Observations - 16/03/23

Hello everyone again. 

And I greet you a very happy Saint Patrick’s weekend! I’m sure you were all wearing green today. 

I set up my William Optics 158mm f/7 apochromatic refractor for the second time this week. The air temperature was 12˚ Celsius. The wind was about 15 km/h. Darren was on the phone as I was having a great time with these 5 celestial goodies. Sorry there is no such thing as a green star!

1. I found the planet Venus with my Williams Optics 70mm f/6 small apo. At 11x the planet looked every bit a -4.0 magnitude star. But in the main scope at 40x I had a gibbous disc alright. Guide 9.1 DVD told me its illumination was 81.9%. Its angular diameter was 13”. I had some shimmering at 112x, 140x and 167x. It was a good start though. 

2. Sunset had occurred at 18.30UT, and I was quite surprised how bright Polaris was in my small apo at 11x. I saw the star at precisely 18.50UT. Its magnitude 9 companion was even visible at 40x. This true binary looked very good at 112x also. 

3. Before I headed into Cepheus, I was waiting for my sky to become darker. And so I stopped by to observe a single star called Lambda Ursae Minoris. I could see it at 40x. Its magnitude is 6.4. It’s always nice to see this M3 orange star and quite near Polaris.  

4. And so I was in the constellation of King Cepheus yet again. It’s getting lower now – as is his queen Cassiopeia. Indeed she has left my skies already. So I wanted to finish my time with the king and include a very special sight. But before I explain what that sight was, I revisited Kappa Cephei (STF 2675). Magnitudes: A = 4.4. B = 8.3. Sep = 7.3”. PA = 120˚. I had an extremely narrow split at 40x. 112x was a lot better. The primary was white, and the secondary was a definite blue. I forgot to notice it's a triple star. Sorry!  

5. But now, I finish with a proper carbon star: S Cephei. The stars Rho 2 (5.5 mag) and Rho 1 Cephei (mag 5. are a great help to locate this famous carbon star. Even at 40x I star hopped my way to a reasonably faint orange-red star. So beautiful! I then increased my magnification to 112x and the star become more of an intense red. My wife thinks it is a scarlet star. At 167x S Cephei was a magnificent sight, and it is my first time to observe it. I was completely bowled over by its sheer beauty! Astronomers say that the star swells and shrinks in size. It is a variable star after all varying from 7.4 down to 12.9 every 486 days. That latter magnitude I would find too faint to see from my home. But the star most likely doesn’t appear that dim too often. S Cephei has a spectral class of C6. The star’s surface temperature is 4700˚ Fahrenheit. That’s about 2600˚ Celsius, and a lot cooler than our Sun (6000˚ C). S Cep is about 1350 light years from us. It is a giant star and one I would be keen to estimate its magnitude over on www.aavso.org the next time. I might try and find this extraordinary star before the month of March ends. It will be interesting to compare its colour with R Leonis which is the only other true red star I have observed. For those interested in history, Lalande discovered S Cep in October 1789. Henke discovered its variability from the year 1855. I can only imagine what both men thought when they first observed this beautiful star.

6. Oh! One last thing. Darren and I both saw a bright meteor at the same time. I thought the magnitude was about -4. The unusual fact was that this meteor seemed to go through the stars of Cepheus. It was as though S Cephei was saying to me “Thank you for observing me. Here is your reward”.      

Thank you for reading this report. 

Comments are very welcome. 

Clear skies from Aubrey. 

Hello Aubrey,

That's another fine report! Your description of S Cephi is fascinating. To think that it varies in size is astonishing - I didn't realise stars could do that. And it will interesting to read how it compares with R Leonis.

That Meteor was a fine sight...with a nice tail!

Also very many thanks for pointing me to Castor the other night. I really liked it, and I agree with your description of Venus. It blazed in the West and I child see its Gibbous phase with some grey shading on its North-Eastern limb.

Great night!

Clear skies,
Darren.