his views.

80 Orientale Basin (Mare Orientale) – failure – this was not in view on the day I observed and needs the right libration.

97 – Inghirami Valley (Vallis Inghirami)* - success – this was not as prominent a valley as a lot of other similar features on the moon. It was more like a faint gouge and shaped a little like the inside of a razor shell that you find on the beach. I had to really concentrate on this and carefully ‘crater hop’ using Rukl to locate it.

So all in all a successful couple of days on the moon with more to come in due course.

Best wishes

Shane

[Tantalus]

Another cracking report Shane, in your usual, inimitable desciptive style. You're obviously enjoying the 6" scope.

I've been reading through your other threads, and I was initially surprised when I read that you'd gone for a 6", but given the greater focal ratio and the quality of the mirror, I can see why.

I really should get a move on with my own Lunar obs, but I've been busy just lately, trying to juggle too many balls and something had to give.

[Moonshane]

cheers matey

I enjoy writing then and hope they encourage others to have a go at 'targeted observation' on the moon. I have found it's really rewarding and I am learning and seeing so much that I'd not have paid attention to previously. the 6" really is excellent and I reckon once it's flocked and has a fan it will be even better. the friction brake is temporarily fixed but the permanent one will have more control.

I love both scopes for different reasons.