Splitting Tools for Almach: Yields easily to 50mm scope at high power.
Splitting Tools for Albireo: Yields easily to 50mm scope at low power.
Gamma Andromedae – Almach
RA: 02h 04m Dec: +42°20′
Mag: 2.16, 5.0 Sep: 9.7″ PA: 63°
Distance: 355 ly
Spectral type: K3, B8
Beta Cygni – Albireo
RA: 19h 31m Dec: +27°58′
Mag: 3.4, 4.7 Sep: 34.7″ PA: 55°
Distance: 380 ly
Spectral type: K3, B0
Well, that’s how they hit me this morning. You may think I mean these famous pairs of stars are the same. Oh no! Far from it. I mean that Almach – the “fall Albireo” in my book – is gold and blue with the emphasis on gold. And Albireo – the real thing – the original – the one and only – is, well, blue and gold, for it’s the intensity of the blue that strikes me. I was glad to see this subjective impression is borne out, at least in part, by the spectral class designations, but, of course, color perception is a very subjective business and there are several other factors that make your overall experiences of these two “60mm jewels” different, including separation, magnitude range, and ease of finding.
Oh – and before saying more – both of these are really triples – but I don’t know anyone who has split either visually, the third star being so close. So as far as the typical visual experience goes, they are doubles – though in your minds eye you can see more – much more.
I think I caught them both under pretty identical conditions, though, one climbing up the eastern sky, the other diving down in the west. I could quickly swing from one to the other in the growing morning twilight. At 4 am Almach was at 50 degrees altitude, Albireo 52 degrees – with Albireo having slightly darker skies for being in the west – but then, I had begun my observation of Almach 15 minutes earlier when the skies in the east were somewhat darker.
It’s my 69th birthday and these old friends had come to the party which began at 3:30 am when I stepped out on the rear deck to find delightfully clear skies. Five hours earlier I had gone to bed to intermittent clouds and I really expected clouds this morning. But here was the Milky Way and I did my best to hurry the 60mm Unitron 114 out the door – I leave it set up in the library – grab eyepiece case and observing chair, and even nuke a cup of tea, all without disturbing my night vision. (Yes, when you wake up in a darkened bedroom your night vision should be pretty good – mine is. The trick is to do what you have to do without ruining it. Sometimes I plan ahead for this by leaving red goggles next to my bed, but I hadn’t this morning.)
I’d like to say I got right down to business, knowing I was already entering astronomical twilight, but I just had to try the 60mm on the Andromeda Galaxy first and to my delight, the 32mm Plossl gave me a wonderful view of M31 with M32 jumping out immediately and almost as quickly, M110! That last was a delightful surprise and brought me from feeling 69 to feeling 13! Yeah – part of me wishes this is what my 13th birthday would have been like, but I’m dreaming. Oh my childhood was wonderful, but on a minister’s pay my parents could not afford something like the Unitron 114 then, nor would I have appreciated it, much less what it could show me. No – it’s taken all of the intervening years for my deep appreciation of the night sky to evolve to where it is now – and with that, my appreciation, for the pristine views provided by small, long focal length refractors.
I didn’t dwell on M31 & company, however. I sucked in a deep breath, took a great picture in my mind which I can still see now, and swept up Almach, a very easy task since it is almost exactly second magnitude and lies at the end of the line of stars that slide roughly down a slope from a corner of the Great Square of Pegasus to the Demon Star, Algol. The 32mm yields 28X and a field approaching 2 degrees, so most of the time I use it as my finder. Sitting behind a long, thin scope makes it pretty easy to point with reasonable accuracy anyways. This is one way, however, that Almach differs from Albireo. In fact, if I were helping someone get started in observing double stars, I’d start them with Almach, assuming it was the right time of year. Finding Albireo isn’t that easy. It’s a full magnitude fainter, so it doesn’t leap out to the naked eye. And when you turn a scope or finder in its direction you’re going to see a much richer – and much more confusing – star background because Albireo is right in the Middle of the Milky Way.
What struck me first about Almach this morning, however, was the intensity – no, that’s not quite right – the hue is the correct word. It had that rich yellow-going-to-brown look that defines the color gold. Maybe a hint of brass, even, but in the end gold – true gold. In the 32mm its companion was hinted at. Were the seeing better – it was average – I’m pretty sure I could have picked out the secondary, but it was much easier to do with a 21mm Plossl at 43X. And the view got better as I marched on up to 69X and then 86X. It was there I stopped. That was perfect: Gold and blue with just the right amount of clear black sky between them. This last is a judgment, of course – find out what works best for you. This suited my taste perfectly this morning – and I did my best to imprint the impression, before turning 180 degrees and sweeping through the Milky Way for Albireo. Here I returned to the 32mm and here, of course, is the most obvious difference with Albireo.
At 28X it is a very easy split – in fact half that should do fine, for Albireo’s components are 33 seconds of arc apart, more than three times that of Almach’s!
So the experience of the two is quite different, though the similarity in color is striking. They are also similar in that they both consist of a primary that is expanding in its old age – the first stages of dying. And secondarys that are relatively young and hot. But where there is nearly three magnitudes difference between the primary and secondary of Almach, there is just a bit more than a magnitude difference between the two stars of Albireo. And while there is no question that the two stars of Almach are gravitationally linked, there is serious doubt when it comes to Albireo. They may be – they may not be – but if they are, they are quite distance and take an awfully long time to complete an orbit.
James Kaler does a great job describing both stars from a more scientific perspective. Here are some highlights from his site. After noting the sky abounds in doubles, he says:
Among the best of all, however, is the last star of the string of bright beauties that helps make the constellation Andromeda, second magnitude (2.16) Almach, Andromeda’s Gamma star. . . Through the telescope the star is extraordinarily lovely, even a small instrument showing a superb pair separated by a good 10 seconds of arc, the brighter one golden yellow the other blue.
While pointing out that the primary is bloated to the point that it would fill our solar system out to the orbit of Venus, he notes:
More remarkable, the fainter blue-green component, Gamma-2, is ALSO double, though the duplicity is far more difficult to see. Fifth (5.1) and sixth (6.3) magnitude white hydrogen-fusing dwarfs . . . orbit each other with a period of 63.7 years separated on average by but 0.3 seconds of arc . . . . Yet again the system splits, as the brighter of these two is ALSO double, though detectable only with the spectrograph . . . The naked-eye star we know as Almach is thus quadruple, making it a feast for both the mind and for the eye.
Kaler goes wild about Albireo as well. In fact, he includes it in his wonderful book, “The 100 Greatest Stars.” On the web site, among other thngs, he notes:
Albireo is actually triple. The brighter yellow-colored member, Albireo A, is a much closer double made of a third magnitude (3.3) class K (K3) stable helium-fusing bright giant and a hotter but dimmer (magnitude 5.5) class B (B9) hydrogen-fusing dwarf, the two stars not readily separable in the telescope. The K giant has a temperature of around 4400 Kelvin, a luminosity 950 times that of the Sun, a radius 50 times solar, and a hefty mass of about 5 solar, while the close companion comes in at 11,000 Kelvin, 100 solar luminosities, and 3.2 solar masses. On average separated by about 40 Astronomical Units.
You can get a good look at Albireo from June to December. Almach is in prime time in the Fall. To duplicate what I did this morning – see them both while high in the sky – you don’t have to get up at 3 am. From mid-October to mid-December Almach is well up in the east a couple hours after sunset, while at the same time Albireo is still high in the west.
In the gathering predawn light I ended a beautiful morning observing session by slowly increasing the magnification on Jupiter. I stopped at 86X. I’m not much of a planetary observer, but I could swear I could detect the ghost of the South Equatorial Belt which went missing a couple of months ago when Jupiter was behind the Sun. Wonder if it’s coming back now? Sure looked like it to me.