Moons of Saturn through telescope

Titan, Tethys, Rhea, Dione, Iapetus are five bright moons of Saturn, the ring planet in our Solar system. They can be observed through amateur telescopes with at least 100mm (4 inches) of aperture. The following picture was taken through a 5 inch telescope, a Celestron NexStar 5 SE XLT. It is an image composed of 84 single subframes of 1 second of exposition each one.

It was taken on 2011-03-06 02h10mUT using a DBK 21AU04.AS Imaging Source CCD camera. Planet was recorded in a different exposition through a video stacked (shift and add) using Registax free software.

Check out the JPL simulation matching the picture above.

Celestron NexStar 5SE vs Takahashi FS102

This week I had the chance to test a Takahashi FS102 refractor apochromatic fluorite telescope and also a Celestron NexStar 5SE Schmidt-Cassegrain catadioptric telescope. First one has an aperture of 102mm and second one of 125mm plus a central obstruction. Their light gathering power is similar and also their theoretical resolution. Nevertheless I wanted to check by myself the mythical optical quality of FS102 in contrast to the well-known Celestron.

Tests were made using the same camera to capture video and similar weather conditions both nights. I took in both cases a video of the planet Saturn when reaching the meridian, its maximum altitude. Celestron C5 perform flawlessly because I could get a sharp view of Saturn and its ring at 500x magnification. Takahashi also let me reach that high powers with a crisp result. C5’s focuser is very precise, but Takahashi’s is even more being a rack and pinion system. Focusing the FS 102 was very pleasant due to its smoothness and accuracy. Probably a better contrast in visual images delivered by refractor telescopes also gave it an advantage here.

Trying to resolve fine details, in both telescopes I could see the shadow of Saturn over the rings clearly. Here it is the final picture after applying Registax and Fitswork4 to both videos.

Probably FS102 performs better on wide field astrophotography, but on planetary imaging this picture above is my conclusion.

Saturn with a 6 inches refractor

This image of Saturn has been obtained after processing a 4 minutes video took with a Casio Exilim digicam. In order to avoid refractor chromatic aberration a Fringe Killer filter was used in combination with a 14mm eyepiece and a Barlow lens.

A bit better Saturn

Fortunately, yesterday was not cloudy and I could do further experiments with Saturn. Using a Barlow 2x and Casio Exilim EX-FS10 camera I filmed some videos at highest resolution through the big dobsonian telescope Meade Lightbridge 16-inch. Weather conditions were good. I did a better collimation than previous days, getting sharp focus from time to time. Stacking the frames with Registax 5 I got this resulting image:

In the left side of the image, it is visible a satellite of Saturn. It is Titan, with 9 magnitude. Over it, a bit at right there is almost visible another one, Rhea of magnitude 10. Visually it was observable another one aligned to Titan and Rhea, but it is not visible in the image. It was Dione with 11 magnitude.

Luckily this image shows the gap between foreside ring and its rear part. The image effective resolution according to my calculations is 1 arcsecond. Two cloud bands are visible one in the north hemisphere and the other in the south.

I would like to break the 1 arcsecond resolution barrier, but I don’t know if it is possible with this telescope. Theoretically it delivers a 0.3 arcsecond resolution because it has 400mm of mirror diameter.

Saturn improved

Saturn is getting hard to be photographed. I have recently bought a low-quality barlow 2x and a ScopeTronix EZ-Pix II. The clouds aren’t giving me many opportunities to see Saturn, but I could find a hole in the sky 2 nights ago. I took a time trying to collimate the dobsonian as better as possible. Nevertheless I couldn’t get a sharp focus. I took video and single frames. After stacking with Registax 5, I have got this image.

Saturn and rings

Saturn is well placed these nights to be easily observed. The rings are edge-on, so they are difficult to capture with photography. Nevertheless I have got a series of shots and have stacked them all with Registax 5. Take into account I have used the Vixen 12×80 binocular to get this image. Imagine seeing Saturn rings edge-on with a magnification of only 12 …