Saturday 5 May 2018

Jupiter - good conditions and a newer scope reveals remarkable detail

Hello everyone,

Well, after so long, I’ve managed reasonable seeing conditions to attempt a sketch of Jupiter.  Last year was a complete non-event with Jupiter as no matter when I looked at Jupiter, seeing was just terrible.  In fact, I haven’t managed a sketch of Jupiter in many years.

I do have to say that one big part of this was due to the old orange tube C8 I was using at the time just wasn’t up to the task.  In terms of focus, that old scope was remarkable and outstanding.  But she didn’t have coated optics, and being close to 40 years old, the optics were not as reflective as when new.  With the Moon this wasn’t an issue, but for planetary detail she wasn’t the best tool for the job.  The new SCT I’m now using, well, there is a big difference!  I am fortunate that the optics are also very good with this new unit, and I can pull outstanding detail with it at high magnification, but the optics are multicoated, and this has made an enormous difference for planetary detail and with DSO’s.

Well, it was good to have a break in the poor seeing and have the opportunity to not only pin Jupiter, but to also try a few illustration techniques I’ve been wanting to have a go with.

As with all my sketching, the longer I spend on a target, the more and more I see as time goes on.  Jupiter was no exception.  As clear seeing windows wafted through, these details revealed themselves as festoons, smaller pressure cells within the two main belts, a mottled structure within the fine bands, subtle colour variations within all the band structures, and most staggering of all was the significant hue difference and structural differences between the two main belts – something that I hadn’t noticed in photographs.  I've also noted the position of the four Galilean moons with just the first letter of the name of each.

Again, the best eyepiece for the night was my modest 9mm TMB Planetary Type II.  My 8mm LVW was just too much grunt, and the TMB just gave a longer and more frequent detail sweet spot as seeing came and went.  I also use two colour filters to help tease out details, a #80A blue and a #8 yellow.  The blue was excellent to tease out the Great Red Spot and the fine cloud banding. The yellow was especially helpful in highlighting the hue differences between the two main cloud bands and the subtle colour variations between the fine bands too.

The sketch at the scope was carried out using a good old graphite pencil on white paper, with a few notes added.  In the light of day I redid the sketch using a variety of coloured pencils on fine white paper – the fine texture paper is important in order to control the scratchy appearance drawing onto paper can have.  Once I was happy with the colour sketch, I cut out the disk and stuck it onto a sheet of the black paper I use for sketching the Moon, Sun and DSO’s.  I think I may need to improve my scissor cutting skills a little! LOL J  I am very happy with the final sketch construct as it gives a better rendition of what is seen through the eyepiece.

Thanks for viewing this piece of mine.


Object:  Jupiter
Scope:  8” SCT
Gear:  9mm TMB, 222X, #80A blue and #8 yellow filters
Date:  4th May, 2018 14:00hrs UTC
Location:  Sydney,  Australia
Media:  Colour and graphite pencils on fine white paper, cut out and stuck onto black A4 size paper.

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