24 Comae Berenices is spring’s hidden treasure, a stunning pair of stars: one yellow-orange and the other blue-white.
Located in a rather tricky part of the sky to navigate, just south of the open cluster Melotte 111, there are a couple of ways to find the stunning double star.
Imagine the mid-point between Denebola (Beta (β) Leonis) and Diadem (Alpha (α) Comae Berenices).
Nudge slightly towards Diadem and look 1.8° to the north to locate 24 Comae.
It can also be found two-thirds of the way between Porrima (Gamma (γ) Virginis – not shown) and Gamma Comae Berenices.
Observing 24 Comae Berenices
This is a beautiful pair of stars, formed from a yellow-orange, K0, mag. +5.2 primary separated by a little over 20 arcseconds from a blue-white, A3, mag. +6.7 secondary.
The position angle is about 280°.
The primary is 590 lightyears away, with the secondary 2,600 lightyears away, making this an optical line of sight double star rather than a true binary.
A small telescope will show them, but mid to large apertures are required to make their colours stand out.
The contrast between both stars’ colours is what makes the view so sublime, each providing a basis for comparison with the other.
Their yellow-orange and blue-white colour combination draws further comparison with that heavenly gem, Albireo (Beta (β) Cygni), the jewel in summer’s crown.
As a consequence, 24 Comae Berenices is often described as ‘spring’s Albireo’. It’s quite similar in appearance to Albireo, albeit dimmer and with slightly less colour contrast.
This guide appeared in the April 2019 issue of BBC Sky at Night Magazine
