Hi, I'm Ruth Medjber and welcome to AdoramaTV.
Joining me today when I get to speak to one of the world's most well-known
astrophotographers Tom O'Donoghue. We get to look at his work,
hear about his techniques and hopefully get some tips and tricks for you.
AdoramaTV presents; Out of the Darkroom with Ruth Medjber.
I'm delighted to be sitting here the Dunsink Observatory,
and that location can only mean one thing, astrophotography. Joining me today is Tom O'Donoghue.
Tom has had some amazing work,
exhibitions, he has given talks all about astrophotography.
His work has even been showcased by NASA, and
he himself has even moved country, in search of clearer skies.
Tom thanks so much for joining us today, it's an absolute pleasure to have you here in this
observatory, I'm sure you've probably been here before.
I've paid a few visits yes! So tell me, how
does one get started in astrophotography? Was it like always a love of
photography and then you just
looked into the astro side of it or how did it happen?
I wanted to try something challenging, and I've always had a love for science and for space,
and for astronomy. So my first purchase was a Canon DSLR,
and a barn tracker mount, and
I attempted to take photos from the suburbs of Dublin.
Just trying to take star trails, just trying to be able to focus the camera, and seeing
what kind of stars, and what kind of objects would come through in a 30 second image,
which was just a very basic setup.
Wow, it sounds basic but I suppose if you are coming from it with
absolutely no knowledge at all, which is what I would be doing,
it sounds a little trickier I suppose. Did you have
n knowledge of photography first? Or did you just jump into this completely?
My knowledge for photography came from a school club,
where we used to develop our own pictures and take your own shots,
and the Astronomy itself came from magazines from the same
astronomy club in school. Just seeing the color photographs,
I just thought they were incredible and someday I wanted to try them.
It took twenty years to finally get a telescope and
progress into the photography. But starting from the back garden,
it's a great way to get into the hobby it's cheap, the
access to clear skies weren't that important to me at the start.
I didn't understand about light pollution, I didn't understand about and how a camera
would pick up the orange lights, and what other kind of problems that will come
across, that would lead to me to
venture to darksides. It was total amateur total novice.
You're learning as you go kind of thing, and still am learning, but look at what you
can create now though, it's fantastic.
Still going yeah!
So explain to me a little bit more about astrophotography, because I know there are
all sorts of different types.
So what what could be an example of them. You do lots of different things from star trails,
which looked very different than your, the Nebula, and everything else that you do.
So explain to me what the types are if you don't mind. Yeah, astrophotography
is such a broad subject,I mean astro really means star.
So we, as astrophotographers do include
items like the moon, the planets, Aurora and
moon dogs, moonbows, iridium flares, there is a huge list of things. A lot of them are
weather phenomena.
A lot of them are atmospheric phenomenon. What really, astrophotography,
the simplest ways are, whitefield star shots, like constellations.
You can zoom in and do deep sky photography, like what I do myself.
You have the moon, the planet's, and solar photography,
which is another section with a different type of setup, and
and then you have hi focal lens: deep sky photography,
which is well,
the equipment constraints are enormous at that stage. I'd imagine so it's kind of
the deeper you go, the more you see,
obviously the more expensive it gets as well. Yes, exactly yeah.
Ok, so bring us back then, to the edge of where we are now, and lets,
take me for example, I've never done
astrophotography before, I've wanted to, and there has been,
nights where I have looked up and I can see the stars so clearly.
What am I going to do? Can you tell me how I would set up
my DSLR and my kit lens to get that? Well the simplest start is what we call star trails,
where you will get a static tripod, okay and, you open your shutter
on manual or bulb mode for 30 seconds okay
and the focal length: the lower the better, but if you live near lights
you will probably get a little bit of light pollution. For the simplest shot,
open your aperture for 30 seconds, pointing at North if you live in northern hemisphere
towards Polaris, and you will notice the whole earth would rotate
in that 30 seconds around the North Star, and you will have your
first star trail astrophotograph. So you get this fabulous shot where
you can still see the landscape in some shots, and then you get the trails.
Exactly, depending on how wide open your lens is, actually the focal length of your lens,
but it is also nice I think, to give a little bit of depth to it, with foreground objects,
trees, people, something landscape,
and the night sky. Lets take it a step further okay,
say I have managed to do all that, so what will be next? How do I
compensate, say, for the trails? You know when you get shots, and they are
pinpoint, and the stars are gorgeous and you can see everything so clearly,
okay, talk me through that. So when you see the final shot you might not
realise all the equipment that go into
some shots where the stars remain pinpoint. Most
of the higher end, deep sky shots are taken on motorized mounts.
So the idea is to counteract the rotation of the earth.
So as you notice the stars, the moons, will come up in the East,
will move across the West. So your mount will counteract that,
and it will drive against the rotation to keep everything in a static position.
That's the next step, a motorized mount, they come in basic forms,
there is a lot of astronomy shops, they are
now bringing out versions for DSLRs, for
Manfrotto type tripods,
which will attach on just like your regular camera head,
and will effectively act as a wedge to elevate
your whole tripod axis to whatever latitude you are on. So here in
Dunsink we are at about 53 degrees, you will attach this
this wedge drive, it will elevate the
mount 53 degrees, and you are then only on one axis.
So you can then use a simplised mount to drive across the sky,
once you have selected a target, and that will allow you to do,
with a cable release, long exposures, capture more objects,
and would also then introduce you to the world of stacking, and
signal to noise. Okay, so that's
so we have done this, we have tracked say,
stars, and we want them to be pinpoint, so we have put on this mount that counteracts
it drives the other way around, am I getting this right? That's correct. Okay,
so now I've got my pictures of the stars.
Noise. That's what you're saying, because I'm open at a 30 second exposure, or for
however long this is open for. Surely my camera is going to be quite noisy.
It will, I mean for shots like the moon, which will be
a single static shot, a good low ISO, 100, 200, in fact
100 is what you're looking for. If you're only shooting 30 second shots,
I would say increase your ISO to 1600, and
enable the noise reduction in
your camera settings. Now what that will do is, if you take a 30 second shot,
it will take another 30 second shot, it will leave the shutter closed,
and subtract that from your initial 30 second image,
and you get a resultant, your image minus the 30 second noise reduction,
and it cleans it up. It removes dark pixels, hot pixels,
it just gives a cleaner, smoother image. So thats if you're going for a 20 second shot.
If you are on a motorized mount you're taking 5, 10 m, exposures,
it's very, very time-consuming and there are better ways to do it. I would say turn off the noise,
sorry, leave on the noise reduction, I would say turn off
the dark frames subs subtraction. Wow, tell me about
these images here for example, how much work will go into them?
Well for the first shot of Orion, this is my first ever proper
mosaic. I started in January and I had
finished taking shots over twenty five nights.
Where were you when you were shooting this? Ar this stage I had moved to Spain
to continue the photography. Ideally for four months
and I ended up staying for three years. So the reason I had taken on the Orion project
was because I realized
I wasn't going to go home, I was enjoying it too much, and I decided, I'm going to try something
difficult, proper project shot and see how long it takes me.
So three months of shooting, and because it was my first attempt, six months on the laptop to put it together.
Three months shooting, six months post-production putting it together.
Unfortunately I had to start again,
and again, because I was self thought, you know, you
build on what other people learn before you. I wasn't reinventing anything,
but I needed to learn new techniques, and try different methods.
Each photograph is different, you have to deal with it differently. So if you did twenty-five nights shooting,
how long are you out there for shooting this?
Well I like to be at the telescope, I don't have automated focusers,
so in that sense I'm old-school. I will stand and watch on virtually every single
frame come off.
You've got to be ruthless, when you're talking about the pinpoint stars,
any aberrations, such as a gust of wind, a cloud passing
will effectively soften your picture,
or give you bad signal. I'll throw it in the bin, I don't mind, I'll stay up a little bit
later it's fine. So other than going into the house to warm myself, to get a cup of coffee,
you stay there, I stay there watching yeah.
Is that how you get such like detail
in your exposures? Or how does that come about? Because
I'm looking at these images and there's so much going on in them,
that I have no idea how. Bacause if I was to point a camera up there, even with all the
equipment in the world, I just come back with
white lights so how does that happen? How do you get that detail? Well
originally the trip to Spain was to go for the the dark site,
so I had gone out there on a little recce, found an ideal spot in the middle of
nowhere and I said okay,
I'll rent here. So I knew it was a dark sky, and even had instruments to measure the light,
and the background darkness. So I knew
that was going to be no problem. Next after that was setting up the equipment.
Focusing is critical,
also I was doing it by hand, but going through each sub frame,
throwing out the ones that are not happy with, and stacking your final images
to get, well for example, just a black and white stacked image.
From there on the post-processing you can sharpen them,
but I like to be subtle. I don't like to over process, I don't like noise in the
background image, so I'd rather go for more data,
rather than pushing the processing too much. But its,
you have got to be careful, you have got to be patient, and you've got to be ruthless.
This is Ruth Medjber for AdoramaTV. Don't forget to check out Adorama's
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So obviously then these kind of shots that you're doing, that you set up in
Spain and your spending months and months and months preparing,
they're not on a DSLR are they? No. You can do this with the DSLR but the
CCD cameras that they use
are generally more sensitive, and you can cool those. So the biggest thing
with the signal to noise ratio, is a cooled camera, or a cooled chip,
gives you a lower noise value. I know a lot of DSLR photographers
who will incase their camera in a lunchbox of
ice. They will cut a little hole, literally its like the underwater camera
covers that you get now. Fill it with ice and just have holes for the cables to come out,
and to try to cool the chip down. It's a fantastic tip!
It's a great way to do things. It might void your warranty but...! Oh yeah, definitely,
because other people take off the back and put a thermo electric cooler on it,
and I don't even know if you can use them for daytime photography anymore,
no probably not. So you just recommend literally cooling down
camera then, so ice and kind of, obviously
just stick some fans on it. Ice packs maybe, not so much ice! Yeah, not in a bucket of ice!
So tell us a bit about the CCD cameras then, how do they differ from the DSLR?
CMOS chips are generally what you get in the DSLR. CCD,
are literally the CCD chips, I won't go into the
manufacturing. But they generally have a lower noise
threshold,they are more sensitive, and with the camera themselves
you will find that there is no lens that comes with them, there's no buttons on the back,
there is no interaction with it whatsoever, you need to control it with laptop, or a PC,
and it's fed kind of straight out. It's got a power cable, USB cable
and then there may be an option to water cool, to even further drop
the temperature of it. But it is just a chunk of electronics and a chip.
Would you recommend that then for, you know a photographer who
has worked primarily with the DSLRs, gotten really into the astrophotography,
would you say that's a step up then? As far as quality goes, it is that's the biggest
step up I've
made. I think, I'd have to say, the difference between
my DSLR, the Canon 350 I originally started with, and going to a small chip CCD,
the signal was better, the focusing was a lot sharper.
The problem is that cost wise, the DSLR chip,
and what you get and in the same see price range for CCD,
is a much smaller chip. So you effectively end up with a lot smaller field of view.
So with 35 mm camera that you might see on any of the full frame
Canon or Nikon's, in that price range, you might only get a 7 to 10,
12 mm version in CCD. Now the prices they are getting
more comparable to each other, but that was the original issue. You know,
vast expanse or the amount, as you say, real estate on a chip.
But I suppose you're attaching it to a scope, so all that's going to come into
effect and you're going to be thinking about all that down the line as well. It is very, very hard to find an object,
even if its as big as the moon. When you've got a small chip, you're trying to line it up by eye.
But I I would say the DSLR people have a great advantage with that,
full frame, nice wide open sky.
I'd say until you're very happy, or you're
well versed, or well proficient in your processing,
I would say then move up to CCT, otherwise
if you're on your DSLR, the fact that you can focus it, the fact that you can download the images,
and process them,
it's a fantastic start. Absolutely. So you know, even a lot of the CCD cameras
I was looking at myself, there is two different versions. There's color and monochrome,
what do you choose? When you're, you know photographing Orion in,
you know, Spain's backyard. Are you shooting in color or are you doing monochrome?
Okay how does that work then, how do you get such vivid colours? I use a filter wheel
in front of the the monochrome chip. So the filter wheel goes inbetween the camera
and the telescope, and you can control it again
with a hand paddle, so you can just flick a switch and it will rotate to the next filter,
or you can control within your laptop, and I'll generally shoot it through red,
green, and blue filters, and there is just one or two extra,
what we call narrow band filters, to capture some
extra chemistry going on in the sky. But it is
all red, all green, all blue, and you stack those together to get master red, green and blue,
you stack that to get full color image, and then you blend that
with the clear filter, which is just the black and white image.
Again so much post production. Massive amounts of post production, I mean
the whole idea is that you set up your equipment, which ma be takes 20 percent,
actually, getting everything ready you spend another few days,
hours, you can take a photo in one night. Then the next section is actually
gathering the data. Then you need to calibrate the data,
sixty hours that are in that image, or the 56 hours I would normally spend
that I'm on the laptop again.
So there's an awful lot of work. Its massive.
You seem to have an awful lot of patience to do this, a lot of dedication.
So how do you, you call it the Orion project, because it has taken such a chunk of your time,
how do you just pick something?!
Do you just look through some books and go okay, I want to do this
next, I want to do this next, how do you come to a conclusion that thats next?
I'm right at the cusp now of changing
from going the classic objects like the Pleiades,
like the Seven Sisters, like the Orion, and the Fiuk Eye,
very different to pronounce. Very, very colourful Nebulae.
But these objects were some of the ones I saw in those magazines twenty years ago.
I just thought, someday I'm going to catch those. They're just very, very famous objects if you're
doing photography
they're first on the list. Like your cat at home, you dog.
Your first shot is something that you are familiar with, and something
that you're aware of,
you know how it should look. What I'm doing now with these large mosaics,
and expanding from Orion, and a few other objects into huge mega mosaics as I'm calling them
you don't know what's out there, and I love that. The most exciting thing has always been
a new object, and watching that first frame downloading
on the screen, and you just get the tingles, because you know straight away
if this is going to be good or not, and then you can invest the time on it. I've started on objects,
didn't like what I'm seeing and moved on to something else. But we've,
in the last couple of years we go deeper, and deeper into these images to put up more details from
the background.
There is a lot in space, and we're finding new objects. Photographers rediscovering
things, its great. It kind of really seems that way, you're pointing it up, you're
looking, and you're spending the time discovering what's out there, and then
everyone else is kind of
catching on. But as well I love the point you say that you're,
you're looking up you're not a fan of what you see, so you change your angle. So its very much
art as well. There is a lot of that. I mean framing is very important as well.
One of the drawbacks to framing is that
we take what is known as 'calibration frames'. Dark frames, we take flat frames, which is
just white light into the camera,
to subtract vignetting from your images. As good as the telescopes that we use are,
there are still a few optical flows in there. So we take these calibration frames.
and subtract them.
Now the problem with one of those, the white light frames, is if you rotate your
camera,
you effectively have to re-shoot your light frames again.
So unless there is a specific object I'm just going to shoot for a few nights,
then orientation and framing, and I guess
a good eye is exactly what you want. For the project shots,
I generally stay in portrait or landscape for months.
Really, and you know. Thats the idea. You probably have an end goal in you head of how this is
supposed to look.
I mean you're selling these to people
you know, from your website, you know from your gallery shows. People can pick up
prints and everything, but you know, it's not you know, astrophysicist buying,
they're not buying them because they like whats out there, you know these people are buying
for an aesthetic value.
So what you are doing is brilliant, its art, its documenting something that
very well might not be there anymore. Yes well I have to say it's definitely on the art side.
Unfortunately with some the post-processing you might have to remove a satellite rail,
there are certain cloning stamps that you would be familiar with in Photoshop.
So people say, well, its not science anymore.
Its definitely, its scientific in that what we're shooting up there is
is pure physics and chemistry. But once the finished product is there
it's definitely art because you've added your own input to it.
Once you've stretched the image you've changed what it is.
So, yeah, art! So I think what you've done with astrophotography is somewhat found the
balance between
science and art. I'd like to think so yeah.
Yeah, and you have got some beautiful results. Thank you very much. Thanks so much for joining us today
that was absolutely brilliant. Cheers for that. That's it for another episode but
join us again on AdoramaTV, where
I'll be speaking to another great photographer, getting to know their work and
hopefully getting some tips and tricks for you!
Bye for now.
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