Posts Tagged double stars

VicSouth Desert Spring Star Party

Pretty much exactly what the name says, the VicSouth star party happens every year at the Little Desert Nature Lodge just outside of Nhill. It’s usually held over the Melbourne Cup not-actually-a-long-weekend, and this year I was fortunate enough to be able to go for most of the weekend. I was very excited.

The event itself

… was very well organised. The location itself is excellent for astronomy – James checked the sky each night and got readings to indicate it’s the darkest skies we’ve ever observed under. There’s a big field that’s perfect for setting up many telescopes; there were lots of cables running to power but that’s always going to be the case. The field’s flat, it’s grassed, and it’s near the dining room which meant that the urn wasn’t too far away when it got to midnight and we were cold but still keen.

The location also works well during the day. We splurged and got a cabin – nice to collapse into a good bed – and we also went with the food package, which meant lunch and dinner. The dining room comes with big round tables that seat 8-10, which meant that we were forced to talk to people (the horror!) at each meal – we had some great conversations about astronomy and even other things. And the food was pretty good too. The organisers planned things for during the day, and I even got to some of it despite needing to nap each afternoon to prepare for the night’s viewing. A number of people volunteered to give talks, on everything from the geology of the local area, to ways the universe is trying to kill you; from astrophotography to organising your observing lists. It was a pretty good mix. And apparently each night there was a movie on the screen (including On the Beach), but I didn’t get to those.

The observing

I went without any preparation, except for the vague desire to get up and see Comet ISON. Since that’s the only thing that could be called a goal, as of the Friday afternoon, you could say that I failed, since 5am did not see me awake on any morning. Given that a small group of people did get up and then reported that it was a fizzer, I’m not too fussed.

We only got in a couple of hours on my first night before the clouds rolled in. Had a great view of Venus… because for a while it was pretty much the only thing to look at, given its insane magnitude and height in the sky. Also 47 Tuc, which rather started a theme for the weekend… I do love me a globular cluster.

The next night more than made up for the first, though, and we stayed up until about 2.30. I had made a List, and got through a number of doubles before I got distracted. I looked at some globular clusters, including some in the Large Magellanic, which I didn’t realise you could do. I also looked at Uranus and Neptune – to my everlasting delight we bagged Triton, Neptune’s main moon, too. James contributed to my distraction by convincing me that Andromeda through my ‘scope was the best idea, given its wider view; and we managed to see the two other galaxies around it, too, which did indeed look spectacular. He was concentrating on some faint fuzzies, and called me over to test my eyesight on some mag 13-14 galaxies… most of which I managed to see, or at least could convince myself that I did. And of course I greedily admired the Orion Nebula; I will never ever get bored by it. I was sad by how late Jupiter was rising – I saw it through the trees, and the Galilean moons were all in a row, but the view was utter mush.

The last night of viewing was also spectacular, but we sensibly didn’t stay up as late since we had to drive home the next day; so we pulled out at about 1.15. Again, I bagged a number of double stars – to my delight I discovered that I could split down to a 4″ separation! I didn’t think that was possible through the 120mm. I looked a few open clusters, but mostly they bore me; the Ink Spot and cluster of NGC 6520 were pretty cool, though, as the dark nebula of the Spot was quite noticeable with it being so dark. Again I got distracted by globulars, doing so a bit more systematically by dialling up all the globs in Sagittarius (there are so many Messier objects there!) on the Argo and working through most of them.

And there was observing during  the day, too. I had taken my solar scope, but someone else had their much-bigger, double-stacked one rigged up next to a white-light solar scope, so… yeh. Mine didn’t come out. I was mighty impressed with his set up: he’d got a piece of core flute, and attached to the scopes, so that they acted as a sun shield. BRILLIANCE. But, um… maybe a little bit TOO attractive….

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Double Star Atlas

When I announced that I might be interested in checking out double stars, James bought The Cambridge Double Star Atlas, by James Mullaney and Wil Tirion, for me. It’s a big book – larger than A4 – although only 148 pages long. It’s spiral bound, meaning that despite its size it’s quite useable: you’re not forced to to deal with an A3 map on your lap while at the eye piece. The paper seems to be good quality and slightly waxy; I’ve had mine sitting on dewy grass and although some of the pages have slight ripples in them now, the book itself hasn’t suffered at all. And it’s got wonderful content, with an excellent introduction and superb maps.

In the introduction, Mullaney takes the reader – anyone from a novice to expert – through the process of making the book itself, then tabulates the codes that are used to signal the discoverer and/or catalogue used when discussing individuals pairs/systems. There is an excellent section on the practicalities of observing – useful not just for doubles hunting – explaining how to train the eye to observe, as well as the impact of sky conditions and the resolution and magnification of telescopes. He also discusses the idea of record-keeping, and it was from reading this that I decided to keep a journal of my observations.

Before getting to the maps, Mullaney has a list of 133 ‘showpiece’ double and multiple stars. As well as giving the name of the object, its coordinates and magnitude, he includes a short and usually evocative description of each object. For those of us who like lists, this is something akin to having a Messier list for double/multiples. It’s a fabulous challenge (although disappointingly for me a fair number are beyond my viewing range, here at 37 degrees south).

The heart of the book is the 30 double-page maps that cover the entire sky (p1 is the North Celestial Pole, p30 the South). The maps show about 900 non-stellar objects as well as the doubles, so it can make an excellent all-round atlas too. The stars making up constellations are connected by faint blue lines, and the ‘spheres of influence’ of the constellations is also shown, which is useful when trying to locate specific objects. The doubles that are specifically listed objects (all 25,000 of them) are labelled in green, making them easier to read under red light. I’ve never been especially good with maps, but these are easy to read and easy to use, both while planning an observation session and while at the telescope.

Finally, there are the Appendices. App A lists the constellations and which pages they appear on; B has the ever-useful table of Greek letters. But C is where the money really is: a list, in order of RA, of the doubles Mullaney specified be in the Atlas. The table has the object’s designation, RA and Dec, magnitude, and the pair’s separation, as well as occasional helpful remarks (this is Antares, this is in the middle of the Pleiades). This appendix can be used to give the astronomer a better idea of exactly what she is looking at on the map; when used in conjunction with an Argo, if a random double is spotted it can be looked up via the RA/Dec to see whether it is listed and if so its name.

Would I buy this Atlas again (or get James to buy it)? In a heartbeat. Of immense value to anyone who is interested in looking at double stars. It’s easy to use, lovely to flick through when planning, and sturdy into the bargain.

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