Lunar X + Lunar V tonight -2/01/20

Good evening, all.

Here is something to get a bit excited about.
From 8 pm tonight Thursday 2nd January 2020 both the Lunar X and the Lunar V will be right on the terminator for 2 or 3 hours.
Telescopes are the only way to see these excellent features.
The Lunar X is caused by the Sun catching the tops of 5 crater rims. The craters are La Caille, Blanchinus, Aliacensis, Regiomontanus and Purbach. These are all large craters just below the centre of the Moon. Anywhere between 40X and 200X can be used.
There is also a double star that may not be a true binary to the  southeast positioned 2 degrees away from the Moon. Its designation is HJ 323. HJ stands for John Herschel. The magnitudes are 6 & 8.5. Sep: 63". PA: 286 degrees.
At the moment at 6 pm the Half Moon is shining brightly.
Who knows it might stay that way?

Clear skies from Aubrey.

Hi Aubrey,

Very many thanks for letting us know about these Clair-Obscur effects. Having just stepped outside to see if the moon is visible I reckon it is possible to observe them, so I must try to take a look. 

Thanks again,

Darren.

My sky is full of cloud, Darren. 
Never mind. 

Aubrey. 

...... and drizzle!

Considering how bad the weather was tonight I did manage to observe the Lunar X, albeit for couple of minutes between 20:28 UT and 20:34 UT. At times the 'X' looked more like a 'Y' though. I'm not sure whether this was due inclement weather causing a hazy image or the time of observation, but there were definitely moments were an 'X' was visible on the rim of the Blanchinus, La Caille, and Purbacj craters.  I had no luck with the Lunar V though - is this a harder effect to spot?

I used my f/8 6" Newtonian Reflector on a Dobsonian base and homemade Dob riser; a 9mm Orion expanse eyepiece with a AFOV of 66 degree. Meaning, I observed the Lunar X at 133X with a .49 TFOV.

Once again Aubrey, very many thanks for posting the event tonight. If you had not I would have missed out.

Clear skies,

Darren.

 

We'll just have to try again in 2021, Darren.
There will be no Lunar X's for the rest of 2020 - would you believe it? Never mind.

The Lunar V would have been north of the centre of the Moon. The Sun is catching some mountains which are shaped like a "V". It is somewhere close to Sinus Medii or Mare Vaporum.

We have more clear skies on Friday 3rd January.
Right now in fact.
Now I realise I have to be very careful here.
I was trusting Guide 9.1 DVD too much last year for the appearance of Rupes Recta on 2019.
But it looks like it is going to be very close to the bright side of the terminator tonight Friday 3rd January.
I hope I have it right this time!!

Clear skies from Aubrey.