10" Orion Optics (UK) Newtonian, focal length 1200mm, F 4.8 eyepieces used for the drawings, Vixen LVW and LV.
And not forgetting a ‘2B’ pencil!
It's something like 150 years since the introduction of photography into astronomy so the era when drawings of celestial objects could be thought of as having real scientific value has long since become part of history. Given the stunning results that can be achieved photographically, it is then perhaps somewhat surprising that some still take up pencil and paper to create images of celestial objects. CPAC member Ed Goward is one of those who does from time to time and judging by these examples of his work, he has clearly developed considerable skill.
Ed told us: "Jupiter put on a fine display in 2010, the giant planet riding somewhat higher in our skies for Northern Hemisphere observers than in previous years. These are a couple of drawings from observations using my 10" (250mm) reflector on a Dobsonian mount. This type of telescope, being hand driven, is not ideal for planetary use, but I love its low-tech nothing to go wrong (well almost!) utility, and so adopt a similar approach when I record my observations, using pencil, paper and a dim red torch. A dim red torch helps to preserve the dark adaption of the eyes, although this is not so essential for bright objects like Jupiter.
"As you may well imagine, it's a bit of a "faff" with an un-driven scope - observe, find my reading glasses, red torch, pencil & paper, back to the eyepiece, hand track, etc. But it's probably a lot simpler than imaging, and definitely cheaper! I find it a pleasant occasional diversion from observing.
"Although I possess a full set of drawing pencils, I just use a '2B' and press lighter or heavier. I spent about 10 minutes max at the scope for each drawing, adding notes to clarify what I saw. In moments of steady seeing much more could be fleetingly seen than I've included in the drawings. The drawings only show what could be easily seen.
"Soon after the drawings were done, next day probably, I did the finished ones, working from the originals. The drawings are then scanned, or copied using a digital compact camera, so they can be loaded into my notebook computer. About 20 mins each drawing for this stage.
"The drawing from 10th October 2010 shows a particularly nice event. The shadow of Jupiter's moon Io ( pronounced 'eye-oh' ) was very sharp. Io itself, to the left of its shadow, was very tough to spot until it moved close to Jupiter's limb (edge), when it became very much more apparent due to limb darkening.
"The second drawing, from 11th October, (yes, two clear nights in a row !) was satisfying also, as the 'great red spot' was readily seen as it transited the centre of Jupiter's disc. As the southern equatorial belt was very subdued ( remember these drawings are south up, as in my type of telescope ) the GRS was far more apparent than I had ever seen previously"