6 doubles + one triple in Corona Borealis

Good day again, everyone.

These observations I did on Friday night 29th May 2020 from 20.29 UT to 23.00 UT with my William Optics 158 mm F/7 apochromatic refractor and its WO 70 mm F/6 small apo. Mirror diagonals are fitted to both scopes. So my north is up and my east is to the right. Temperatures were pleasant at 14 degrees Celsius and not much lower at midnight.

Sunset occurred at 20.37 UT. Add one hour for Irish Summer Time.
Each and every one of these objects were invisible when I successfully observed them.

1. Having bidden Venus a final farewell, I observed Arcturus at 20.29 UT. That's 8 minutes before sunset. And I wouldn't mind the golden-orange star had high cloud passing by. What a start!

2. Of course, who was next? Izar. I then noticed the seeing conditions were not at all good for now. Both stars were shimmering away at 112X. But I was pleased to see black space between them. 140X, 167X and 225X were once again highly advantageous to use within the hour. When I went back to Epsilon Bootis later the seeing conditions had much improved.

3. I then thought I ought to gave the planet Mercury a try. But instead I bumped into a single star through my WO small apo at 11X. In the main scope using just 40X, I immediately recognised I had Castor split cleanly at that power. There was the tiniest black gap between A & B. Nice!

4. When I finally saw Alpha Coronae Borealis with my own eyes, it was an easy decision to make to observe some more doubles in this small-in-area constellation. This time they are all easy to split. First up was STT 302 and it is an uncertain double. Magnitudes: A = 7.2. B = 10.4. Sep = 28.6". PA = 51 degrees. Nice split at 40X of course. But at 112X and 167X I could see A was A2 white. B, on the other hand, had a delightful orange hue. I've no way of finding out its spectral class, but that's okay.

5. Rho Coronae is an optical double. Magnitudes: A = 5.5. B = 10.5. Sep = 141.7". PA = 47 degrees. It's easy to see both stars at 40X. A is a very slight G2 yellow-white star. I just needed to see it just this once as I was in the area.

6. HJ 577 is a true binary. Magnitudes: A = 9.3. B = 10.5. Sep = 9.4". PA = 13 degrees. Nice split at 40X. But A is K0 orange; and at 112X its hue was quite delightful.

7. STF 1973 is a true binary. Magnitudes: A = 7.6. B = 8.8. Sep = 30.8". PA = 320 degrees. Split at 40X. But I would have to say this double is rather pleasant to the eye at low power.

8. STT 305 is a true binary. Magnitudes: A = 6.4. B = 10.2. Sep = 5.7". PA = 263 degrees. I required 112X to see A & B straight as at 40X I could not see B. A is a good orange.

9. Sigma Coronae is a triple star. A & B are a true binary. But C is strictly optical.
Magnitudes: A = 5.6. B = 6.5. C = 10.8. Sep's = 7.3" and 118". PA's = 239 and 82 degrees. This system ought to be for beginners. I had a wonderful tight split at 40X between A & B. Plus C was seen also at this low power. A is G0 yellow. G1 B is less yellow. However I must say the 3 stars are a fine sight at 112X, 140X and 167X. It's my first time to observe this good triple system. It's definitely my finest observation this night.

10. Lastly, I finished with an optical double star which for some reason Sissy Haas has highlighted in her famous book called Nu Coronae. At 11X through the small apo there is no problem seeing these 2 widely spaced stars. Magnitudes: A = 5.4. B = 5.6. Sep = 355". PA = 164 degrees. It's definitely one for binocular users. The colours are slight. A has a minimal orange hue. B has a very minimum shade of red.

As the midnight bells rang out, I ended my 16th observing session of May 2020.
I hope to observe again on Sunday night.
I'm waiting till then because I have just been observing 3 nights in a row. I'm jaded!

Maybe next time I will have some tougher doubles for you all.

Thank you for reading.

Comments are very welcome

Clear skies from Aubrey.

Excellent Aubrey, I think that's 30 observing sessions for you between April and May, which is quite incredible. Of course Corona Borealis has two famous variables, R and T. R is currently near maximum at mag 6.4 and can fade spectacularly and unpredictably within a few weeks. T was discovered by our own John Birmingham as a nova in 1866 and flared again in 1926. Another outburst is anticipated in the next few years, rising to mag 2 or 3 from its current mag 10. Worth giving these a glance as you wade through those doubles.

Finbarr.

Indeed it is 30 nights, Finbarr.
I didn't pay attention to that fact.
And 47 since the 1st January!
I'm thinking of having another go on Sunday night - the last night of May.

I did observe R Coronae on the night of 24th May.
But not the other chap T Crb.
Must give it a go some time soon.
I also have 13 more doubles to split in Corona Borealis.

Best regards from Aubrey.

Another detailed report... Wonderful stuff! 

Arcturus is a real beauty, so to see it before sunset must have been a delight. 

Between Bootes, and Corona Borealis you've highlighted so many double (and triple) stars that require closer attention. 

This area of the night sky seems like a real treasure-trove for multiple star systems. 

Over the past couple of months I've stumbled across many nice doubles in and around these constellations, and your fine reports always help me to better understand what I observe. Thank you Aubrey! 

Clear skies, 

Darren. 

Thank you, Darren.
I also use your observations to encourage me to set the scope up to see some wonderful treasures.

The 3 weather websites I rely on are all promising very clear skies for tonight Sunday 31st May. The current hazy sky conditions are due to go away from 8 pm local time.
If they are right it looks like we can have a good night's viewing.

Clear skies to everyone from Aubrey.

You're very kind Aubrey, as they say 'it takes two to tango'. In saying that, this forum has been great in recent months with so many individuals sharing their tales from the eyepiece. One cannot read all the posts and not want to look up. 

Also, many thanks for the weather update. I was delighted to read that the sky should be clear tonight. I have only six hours left to sketch this month's lunar image. I tried on three separate occasions to sketch the Moon during May, but it never got done. I came very close at the start of May, but the wind had a different idea. I thought I was going to have to sketch one from a photo, but it looks like I'll be out with my pencil and paper this evening  

Kindest regards, 

Darren.