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Plato Craterlets tonight ... 1st serious attempt!

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#1 AJK 547

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Posted 18 September 2019 - 09:04 AM

I’ve truly enjoyed reading/re-reading the various excellent threads on attempting to ‘bag’ Plato’s craterlets.  It seems tonight, I might have some VG ‘seeing’ and transparency with moderate humidity and slight winds.  The projected jet stream winds should not be a factor. If this holds true, then I’m goin’ for craterlets A, B, C & D as true craterlets (hopefully not just Albedo).  

 

FWIW, I was testing my C8 awhile back and sun angle allowed me to view craterlet A immediately as a true ‘pit’... but sadly B, C or D was only ‘albedo’. The ‘seeing’ was only average with good transparency.

 

Question, any suggestions on filters, etc?  I have a variable polarizer (Meade (Japan)) and Baader M&SG but no colored filters as yet in my kit.  My ep’s I plan on using will be my TV Delos 10, 8, 6 & 4.5

If seeing holds to VG /Excellent.  These ep’s will give me 203X, 254X, 339X & 454X respectively.  I plan to let my C8 and C6 acclimate the entire evening and start viewing at about 3am when conditions should be most stable.

 

side note, if I can resolve the ‘Big Four’ with the C8, then I plan to try the C6 (which has excellent ‘star test’ optics)...

 

Keeping fingers crossed!!!  

 

 

 



#2 Tom Glenn

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Posted 18 September 2019 - 05:04 PM

I assume that by "tonight" you mean early morning hours on September 19.  The Moon's declination is quite favorable now at this phase for the northern hemisphere, so if you can catch it near culmination it will be fairly high in the sky which always helps.  But this will occur in the pre-dawn hours, so not the most comfortable from a sleep perspective!  I can't give any recommendation on filters as I've always just observed unfiltered when doing visual.  One thing to keep in mind is that the Plato craterlets will take on difference appearances depending on the proximity of the terminator.  When the sun is high, there is no contrast, but when the terminator is very close, the scene becomes so dark that they can also become difficult to detect.  There is somewhat of a sweet spot that occurs when the terminator is just far enough away to maintain good illumination, but not so far as to wash everything out in high Sun.  The morning of September 19 is not a bad time to observe, although the illumination angle will still be somewhat on the high side.  The elevation of the Sun above the horizon in Plato will be about 22 degrees on the morning of the 19th, and will be about 15 degrees on the 20th, and 8 degrees on the 21st.  All things being equal, I think the 20th and the 21st will have better lighting, but everything is not equal, so if your weather window is on Sept. 19, you'll have to make the most of it!  Good luck.  


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#3 AJK 547

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Posted 18 September 2019 - 10:09 PM

Thanks for the response Tom!

 

Ive got the alarm set for 3:00am so hopefully I can have a good 2 hrs. of visual early tomorrow morning.  I really hope the seeing is as good as predicted!  Both ‘scopes are outside now, so they will have 9 hrs. to acclimate.  Fri. early morning the transparency is projected to be only ‘fair’ sadly...



#4 BillHarris

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Posted 19 September 2019 - 02:23 AM

Good reply, Tom.

I'm going to do the Moon on Sept 23, 24 and 25. With the sunset terminator at longitudes 7E, 6W, and 18W, respectively, the areas I'm interested in will be nicely illuminated. Wee hours of the morning, but the Moon will be at a high altitude (much better than the First Quarter Moon this month).

#5 AJK 547

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Posted 19 September 2019 - 03:39 AM

It’s 3:23am....  and i’m  EXTREAMLY happy !!!

 

It took my C8-A, TV Delos 8 (barlowed with my Baader 2.25X (571X) (71.4 X/in.)) and during moments of VG / Excellent ‘seeing’ became visible:

 

1) Craterlets A, B, C & D (actually C & D are spaced reasonably far apart!)

 

2) Craterlet W (actually pretty easy to discern!)

 

3) Craterlet F

 

4) possibly East Wall ‘pit’

 

I repeated my observations of the ‘Big Four’, and found out that it became a bit easier to re-acquire them over the course of the next hour.  It was fun just letting the ‘seeing’ conditions stabilize to excellent and have other smaller craterlets pop into view (ie. F)...

 

 

notes:  I tried the variable polarizer and also tried the Baader M&SG filter, but viewing the Craterlets seems best w/o either.  I thought the VP would help in cutting down luminosity and improving contrast but interestingly this wasn’t the case.

 

The important thing was that it took a combined shadow within the ‘craterlets’ and Albedo to get a true feeling that these are craters and assist in detection.  Soooooo Cool.

 

Sadly, a slight breeze coupled with high clouds showed up and made viewing extremely difficult with the slightly degraded ‘seeing’. I now understand that sun angle (as Tom mentions above) and excellent seeing conditions are critical for Plato Craterlet success...

 

AWESOME NIGHT.....  smile.gif


Edited by AJK 547, 19 September 2019 - 09:08 AM.

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#6 Greyhaven

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Posted 19 September 2019 - 01:29 PM

2am this morning showed wonderfully clear and steady skies, but unless properly prepared to do battle with extreme dew, very problematic for successful observing. 4.:15 am  after the temps dropped a bit more and the dew had morphed into scrape-able frost and new issues plagued the Lunar observer. Hey if it were easy there would be more people doing it.

Grey


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#7 AJK 547

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Posted 19 September 2019 - 02:57 PM

Grey, luckily the temps for me this early morning were in the low 60’s and excellent viewing conditions.  I set the alarm for 3:00am but actually got up at 2:11am... checked the transparency and ‘stability’ of the stars and decided it was a ‘GO’ !!! 

 

As as soon as I trained the C8-A on Luna I knew conditions were stable enough for me to seriously attempt those pesky Craterlets in Plato.  You can imagine how stoked I was when A... then C & D .... then finally B materialized in view as true Craterlet ‘pits’. YES !!!!   It became easier to spot F and W later during the session.  Never did all craterlets come into view simultaneously.  Just one Craterlet at a time based on the stability of the precise column of atmosphere I had to view through at the extreme magnification I was using (571X).  I was hoping the optics of the C8-A would be up to the task, and thankfully I think I have a pretty good one.  smile.gif

 

i learned quite a bit last night!


Edited by AJK 547, 19 September 2019 - 05:42 PM.


#8 Tom Glenn

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Posted 19 September 2019 - 04:19 PM

I'm glad it worked out for you!


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#9 Tom Glenn

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Posted 19 September 2019 - 04:31 PM

Good reply, Tom.

I'm going to do the Moon on Sept 23, 24 and 25. With the sunset terminator at longitudes 7E, 6W, and 18W, respectively, the areas I'm interested in will be nicely illuminated. Wee hours of the morning, but the Moon will be at a high altitude (much better than the First Quarter Moon this month).

Bill, are you sure about those dates?  The sunset terminator longitudes you quote do not match up.  Last Quarter is September 22, and in the early morning hours (local time), the longitude of the sunset terminator on Sept. 23, 24, and 25 is approximately 24W, 36W, and 48W.  On the morning of September 25, the waning crescent will be only 15% illuminated, with the sunset terminator sitting directly on Aristarchus.  



#10 AJK 547

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Posted 19 September 2019 - 05:07 PM

I'm glad it worked out for you!

Thanks Tom!  You can’t imagine how stoked I still am in getting the results I wanted on my 1st serious attempt...  what still amazes me is I was pulling ~71.4X/ in. magnification and when craterlets C &  D appeared they truly were sharply defined ‘pits’.

 

Man are those perfect seeing moments rare, but indelibly ingrained in my mind!



#11 BillHarris

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Posted 19 September 2019 - 07:47 PM

Tom-- Oops, I did copy those dates incorrectly. Sorry...

#12 azure1961p

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Posted 20 September 2019 - 10:12 AM

Extreamely????

That's a word?

 

Who spells like that?

 

Oh.

 

Pete


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#13 azure1961p

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Posted 20 September 2019 - 10:18 AM

That aside, that should be fairly basic for a decent C8 and the C6 ought to manage too.

 

A curious thing though, and yes I like looking at Plato's craterlets too but so many other craters have equally good craterlets to hunt for.  I Kno the attraction of Plato's family of small craters is due part in that they often are under table when you'd think they should show (low sun angle) but often easy in those same bigger scopes when it is lit from a high sun angle.  The fly in the ointment is simply that the crater floor are a higher albedo than the surrounding darker crater floor so full moon for example is a nice time to look.  Other craters may not have this albedo effect? And that'd be further cause for the mystique of these small small features.  

 

Both those instruments are nice for this sort of thing.

 

Pete


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#14 AJK 547

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Posted 20 September 2019 - 11:51 AM

Thanks for the reply Pete!

 

 Do you have any other suggestions for other interesting lunar features that I can further test the optics of my C6 & C8?  



#15 AJK 547

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Posted 08 October 2019 - 09:14 PM

Tonight, I had good transparency and ‘seeing’ conditions (very little jet stream impact) and was able to use the C6 this time to bag craterlets A (seen as a true ‘pit’ again) along with B, C&D as albedo.  It took the Delos 4.5 (@333X) to begin to observe the craterlets (mainly A), then used the Delos 3.5 (@429X) to bring into view B, C&D properly.

 

IMHO, it REALLY takes excellent transparency and ‘seeing’ to have a stable enough air column to more easily view the craterlets.  Also, the sun angle wasn't as cooperative as my prior nights viewing.  However, all in all, I’m happy the C6 was able to give me views of ‘The Big Four’...  Of note, this C6 gives near perfect Star test patterns both inside and outside of focus.


Edited by AJK 547, 08 October 2019 - 09:56 PM.

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#16 elwaine

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Posted 09 October 2019 - 07:15 PM

Agree. Seeing and transparency are key to visualizing small details.


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#17 Cali

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Posted 14 October 2019 - 12:51 AM

Well I spotted the crater Plato but ...

 

Found this 2005 CN thread on the subject.

 

- Cal


Edited by Cali, 14 October 2019 - 02:00 AM.



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