Crimsom Sunset - Orange Moonrise

Due to wildfires in western Canada my sky (and the sky over much of the U.S..) has been quite smoky. Combine a smoky sky with a full moon and many would write off an otherwise clear sky as 'worthless'. OTOH, smoke can have a calming effect on seeing conditions . . .

Once again, early in the evening, Jupiter's belts, zones and GRS showed up in the 6-inch f/6.5 achromat. No filters were used. Venus's white crescent looked remarkably good at low power in bright twilight. A low magnification along with the bright sky helped cloak the achromat's chromatic aberrations.

Most of my time was consumed observing Saturn with 5mm and 3mm eyepieces (about 200x and 330x respectively). A #8 Yellow filter was tried a couple of times, but I preferred the unfiltered view.

The smoke did its thing and gave me improved seeing conditions. Cassini's Division was better than on previous nights. It could be made out everywhere except where the ring passed in front of the planet. The rings were brighter than the planet's disk. The C Ring was visible where it passed in front of the (brighter) planet. The shadow of the planet on the rings was evident. A slight phase effect was visible. Saturn's following limb was darkened more than its preceding limb.

Bordering the north edge of Saturn's bright Equatorial Zone was the darker North Equatorial Belt followed by a hint of the North Tropical Zone, the North Temperate Belt, the North Temperate Zone and the North Polar Region. Most of these transitions were quite subtle.

After completing my Saturn observations I made three careful sketches of Alioth using the 3mm eyepiece. One sketch was made with the scope de-focused by 5-wavelengths inside focus, one sketch de-focused by 5-wavelengths outside focus and one sketch of the focused star. Sketches were made with my eye-glasses off and the 2-inch diagonal in place (Not the way a star test should be conducted, but it was the way I chose to do it - this time.)

The test patterns weren't perfect. Small amounts of missalignment and astigmatism were present, but neither were enough for any concern. The focused image showed a nice airy disk with fragments of the first diffraction ring (seeing wasn't perfect). Additional ring fragments and 'dancing' rays were much fainter.

The scope's "10:1" fine-focus knob was *very* helpful in achieving precise focus - due to the short f-ratio and high magnifications. An earlier indoor test showed that the fine-focus knob is closer to 7.7:1 than 10:1, but that hardly matters. It works and it works very nicely.

I wasn't expecting a 'planetary scope' when I purchased an f/6.5 achromat, but I'm pleased with the scope's versatility. I have no doubts that it will meet my expectations for deepsky observing when the moon goes away and my sky becomes more transparent. Until then . . .

P.S. Prior to nightfall my wife and I were out for a walk and encountered a hog-nosed snake. After identifying the snake it was allowed to continue with its own life . . . The end of my observing session was punctuated by an unseen hissing snake. I recalled the time when a Prairie Rattlesnake brought an abrupt break to an observing session (a double shadow trasit on Jupiter). That snake didn't live to see the sunrise.

Sketcher,
To sketch is to see.

On Friday, July 3, 2015 at 11:15:16 AM UTC-7, Sketcher wrote:
Due to wildfires in western Canada my sky (and the sky over much of the U..S.) has been quite smoky. Combine a smoky sky with a full moon and many would write off an otherwise clear sky as 'worthless'. OTOH, smoke can have a calming effect on seeing conditions . . .

I remember quite well an observing night in the desert, in San Diego County's Anza Borrego Desert State Park, when there was an 600,000 acre fire in the local mountains. There was a shift in the winds and the smoke over the desert was intense. Only a few of the brightest stars were visible, along with Jupiter and Saturn, and with virtually no other choice, we took a look at these planets, using my 25" f5 Obsession... an enjoyed the very best planet viewing session of my entire life. The seeing was rock-solid, and each planet in turn gave up the most incredible views I have experienced, to date.. Normally, my circle of astro-buddies shies away from viewing the planets (usually reserved as the last objects of the evening to view) because they are so bright that they ruin your hard-earned night vision... but on this night there were virtually no other object to view!

Both planets appeared to be 3-D, looking like basketballs, something I never experienced, before or since! One of my all-time best observing sessions, with only 2 objects on the check-list!

In any case, I have experienced first-hand just how smokey skies can provide super-steady seeing conditions. Yet another situation where you can use lemons to make lemonade...

\Paul A