More observations in Bootes

Hello everyone.

Here are more wonderful observations while using my William Optics 158 mm f/7 apochromatic refractor.
As I do have mirror diagonals fitted at all times, my north is up and my east is to the left.
We had very clear skies on Monday and Tuesday night (28th and 29th May 2018).
Here are the details.

1. Arcturus always blows me away with its golden colour. I can find it now right after sunset -even before I can see it with my eyes. It is my favourite bright star. I rarely go beyond 40X when observing it.

2. I finally succeeded splitting Izar at 112X in 2018. My personal advice to you all is to find it before you can see it with your own eyes. Then point your scope at it at your lowest power. Then increase your magnification to over 100X. I use 112X; then wait for a few more minutes until you see that A is orange and B is blue. My sky was remarkably pure with no wind whatsoever on Tuesday night. I totally agree it ought to be called Pulcherrima because of its quite vivid colours.

3. Alkalurops (Mu Bootis) is always going to be a huge favourite triple star of mine. Its yellow white primary and its B secondary are instantly observed at 11X in my 70mm apo. But I do require 112X to see B and C split real tight in the 158 mm apo. It is a marvellous sight to see a tiniest gap between these 2 stars.The B star in my eyes is yellow and C is orange. I should also state that the B star is the furthest away from the A star. Therefore the C star is between A and B. The magnitudes are 4.3, C is 7.6 and B is 7.1.

4. I had to revisit BU 1442. This superb wide triple has a wonderfully unusual set of colours. Red, red and almond brown are truly remarkable to behold. They are all the fascinating at 167X although 40X is sufficient to see all 3 stars. The third star has a spectrum class of K7 which suggests a deep orange hue and is the brightest of the 3. So deep, in fact, it is brown. I have observed only 2 other K7 stars. Please come back to me and see what you think.

5. Struve 1825 is indeed remarkably close to Arcturus. I see the primary as yellow. Maybe B is a slight blue. But I love the way the 2 stars point downwards.

6. A few years ago I did greatly admire Struve 1835. A is white and B is slightly yellow -white. Lovely at 40X and 112X.

7. STT 281 is definitely 1 tough double. A is yellow alright; its magnitude is 7.7. B has no colour at all. It probably is plain white. At 167X, I can barely see B separated from A. B's magnitude is 9.7. The PA is 166 degrees. So it is another straight down effect for my apo. It is more cleanly separated at 225X. STT 281 is directly west of Stf 1835.

8. Hey lads and lassies, I finally have seen the A and B components of an Aitken binary. A 1103 is directly north of Stf 1835. But be warned! It is nearly impossible to find because of its very faint magnitudes. As a star hopper I discover that there are so many magnitude 10 stars in this tiny area when using my 40X eyepiece (which is a 2"). Looking for a 9.9 magnitude star is like looking for a needle in a haystack! And it is even harder to see a B component right next to it. So I try and pick the "right" star at 40X, and then change to my 10 mm Pentax eyepiece which gives 112X. And there he is! It is split at this power. The B star is 10.9 mag. The separation is a mere 4.7". The PA is 204 degrees. I did not bother with the colours. I was just so relieved to see a first double star which has an A designation! I am very sure Mr. Aitken had the use of a much larger apertured telescope to split these extremely faint and tight binaries.

9. Further north is a real gem of a binary. Struve 1838 is beautifully split at 40X and even finer at 112X. A is yellow -white and B is white. I hugely enjoyed this double. At 112X I did greatly admired it even more. The unusual PA does seem to make all the difference. It is 334 degrees and the separation is 9.5". The magnitudes are very similar: 7.5 and 7.7.

10. And so I come to my final binary. I have to say I have not observed Pi Bootes for about 20 years. (I will check my previous records). It is the most beautiful binary on this particular night. The magnitudes are 4.9 and 5.8, The PA is 113 degrees. At 40X I can certainly see that it is a true double -but no split. However everything changes at 112X. Not only can I see A and B but there is 10.6 mag C component. Its PA is 163 degrees some 127" away from A. C must be an optical companion. There is a lovely dark gap between A and B at this latter power. There is no need for me to go higher in magnification. I personally do not observe any definite colours in this system. My wife thought there was a hint of blue with one of the stars. But I am recording white and white. It is nice to see I am in agreement with Sissy Haas on this one.

I would love to see some replies on this post.
In my skies, Bootes is good and high in my southern sky during May and June after sunset.
When I do get another clear sky, I will star with Pi Bootis and then head northwards to find even more doubles and triples and anything else that the grand constellation of Bootes has to offer.

Thank you for reading this report.
It has been a real thrill compiling this list.

Clear skies from Aubrey.