Saturn: 25 February 2007

Date: 25 February 2007 U.T.
Time: 5:55 - 6:48 U.T.
Telescope: 30cm Newtonian
Magnifications: 250x and 300x
Filter: #80A and unfiltered
Seeing: Fair to Good
NELM: 5.3 (Moon in sky)
Temperature: +17 F (-8 C)

The above sketch shows the basic appearance of Saturn on this night. South is up. Preceding is to the left.

After initial collimation of the truss-tube telescope I pointed the scope at Polaris, increased the magnification to 400x, and used the de-focused star's Fresnel pattern for a final 'tweak' of the collimation.

The scope had been outside for a few hours prior to the session. At the beginning of the observation the seeing was Fair. The sketch was initially made at 250x with the #80A filter.

As the session progressed the seeing improved. I removed the filter and increased the magnification to 300x. At times of steadier seeing the image was quite sharp. Tethys, one of Saturn's moons is shown just south of (above) the preceding (left) portion of the ring system.

Initially, Cassini's Division was not visible all the way to the limb of the planet, but that changed after the seeing improved. Both the preceding and following limbs of the planet were darkened a little. The C-Ring was visible against the background sky as well as against the ball of the planet. The filter may have darkened (increased contrast) of the planet's southern hemisphere belts as well as the C-Ring against the planet. The outer portion of the A-Ring was darkened somewhat and some structure was hinted at. The inner portion of the B-Ring was darkened somewhat.

Some clouds came and went during the observation. The outside of the telescope had attracted a fair amount of frost during the session.

This was my first high magnification planetary observation with the 30cm Newtonian. It's not likely to be the last!