Contains:  Solar system body or event
Mars under excellent seeing conditions - still only 7.3" apparent diameter, Niall MacNeill

Mars under excellent seeing conditions - still only 7.3" apparent diameter

Acquisition type: Lucky imaging

Equipment

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Acquisition details

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Description

I had extraordinarily good seeing for this capture of Mars. It was one of those rare occasions where the seeing was probably sub one arc second.

I am somewhat under sampled with the 2.5X Powermate focal length increaser which gives an 9.8m focal length and I have seen images of lunar features recently being resolved at well below the Dawes Limit for a C14 (0.34"). Therefore it occurred to me that I don't have enough pixels to realise the potential resolution of my OTA, under excellent seeing conditions. There I decided to buy a greater focal length increaser and to that end purchased a Tele Vue 3X Barlow. I used this for the first time on Jupiter and Mars during this session. I calculated, based n the image size that this Barlow is giving me a focal length of over 15m, equivalent to 3.9X, due to the slightly longer set back distance of the camera's sensor.

Mars is quite suitable to try this with as it is very bright so frame rate is not an issue and with the seeing so good this morning I thought it worth the trial. Due to set back distance I was apparently achieving a focal length multiplier closer to 4.

I integrated 3 runs of 4 mins per colour channel with WinJUPOS, which helped greatly to deal with a stronger Gibbs Effect than I normally see. The resolution achieved here I think bears out the benefit of increased sampling when the seeing warrants and the detail is quite pleasing considering the apparent diameter of only 7.3".

Of course I am still seeing much the same region as I have imaged in recent times. Most interestingly I believe the Hellas Basin is becoming clearer. In this image you can plainly see its distinctive shape and its white-yellow colour coming through. There are still however what looks like some remnant light brown dust clouds to the north and on its f side. Nevertheless it seems the dust activity is subsiding in the region.

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Mars under excellent seeing conditions - still only 7.3" apparent diameter, Niall MacNeill