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cloudsweeper

Pits In Plato's Floor

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Set up last night, waiting for dark, but clouds arrived and spoiled the fun.  So at 5.15 this morning when a I saw a waning gibbous Moon, high to the west of south, I quickly set up the Bresser Dob (from its outside Dobhouse) to grab some action at last.  With the Moon being high, I was able to view it safely, unlike last time when the Dob was perched precariously on a small garden table.

The initial view (x127/0.54deg) showed splendid clarity and detail, especially along the terminator.  Better than I've seen in smaller apertures, perhaps.  And since it was not very dark, there was little glare (Moon filter had little effect), although detail off-terminator was of course less pronounced.  This wider view also gave an occasional border of wispy, misty cloud sweeping rapidly by to add mood to the spectacle.

Next, the TV Radian 6mm (x212/0.28deg), with which I concentrated on Plato, hoping to see the pits in its floor for the first time, and Bingo, a few distinct specks popped out in AV.  What a delight!  Up to x254, and the image was moving a bit too fast, so then down to x190 at which the view was sharper, revealing 3 or 4 of the larger pits quite clearly.  

After half an hour, the sky was lightening, so I finished this very brief, unplanned, yet rewarding session.

Doug.

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Nice one Doug, although I think I prefer ‘craterlets’ to ‘pits’ ;) 

I’ve managed 3 or 4 with the Tak, but you should be able to do better when the illumination is better ie Plato close to the terminator. It can be an addictive pastime, trying to tease those little devils out! 

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Nice one Doug, I feel your frustration at the clouds.

The finer detail of the Moon is such an addictive prey.

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1 hour ago, Stu said:

Nice one Doug, although I think I prefer ‘craterlets’ to ‘pits’ ;) 

I’ve managed 3 or 4 with the Tak, but you should be able to do better when the illumination is better ie Plato close to the terminator. It can be an addictive pastime, trying to tease those little devils out! 

Yes Stu, I was a craterlet kind of guy, but picked up "pits" from the 21st Century Atlas Of The Moon.  Back to craterlets, perhaps......

Doug.

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12 minutes ago, cloudsweeper said:

Yes Stu, I was a craterlet kind of guy, but picked up "pits" from the 21st Century Atlas Of The Moon.  Back to craterlets, perhaps......

Doug.

Sorry Doug, was just teasing. I felt like I was back watching a McEnroe tennis match for a moment ‘The pits!’ ;)

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Nice report Doug. I think the craterlets/pits on Plato's floor are a real challenge . Looking back through my observations I've found only one sketch of Plato, though I've observed it and must have drawn it many times. Like Stu, I've seen three or four craterlets at best, but in the attached sketch the apparently bland floor appears to reveal Plato's subterranean past. While sketching the various light tones of Plato's floor, there is a hint of larger impacts beneath the surface (ghost craters) which I found interesting. Also, using only a 100mm aperture, there were two largish bright circular areas that may represent ejecta but I couldn't make out any impact craters or craterlets. May be your larger scope will stand a better chance than mine of detecting the impact sites.

1287201773_2018-08-3008_53_03.thumb.jpg.41906df372531afdad6e6cb2139e8af5.jpg

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2 hours ago, Stu said:

Sorry Doug, was just teasing. I felt like I was back watching a McEnroe tennis match for a moment ‘The pits!’ ;)

Too late Stu - I've already written to the authors about sloppy terminology!  ?

Doug.

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Very nice report Doug :icon_biggrin:

The Plato craterlets are one of my favourite lunar challenges. Under some illiumination they appear as bright spots but I prefer to try for them when the phase will enable you to see them as actual pits with shadow within and tiny ramparts. I think 10 is the best that I've managed with my 12" dob. There are the "Big 4", the "Little 4" and the "Tiny 9" to work your way though as set out here by David Knisely:

https://www.cloudynights.com/topic/34841-guide-to-plato-craterlets/

 

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I have definitely managed  the 5 larger  craterlets with my 5" F15.

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38 minutes ago, John said:

Very nice report Doug :icon_biggrin:

The Plato craterlets are one of my favourite lunar challenges. Under some illiumination they appear as bright spots but I prefer to try for them when the phase will enable you to see them as actual pits with shadow within and tiny ramparts. I think 10 is the best that I've managed with my 12" dob. There are the "Big 4", the "Little 4" and the "Tiny 9" to work your way though as set out here by David Knisely:

https://www.cloudynights.com/topic/34841-guide-to-plato-craterlets/

 

Great link, thanks John.

Do you have a preferred phase for trying to spot them?

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I had a lot of fun earlier this year trying to see how many I could spot in a couple of my refractors. The TEC160FL won with 10 spotted. Need to try this again soon.

 

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16 minutes ago, Stu said:

...Do you have a preferred phase for trying to spot them?

Not really Stu, do you ? :dontknow:

I do find that you need to "get your eye in" with them and then you can gradually tease out the smaller ones as the seeing fluctuates.

 

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1 minute ago, John said:

Not really Stu, do you ? :dontknow:

I do find that you need to "get your eye in" with them and then you can gradually tease out the smaller ones as the seeing fluctuates.

 

Well, I always made an assumption that times when Plato is near the terminator make them easier to see in relief. Nearer full shows them as brighter spots I think. Somewhere around day 9 or 10 I think.

Some discussion here:

https://www.cloudynights.com/topic/398004-whats-the-best-lunar-phase-to-view-plato/

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20 minutes ago, Stu said:

Well, I always made an assumption that times when Plato is near the terminator make them easier to see in relief. Nearer full shows them as brighter spots I think. Somewhere around day 9 or 10 I think.

Some discussion here:

https://www.cloudynights.com/topic/398004-whats-the-best-lunar-phase-to-view-plato/

Ooops !!! - I totally misunderstood your question by misreading "phase" as "phrase" - hence my rather puzzled reply !

I was thinking along the lines of phrases such as "Pitting", "Craterletting" or "Plato-browsing" (quite wrongly !) :rolleyes2:

Yes, I agree, Plato needs to be relatively close to the terminator to throw some shadow into the craterlets. More direct illumination shows the "Big 4" as bright spots but the rest are very hard to spot under those conditions.

Now I understand what you were getting at ! :smiley:

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32 minutes ago, John said:

Ooops !!! - I totally misunderstood your question by misreading "phase" as "phrase" - hence my rather puzzled reply !

I was thinking along the lines of phrases such as "Pitting", "Craterletting" or "Plato-browsing" (quite wrongly !) :rolleyes2:

Yes, I agree, Plato needs to be relatively close to the terminator to throw some shadow into the craterlets. More direct illumination shows the "Big 4" as bright spots but the rest are very hard to spot under those conditions.

Now I understand what you were getting at ! :smiley:

Funny, I did wonder what I had said to confuse you :)

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