Lunar 100 Update

[Moonshane]

Observing Report 26th April 2010

Location Stockport, England

Equipment – f5.3 300mm Orion Optics UK Dobsonian and f8.3 120mm Celestron OMNI XLT Achromatic Refractor

Main Target: Lunar 100

I am currently working my way through the Lunar 100 and have reported previous observations as follows:

http://stargazerslounge.com/observing-lunar-solar/102999-another-lunar-100-ite.html

The moon was almost full tonight so viewing was not ideal. However, I managed to add a further 14 targets to the list taking my total to 32/100. As previously I have added links to the objects which are all open access and I thank the photographers who have created these great images.

The night was reasonably clear tonight but despite this the low angle of the moon led to seeing being a little patchy with a fair amount of ‘boiling’ at most magnifications. This was particularly obvious as magnifications were increased. A number of features previously seen were not visible tonight and it is becoming clear to me that a Lunar 100 Marathon, where you see all of the 100 in one night, is likely to be bordering on impossible – any comments anyone?

During this evening’s observing I concentrated on the area around the terminator but also searched for some of the larger targets at the start of the Lunar 100 list, and I presume easier to locate, that were not visible the last time I observed. Here are the new additions for this evening’s observation:

5 Copernicus

http://the-moon.wikispaces.com/Copernicus

This is a large and complex crater with almost every feature you can wish for. There’s a central peak, ruffled rim and large basin as well as enormous rays extending over a large portion of the lunar surface. If asked for a suitable onomatopoeia to describe this crater, I’d probably use the word, splat! If you think of how a moon crater should look, this is it. That said, upon reading ‘Moon Venus and Mars’ by Rukl, purchased since this session, it seems that this is technically a walled plain and not a crater being in excess of 60 kilometres across. For the sake of argument though, I will be using the term crater for all sizes of ‘hole’ in the moon.

9 Clavius

http://the-moon.wikispaces.com/Clavius

This is a huge crater at a diameter of 245km, and towards the south polar region of the moon. Although it is described in the Lunar 100 list as a crater that ‘lacks basin features in spite of its size’, I tend to disagree with this. There is a striking arc of smaller craters within the basin which seem quite diagnostic, being sequential in their size across the across the basin; starting larger and ending smaller (or of course vice versa). I think this object will be another I will return to again when the terminator is closer to it.

11 Aristarchus

http://the-moon.wikispaces.com/Aristarchus

This was a favourite target on the night and although quite a small crater it is a really obvious feature, looking a little like one of those gobstopper eyeballs but from the inside! The walls are bright, chalky white and there are dark bands in the walls of the crater. It is an quite a feature rich area, with Schroter’s Valley (see below) and other rilles and craters close by (although on second thoughts, is this not the case with all areas of the moon??). This is one of the craters that can be seen even in earthshine.

13 Gassendi

http://the-moon.wikispaces.com/Gassendi

Gassendi is a large floor-fractured crater at the top end of Mare Humorum. Although I correctly identified the crater, the basin features were not too obvious as there was little shadow when observed.

14 Sinus Iridium

http://the-moon.wikispaces.com/Sinus+Iridum

This very large (236km) crater is just to the west of Plato in the northern half of the moon. It is almost Mare-like in appearance and is edged to the north by the Jura Mountains and to the south the missing rim has been ‘washed away’ by Mare Imbrium.

17 Schroter’s Valley

http://the-moon.wikispaces.com/Schr%C3%B6ter%27s+Valley

This is a very obvious giant sinuous rille which is north of Aristarchus and Herodotus. Looking south, if these two craters are the eyes of a face, then Schroter’s Valley is the nose. As with many of the things I looked at, this will certainly reward further viewing with differing ranges of shadow and light.

22 Aristarchus Plateau

http://the-moon.wikispaces.com/Aristarchus+Plateau

The listed description of this feature is somewhat vague and I am sure I saw the area it refers to being a raised area cleaved by Schroter’s Valley. However, it did not seem too ‘mysterious’ to my eyes and perhaps I need to look again at this one.

23 Pico

http://the-moon.wikispaces.com/Mons+Pico

This is a little chunk representing the remnants of the Imbrium basin-ring. Not really very impressive but resembles a small archipelago with it’s other local companions.

27 Archimedes

http://the-moon.wikispaces.com/Archimedes

This large crater has no central peak but is a very obvious feature over the other side of Mare Imbrium from Plato.

30 Schiller

http://the-moon.wikispaces.com/Schiller

Schiller is a long slim crater towards the outer margins of the moon and at approximately 7 o’clock. Not particularly impressive but is suspected to be the result of an oblique impact.

42 Marius Hills

http://the-moon.wikispaces.com/Marius+Hills

I initially found this feature quite hard to define but after looking for a while, I realised that the complex of volcanic domes and hills were a lot lower profile than I had appreciated; imagine a ladies stocking stretched over peppercorns and you have it – that said, it’s a long time since I stretched a lady’s stockings over peppercorns. They can be found to the west of the crater Marius which is at the end of the Kepler ray angled at 10 o’clock.

49 Gruithuisen Delta and Gamma

http://the-moon.wikispaces.com/Mons+Gruithuisen+Delta

Having mastered the much smaller domes of the Marius Hills, these were a much more obvious feature. They are reasonably large volcanic domes formed with viscous lavas positioned approximately where Mare Imbrium meets Oceanus Procellarum.

57 Reiner Gamma

http://the-moon.wikispaces.com/Reiner+Gamma

Just to the west of Reiner crater is a small oval patch of light coloured material which is Reiner Gamma. This is apparently a magnetic anomaly and to the eyes there is something slightly unusual looking about it. I cannot quantify what I mean by this unfortunately – have a look and see if you agree.

62 Rumker Hills

http://the-moon.wikispaces.com/Mons+R%C3%BCmker

The most impressive laval dome of the evening was this huge mound of material just to the west of Gruithuisen Delta and Gamma. Very obvious feature and it would be an impressive sight for anyone standing at the foot of the hill.

With all of the above targets I used both the refractor and the dobsonian scopes to see if there was a difference in sharpness, definable detail or contrast etc. Overall, both scopes performed very well. The achromatic refractor did show a little false colour at the limb (purple or yellow fringe depending on the angle of the eye) but this was not a detraction from the view. Also, there did seem to be a general slightly pinkish tinge (not obvious and I had not noticed this before) to the colour of the moon when compared directly with the dobsonian that showed, as expected, none of these ‘aberrations’.

In general terms the magnifications available to the dobsonian were higher than the refractor and the field of view seemed wider somehow, it was also more comfortable for prolonged viewing and easier to track and move around to new objects than the refractor in my view. The comfort element could have been affected by the low altitude of the moon, forcing me to sit a little higher on the chair than with the dobsonian.

Overall I definitely prefer the dobsonian for lunar observing.

As a further test I also tried the scopes on Saturn as it was quite high in the sky at the end of the session. I was keen to establish how many moons I could locate with both scopes and compare the detail visible on the planet. This may not have been ideal with the pinprick-sized pupil I had after observing the moon but I carried on regardless. Again, against the popular view, the faster dobsonian was better than the refractor in all aspects. The planetary detail was sharper and larger in the field than the refractor before the image started to deteriorate; more banding was visible in the dobsonian. I noted the same moons in both scopes (Lapetus, Dione, Rhea and Titan) but then after a period of observing, managed to see the combination of Tethys and Enceladus at the edge of the rings. Despite trying for some time, I could not see this with the refractor.

I will continue to test these two against each other but for now, it’s dob 2 refractor 0.

Best wishes

Shane

[Doc]

Fantastic report Shane and your writing style is brilliant, it makes for one very easy and entertaining read.

Did you manage to see more then one central peak within Copernicus, I was just wondering the differences between our scopes.

You must visit Gassendi again as there are at least seven mountains within the crater, let me know how many you can see Shane.

[Moonshane]

cheers Mick - what a really nice thing to say!

I enjoy reliving the experience when writing these reports. At the minute I am feeling happy enough to have actually identified the various list items and I reckon that in a few more observations, I'll settle a bit and start seeing more and spedding more time on each one. I will take a look at Gassendi and Copernicus next time the terminator is closer to them and report what I can see. will be interesting!

I might even try a sketch but to be honest, I am rubbish at anything other than photography and even then only really any good with insects and macro work eg

I don't care what it says in the manual, something's wrong.....DSCF0538 on Flickr - Photo Sharing!

cheers again and I am glad you enjoyed it. the other good thing is that I may get corrected if I make a mistake and then I can go back and check again based on comments. on this basis, anyone can feel free to comment on / challenge any of the details / sightings.

[PeterW]

The speed you're posting these, it'll be shame when you finish the list.... will none of the objects hold you back?!

PEterW

[Moonshane]

ha ha

you are right Peter that I have posted these in quick succession but they were last week when the moon was about and I cannot see us having a chance again for a while !

I think the first lot were fairly easy and they will definitely get harder. in fact I really struggled with Hipparchus and the Aridaeus Rille and gave up on these in the end as I could not be 100% sure I was seeing them. I think I would have found them with the book.

I suspect my MO will now be to follow the terminator and work my way down the pages that cover the area. I can then also look and find other things not on the 100 list too.

[Tantalus]

Another good report, Shane. I like the descriptive language you use - 'splat', 'gobstopper' and particulary 'ladies stocking stretched over peppercorns' ... I can't wait to see that one (two nights of cloud for me).

Your comparisons of the two scopes are intriguing. I'm not surprised that the Dob is winning, all that extra aperture has to give you something extra, and I'm glad you're getting on well with it. Personally I'm becomming a bit sceptical with 'the popular view's and perceived wisdom - there's so many variables, and so many conflicting 'expert opinions'. There are times when I think it'd be nice to have a 12" Newtonian, but at this time I can't really accomodate an additional setup. And personally I'm happy with my 'little' 120mm refractor, and I'm in no rush to get rid of it.

Please keep the reports coming Shane, when mother nature allows, of course!

[Moonshane]

cheers Tantalus

I'm glad that others enjoy reading my reports. I do them for my own purposes to ensure I can remember what I have seen and to allow me to return to the features in the future if needs be. I feel that as I am writing them anyway it might either entertain or help others (or both!).

my sense of humour and imagination has been referred to as many things over the years (often followed with groans and the occasional chuckle) and using these sorts of descriptive terms whilst pretty 'unscientific', help me recall what the features were like and will hopefully also help others find the targets, especially when then were not quite what I expected - I work on the basis that they might not be what others expected too.

making your own mind up is definitely the best thing to do, especially as one person's eyes and views are never the same as another's. don't get me wrong about the refractor. I still love it and will not be selling it either, it's a really great scope and I still see loads with it. the dob just has the edge as you say due to the increased light gathering pushing the limits less.

the dob takes up less space than the refractor which is the only reason I got away with both

[PeterW]

You'll start to find that some objects keep hiding 'round the edge' of the moon and you'll need to wait ages for the moon to 'nudge round' to make them visible. Also some of the lunar domes are totally invisible unless near the terminator, when they're really obvious (if you know where to look). With a 12" I won't be betting against you hoovering up the whole list... be good to hear you at it!

Cheers

PEterW

[Talitha]

Very enjoyable report, Shane. Regarding your question on a Lunar 100 Marathon... it wouldn't be 'bordering' on impossible, it would definitely be impossible.

Some of the features require specific light angles and/or favorable libration to be seen, and the windows of opportunity may only last a few hours. It can be quite frustrating, but it makes for a bigger celebration when you finally bag the one you've been trying for.

True story:

A Gent swaggered into a lunar group i was in a number of years ago and laughingly wondered what was taking the rest of us so long to complete the Lunar 100 list. He claimed to have covered it in 3 sessions and to back up his claim, he supplied us with the dates and features seen.

I checked the lists and found a number of things he couldn't have seen on the nights he claimed to, and brought them to his attention. For example, you can't see the Valentine Dome during the waxing gibbous phase, and you won't see Mare Orientale when libration is favoring Mare Humboldtianum. IIRC, he never posted a reply.

It might be fun to try a Lunar 100 marathon when the Moon is full, though. Understandably many of the features will be impossible, but try finding ones which you think might be do-able. Just for grins and giggles i've sat out all night using the Clementine Atlas as a guide and tried to positively identify features which seemingly vanish during lunar noon. (Yep, i'm an easily amused geek. )

[lunator]

Shane

Very nice report

Good luck on getting the tricky ones

Cheers

Ian

[Moonshane]

You'll start to find that some objects keep hiding 'round the edge' of the moon and you'll need to wait ages for the moon to 'nudge round' to make them visible. Also some of the lunar domes are totally invisible unless near the terminator, when they're really obvious (if you know where to look). With a 12" I won't be betting against you hoovering up the whole list... be good to hear you at it!

Cheers

PEterW

Thanks Peter! It's a really good way to learn the moon features and actually retain some of it in my squishy melon contents! I think the book will definitely help too as I can grab a few Lunar 100s near the terminator and also have a zoom about on the same page in the book finding the other features mentioned.

Very enjoyable report, Shane. Regarding your question on a Lunar 100 Marathon... it wouldn't be 'bordering' on impossible, it would definitely be impossible.

Some of the features require specific light angles and/or favorable libration to be seen, and the windows of opportunity may only last a few hours. It can be quite frustrating, but it makes for a bigger celebration when you finally bag the one you've been trying for.

True story:

A Gent swaggered into a lunar group i was in a number of years ago and laughingly wondered what was taking the rest of us so long to complete the Lunar 100 list. He claimed to have covered it in 3 sessions and to back up his claim, he supplied us with the dates and features seen.

I checked the lists and found a number of things he couldn't have seen on the nights he claimed to, and brought them to his attention. For example, you can't see the Valentine Dome during the waxing gibbous phase, and you won't see Mare Orientale when libration is favoring Mare Humboldtianum. IIRC, he never posted a reply.

It might be fun to try a Lunar 100 marathon when the Moon is full, though. Understandably many of the features will be impossible, but try finding ones which you think might be do-able. Just for grins and giggles i've sat out all night using the Clementine Atlas as a guide and tried to positively identify features which seemingly vanish during lunar noon. (Yep, i'm an easily amused geek. )

Thanks Talitha,

I am definitely becoming a moonatic - last night I had a chance to observe again and was almost disappointed the moon would not be up!! I 'made do' with three new Messier galaxies and a host of globs and double stars - talk about second best . I think the last line on your signature says it all about three session guy. I used to be into birdwatching which is quite competitive in terms of who has seen more species or rarities than who but 'turned back' to insects some time ago - with insects, you'll never see them all so enjoy each one as you see it/observe and photograph it - much more relaxing and enjoyable. I see astronomy as being like this. You'll never see them all and stars etc are going nowhere and with the exception of maybe meteors, eclipses and comets, will always be back again to be seen given a little patience. running out of suitable targets is not going to be likely

I have to say that you've definitely stepped over the line actually seeking features that you cannot see

Shane

Very nice report

Good luck on getting the tricky ones

Cheers

Ian

Thanks Ian

I think I am gonna need it

[Talitha]

Yep, you're a real moonatic. Actually though, it's good to be a well-balanced observer. Congratulations on sweeping up the new Messiers, globs and doubles.. well done!

BTW, have you heard of the Virtual Moon Atlas? Go here and scroll down to the bottom till you see the 'Older Versions' section. The 14Mb "Expert" version is the one i use... the "Light" version doesn't include the libration zones, and the super-duper versions are overkill for simple observing purposes.

[Moonshane]

Yep, you're a real moonatic. Actually though, it's good to be a well-balanced observer. Congratulations on sweeping up the new Messiers, globs and doubles.. well done!

BTW, have you heard of the Virtual Moon Atlas? Go here and scroll down to the bottom till you see the 'Older Versions' section. The 14Mb "Expert" version is the one i use... the "Light" version doesn't include the libration zones, and the super-duper versions are overkill for simple observing purposes.

great stuff! thanks for this. it will allow me to get more context before I try and find the more difficult targets

[Brendan of Borg]

Hi all,

Talitha - I saw on ebay someone trying to flog this software!! Cheeky man! But, with it he was saying/selling some other software or maybe included(?) with it! There was an image of a moon map,which shows hill/crater detail like an earth ordnance map!! Is that included in the pro version of VMA?

Cheers.

Brendan

[Brendan of Borg]

or... does even such a map exist? I would love it if it did!!

[Talitha]

You're welcome Shane. On the VMA's 'Ephemeris' tab, you can toggle the time back and forth (by hour or day), and see how different limb areas become exposed or hidden due to libration.

Click the 'configuration' button at top left (above the lunar graphic). When the dialog box is generated, click on the 'display' tab. Make sure there's a check mark in the box listed "mark the point of maximum libration"... it will place a floating arrow outside the limb, indicating the exact spot where libration is the most favorable. You'll see it moving around as you toggle the time back and forth. Pretty cool feature.

As you toggle the time back and forth, you'll also notice that the numbers are changing on the ephemeris tab. Favorable libration in latitude or longitude is indicated by a '-'. This indicates how many degrees (lunar) the favorable libration allows us to peek over the limb. Anything over -6 is good but i've seen it go almost to -8... that's when i got the best-ever view of Mare Orientale.

Brendan, i don't know whether or not the feature you mentioned is included in the Pro version. Try checking around on the VMA pages and see if there are any screen captures of the different versions. Or maybe do a websearch on 'VMA Pro version screen captures' or something similar.

[Moonshane]

brilliant Talitha - I'll be using this I reckon

this thread will be firmly in my faves until I get the hang of it

[Brendan of Borg]

Talitha! Merci!