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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Astronomical Society of Victoria – Annual Messier Star Party

Last year we became members of the Astronomical Society of Victoria and one of the perks is access to the club’s dark site. Each year they run a few public access events to promote the club and astronomy, so we took it as a good chance to head up – check out the dark site and share our scopes and love of the night sky with some new folks.

We headed up under perfect clear blue skies and set up on the main field – I picked a spot between three big Dob brothers, an 18″, 20″ and 25″. Secretly I hoped they might act as a bit of a decoy for my baby 16″, to keep away most of the crowds, but once again the magic of observing with both feet on the ground seemed to draw people in. Alex set up our 5″ APO next door; she drew a bigger crowd than me!

It was fabulous to see so many people having their first experience of astronomy under a proper dark sky (SQM 21.5 last night). The local Lions Club put on food, the club put on a range of short and interesting talks as well as tours of the site, and after dark one of the night sky.

The evening started off pretty quietly with most of the visitors engaged with the night sky tour but that soon ended and for the next few hours the observing field was awash with the curious, interested and far too many far too-bright red lights. But hey, we’ve all gotta start somewhere.

In keeping with the Charles Messier theme of the evening I made a point to try and show people a few interesting Messier catalog objects as well as a number of the usual showpiece objects. I also always like to show people one or two of the more impressive galaxies that are up too; regularly seeing these objects which put everything else in the sky into context is one of the privileges of owning a big scope.

Over the evening I observed and shared these and more:

M46 OC + NGC2438 PN
NGC 3115 Gal – Spindle Galaxy
NGC 5128 Gal – Centaurus A (saw the bright strip through the dust lane)
M104 Gal – Sombrero Galaxy
NGC 2392 PN – Eskimo Nebula
NGC 3242 PN – Ghost of Jupiter
M42 and M43 Neb – Great Nebula in Orion
NGC 1365 Gal – Zorro is sadly chasing the sunset at this time of year.
NGC 2024 Neb – Flame Nebulae.
B33 Dark Neb – Horsehead (Hb Filter) – With Orion high in the sky it was the easiest view I’ve had of the normally elusive Horsehead, I managed to show Alex and 2 or 3 others who all saw it. Normally I struggle to see it myself, let alone help anyone else see it.
NGC 2070 Neb – Tarantula and region in the LMC
NGC 3372 Neb – Eta Carinae
47 Tuc GC
NGC 5139 GC – Omega Centarus
NGC 4755 OC – Jewel Box
NGC 3293 OC – Gem Cluster

While I wouldn’t want all my observing sessions to be like this it feels good to go and be part of an event like this a few times a year.

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Pocket Sky Atlas

Just buy it.

Seriously. Just buy it. Are you just getting into astronomy? Can’t actually buy a telescope yet but interested in learning about constellations and the various objects you’ll be able to see when you do get one? Just buy this. Been observing for a while but don’t have a nice handy little reference to take with you for short sessions at the telescope? Buy this.

We own two, because we each need one when observing. (And we’re bad at sharing.)

Halfway between A5 and A4 in size, and spiral-bound, this is immediately an appealing book. The blurb describes it as fitting into the glove box, which is a good way of selling it. It’s not quite a genuine pocket-book, but compared to most atlases it’s a treat. It has slightly waxy pages which means they don’t mind a bit of dew, too, which is marvellous when observing in damp conditions.

The book opens with a very brief introduction, explaining the origins of the atlas – in the search for convenience – and what it actually shows – stars down to about mag 7.6; doubles, variables, galaxies brighter than 11.5, globular clusters brighter than 10.5, planetary nebulae brighter than 12. It also explains the labels used, how the charts are arranged, and includes a select bibliography which can be used for those wanting something than goes further (or just a good collection…).

The charts are arranged in order of Right Ascension, in sets of ten. It begins with RA 0-3, and the introductory page (a similar one appears at the head of each ten) explains in which months this part of the sky is high in the evening, at midnight, and in the morning (in this case, Nov and Dec; Oct; Aug and Sept). It also has a map, repeated in many places, of the entire sky, with major constellations and the maps on which they appear; the section under specific consideration is shown in bold. Turn the page and, before getting to the maps themselves, there is a key to understanding the maps: how to identify galaxies, nebulae, clusters, and stellar magnitudes.

The maps themselves are quite detailed, with lines connecting the stars of a constellation in green, galaxies in red and other non-stellar objects mostly in yellow. Each map has arrows and labels showing which other maps it connects to (there is good overlap), and RA and Dec are easy to follow. There are four detailed maps: of the Pleiades, of Orion’s Sword, the Virgo Galaxy Cluster, and the Large Magellanic Cloud.

One of the most useful aspects of this map is that the front cover is not part of the spiral binding, meaning that when the book is laid open the front cover juts out beyond the page. On this jutting-out section there are three things: a ruler indicating angular distance on the charts (up to 15 degrees); the scale for determining star magnitude from -1 to 7 (because as usual this is indicated by relative size on the map); and a red Telrad finder with circles at 2 and 4 degrees. For quick referencing while observing, this inclusion is invaluable.

The book closes with several indices. It has a list of bright stars, by name; a list of galaxies by NGC and IC reference, as well as name; open clusters; globular clusters; bright and dark nebulae; and planetary nebulae. All of these, listed separately, also have a reminder of the legend used to indicate them on the maps. Lastly, the book includes objects in the Caldwell Catalogue and the Messier Catalogue. Excellent for those of us who like lists and/or challenges, or who are feeling lazy when it comes to planning an observing run.

Would I buy it again? I already mentioned that we own two, so: absolutely. It’s invaluable.

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