Capella is the brightest star in Auriga constellation. It is very easy to spot in the Northern hemisphere. It is a circumpolar star, very bright one. The picture has been taken through a 300mm telephoto lens and Canon EOS 450d over a Sky Watcher EQ6 equatorial mount.
Archive for DeepSkyStacker
This is a crop of the resulting stacking of 36x30s + 2x360s subframes taken this month in two different sessions. The area showed corresponds to M101 and surroundings (in Ursa Major), in which we find other 2 galaxies NGC 5474 and NGC 5477. Below, I have added a DSS2 image of the are for comparison. My stars are blobs, meanwhile DSS2 are pinpoint. On the other hand, I use to lose star colours specially in the brightest ones , when postprocessing and stretching histogram. Maybe some day I will learn how to fix all these errors …
I took last winter 92 shots of 30 seconds to M31 using my 300mm telephoto lens. An EQ6 equatorial mount holded the Canon EOS 450d (Rebel XTi) camera. After stacking them with DeepSkyStacker and some post-processing with PSP9, here it is the result. The imaga shows M32 and NGC 110 too. I hope you enjoy it:
Light pollution in suburban skies makes nearly impossible astrophotography. Nevertheless, there exists some computer techniques to make it possible. I have used a dark frame to catch the exact pattern of the light pollution in the photographed area. The way to accomplish this is not difficult. Shooting in continuous mode the DSLR camera facing the zenith in my home window, and forcing every frame to last 15 seconds I got a sequence of subframes to be processed afterward.
To get the dark frame I do some image arithmetic with Paint Shop Pro 9: I choose 3 or 4 distant subframes and compute them using “darkest” option. This way, stars become to fade until disappearing.
With Paint Shop Pro 9 and batch processor I apply a barrel lens distortion of 17 (empirical value to correct a 18mm focal lens like Canon’s) to every subframe and also to the dark frame.
Once got the dark frame DeepSkyStacker is needed to stack the single subframes and substract the dark frame. The sideral drift of the field is automatically compensated with the intelligent algorithm that DeepSkyStacker provides.
The resulting image is surprising taking into account this is an urban sky.
It is important to apply the best astronomical software to enhance your pictures. Otherwise noise, blur, light pollution, hot and cold pixels and low exposures can degrade our work. Here is a list of my favorite astrophotography software:
* Image Stacking: Registax, PhotoAcute Studio, Nebulosity and DeepSkyStacker.
* Retouching: Paint Shop Pro and Photoshop.
* Zooming: onOne Genuine Fractals.
* Sharpening: Maximum entropy deconvolution with AstroArt, and wavelets with Registax.
* Noise removal: Neat Image.
* Video edition: VirtualDub, Adobe Premiere and EasyBMPtoAVI.
* Night sky renderers: Stellarium, StarryNight, Google Earth & WikiSky.