Jupiter Sketch

Date : 4th Sept 08, Thursday
Time : 8:15pm to 9:30pm (1:15 hrs)
Location : SD Home
Weather : Seeing was okay (4/10). Moon with 5th phase on west.
Instruments : My 10” dob.

Observed Jupiter tonight for an hour. "starrynights" email threads were indeed helpful in detailed observation.

Seeing was okay around 4. 9mm eyepiece (135x) was crisp image, but 270x was really blurry and no sharp focus. 6.25mm (12.5mm x 2x) (i.e 194x) was still better than 4.5mm, but going in & out focus. so I guess seeing was 194x/10 - 20x magnificaiton per apperutre..so around of 4/10.

Four moons. Two on each side. All of them at different distances.

With 9mm (135x) indeed sharp image. NEB and SEB were bright and brown in color. NEB is darker than SEB. NEB is closer to equator than SEB. The SEB is almost 1.5 times in size than NEB, still smaller than EZ.

At 194x, NEB on right side (East) is darker than NEB on left side (West). NTB and NNTB were initially hard to see, but once eyes were set, they indeed showed up nicely. Both fainter than SEB. The south polar region or prrbably STB were visible, but both merged together, wasn't able to differentiate. Still clearly saw STZ, the zone between SEB and STB.

In NEB, there was a small white fissure across the center of the belt making 45 deg angle. Moderately visible. Saw the Great Red Spot couple of times, when image was crispy and really in perfect focus. It was on SEB on the upper right corner (South East). It was protruding from the SEB on south side. White in color. In a side view. Almost 40% visible.

It was indeed hard to see GRS. From my last TDS & BO session, it was amazingly clear, but this one wasn't really great. Realized the importance of crayford focuser. Also, would have been great to have double focuser or high speed focuser.

I also made a small sketch of Jupiter texture. Considering my first attempt, its not bad. Observing and Drawing the sketch indeed helped me to improve my visibility in the eyepiece w.r.t distances, size and attention to details. Should do it more often. Drawing complete eyepiece view than just the Jupiter disk is much harder. The tracking on Jupiter would have helped while drawing the sketch.

TBD:
Tracking GRS visibility. (Sky & Telescope - GRS Transit times)