Double Star Joy

[David Levi]

I started the session with a good look at the crescent Moon. Around Mare Serenitatis, the crater Posidonius was looking superb and I enjoyed studying Le Monnier, Plinius and the Serpentine Ridge. I also spotted the dark edges around the sea. In Mare Tranquillitatis, the Arago Domes were quite obvious but I didn't get a good view of the Lamont oval ridges except the ones leading from the oval. I had a look at the twin craters Sabine and Ritter but their best too was yet to come. I think the sun needed to be a bit higher to get a better view inside these. On the outskirts of Mare Nectaris the Altai Scarp was very clear.

With Jupiter opposition approaching on the 10th of June and mostly clear skies forecast I was desperate to have a look at the gas giant.  Without a view to the east, Jupiter is now rising such that I can see it south east at a reasonable time, about midnight last night.  I was using binoviewers at I guess somewhere between 150x and 200x magnification. The seeing was not great. It took me a few seconds to realise that the GRS was in view, although after noticing it, it was quite obvious. Details of the clouds in the equatorial belts weren't very well resolved. The Galilean Moons were well strung out in a three to one split.

The highlight of the night for me was the performance of the 100mm refractor, that I was using for the session, on double stars. Again using binoviewers, it just ate them up far better that my 8" reflector. The star shapes, and views without diffraction spikes are just so clean. Colour rendition is also better. I took in the following binary stars.

ε Boo, Izar, 2.5/4.9 mag, 2.9" sep, much cleaner and easier split than my 8" reflector

λ Oph, 4.2/5.2 mag, 1.6" sep

τ Oph, 5.2/5.9 mag, 1.6" sep

61 Oph, 6.2/6.6 mag, 20.7" sep

67 Oph, 4.0/8.1 mag, 54.4" sep

70 Oph, 4.2/6.0 mag, 6.6" sep, nice yellow pair

72 Oph, 3.7/7.5 mag, 297" sep

I was really surprised that I could see the split of λ and τ Oph.

I did try a look at the globular clusters M10 and M12 but they were very indistinct. Not the correct targets for my location.

From the light polluted skies of my suburban back garden a very pleasing session.

Edited June 10, 2019 by David Levi
degree symbol ° to arcsec symbol "

[NGC 1502]

 

Indeed, double / multiple stars are great to observe, fascinating in their variety, show up well with a light polluted or not quite dark sky, involve a lot of interesting astronomy, the whole sky is stuffed with them........

BTW, when you observed the Ophiuchus doubles, you were close to Barnard’s star, the nearest naked eye star being 66 Oph.

Ed.

[David Levi]

42 minutes ago, NGC 1502 said:

BTW, when you observed the Ophiuchus doubles, you were close to Barnard’s star, the nearest naked eye star being 66 Oph.

I did think about looking at Barnard's Star but it's quite faint at mag 9.5. I have observed it before with my reflector so it wasn't a priority last night compared with my double star hunt.

[cotterless45]

Hurrah , another pilgrim of the skies turning to binary and multiple stars ! For anyone with light polluted skies these are wonderful targets .

In addition a colourful range of carbon stars will provide hours of pleasure . A 4" frac will produce the best colour show.  Enjoy !

Nick.

[wookie1965]

Great haul there another convert to a Frac for double, multiple and carbon star observing, It is very surprising what a 4" Frac can catch.

[Mike JW]

Hi, Refractors (quality ones) are excellent for doubles but quality Mak Newts are right up there (enjoyed a MN76 for a couple of years - apo like views with 7" aperture). Orion Optics OMC 200  (F20) also are amazing - very expensive new but they do come up second hand. It has been the best doubles/lunar/planetary scope I have ever owned. The extra aperture enables faint double companions to be picked up as well.  Mike