Izar double star

Good evening, all (especially double star observers). Last Friday night, I returned to an old double star favourite of mine -Izar or Epsilon Bootis. It is situated to the west of bright Arcturus quite high in the north eastern sky.
2 years ago, I tried to split Izar and found great difficulty separating it. I needed 280X in May 2009. I spoke to Michael O'Connell about it at the time and he suggested I try again. Last night was my 30th observing session of the year -so I decided to do something special. After looking at Venus once again, I would set out to split Izar.
Izar's components are magnitudes +2.6 and 4.8. Their separation at present is 2.8", and the position angle is 343 degrees. At 112X in my 6.2" apochromatic refractor, I could just see it beginning to separate, I was amazed! Component B's position is about 12 o'clock -almost due north of component A. At 140X, the telescope cleanly seperated it. However, the view was stunning at 167X. As we know, apochromatic refractors kill most false colours. But I could easily see component A was quite orange and component B was just bright white. This is in agreement with the 2 stars' spectral classes.
As I was very delighted observing this great double star Izar, I called it a night -wonderfully satisfied. It would be nice if a few more people could check out Izar, and report back on this website. What magnification is needed to split it with other telescopes?

Aubrey.

Hi Aubrey,
Nice report on Izar this is one of my favourite double stars
I have split it with a 80mm refractor, at 120x the two stars
are just touching and at 200x they are well split a beautiful
sight. I see the colours as orange primary and blueish secondary.
Another double you should try is Porrima in Virgo well placed at the
moment, both stars are 3.5 magnitude and seperation is 1.9"
to me both stars are orange.

Pat.

Thank you, Pat, for your kind words. Porrima is indeed another favourite double star of mine. When Valerie and I were married in 2007, Porrima was completely inseparable, but last year, the planet Saturn was in the same field of view, and the telescope managed to split them cleanly at 167X. Both stars were a deep yellow. However, on May 5th this year, I did observe it again, and at 112X, both were similar to a figure 8, and at 140X, we had separation. Porrima is a double star which has a cycle. I notice back in 1993, I could split it at a mere 100X. It will be fascinating to see the gap widen over the next decade.

Aubrey.

Hi Aubrey, just back in from viewing porrima, I was comparing
the view in two scopes a 80mm zeiss and 100mm Tal and although
both scopes split it, the Zeiss at 200x and the Tal at 167x the
image in the Zeiss was much cleaner and sharper. I would love a
bigger refractor sometime, what scope are you using.

Pat.

Good to hear from you again, Pat. Thank you for showing interest in my scope. It is the William Optics FLT158 f/7. It is a apochromatic refractor and is mounted on a Berlebach Planet altazimuth mount, and I hope to bring it once again to the Martello tower in Sandymount on Friday 1st June -if you wish to see it, Pat. The focuser is a Crayford 2 speed, and as a guidescope I have the ZS70 f/6. So far I have observed planets, double and multiple stars, carbon stars, star clusters and a couple of eclipses.

Aubrey.

Aubrey I am away on holiday in early june so will not get
down, maybe some other time. What do you think of the William
optics telescopes in comparision to the other scopes you had.

Pat.