Planetary – Page 53 – Astronomy Sketch of the Day

A Brilliant Irony

Venus
Terrestrial Planet
By Eric Graff
Parks Astrolight EQ6 • 6″ f/6 Newtonian Reflector
7.5mm Parks Gold Series Plössl + 2x Barlow • 240x, 13′ FoV
30 September 2007 • 13:00-13:30 UT

It is somewhat ironic that the most brilliant planet in the sky is also the most challenging to observe. On 30 September 2007 Venus appears as a dazzling crescent (32% illuminated) in the morning sky, 42° west of the Sun and shining at magnitude –4.7.

This observation was made during morning twilight and the white cloud-tops of Venus displayed a fair amount of subtle, dusky shading, seemingly in a series of roughly parallel arcs curving northward. The shadings were most prominent toward the terminator, while the polar-regions were quite bright, particularly the southern cusp. In spite of the atmospheric subtlety, I found the observation of the large Venusian disk quite relaxing and relatively easy compared to the previous observation of the tiny Martian disk.

Holmes in a Spin

Comet 17/P Holmes
28th October 2007
18:40 UT Mag 2
Reflector FL 1200mm/8mm eyepiece/150X Pastel/Conte/Black Paper

Here is my sketch from October 28th, I got going early to avoid the predicted cloud cover. I had a long look into the halo around the nucleus. The material emanating from the pin point center seemed to be heading in a more southerly direction than I had observed in previous evenings. I could see darker areas fanning in the opposite direction in the inner halo. A star was visible just inside the outer halo. Because I could see a star through the out gassing then it must be very thin? The star was visually similar in size to the comet nucleus but a little dimmer. Sometimes the coma seemed to momentarily have transparent spaces within it. I have not seen a star in the area of the dark spaces, I wonder if these spaces are filled with dust?

All this was visible even though there was a 17 day moon rising almost directly under the icy action.

Deirdre Kelleghan
President
Irish Astronomical Society 1937 – 2007
Public Relations Officer IFAS
http://www.deirdrekelleghan.com/
http://homepage.eircom.net/~irishas/index.htm
http://www.irishastronomy.org/

The Eye of the Coppery Orb

Mars
Terrestrial Planet
By Eric Graff
Parks Astrolight EQ6 • 6″ f/6 Newtonian Reflector
7.5mm Parks Gold Series Plössl + 2x Barlow • 240x, 13′ FoV
30 September 2007 • 12:30-13:00 UT

The December 2007 opposition of Mars will pale in comparison to the very favorable oppositions of 2003 and 2005, achieving a maximum angular diameter of 15.9″ on 18 December 2007. On the other hand, it will not appear this large again until the opposition of 2016; also, unlike the previous two favorable oppositions, the Red Planet rides high over the northern crest of the ecliptic, placing it nearly overhead as it crosses the meridian for northern hemisphere observers.

On 30 September 2007, the Martian disk measures a mere 9.6″ and still shows a strong gibbous phase (the disk is 87% illuminated). The central meridian (CM) at the time of observation was approximately 110°. The principal Martian surface features identified during this observation include the dusky circular feature Solis Lacus drifting toward the terminator and the dark band of Mare Sirenum emerging from the limb. The Tharsis plateau, home of Mars’ mighty shield volcanoes occupies the relatively featureless golden plain near the center of the disk. Bright patches were detectable in the vicinity of both the north and south poles; I’m not sure whether these are the actual polar ice caps or “polar hoods” which are atmospheric mists associated with the evaporation of the caps. A few other patches of haze were detected around the southern limb.

Outburst of Comet Holmes

Many veteran comet observers regard the outburst of Comet Holmes (17P)
as one of the oddest sights they have seen. Not only was the sudden
brightening unprecedented in modern times, but the perspective we have
of this distant comet gave it an appearance all its own. From night to
night you can see it growing in size and yet, due to the dimming of the
expanding coma, it maintains a fairly constant brightness when viewed
naked eye.

Initially, the first images of this comet online indicate that is
difficult to capture the visual appearance with our imaging technology
and sketching is proving to be a satisfactory way to convey the visual
perspective at the eyepiece. I quickly opted for the sketching option,
but soon found that I had trouble getting a perfectly round coma that
also conveyed the contrasty ‘pop’ that this comet presented that first
night after announcement of the outburst. So instead of just using
image processing programs to get my onscreen-sketch looking like my
on-paper sketch, I decided to try to do more than embellish it and do
the sketch entirely with the image processing program. I refer to this
as digi-sketching.

So here is a series three ‘sketches’. The first is my original ‘paper
sketch’ captured and rendered to reflect what I had on paper. It was
graphite on paper with the colour added digitally.   It was
disappointing to me in that the brightness, contrast and the colourful
‘pop’ factor of this weird sight in northern Perseus was not entirely
captured.   The second sketch is my digi-sketch version of that same
night based on my original sketch. I soon appreciated that I could
quickly and easily correct some failings of the original.   The third
sketch is from three days later and is done to the same scale showing
the dramatic changes that took place in this short span of time. The
image processing program that I used for teh last two images is a PC
version of iPhoto that came with an old scanner. This makes me wonder
what is possible with some of the newer and more capable image
processing programs.

All three sketches were done from my view through a 12.5 inch home-made
Dobsonian using a Discovery mirror.   Binoviewers 23mm eyepieces and a
2x barlow gave a magnification of something well over 250x.    The first
two sketches are a result of my observations on the night of October
24th at around 10:45 CDT (UT 3:45 Oct 25th 2007).   The third sketch was
done on October 27 CDT at 11 PM (UT 4:00 on Oct. 28th 2007).   Note the
two 11th magnitude stars that could be seen shining through a relatively
colourless coma in this third sketch (bottom/south part of the coma
about 1/4 the way in). Since the equipment is constant for both nights,
the images can be directly compared for size and this gives one an idea
of just how quickly this comet grew in size.

This has to be one of the oddest and most unusual events in comet watching.

Gerry Smerchanski

Necre Hearted Visitor

Comet 17/P Holmes

I just couldn’t resist doing a quickie of this very unexpected object. As you may know, comet 17/P Holmes went from an unobscure magnitude 17 to 2.8 in just a little more than 24 hours…which it is now easily seen naked-eye in the constellation Perseus!! The coma is very bright and just a tad off-center, and the surrounding gases are emitting a slight off-yellow color. This comet does not (at present time) display the familiar “tail” that we are used to seeing with other comets, but this is still spectacular to see. Grab your scopes and head outside to see this beauty!!!

I will be observing this excellent and unexpected comet throughout the night and complete many sketches of this comet with differnt EP’s/magnifications. But for now, here is what it is looking like:

Wade V. Corbei
Lodi, California

On the Tail of a Comet

I had a few failed attempts at spotting comet C/2007 Loneos before we finally met.

I caught up with it about 4 degrees below Arcturus in the evening twilight low in
the west to North western sky. With the Moon at around 50% on the eve of the 19th
October this didn’t help detection either. My village is in a hollow so to get a
good horizon I need to walk about half a mile along a track which runs up a hill
at the edge of the village ( Capon’s Hill). I used an old 6″ (150mm) F5 Helios
refractor on an alt-azimuth mount, slung it over my shoulder and set off. Equipped
with a couple of eyepieces and a BAA locator chart. I found it within a few
minutes of commencing the search. The tail was very hard to pick out in the orange
murk of the horizon although the head and coma with bright nucleus showed a hint
of a blue/green tinge. I nudged the scope to initiate movement and employed every
bit of averted vision I could must muster in an endeavour to detect what I felt
(at the time) to be a realistic interpretation.

The eyepiece I used was a 22mm Nagler so I feel the tail in the sketch equates to
around 0.75 of a degree. I tried again the following evening and located the comet
with a little more difficulty but couldn’t detect the tail at all, the 65% Moon
had washed it away.

Guess that I was lucky to have picked the interloper out when I did.

Sketch made in a A6 sketch pad with a HB Derwent pencil and blending stump,

scanned image turned into a negative in photo-shop.

Clear Skies,

Dale Holt, England

A Dance before the Laughing Giant

Europa Transit of Jupiter

The moon Europa, denoted by the tick marks as a bright spot against the North
Temperate Band was just beginning its transit across the disk of the planet
Jupiter. At about this same time the great red spot had just crossed Jupiter’s
meridian as the planet crossed my observing site meridian. I deemed this worth an
attempted sketch.

Sketching:
7/7/2007 2:50-3:15 UT
Scope 10” f/5.7 Dobsonian 9 mm UO eyepiece at 161x
4”x 6” white sketching paper, B, 2B, 4B graphite pencils,
Jupiter Sketch cut out and scanned with Europa added electronically using Microsoft
Paint
Seeing 7/10
Transparency average 2.5/ 5

Frank McCabe

Giant Colorful World of Gas

This sketch was done on Rite in the Rain paper with colored pencils. I used the
edge of my eraser shield for the bands and blending was difficult with the waxy feel
of the Prang pencils.

An Orion ED80 was used on an LXD75 mount, all of which were on antivibration pads in the observatory. The eyepiece was a Zhumell 21-7mm zoom

Erika Rix
Zanesville, Ohio

A Jovial Pair

This sketch was done on Rite in the Rain paper with a number 2 pencil. I used the
edge of my eraser shield for the bands and blending was done with my finger.

An Orion ED80 was used on an LXD75 mount, all of which were on antivibration pads in
the observatory. The eyepiece was a Zhumell 21-7mm zoom with a WO dielectric
diagnoal

Erika Rix
Zanesville, Ohio

Canals and the skeptic

The above drawings show the canals and oases of Mars which in the late 19th
century became more prominent with the melting of the nearest polar cap or so it
was claimed at that time. In a never ending on going process, science progresses
by continuously cleaning out its closets of old incorrect information as new
observations and experiments reveal the errors. Our Earth continues to overtake
Mars for the rendezvous in December. Have you ever wondered what Schiaparelli,
Lowell, W. H. Pickering, Campbell, Hussey and others were seeing at the eyepiece
to draw the canale, channels or canals on the Mars sketches they made? The answer
may have been explained by Vincenzo Cerulli an Italian astronomer living at the
same time as Giovanni Schiaparelli and Percival Lowell. After the “canal skeptic”,
Cerulli studied Mars for a couple of oppositions, he found he could duplicate
the canals or lines seen by many Mars observers using opera glass to examine small
features on the moon.
This phenomenon is neither an illusion nor a real exact representation. It is the
eye and brain interacting to fill in small faint features. If you casually examine
the faces on USA paper currency you will see lines across the foreheads. If you
look again using a magnifying glass you can see these lines are dashes and dots. So
if you begin to see canals on Mars near the end of the year, its just you eyes and
brain conspiring to play tricks on you. The time to observe Mars again is just
beginning. Don’t forget to make drawings or log records.

The above drawings are from page 358 of David P. Todd’s, A New Astronomy © 1897,
American Book Company

Frank McCabe