Posts tagged “saturn

This astro stuff DOES get easier, slightly…

Equatorial mounts, Newtonian reflectors, refractors, registax, counterweights, polar alignment, autostakkert, wavelets, webcams, tracking motors, collimation, Saturn, Venus, avi’s, sharpcap… Astro photography, it’s enough to put you off just thinking about the bewildering array of stuff to learn. What the hell are those things, where are they, what do they do, how do I use them? Well, with a little perseverance it DOES get a bit easier.

Take the telescope and mount to start with. When I first got it I had no idea what I was doing, Even now the EQ5 mount seems more like an instrument of mental torture than something to mount a telescope on but I am getting used to how it works. I’ve never attempted an accurate polar alignment yet mainly due to how late it is in summer until I can see Polaris but even a rough alignment is enough to get you moving. Simply set your latitude on the mount, 55 degrees for Edinburgh point the North leg funnily enough North and make sure the mount is level. It’s not perfect but it’ll allow you a go at some planetary imaging at least.

Just doing the above steps I’ve found that it’s adequate enough to keep a planet in the field of view for ages with the tracking motors engaged. It wouldn’t be any use at all for imaging deep space objects but for now, for planets and moon its working ok.

The tracking motors too came with the vaguest of instructions, now though I’m confident enough to find my target, lock the clutches and start the tracking and it works fine.

So, as I’d got hold of a Philips SPC900 webcam, all ready to be used with the scope and the skies had cleared it was time to give this planetary imaging a shot.

There’s not a lot of targets at this time of year, Venus is rapidly heading for its appointment with the Sun in June and Jupiter is long gone is the twilight sky. Saturn is getting higher and Mars to be honest has never been my favourite subject so Venus and Saturn were to be the targets.

When I setup, only Venus was visible in a still twilight sky. I can’t wait till dark as it’ll be lost behind the neighbourhood roofs. It’s so easy to locate in a twilight sky and the crescent shape is very visible in the scope and it’s quite a thin crescent now too. After centering Venus in the eyepiece I slipped in the 2x Barlow and made sure it was centered and then switched to the webcam.

Luckily for me, Venus was still there with the webcam and using the free capture software, SharpCap I was able to get it centered on the camera and adjust the settings till I got a clear view. I got a couple of short captures with the webcam until Venus was lost to the shed roof. I then ran the avi file through another free bit of software, Autostakkert which stacked the best frames from the movie.

The resulting image was saved as a TIFF and then opened in Registax 6 where you can adjust the wavelets. I have no idea what a wavelet is but it certainly works and greatly brings out the image detail and sharpness. I then finally opened the image in Photoshop CS5 for some final tweaks and this was the end result.
Venus 19 May 2012 Cropped

A million times better than I’ve managed with the DSLR, the webcams much smaller sensor gives a much bigger final image which in turn lets you get more detail. Using a webcam also lets you capture those microseconds of clarity through the atmosphere where the viewing is at its clearest and the stacking software puts all these together to get your final image. It takes a bit of getting your head around but it does work!

Saturn was next up and this was the AVI file I processed to get to the final image:

It’s probably way too long but after processing this in the same way as the Venus image I got to this final shot.

Saturn 19 May 2012

Which is a vast improvement on my best with the D90 attached to the telescope:

Saturn

As you can see, there’s a lot more detail in the stacked image, some colour too.

For a first shot with this style of imaging I’m pretty pleased especially as the seeing was pretty bad. There’s a lot of room for improving especially with the software end all of which I’ve hardly even scratched the surface of yet. I also need to get hold of a quality 5x Barlow lens to get a larger image. Lots to do, I just a few more clear nights!

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First time photography with a telescope

After only a mere 3 days of frustration of owning a telescope and not being able to use it for the purpose it was designed, I finally got a clear night to try out a bit of photography with my newest photography acquisition, my Skywatcher Explorer 200P on an EQ5 mount.

With a clear sky looking almost certain the hardest part of waiting till it was dark enough to actually see anything in the night sky on Friday night. The moon was coming up frustratingly low and was steadfastly refusing to peek over the top of the house from my back garden so I was forced to wait until the sun had at least waved goodbye for the day.

While still in a twilight sky I obviously couldn’t properly polar align, not that in a dark sky I’d probably have had any more luck either if I’m honest! I did make an attempt though, first finding north using the iPhone compass, so it was probably east or something knowing the accuracy of the iPhone compass and I did level out the mount properly too. With this being the best I could do in a twilight sky I made an attempt at balancing the telescope and that was me ready to go.

I’d spent time earlier in the day setting up the finder scope so with Venus bright in the sky that where I headed. Centred nicely in the finder scope I looked through the eyepiece to find… nothing at all. After some searching I did find Venus and even in the 20mm eyepiece it was a brilliant sight. The crescent clearly defined and even better, the tracking motors seemed to be keeping it in the field of view as well. So far so good.

With Venus in my sights I setup the MacBook pro and tethered it to my Nikon D90, fitted the t-ring and the 2x Barlow (which is needed to get the prime focus) and switched out the eyepiece for the camera and watched the scope drift off on a tangent with the extra weight fitted. Re-balancing and trying again finally I got Venus in the D90 viewfinder and switched the live view on the laptop. This gave me a chance to play with some settings and get a few shots, none of which I’d be willing to stick up online…

By this time Saturn had peeked over the top of the house so that’s where I headed next. Despite a glaring moon just below it the view wasn’t bad at all. Easy to find, find the roof and move up, Saturn was an awesome sight, the rings and some of the moons clearly defined in the eyepiece. With the tracking more or less working I got a good chance to try out some single frame shots of the ringed planet before youngest son walked into the 5m USB cable between the D90 and MacBook pro knocking everything out of line again.

This was the best I got of Saturn, not exactly epic but I was pleased enough for a first go.

Saturn

Next up was Mars which was… unexciting so I skipped Mars and went in search of the Moon which was still hiding around the front of the house. Moving the scope I got a view of the Moon and within mere milliseconds of getting it in the eyepiece I realised the importance of having a Moon filter. There’s no way you should be looking at a nearly full moon without one. I worried for a bit I had damaged my left eye, the black spot the Moon left in a field of vision a bit of a worry to be frank! Thankfully it subsided and I won’t be doing that again. I did however hook up the camera and use the live view to the laptop to focus and get a few shots, the best of which is below although I’m frustrated at the lack of sharpness in the shot.

Moon 4th May 2012

The list of questions and things to learn is still massive. Among these…

1. How can I get the whole moon in a single photograph with the camera, the 2x Barlow means only bits at a time and when I tried eyepiece projection the result was more like a lensbaby shot with selective focus!

2. How the hell do you find deep space objects without a GOTO? I’m really thinking I’ll need to invest in the SynScan controller soon.

3. The tracking motors SEEM to work but I’m not convinced, Skywatcher seem to be overly vague in their operation.

4. How the f**k do you balance a telescope for the eyepiece and camera without having to adjust where the scope sits on the rings?

5. Where the hell did all these eyepiece caps come from? As the night wore on I seemed to have more than I had places to fit them?

6. Why do I need a woolly hat, scarf and big jacket in May!

7. Why did I buy such a heavy unwieldy telescope in the first place!

These, and not doubt many more questions may or may not be answered in the coming months…


Preparing to photograph the ISS

I have to say, the International Space Station is an engaging photographic subject. Hundreds of miles above the planet traveling at 17500mph it wouldn’t be the first thing you’d think of nipping out with the camera to capture. However, once you figure out roughly where it’s coming from, what you’re looking for and when it’ll be there it’s almost addictive.

If you happen to be on Twitter try following some of these accounts and you’ll be amazed at how many retweets they send out of images after every visible pass over the UK.

@VirtualAstro
@PeoplesAstro
@NewburyAstro

Planning for the ISS makes a huge difference. The @VirtualAstro twitter account is a good place to start, there’s a wealth of info for every pass from that particular source. The website, http://www.heavens-above.com is also good for working out the directions, altitude and brightness of the ISS for any given pass. The free astro programme, Stellarium for Mac or PC is also very helpful, it’ll show you the exact path the ISS will take and from this you can work out in relation to the planets where it’ll be which makes planning a lot easier. The iPhone app StarWalk also allows you to do this.

Here’s a screen dump from Stellarium and from it you can see the ISS path for tonights pass in relation to Sirius and Mars, two of the easier night sky objects to spot.

This is a screen dump from the iPhone Star Walk, from here you can see the ISS and you can advance the time with the bar on the right to watch the path it’ll take over the sky.

Typically the nearer to sunset the longer the ISS will be visible, approx. an hour to 1.5 hours after sunset you’ll get a very bright pass almost from the western horizon to the east later in the night, it’ll disappear into the earth shadow quicker.

So, with this info in mind the temptation is to sit in the house watching the telly and nip out just as it’s about to pass. I’m guilty of it too. But if you apply a little landscape photography principals to the astro info you can totally change the shot you get.

Photographing just the sky is fine, and even better if you can get something significant in the sky to reference the ISS path, i.e. passing Mars, or Saturn. However, get the land in the shot and you’re starting to tell a story with your shot, you’re showing the whole event. The pass of this object over the scene you’re looking at. So tell me whats better here…

The ISS crossing over my back garden, passing just over Saturn

ISS flies over Saturn 14 April 2012
Or this image taken on the Cammo Estate in Edinburgh

ISS over Cammo Edinburgh

The 2nd image took a stack of planning to get. All the info above plus looking at Google maps to find a location with good views to the west, south and east. The only issue I had with this image was the clouds were obscuring Mars so I couldn’t get a reference for how high the ISS would be in the sky, with hindsight I should have used a wider lens but we can all be great in hindsight can’t we?

Using Star Walk I figured out roughly where on the horizon the ISS was going to emerge from and composed the shot to catch it as quickly as I could as it rose, also keeping in mind I wanted Cammo Tower and the copse on top of the hill in the shot. Ground was kept to the bare minimum required and the sky was the main focus.

The sky was still quite light so I went for a balance to catch the ISS. I used ISO320 and f4.5 and limited the exposures to 10s, this gave a nice balance in the shot but meant enough sensitivity to get the light from the ISS.

In the end I got 12 frames of 10s each until the ISS left the field of view, being an early pass I had time to recompose and get another few frames before it disappeared.

The 12 raw images I took into ACR and processed them all exactly the same and saved as jpg files. These 12 jpg’s were loaded into StarStax and blended on lighter mode. This was fine, the ISS trail was night and bright but the cloud movement was nasty and not smooth. To get around this I stacked the 12 images again using the “average” method which gave a much more pleasing image with the clouds but a faint ISS trail. I then blended the first image into this on lighten mode and decreased the exposure until only the bright ISS trail and stars remained. The resulting image was flattened and tweaked in photoshop to produce the final image.

If I were to process again I may patch in the gaps in the trail between the exposures and as a personal preference I would also try to lose the star trails by blending in another image and selectively deleting the trails.

With a location like this though and a nice (nearly clear sky) it’s worth taking time for a few other shots before you back up.

This was a single from from the composite image. Notable objects in the shot are the ISS, Mars, Regulus, Sirius, and Orion.

Mars and ISS over Cammo Tower

In this shot, the ISS can be seen behind the clouds passing just over Saturn and Spica.

Saturn Spica and ISS over Edinburgh

In this final shot taken just after the ISS pass, Venus is nestling on the branches of this particularly creepy tree!

Venus in the spooky tree

A little planning can work wonders, it’s all just about planning and crossing your fingers for the weather to play ball. It won’t work out every night but for that odd one it does you’ll be well pleased you put in the effort.

Get out and look up tonight and for the next few nights before it disappears under the horizon for another few weeks!


First tentative steps with Astrophotography

Well, I knew it was going to happen. This tale kicks off back in early December when I made my first ever attempt at a star-trail image, it never happened that night as cloud rolled in but I did get a natty shot of the Forth Bridge and the Big Dipper next to it in the sky. That was the start of the near obsession with the night sky.

Winter is a difficult time for me photographically, especially a winter with little or no snow like this year. Sunsets are difficult, due to working when the sun in setting and the position of the winter sunset is tricky in Edinburgh to so I typically resort to night-time shots and to be honest, I get a bit fed up with photographing the city at night so I needed something new. That something new turned out to be the oldest thing I could photograph, our universe.

Since that night I’ve progressed though star-trails, photographing star fields, the Milky Way, the planets the ISS and anything else astro related I could manage with my current photography equipment but I still lacked one thing, mega zoom!

I needed a telescope. So I bought one for the exorbitant fee of £30 from Jessops. Now, I didn’t expect much from a £30 Jessops junior telescope with a 50mm front on it. What I didn’t reckon for was how bad it actually was. This spindly thing was dreadful and nearly put me off a telescope all together. It was so frustrating to use. I went off the idea since then and started looking at a Sigma 150-500mm lens instead, which combined with my Sigma 2x teleconverter would have gave me a 1000mm lens, 1500mm on the crop sensor. To be honest I’d have bought this but I lacked the £800 or so I needed to get one.

Then Gumtree happened. Up popped a Meade 4504 114mm Newtonian Reflector and motor-driven equatorial mount. The usual Googling was done and off I went to see it. As soon as I laid eyes on it I knew I was buying it. It was huge and that’s what matters right? £80 paid and off I went with my bazooka sized new toy. Satisfyingly filling the boot and back seat of the Mondeo it looked perfect, there was even a camera adapter with it. Glorious up close moon shots were just around the corner, or so I thought.

If you’ve never used a telescope on an Equatorial mount before then you are well unprepared for how difficult it is to get the thing pointing where you want it to. Then when you discover that your 2nd hand bargain has had a harder life than you first thought the bubble slowly starts to burst. Over the next 2 days I discovered that the mount won’t lock in place, a real pain, once you located an object it requires little more than a gnats fart to move the scope and lose the object. Not that bad with the moon but a real bollock ache with the planets.

No matter thinks I, it’s got a motor drive that’ll fix the problem! 10, yes 10 AA batteries later and the motor drive whirred into action. It works, yes. But wait, shouldn’t the mount actually move when I tell it to? Scratch that, it doesn’t work. So, I now have this massive malfunctioning telescope sat in my shed, the wife wont let me keep it in the living room. To be fair, it’s that heavy I don’t really want to carry it from the house to garden to use, 8ft out the shed is much better so there it lives under an old blanket.

Much as I was disappointed by the mount I still figured I could at least get some moon shots with this setup. That’s when I got a stark lesson in focal lengths of telescopes. No matter what I do I cannot get the D90 to focus when attached to the telescope, either using the prime focus or eyepiece projection methods. It seems as if the camera is too far from the telescope mirror. I tried every combination but nothing worked. I’ve since read that using a 2x Barlow lens might correct the issue, I’ve got one of them so that’ll be the test for tonight.

All in, it’s been a frustrating and disappointing experience so far, I didn’t expect to jump right in and be photographing details on Saturn or distant galaxies from day 1 but I had hoped at least for a sharp shot of the moon filling the frame. I’m treating this as part of the learning curve for now, I had similar issues when I first delved into proper long exposure photography but with a little dedication I did get there in the end.

But, and there has to be a but. This post sounds fairly negative, it’s not been the best of experiences but there has been a massive positive. Even with the scope not perfect, I’ve managed to observe the moon really close up, right into individual craters and even a view of the moon on the lowest magnification is awesome, it’s so sharp. A truly breathtaking sight. If that wasn’t enough I’ve also observed Jupiter and close enough in to pick out the moons and the coloured bands around the planet. Something which amazed my youngest son too. I’ve also seen Saturn and the rings around the planet, a sight so awesome it’s hard to describe. When you think about the distances involved in where these objects are its mind boggling.

Even if this telescope never takes a picture for the views I’ve had so far it’s been worth it alone. I’ve seen things that relative to the amount of people on the planet, few have seen. I get fairly awestruck seeing historic landmarks you’ve only heard about of seen pictures off, places like the unfinished cathedral in Barcelona, the leaning tower of Pisa, Pompeii to name a few but seeing Jupiter and Saturn? That’s quite a special feeling and one you can get from your back garden with an £80 investment.