Observations - 10/04/21

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Observations - 10/04/21 was created by flt158

Hello again, everyone. 

Once again I set up my William Optics 158 mm F/7 apochromatic refractor and its accompanying WO 70 mm F/6 small apo in my own back garden on Saturday 10th April 2021 for 1.5 hours between 9 and 10.30 pm local time. 
Sunset occurred at 20.16 local time. 
Thankfully the wind wasn't strong at all - about 7 km/h from the northeast. 
The air temperature was very cold at -2 degrees Celsius.
Some passing clouds passed by now and again but they kept moving on.  

I'm very much had planned to look for more doubles in Leo for this observing session. 
And what a great time I had!
No less than 4 new doubles I successfully separated for the first time. 
As usual, I started with Regulus (Alpha Leonis), Algieba (Gamma Leonis) and Subra (Omicron Leonis). 
Those systems I have described here before recently.
And so, it's time to go straight to the first timers. 

1. STT 216 is right next to the brighter 6.2 magnitude star 42 Leonis. The magnitudes of STT 216 are: A = 7.4. B = 10.3. Sep = 2.3". PA = 228 degrees. STT 216 is a true binary and I was thoroughly thrilled to see the very small dot of the secondary at a mere 112X right next to the primary in the correct position angle (PA). I was greatly surprised that even with a delta magnitude of 2.9 I could clearly see a tiny amount of black space between these 2 stars. The primary is G5 yellow. B is white. It also looked delightful at 140X. STT 216 was my new showpiece of the night for sure. STT stands for Otto Struve (1897-1963)

2. WAL 56 is a nice and easy true binary very near to Omicron Leonis. Magnitudes: A = 6.7. C = 10.7. Sep = 85.7". PA = 81 degrees. Very easy split at 40X of course with plenty of black space in between these 2 stars. WAL stands for Ake Wallenquist  who was a well known Swedish astronomer and lived from 1904 to 1994. You may have noticed I used A and C for these. But what about the B star?

3. Well, the B star is part of the designation STT 204 which is an uncertain double. Magnitudes: A = 6.7. B = 10.7. Sep = 8.3". PA = 99 degrees. Of course the A star is the same star as the primary of WAL 56. But it took 112X to split STT 204 cleanly. However taking these WAL 56 and STT 204 together we have a rather nice triple star which my scope separated at 112X. And I highly recommend it to you. 

4. STF (Struve) 1399 is a true binary a few degrees west of Gamma Leonis. Magnitudes: A = 7.7. B = 8.4. Sep = 30.2". PA = 176 degrees. Good clean split at 40X at first. At 112X I could see that A was G0 yellow. B was white. But wait a minute! I moved myself over to the WO 70 mm apo to discover there was a tiny section of black space between the 2 stars! I do keep a 28 mm 2 inch eyepiece in the small apo at all times. 11X is its magnification. This was, for sure, a super sight for yours truly. As north is up and the PA is at 176 degrees, the secondary was seen hanging straight down from the primary. 

5. Lastly, I observed STTA 103 which is an optical double a very short distance from STF 1399. Magnitudes: A = 8.4. B = 9.6. Sep = 79.9". PA = 130 degrees. Not much to get excited about here. The secondary wasn't visible in the 70 mm apo. Therefore there was a good deal of separation at 40X between these 2 white stars in my main refractor. STTA stands for Otto Struve Supplement.    

I do thank you for reading my latest report. 

Comments, corrections and images are very welcome. 

By the way, this observing session was my 20th of 2021. 
That's not bad at all - is it?

Clear skies from Aubrey.   
The following user(s) said Thank You: lunartic_old, Fermidox, Until_then-Goodnight!
Last edit: 1 year 7 months ago by flt158.
1 year 7 months ago #110130

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Replied by Until_then-Goodnight! on topic Observations - 10/04/21

Hi Aubrey,

Great to read another report from you. Very well done on observing four new doubles last night -STT 216 sounds delightful.

Also, I was amazed to read that you've reached 20 observing session in 2021 already - that's some going! I wonder how many you were on this time last year? I remember that 2020 was a record year for you, and it seems like 2021 is shaping up to another bumper year for you.

Great stuff!

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1 year 7 months ago #110134

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