Brasspoodle Posted March 23, 2016 Share Posted March 23, 2016 Apologies as this is a bit of cross posting from the Astronomy Forum... Finally, after lots of sessions with the f5 ST120 Achromat, I got out the 12" Dob and had a look at Jupiter. I started out with the 7mm XW (214x) and was straight away amazed with the view: the usual two equatorial bands, the red spot (white rimmed) entering from the left, two broad fuzzy grayish bands further down around the pole separated by a clear white line, the messier darker upper equatorial band was reasonably complex and there were just visible a further two bands around the upper pole (the pole itself and another less defined band below it). I then tried the BCO 6mm (250x) and was surprised to notice a thick notched line running along the bottom of the lower equatorial band, running up around the red spot on one side. There was nice contrast (polar bands perhaps clearer) but as soon as the planet got into the outer 20% of the FoV the image deteriorated quickly into an unfocused blob. Lots of nudging was required to keep Jupiter centered and in the end the narrow, limited FoV in my undriven Dob was just too frustrating to deal with. The 6mm Delos proved a much better option with the image staying in focus right across the FoV. Little changed in the quality of the view with perhaps slightly less contrast but the eyepiece showed the same detail. Then I tried the 5mm XW (300x) and initially it looked pretty hopeless, with the view being a slightly less distinct version of the 6mm. However the sky magically settled and the image sharpened. I noticed between the two main equatorial bands a thin curved arc (or loop) coming out of the upper darker equatorial band above, and slightly behind, the red spot. The notches on the line on the bottom of the lower equatorial band seem more distinct. I detected 3 notches (there could have been more), one near the red spot and others further along. I thought I may have seen another upper line in this lower equatorial band above the thick notched line. The lower polar bands were distinct (as before ) although more texture seemed apparent. The upper polar bands were similar. At one point the whole planet looked as complex and detailed as I've ever seen it, almost quasi photographic! After a while the sky resumed its turbulent ways and 300x became once again not so usable. I felt like I lucked onto a momentary window tonight in which conditions conspired to produced excellent planetary viewing. Having spent so much time eeking out details on Jupiter through the ST120 I was certainly well prepared to see as much as I could through the 12" Dob. Clear, steady skies to you all :-) 10 Link to comment Share on other sites More sharing options...
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