[AZ-Observing] Morning observing report

  • From: "Frank Kraljic" <fjkraljic@xxxxxxxx>
  • To: "AZ Observing" <az-observing@xxxxxxxxxxxxx>
  • Date: Mon, 17 Sep 2001 12:36:22 -0700

Late last night I set up the scope (Spooner 10" F5.5 Dobsonian) for
observing early this morning.  Surprisingly, I had no problem jumping out of
bed at four in the morning when the alarm clock rang, as opposed to Saturday
when the alarm sounded for close to three hours--not good.  Thankfully, I
had no pressing commitments early Saturday morning.

Saturn was placed near the zenith and Jupiter relatively high in the sky.
At 225x, Saturn was stunningly crisp accepting magnifications of 400 and
560x.  (17 and 12.4mm Plossl combined with a 5x Powermate.  I also utilized
a 2x barlow with a 7mm Ortho at 397x, which at times seemed to give me
greater contrast, but less eye-relief.)  The image softened slightly at 560x
and I did most my observing during an hour's time at 400x.  (By the way, did
I mention how nice high magnification is with an equatorial platform?  Or
tracking in general.)  My mental notes are as follows:


A sight for sore eyes.  I am pleased to see this planet return to the night
sky and look forward to the remainder of its apparition.  Tom Polakis noted
a dark polar hood earlier this month, as Saturn's equatorial plane is
considerable skewed favoring the southern hemisphere greatly.  I confirmed
this and found something even more interesting.  Two thin white bands in the
temperate region.  Never seen this before.
        Although the C-ring was obviously apparent--the same for Cassini's
division--observing either the Encke minimum or Encke division was


The GRS rotated into view becoming plainly visible within the hour.
Although I couldn't find any white ovals in the southern polar region, I did
notice two very small white features near the separation of the north polar
region and temperate zone.  (I believe the temperate region is the white
zone separating the north equatorial band from the north polar region.  I
searched the ALPO website for a diagram and description, but found nothing
surprisingly.)  The north equatorial band has considerable mottling, however
the SEB appears fainter than last apparition and distinctly halved.  Even
the GRS is less saturated and more prominent at the core.
        Meanwhile, I was treated to the reappearance of Io from behind the limb 
Jupiter.  I was engaged to notice the moon's color and brightness change
substantially from third contact to complete reappearance.  When I first
caught glimpse of the moon coming out of occultation, Io appeared red/orange
then brightened to its typical blazing off-white manner.  I should point
out, the color was not red/orange as one may imagine from face value of the
term.  But in comparison to the end result, the difference was noticeable.
I am curious to eye a similar event, as well as an eclipse of Callisto or
Ganymede should one occur this apparition.
        With Ganymade far from the planet and the atmosphere stable, now was the
time to observe the moon's subtle albedo shades ... Barely anything!  As a
matter of fact, I don't ever recall having difficulty finding surface detail
at magnifications higher than 400x under good seeing.  What's the deal?

This past month I've talked about cleaning my mirror, and well, I am
overdue.  I think missing the Encke division and surface detail in Ganymade
is either the result of being four months from opposition or light scatter
from dust on the mirror.  Aside for the object, I first noticed a glow
surrounding the planet much greater than I've found in past sessions minus
the secondary's spider.  This is what is leading me to believe how important
clean optics are for observing the planets--or other bright objects--with
great contrast.  I'm going to test my theory throughout the week and
hopefully have my mirror cleaned by the weekend using Collodion.

I recommend everyone take the chance to begin observing these planets; it's
never too early to start--no pun intended.


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