Moon - 8/4/22

Hello everyone. 

I will be looking forward to observing the 7.6 day old Moon on Friday night 8th April which is in Gemini with my William Optics 158mm apochromatic refractor. We are supposed to have clear skies, calm winds and cold temperatures. 

There are going to be some interesting happenings with the Moon.

1. The Lunar X and presumably the Lunar V will appear right on the terminator at 20.20UT. That's 21.20 Irish Summer Time. 

2. A very strange star called SAO 78940 (HD 267257) will reappear from behind the Moon's very bright western limb at 19.52UT (20.52 Irish Summer Time). This 8.8 magnitude star has the ultra rare spectral class of K8. It ought to have a reasonably intense orange colour. I have never observed a K8 star. I know that the star is going to be extremely close to the western side of the Moon. But I'm looking forward to studying it all the same.

3. SAO 78973 (HD 52148) will be occulted by the Moon's eastern limb (the dark side) at 19.52 (20.52 IST). Its spectral class is a simple A2 and its magnitude is 8.8. 

4. Finally, SAO 78979 (HD 267827) will be occulted by the Moon at 19.54 UT (20.54 Irish Summer Time. Its magnitude is 8.1 and its spectral class is G5. So its ought to have a decent yellow colour. 

It could be a super night to remember - weather permitting. 

All the above information is from my Guide 9.1 DVD. 

I wish you all clear skies for this coming Friday night.    

Aubrey. 

Quite difficult to observe a 9th mag star at the bright limb I'd imagine Aubrey, best of luck with it all the same.

I'm a bit confused by the geometry - is the bright limb not the eastern side, as we look at it visually? Oceanus Procellarum is definitely on the western (left) side, and in darkness until the phase increases. Of course these directions can be reversed in a telescope.

Clear skies,
Finbarr.

Okay, Finbarr.
The K8 star (SAO 78940) reappears on the bright side of the Moon as the Moon goes "backwards" in the sky. .
The occultations are on the dark side. 
You are right to say that all these stars are faint. 
They probably are near the faintest magnitude limits of our scopes. 
And yes - Oceanus Procellarum is on the west side of the Moon. 
It's clearly not visible until after gibbous Moon occurs.  

The Lunar X and V should look very good on Friday night.  

Clear skies from Aubrey.   

Hi Aubrey, 

Very many thanks for sharing this information. 

Assuming the weather will be good, I'll be ready. 

Clear skies, 

Darren 

I believe I have it sussed now, Finbarr and Darren. 

The western side of the Moon is closer to our eastern horizon. 
And the western side is in darkness okay. 
So the western side is doing all the occulting of these stars. 

But the eastern side is the bright side and it's nearer to our western horizon. 
And it's moving away from the K8 star SAO 78940. Confusing isn't it?

Still we shouldn't mind any of that.

Let us hope for clear skies on Friday night to see the Lunar X and V. 
By the way, our Celestial Calendar 2022 is saying that these 2 clare-obscure lunar features are going to be seen on Friday night. 
Many thanks to John Flannery. 

Thumbs up from Aubrey.    

I was surprised by how quickly the 'X' moved out of shape; I only got set up by 21.36, 16 minutes after maximum, and it was already less obvious. Anyway this was the result, the 'X' circled red and the 'V' in blue:



Clear skies,
Finbarr.