Following on from my recent experience with binoculars I thought it would be appropriate to share some of my ideas.
It's interesting how I'm comfortable pointing my 17.5" dob at some big and complex DSO, like Eta Carina, no problem. But my recent experience at a dark sky site with a pair of 11X70 binos had me stumped on EVERY aspect - where to start, how to go about it, what to use, boarder or none?
Why the problems with a wide field? Under a dark site sky, the background glow of the Milky Way is astounding! It is omnipresent, and complex in its structure. What may seem like a modest aperture with the binoculars reveals such an involved image, it is not so much about the actual wide field view.
The silver lining in my binocular session was that I didn't get to do a sketch! Clouds saw to that. But the result was that it got me thinking on how to tackle such a sketch. Inspired by this experience with the binos, I had a go at a sketch at home. I sketched the region around M8 and M20, for the striking dark nebulae around them, the extraordinary expanse of M8 itself and I also had another "wide field" sketch of this area done with my 8" f/4 scope from home a couple of months before as a reference for the placing of the key stars in this area.
First I envisaged how I wanted the final sketch to look like, and then developed a process to achieve this. The various illustration techniques are those used in the Mellish Technique - I've just employed them in such a way to give me the effects I was after.
I started by marking the boarder circle with a Chinagraph pencil. The Chinagraph would be able to resist being rubbed out with an eraser when the time came to remove the material that extended beyond the sketch - a part of the final sketch I wanted to achieve would have a sharp, clean edge to give the viewer an indication of the brilliance of the image compared to the blackness of the inside of the binos.
I next used a big soft brush to start laying down an overall glow to the circle. I deliberately went over the boarder as it is the only way to achieve an even colouration to the FOV. As mentioned above, this "overhang" can be removed later.
I then used a large stiff bristle brush to give me the tiny starkle, a stronger glow, and to provide the mottling. This is a little time consuming to cover the necessary area, but the effect is well worth the effort.
Once the background glow is finished I start adding the nebulous features with smaller soft round brushes. The dark nebulae & dark lanes are also added using charcoal and the various brushes. The star fields are next added.
What may need to be done afterwards at the desk is accentuate the intensity of the background star field. This is done by lightly pot-marking the entire background with a sharp soft pastel pencil. This too is time consuming, and I had to do it in over a couple of sittings. The depth that this pot-marking achieves is beautiful.
The finished sketch below shows the brightest stars with difraction spikes. I'm not too happy with them, particluarly with the sting of them across the area where M20 sits. They could be too big, too bold, incorrect orientation, that they are there at all. As this sketch is just an experiment I'm not too concerned and will help me be more careful in my next sketch.
Once I was happy with the end result I removed the overhang with an eraser, being careful not to cut into the circle.
All the dark nebulae and lanes were added with a brush and over the background glow. This allowed me to texture the FOV very easily and accurately. Amazing stuff black charcoal!
Have a go at a wide field sketch. My biggest hinderance was just were to start, so I just did an experimental sketch first. I'm ready to tackle the real thing now,
Clear skies and sharp pencils,
Mental.