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