Observations - 15th April 2021

Hello, one and all. 

All 3 weather websites which I check informed me I was due to have clear skies on Thursday night 15th April 2021.  
Sunset had occurred at 20.25 local time. 
The air temperature dropped from +4 to +2 degrees Celsius. 
The wind died down from 10 km/h completely. 

Therefore I set up my William Optics 158 mm F/7 apochromatic refractor on its Berlebach alt-az mount in the back garden. 

1. A very fine 3.8 day old crescent Moon was getting a bit low in the north western sky within the boundaries of Taurus. Its magnitude was -7.6 and a distance of 404,400 kilometres from Earth. Its angular diameter was 29.5 arc minutes. Mare Crisium looked good. Southwest of it was a fairly large 56 km crater called Taruntius. Our Sun had not yet shone into its centre. As a result, the floor was in darkness. But there was the delightful sight of a central peak which looked stunning at 112X. Also observed was the large 132 km Langrenus with its 2 central peaks (alpha and beta). The even larger 177 km crater Petavius and its 80 km long Rima Petavius looked good. One last bit of drama was the sighting of a very small piece of manmade space junk which flashed through my field of view travelling from the bright side of the Moon over to the earthshine side. It was quite bright. 

Leo the Lion then appeared. The sky was totally clear! As usual I started with the usual suspects – Regulus and Algieba. After them, I headed up to Mu Leonis whose magnitude is +3.0.  And I sought out these 3 doubles which are very close by. 

2. AG 340 may be an uncertain double with magnitudes: A = 10.1. B = 10.6. Sep = 4.8”. PA = 310˚. But what a very nice sight it was at 112X. The 2 white stars were cleanly separated at this low magnification. I refused to go higher as it was so attractive. 

3. The true binary STF 1389 was the new showpiece of the night. Magnitudes: A = 9.1. B = 9.5. Sep = 2.5”. PA = 289˚. What a true beauty it is! I had black space between the 2 stars at 112X. Plus I noticed, as the primary has a spectral class of K0, it had a slight orange tinge to it alright at 140X. The secondary was white. 

4. STF 1388 is quite a let-down after those first two doubles. But it has been discovered that it is a true binary. Magnitudes: A = 9.5. B = 11.5. Sep = 33.5”. PA = 122˚. I could only get brief glimpses the secondary at 167X as I live under Bortle 9 skies. The primary has a spectral class of F2 and it had a yellow-white hue. 

I have yet to observe 2 carbon stars in Leo. So they are next on my observational menu. 
We are supposed to have clear skies next Tuesday night 20th April. It’s going to be cloudy until then. 

Thank you for reading my report.    

I wish you all clear skies, 

Aubrey.  

Hi Aubrey,

I was delighted to read that you observed the Moon on Thursday. Having seen how pretty it looked in the night sky I had hoped to sketch a crater or two, but it wasn't to be. So, your report gave me a good idea of what features were available. 

Langrenus and Petavius are nice craters, and Rima Petavius must have looked great. I've not observed Taruntias, but it sounds like an interesting crater with its central peak. 

Nice job on splitting those three double stars too. 

Clear skies, 

Darren. 



 

Or is it Taruntius? 

Either way, it is a crater which might be difficult to sketch, Darren.
That's because of the surrounding area around Taruntius. 

Thank you for your kind comments. 
Thumbs Up to you, Darren.   
 

Hahaha! Me and typos.

I really need to proof read what I write.

All the best,

Darren.

Hello again, Darren. 

I have been doing a small amount of research in regards to our friend Taruntius.[justify]It turns out Taruntius is an incorrect spelling in Rukl's atlas. 
His full name is Lucius Tarutius Firmanus.  
How about that? 

He was a mathematician, a philosopher and an astrologer who died in 86 BC. 
So he appeared to be a clever man - apart from dabbling in occult. 

Clear skies from Aubrey. [/justify]

Evening Aubrey,

Many thanks for providing those details. Speaking of Rukl's Atlas, map 54 is open next me. The scope has been set-up since early as I'm going after one very interesting crater tonight...any guesses?

Kindest regards,
Darren.