OzSky Star Safari: the Stars

James and I had the pleasure of volunteering at the 2014 OzSky Star Safari a few weeks ago. Originally designated the Deepest South Texas Star Party, OzSky aims to show northern hemisphere astronomers just what they’re missing out on by living on the wrong side of the equator.

A good star party has two nearly-equal aspects: the star part, and the party part. So I’ve split the recap into two, to match.

The party part

The star part

Saturday night: cloudy when we went to bed… then clear by 1.30am. There was thumping on doors at 2am with the announcement that “Sky’s clear!!” – so we observed until 5am.

Sunday, Monday, Tuesday, Wednesday: clear as clear, only forced to bed by that stupidly bright Venus rising pre-dawn. (Alex piked early on Wednesday.)

Thursday: cloudy. Alex was sad but not too sad.

Friday: cloudy… until 10.30pm. When it came clear and some of those crazy northerners announced that hell yes, it was their last night observing in Australia so they absolutely wanted the telescopes uncovered, thanks. It fogged out at 12.30am, but over those two hours more and more L1000535people emerged from their rooms to have one last look at southern glories and faint fuzzies. It was a near perfect end to the week.
Part of the attraction of OzSky as an event is that the organisation behind it owns a bunch of big Dobsonian telescopes which get brought along, set up, and collimated by the volunteers. We decided to take along our own telescopes as well, figuring that there wouldn’t be any other refractors so ours would enable people to see things a bit differently – especially with its very wide field, plus Jupiter was going to be primo early in the evening – and that another Dob wouldn’t go astray.

 

We had quite different observing experiences.

 

Alex

I spent most nights at my own telescope. Of the southern stuff, I particularly enjoyed showing off the Eta Carina nebula in the widest eyepiece I could. It’s all very well and good to go zooming in on the Homunculus (which is awesome and we managed to see lobes just resolving in my 4.7mm), but the entire nebula really is incredible. Additionally, there was the Jewel Box and Gem Cluster (best at lower power where the colours really came out), and Omega Centauri and 47 Tuc (I hadn’t realised our globular clusters were another thing the south does better). The Tarantula Nebula and LMC in general were also winners in the wide field.

Of the non-southern stuff, I did indulge my weakness for planetary observing and forced anybody wandering past to blast their eyeballs, despite occasional protestations. And I don’t think anyone complained… well, not much. Early on, Jupiter: I didn’t think they were the absolute best views ever, but still seriously awesome. Several cloud bands evident, plus the Red Spot, and on one night the end of a moon’s shadow transit, which is always exciting. Later in the evening, Saturn was looking very fine: the Cassini division very obvious, striations on the surface, etc. And then there’s Mars. I have never, ever seen Mars that well. To my lasting joy, we saw ice on Mars – Hellas Basin and a polar cap. We saw markings on the surface of Mars. We saw clouds on Mars. I felt like I was living in a science fiction novel.

I did go off and look through other telescopes occasionally, when someone wanted to play on my telescope or someone else convinced me that there are other things worth looking at. I risked my neck climbing a ladder at midnight to see the Eight-Burst Nebula through the 25 inch, and I saw some galaxy through the 30 inch (when it wasn’t pointing straight up because that ladder was a frightening prospect for me). I got to be a guinea pig on the star chair with its 25×150 binoculars attached; using the joystick to move around was like being in a 1980s-SF-movie VR game. And when I got to the point that my feet left the ground and I felt like I was lying on my back… well. Someone likened the experience to being Luke in the gun turret of the Falcon. And I also got to play with the ground-mounted 12″ binos, whose view of Omega Centauri blows every other view out of the water. And, of course, I got to look at a few things through James’ scope – including Pluto! Which means I’ve bagged every planet (Mercury only naked eye).

Also, the Milky Way in general. It was dark enough that the Emu (Coal Sack + dark lane through the Milky Way) stood out beautifully, and the LMC and SMC were visible even when I wasn’t wearing glasses (that’s my litmus test).

 

James

8x10 Print Scan4

 

So the first thing to note about all the observing was the unseasonably damp nights we had.  It’s pretty unusual in Oz to end up with water pouring off dew shrouds on big scopes etc.  In Victoria I hardly bother even putting mine on most of the time. In a curious reversal from normal Coona conditions, then, we had exceptional seeing and only ok transparency – it was still a dark site, but not the ink blackness which it can have.  The views of objects which need high power, though, were among the best I’ve seen… Jupiter, Saturn and Mars all gave up all their visually discernible secrets; the Homunculus was nothing short of breath taking – a true treat for our international friends to enjoy.

I split my time helping folks with the various scopes, aligning Argos and giving little sky tours with my 16″. I spent one evening setting up the 30 inch solo; that’s enough to make me glad I only have a baby telescope. Puffing at the top of a 15ft ladder after hauling the scope around to yet another object! The 12inch binocular scope is spectacular to look through, but suffered badly without dew heaters etc.  The 25×150 Fujis on the star chair is likewise an exciting way to explore the broad subject which is our Milky Way view.

Some folks were chasing down long lists of southern objects, others were making photos and enjoying the eye candy.  One of the more enjoyable evenings was spent with fellow SDM owner Robert Werkman as we worked through a huge range of objects culminating in a tour of the Centaurus Galaxy cluster before kicking back and enjoying some of the best Mars views any of us had seen in our lives.

The combination of lots of big scopes, friends and guests to share with is pretty unbeatable – that and a motel room 100m from the field. We look forward already to next year.

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OzSky Star Safari: the Party

James and I had the pleasure of volunteering at the 2014 OzSky Star Safari a few weeks ago. Originally designated the Deepest South Texas Star Party, OzSky aims to show northern hemisphere astronomers just what they’re missing out on by living on the wrong side of the equator.

A good star party has two nearly-equal aspects: the star part, and the party part. So I’ve split my recap into two, to match.

The star part

The party part

Despite the fact that most of the observers are staying up until ridiculous times, OzSky very sensibly still organises daytime events. Partly this is to make sure the non-observing partners (not just wives!) don’t go stir-crazy; partly it’s a fall-back in case the nights are all clouded out; partly it’s
because for many people, this will be their first visit to Australia, so it’s good to show off. On top of all of that, the location of the Safari meant that going to astronomy-related things is entirely feasible. So off-campus, there were bush walks, and visits to the radio array at Narrabri (picture below).

L1000512

 

L1000551 And then there was the  Anglo-Australian Telescope at Siding Spring (inside, at left) which was AWESOME because they made the dome move while we were inside it which was FREAKY. (James loved the control panels, below.)L1000546

 

 

Back at the ranch, attendant experts gave talks in the afternoon – on photography and polar alignment and Charles Messier. We made a massive Aussie-style BBQ on the second night that introduced the foreigners to kangaroo meat, cabbage and noodle salad, and pavlova. (I say we, but the organisation was done by one person working all day – the rest of us helped with a bit of grunt work in the evening.) Probably the best thing for the party aspect was that dinner was available each night at the motel, so we got to sit at big tables and compare cultures. We discussed drop bears and education; politics and triathlons; guns and history; accents and the singularity. It was intriguing to spend a week with people brought together by one consuming passion, and then find all the ways in which we diverged.

 

 

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The view from the railing on the outside of the Anglo-Australian Telescope

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ASV Star-b-cue 2013

Last weekend we travelled to the ASV dark site for the annual star-b-cue, and it was awesome.

We went up on the Friday night. We set up in the early evening and then had to wait around for hours as the sun slowly went down. I did manage to get a good look at the moon, in a lovely crescent – I haven’t made the effort to see the moon in a long time, and it was glorious. That night involved a lot of reminding ourselves of the sky and also introducing some friends to our telescopes. One of them is an exceptional astronomer but from the northern hemisphere, so it was amusing to hear him talk about which bits he can’t see at all from home (like 47 Tuc!). And complain that Orion is upside-down. I didn’t have a viewing plan for the evening so I went with whims. Amongst the best things I saw was two moons around Uranus (Oberon and Titania, apparently) and I split Sirius! Unbelievable! I piked earlier than I had hoped – around 1am I think – I had hoped to see Jupiter but we were in spot such that it was still behind the trees when I was flagging.

Saturday was the actual star party. During the day I set up the solar telescope and various people looked through it; there were, I think, maybe six solar scopes set up – more than I’ve seen at any other time. And the sun was looking pretty fine; not incredibly active but some beautiful prominences and a set of sun spots in a cluster. I also took a wander around the site and checked out the new radio shack they’ve set up, recording the sun, meteors and Jupiter. The guy in charge was very pleased to play us the recording of a solar flare from October.

The evening progressed as these things do. The Lions Club provided a great BBQ dinner; there was a quiz – entirely music based this time, so I did ok; and there were heaps of people. There were dozens of scopes set up on the observing field; I didn’t bother going down to the photographers to check out their set ups. It makes me too sad to see Takahashis being used solely for imaging. Anyway eventually the sun went down, again; I looked at the moon, again, and had to make sure I stopped doing that early enough that I could get light-adapted, given how very bright it was. Again, I had no plan… so I looked at some globular clusters, and some planetaries; I saw some galaxies through the Dob. And I stayed up late enough to see Jupiter. Not a great view, to be sure, but when the seeing snapped in it was definitely worth staying up until *mumble230mumble*. Galilean moons all in a row.

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The Argo Navis, as reviewed by a non-technical user

When we were debating which telescope to buy initially, one of the considerations was whether to get something with a guidance system or not. I voted nay, at least partly for money reasons, but also because I felt like a guidance system was basically cheating. I wanted to learn my way around the sky, and find things all by myself thank you very much.

About a year later, we went to the 2010 Ice in Space camp. It was the first time I’d ever been around lots of fellow amateur astronomers, and it turns out that actually a lot of them have guidance systems of one sort or another. And most of them still know something about the sky and finding their way around it. By this stage I had started getting interested in searching out double stars, and was finding it increasingly frustrating: I was often having trouble just finding the point-of-reference star, let alone the faintish double that was meant to be close by.

You can tell where this is leading. I soon sucked it up and agreed to getting a guidance computer. It helped that James had had his Dobsonian blinged out with a ServoCat and a computer and that I was just a wee bit jealous.

UnknownWe both got an Argo Navis. The first thing I asked on seeing the product was “Why is their symbol an Egyptian hieroglyph when their name is Greek?”, but that’s neither here nor there.* The Argo is of Australian design and manufacture, which is very cool, and it works an absolute treat. (I also had to get a new mount to go with the Argo, and we went with the Losmandy GM8. But that’s another post.)

The Argo is very simple to use. It has two buttons and a scroll wheel, and a screen that can show two lines of text. The Losmandy is a GEM (German Equatorial Mount), so setting it up is easy: having aligned the mount with celestial south (so that it tracks properly… and let’s be honest, it’s close to south but probably usually “southish”), wait for two bright stars to be obvious, line the telescope up with your finder/telrad, let the Argo know which stars they are, and you’re away.

There are several ways you can use the Argo, and you can of course change your method over the night. If you don’t have specific plans for your night’s viewing, you can use the Argo’s Tour mode, and choose what you’d like to have a look at: Popular Deep Sky objects? Planets? Messier objects? Planetary nebula? Choose your category, state whether you want to look within a small area (if, say, Sagittarius is high and you want to know what’s within it) or over the entire sky, and what magnitude limit you want, and then… go where the Argo tells you. What sort of mount you have will determine how you actually find things, of course, but for me it’s just a matter of pushing the scope around, following the arrows, and watching the numbers for RA and Dec count down to zero (and then the arrow reverse, and the numbers rise, when I overshoot…). The Dob has a ServoCat, so it automatically goes to your object when you hit ‘enter’. The whine of the motors is amusing in the middle of the night…

Alignment is an important part of how the Argo works. The Argo gets a sense of where it is, what the sky looks like, and hence where other stars and objects should be according to Right Ascension (RA) and Declination (Dec). When you dial up M42, for example (who doesn’t love the Orion Nebula?), the display will indicate in which directions (up/down, left/right) the telescope needs to be moved in order to centre on it. The numbers reduce as you get closer, and become more precise as the object gets closer. I found it quite intuitive, and easy to use. And I’m pretty hopeless spatially.

As I said, there are other ways of using the Argo while observing. There are some clever flow-on effects of the Argo knowing where it is pointing; for example, you can identify an object you’re looking at, by going to the appropriate mode setting (Identify). Because it also tells you the coordinates of the area in the sky you’re pointing at, you can also use the Argo to find something – say from an atlas – that isn’t otherwise listed in the Argo’s menus. This is particularly useful when looking, for example, for double stars.

The Argo comes with a cradle, and with the Dob it was simply a matter of constructing a little tray for it and the Servo controls. The ingenious solution for using it on my tripod was velcro. I have velcro on all three legs of the tripod and on the back of the Argo (and the hand control, and the dew heater…). So I can move the Argo around to whatever side I’m on, and I can just slap it onto the tripod when I want to have my hands free. Velcro: best invention ever.

In all, the Argo is very easy to use, even for someone like me who is neither particularly tech-savvy nor very good with directions.

*Turns out Argo Navis is the name of the constellation that today is Carina, Puppis and Vela. There you go.

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Moon Calendar

A while back James emailed me the link to this moon calendar. Sure, I said! Get one! It took some time for him to do so, but finally this arrived on our doorstep*:

photo 8.39.57 PM

This letter and the accompanying moon calendar arrived in an awesome triangular package that kept the calendar nice and secure. We’ve stuck it on the wall – and although it looks wonky because the new moons keep shifting back a day each month, it looks great and I look forward to referring to it over the year. Thanks Erik!

ETA: the moon calendar looks like this:

mooncalendar

 

- with thanks to Erik for permission to post this!

*I mean literally. I walked out the door and nearly tripped over the package. 

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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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UHC, Oxygen III and Hydrogen Beta Filters by Astronomiks

OIII Transmission

If you own a scope 8 inches or larger then filters can make a big difference to the fine details you see in a range of non-stellar objects. They work by blocking out some wavelengths of light, while allowing full transmission of others. Depending on their type and composition, different nebulae emit light at different wavelengths and by using a filter matched to these the overall background and star brightness is reduced significantly more than the nebulae itself. While all filters cause some overall reduction in light transmission, the differential reduction of the background (especially under light polluted skys) and the transmission of the nebulae’s specific emission lines increases the relative contrast allowing the eye to see more detail than is possible without the filter.

Filters are not magic; their effect is minimal or negative for many objects because of the reduction in total light transmission. However, for some objects – especially marginal ones – the contrast increase can make it significantly easier to make out the details of an object. The Tarantula Nebula in the LMC is one of my favourites to view through a UHC or OIII filter: it reveals different and fascinating details through both. The OIII filter is also ideal for making planetary nebulae stand out from the background stars. NGC2438 in M46 is a excellent example for this.

UHC Transmission

David Knisely has done an extensive and detailed comparison of the UHC, OIII and Hb filters on almost 100 objects using a 10 inch scope. I’m not going to try and replicate this excellent analysis; instead I recommend you read the descriptions for objects you’re familiar with to get an idea of the improvement you can expect with the different filters.

Many companies make filters. Personally I have the UHC, OIII and Hb 2″ Astronomik filters mounted on a moonlight filter slide with a heater strip and temperature sensor set up to keep them dew free. The filters don’t appear to introduce a colour cast, or any other undesirable artefacts when viewing. They do however require a slight refocusing when changing between a filtered and non-filtered view.

Like many astronomy accessories filters are not cheap, so here’s my buying advice. If you’re only going to buy one filter, get a UHC. Next buy an OIII, especially if you enjoy planetary nebulae. An Hb filter is honestly an excessive luxury, but if you have a big Dob (15+ inches) and you want to be able to enjoy some very faint nebulae objects like the Horsehead it makes a noticeable improvement.

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