As Mars moves closer to April 8-th opposition, it is still a difficult imaging target for an 8″ telescope; the poor observing atmospheric conditions don’t make it easier. In Johannesburg, RSA, we had very few clear evenings with very strong turbulence and early dew. Atmosphere becomes more stable by the time Mars reaches an altitudes over 40 degrees above the horizon. At this point on several evenings thin high cloud layer appeared, making imaging almost impossible. Nevertheless, I did use the opportunity to fine-tune the equipment, experiment with various optical configurations, trying to find an optimal setup for future observations.
The configuration with 4x Barlow, giving an attractive 8-metre focal length for my 8″ TAL-200K, produces perfectly-sized image of Mars for the imaging with entry-level digital SLR cameras with video recording function. On the other hand, a 2xBarlow will produce a smaller, brighter and more contrast image, which is much easier to work with. This is specially important if the turbulence is strong and the telescope tracking is not quite perfect.
The most rewarding is observing the Martian surface and atmospheric features moving across with the time. A time gap of 1 to 2 hours is sufficient to produce two images which will clearly show the rotation.
The featured animation comprises two images, produced by stacking some 1,600 frames for each image in Registax and adjusted for contrast and brightness. The video files were acquired with TAL-200K telescope at f/40 on a TAL motorized equatorial mount and Canon EOS-550D DSLR in video recording mode. Apparent angular diameter of the planet was 14.87 arc-secs at that time.
Observers around the globe are looking forward to April 14-th, when Mars will be at closest distance from Earth for this year- only 92 million km and it’s Apparent angular diameter will increase to 15.16 arc-secs, offering the opportunity to produce a higher resolution images. Worth mentioning is also the fact, that on the same evening Mars will rise together with Full Moon and will be separated from it only by 3.5 degrees, making a wonderful photographic target for 100-200 mm lens.
More images to follow.