Porrima,an easy binary star for beginners

[DavidU]

Here's an easy challenge for beginners.Finding close double or binary stars can be difficult to find however at the moment there is a nice binary double star Porrima (Gamma Virginis γ Vir, γ Virginis) very close to Saturn.Located about a 1/3 the moons diameter to the North of Saturn.
Gamma Virginis is a binary star consisting of two stars of approximately equal apparent magnitudes 3.48 and 3.50, and of spectral type F0V. With an orbital period of 168.93 years it was an easy object for amateur astronomers until the beginning of the 1990s, but now the smaller apparent distance between the stars requires a larger telescope.
The last time they were at periapsis was in 1836. The distance will again be wide enough in 2020 to view with a small telescope. The star system has a combined apparent magnitude of 2.9. The system is 39 light years away from the Sun.
I tried this binary split with my 12" Dob @ 300x without a problem tonight. A good 6" or 8-10" should be able to split it as well.
Have a go at it !

[The Mekon]

Yes I can split this in my new 4" refractor at 140x

Harder is to get both Saturn and Porrima in the same field AND split the double. At 99x both are in the field of a wide view eyepiece but Porrima is only a "figure8" and not clearly split.

This is one event that must be recorded in your observing log!

[The_bluester]

Arrrgh, why did I just read this now?

Literally just sitting down to the PC after packing up the scope (To stay relatively in the good books with the wife) having spent quite a bit of the night observing Saturn, including dropping to a low power to get it and Porrima in the FOV together!

[Robh]

Hi Dave,

The Porrima components seem to be about 1.3 arcseconds apart (WDS Catalogue) which seems to correlate with the ephemeris given in this article ...
http://articles.adsabs.harvard.edu//full/1989JBAA...99..179H/0000181.000.html

Regards, Rob

[Suzy]

Thanks so much for that information David, I will definitely give this one a try! :thumbsup: I want to try splitting some easy ones so this information comes at a good time. Alpha Cent. is the only one I've split so far.

It does look so beautiful together at the moment with Saturn doesn't it?! :)

[casstony]

I split this tonight in the same 106mm refractor and similar magnification as John B above.

[renormalised]

Albireo (beta Cygni) is another good binary for newbies to have a go at. Another target of note is Hadar (beta Centauri) but you'll need a large scope to separate the two (1.3"). What's more, the primary is also a spectroscopic binary of nearly equal sized stars...both blue giants and variables of the beta Cephei type. 61 Cygni is also a classic binary for newbies to track down. It consists of two K class stars (primary star is K5, the secondary K7) in a wide orbit (about 700 or so years) and lie about 11.4ly from Earth. Their particular historical note is in their high proper motion (one of the highest) and the fact they were the first stars to have their distance measured by the parallax method.

[Robh]

Maybe we should resurrect this thread...
http://www.iceinspace.com.au/forum/showthread.php?t=45555

Regards, Rob