Date: June 6, 2009
Title: Backyard Astrophotography – a Visual Effects Artist’s Escape to Reality
Podcaster: Paul Caggegi
Organization: The Process Diary – showing you how it’s done by going out and doing it.
http://www.theprocessdiary.blogspot.com
Description: Paul Caggegi is a freelance motion graphics artist from Sydney Australia. He graduated from University of Western Sydney in 2001 with a BA in communication. He is an experienced video editor, motion graphics designer and 3D modeler. His personal work can be seen at www.theprocessdiary.blogspot.com. Kynan Stephenson is a freelance 3D modeler and animator from Canberra Australia. He holds diplomas in both 3D animation for game and film, and micro-computer technology. His work includes 3D models, animations and matte paintings have been used for TV, game cinematics, and short films.
Bio: Paul Caggegi, host of the process diary, interviews Kynan Stephenson, a fellow motion graphics artist, about his new hobby: astrophotography. Kynan gives a run down of his equipment and method in capturing stunning shots from his backyard. Pictures are available via Paul’s blog: www.theprocessdiary.blogspot.com
Today’s sponsor: This episode of ‘365 Days of Astronomy” is sponsored by the American Astronomical Society, the major organization for professional astronomers in North America, whose members remind everyone that One Sky Connects Us All. Find out more or join the AAS at aas.org.
Transcript:
PAUL:
G’day to astronomy fans everywhere, my name is Paul Caggegi – host of the process diary: a blog and podcast about showing you how it’s done by going out and doing it. Normally, this applies to the practice of storytelling, 3D modeling and animation, but for this special 365 days of astronomy podcast, I turn my eye to astrophotography. I’m joined by fellow freelance graphic artist, Kynan Stephenson all the way from Canberra Australia. G’day Kynan.
KYNAN:
Hey how’s it going?
PAUL:
Now, I’ve known for a while we both have similar jobs, we’re both freelancers in the motion graphics business, but it’s only recently I discovered we also share a love for um astronomy, um, and in your case, you’ve picked up an interesting hobby. So how did you get started with the astrophotography?
KYNAN:
It’s really just out of interest I guess, more than anything. I mean, like yourself, I’ve kind of always had a bit of an interest in it. And I sort of bought those crappy telescopes from the mall and sort of been out star gazing in the backyard for years and years. I only recently got talking to one of the local astronomers around here and he was showing me some photos that he’d actually taken which kind of blew me away. So yeah, I went out and actually bought a rig and got myself into it just purely for the love of it more than anything else.
PAUL:
Tell us a little bit about the rig.
KYNAN:
The rig itself is a stock-standard Celestron scope, I think it’s called the NEXSTAR C-11. It’s a GPS system, so it’s automated. But yeah, I did a bunch of research initially, I had to, just so I didn’t get stuck with bad optics. Some of the experience I had with the ones from the Mall, they’ve got like pretty pictures on the side of it, sort of showing all these nebulas and galaxies and things like that but I mean basically that can’t show you that. Yeah so after the research I came up with that particular scope which was going for I think about six or seven thousand dollars so it’s reasonably expensive
PAUL:
Wow, that’s more than just an amateur set up I mean that sounds like you…
KYNAN:
Yeah it’s a sort of a semi-serious scope. The actual spec of the scope itself has an eleven inch aperture – so it’s 279mm. So that’s a pretty big opening right there at the front so that’s a lot of light gathering power for a lens. It’s got a focal length of about 2800mm which gives it a fairly narrow field of view. The scope speed is about an F10, which is pretty slow, so that’s the speed it can actually gather light. So basically that’s the stock set up, and then you go and plug a bunch of accessories into the thing. For this particular one I’ve got probably the golden accessory which is a focal reducer, and what that does is actually reduce the focal length of the scope down, and actually speeds the system up to an F6.3. So it makes it a lot faster. When I was doing the research, the benefit of being able to do that is you can actually plug that accessory in, run your 6.3, or you can take it out and run your F10 so it gives you a much wider base to work with, so you can actually take a wider variety of shots.
PAUL:
So you’re shooting in Canberra, now, like, in Sydney we’ve got heaps of light pollution we gotta kinda go out, maybe… if you’re lucky the Blue Mountains, which is about a forty minute drive from the centre of town. What’s Canberra like for night-time photography?
KYNAN:
It’s not too bad, I mean there’s still a bunch of light pollution if you’re looking out over the city which I, which I have to. Most of the good stuff you want to see in the night sky is generally speaking towards the South. And that unfortunately is right where the city is from where I am, so I’m looking straight over the city. It’s reasonable, as long as you’re not focusing your camera on the horizon, and you get up a bit higher, you get a good look at the Milky Way, but ideally, yeah you’re right it’s much better to go out where it’s dark, away from street lights I mean I got neighbours right next door and, you know they’re out in their backyard and they’ve got the lights on and it completely destroys your night vision and things like that as well.
PAUL:
Yeah. So tell me a bit about the photography, how are you hooking up the camera, what kind of camera are you using to get these pictures?
KYNAN:
Well it’s actually a really old camera, is one of the Canon 300Ds so I mean it’s… it’s ridiculously out of date really, it’s ancient. So it’s only about a six megapixel camera, I think the fastest ISO it’s got as well is 1600 so it’s light gathering on the CCD chip isn’t that great. It gets a lot of grain as well.
PAUL:
Are you telling me that the megapixel ratio of the camera isn’t as important as other bits in the rig?
KYNAN:
Oh it’s not a priority. I mean it always helps to have a higher megapixel and a better CCD so you’re getting clearer shots but I think the optics is much more important. I mean any photographer I think will tell you that it’s the glass that’s more important than the actual camera body itself. Most of the quality of the reasonable looking shots are because of the scope, because of the actual optics in the telescope itself.
PAUL:
Gotchya. So how fast, like, do you need a fast shutter speed, I mean, I’m gathering because the starlight in usual photography, if you go out and you’re taking pictures with your friends you never really get the star light for two reasons: one, the flash, and two, the lights are too dim. I mean do you have to have a reasonable time for the shutter to go off? Or like…
KYNAN:
You’ve gotta expose it over a period of time so it’s like any sort of low light photography. If you’re doing deep space photography – so that’s anything outside of the Solar System, so things like, you know, nebulas, galaxies, planetary nebula, star clusters, that sort of business, you need to operate probably on a film speed of about 800 to 1600. It’s always a bit of a balancing act: the higher up your ISO speeds go the more grain you get, or the more digital grain you get. Generally I’ll operate at about 800 ISO – film speed of that, and I expose for around about 30 second to start with.
PAUL:
Do you get any streaking in the shots, or do you have a way to compensate for that?
KYNAN:
Well that’s biggest problem, that’s probably the biggest challenge with the photography, is the actual alignment aspect of your telescope. A telescope like I’ve got with general observations operates on altitude and azimuth to actually track, which is a left and right, and an up and down motion. So as it actually tracks through the sky it’s got a bit of a step, so it’s sort of “down, left or right, up, down, left or right, up”. And what that does is actually leave a lot of streaking ’cause there’s a lot of motion to actually track. And the closer to an object you get the worse it actually is. So anything wide-field you don’t have to worry. So basically, what you’ve got to do is have a thing called an equatorial wedge which is a bit of a strange sounding thing! Basically your telescope sits on this wedge and you actually, um, rotate it, it actually allows you to rotate the telescope so it can point at what’s called the um, Southern celestial pole, I guess you could call it. Actually just align your scope to that so it only rotates in right ascension, so basically it counters the rotation of the Earth. And then when you actually point at the sky with that rotation countered, it actually stays still and that avoids your streaking. That’s the hardest part, though. Basically the first thing you have to do before you shoot even any photos at all is figure out where the hell the south celestial pole is and what it looks like.
PAUL:
And how do you automate this? I mean, naturally you’re not doing this by hand every thirty seconds?
KYNAN:
No, the actual scope itself, I’m lucky enough to have a GPS Go-To system. So it’s completely automated, it’s on a.. it’s got its own little computer that plugs into it. I manually align it, you have to manually align it basically through know-how, and then you actually have an equatorial tracking mode which only allows the scope to rotate in right ascension. There’s a particular rate of spin that’s basically set in there, I don’t have to do anything, and it just runs on that rate of spin to counter the Earth’s spin.
PAUL:
What kind of things have you been shooting lately?
KYNAN:
Because I’m fairly new to it I’ve just been going with the fairly blatantly obvious stuff, things like um, the Orion Nebula. I’ve also been having a bit of a look at um, globular star clusters, I think it’s called Omega Centauri, which is in the Centaurus constellation. Basically what that is is just… gravity for whatever reason, is pulling a bunch of stars into a big cluster. So to the naked eye it kind of looks like a bit of a smudge in the sky. When you actually point a telescope to it it actually resolves a bunch of stars like millions and millions of stars all coming together into a big cluster. That one was pretty interesting, and also the Corina Nebula which is up in the Milky Way.
PAUL:
Great stuff. Well, Kynan, it’s been really great talking to you, thanks for taking the time out to explain this hobby to us. To all the listeners out there, if you swing by theprocessdiary.blogspot.com Kynan’s been good enough to give me some photos of the rig and of some of his work, so you can sort of see what kind of things you can get in deep space astrophotography from the ground and even close to cities, so that’s pretty amazing stuff. Um, from the process diary this is Paul – bye for now.
KYNAN:
See ya!
PAUL:
The process diary is a fortnightly blog and podcast documenting the making of an independent animated series. Search for the process diary in the iTunes music store, or subscribe via the blog: www.theprocessdiary.blogspot.com Music used in the podcast is used with permission, and credit goes to users SFX Bible and Warg from www.soundsnap.com For the 365 days of astronomy podcast, my name is Paul Caggegi – thanks for listening.
End of podcast:
365 Days of Astronomy
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