Far Ranging Thoughts

Last night was my best night with Jupiter this season. My third and fourth sketches of the planet for this year were completed. Excalibur was used at 218x.

For the first sketch (started at 6:45 UT) I employed a Moon-SkyGlow filter which had perhaps a subtle effect. I feel that my 'Jupiter Observing Eye' has returned now. I was able to sit down and make my most carefully rendered Jupiter sketches of this season. Callisto's shadow showed up as a small, round, pitch black spot below the trailing edge of the Great Red Spot. It looked really nice in such close proximity to Jupiter's most famous feature.

The GRS was very pale. It's leading edge was darker than it's following edge. Nevertheless, even the leading edge was very pale. Some structure within the planet's two primary belts (as well as a little zonal detail) was also recorded.

The second Jupiter sketch of the night was started at 8:50 UT. The GRS had moved to the preceding limb of the planet and was no longer visible, but the disrupted end of the South Equatorial Belt following the GRS remained visible. Callisto's shadow remained on the planet, but it now lagged a little behind the GRS.

In the second sketch the impact scar was visible near the planet's south limb. It hadn't quite reached the planet's central meridian at the time of the sketch. The scar seemed to be a little smaller than Callisto's shadow and clearly elongated in the east-west direction. It was considerably less dark than Callisto's inky, black shadow. The scar was about as dark as the matter making up Jupiter's major belts. In other words, it was far less obvious to the eye than was Callisto's shadow.

I'm hesitant to upload these latest sketches, preferring to keep them for my selfish self. Both would provide good material for future paintings -- if I ever get around to it . . .

I've recently become quite discouraged with an astronomy forum that I've been frequenting lately. Forum content has had little to offer me despite my own attempts to increase its faltering signal to noise ratio. Of course, my own lack of a full night's sleep might be adding to the feeling. Time will tell . . .

Anyway, I've been rethinking my Internet presence in general. Eventually re-working my website is a possibility. Also being considered is a limitation on my blogging -- perhaps making one entry at the beginning of each month describing one night's observing session (with sketches if applicable) from the just ending month.

I find it discouraging that there appears to be so little (relatively speaking) Internet discussion and sharing of observations relating to the recent impact on Jupiter. This is only the second time in recorded history that a Jovian impact event has been positively identified and observable with backyard telescopes.

Then there's imaging. It seems that more and more amateurs are becoming interested in setting their eyes aside and letting their cameras do the looking. With visual observing and sketching I feel that I'm in a minority special interest group within a minority hobby. I get the impression that few care to see sketches when digital cameras can show more detail and more color with less work under worse conditions. Such are a few of my thoughts in the early twenty-first century.

Impact on Jupiter!

Date: 21 July 2009
Time: 8:52 - 9:02 U.T.
Telescope: 13cm refractor
Magnification: 218x
Seeing: Fair
NELM: 6.5
Temperature: +46 F (+8 C)

The above sketch is mirror-reversed due to the use of a star diagonal. North is up. Preceeding is to the left. The dark spot to the lower left (southwest) is a new impact scar on Jupiter. The small, dark, impact scar was spotted as soon as I looked into the eyepiece and focused the telescope at 218x.

Anthony Wesley, an amateur astronomer in Australia, was the first person to discover this impact scar on the 19th of July. Thanks to the Internet, I heard about the dark spot shortly thereafter.

Considerable fine detail was visible within the two major belts, but I would have had to up the magnification a bit (and taken more time) in order to sketch it. Meanwhile, Jupiter's rapid rotation would have taken the impact scar closer to the planet's preceeding limb and shortly thereafter onto the far side of the planet.

Moon Occults Venus

The above sketch shows Venus and Earth's moon after sunrise, but just before the moon passed in front of Earth's sister planet on Earthday morning. The sketch is a fairly close approximation of the view through 20x80 binoculars. East is toward the lower left. North is toward the upper left.

Later in the day I showed students our moon, Venus, and the sun using Buttercup (a 60mm refractor) at 28x. Some of the students managed to see the moon and Venus in the daytime with their unaided eyes! By this point in time Venus was a fair distance west of the moon.

Buttercup views Saturn: 16 March 2009

Saturn and Titan were sketched last night while observing with Buttercup, a 60mm refractor. The planet was tiny at 28x and still rather small at 70x -- the magnification used for the above observation. North is approximately up. Preceding (west) is to the left. A subtle, slightly darker band was just visible (or suspected) north of and running parallel to the ring plane. The point of light to the left of Saturn is Saturn's largest moon, Titan.

Sun & Venus 15-16 March 2009 U.T.

The above sketch shows Venus at 0:55 16 March 2009 U.T. as it appeared in "Buttercup", a 60mm refractor, at 70x. The observation was made around sunset under fair seeing conditions through thin clouds. The planet's apparent diameter was quite large. Even at 28x the planet seemed large! North is up. Preceding (west) is to the left. Though a complete disk appears in the sketch, only the bright, thin crescent was visible.

The sun appears in the above sketch with clouds sihlouetted against the bright solar disk. The observation was made through thin clouds at 28x with a full-aperture, objective solar filter at 23:10 on 15 March 2009 U.T. The densest clouds were even visible against the background sky. Unfortunately they don't show up in the scanned image of the sketch. No sunspots were noticed. Limb darkening and clouds were all that was noticed on (or in front of ) the sun's disk. The solar filter was home-made using Baader Solar Filter material. Never look at the sun without proper eye protection!

"Buttercup"

Shown above is the same old, banged-up 60mm refractor that appeared earlier in this blog. The telescope has been improved here and there. After adding some weight inside the rear of the OTA the scope balances better in its fork. The altitude trunnions have been attached more solidly than before. The tube assemblies have been painted yellow with black trim. The wood tripod legs have had their dark paint removed and replaced with a somewhat lighter stain and varnish.

In the tradition of my other telescopes, this one also has acquired a name. Today marks the birth and first-light of "Buttercup".

Venus was Buttercup's first target. Shown above is the rough, at-the-telescope sketch of Venus made at 1:00 on 04 March 2009 U.T. at 70x. Unfortunately the sky had clouded over by the time I went back outside in the hope of observing the moon.

Venus & Pythagoras

The above photo shows our visiting wild turkeys on the run. I like this photo for showing some of the resemblance between wild turkeys and their T-Rex and velociraptor relatives. Really though, I felt like showing something but didn't feel like putting in the work to polish up the evening's astronomical sketches.

Venus was easily found with the unaided eye shortly before sunset. I took out the 60mm refractor and made a more careful (than last time) sketch. This time I recorded some background colors to give a better idea of the visual impression of the planet as seen in the small, low-cost telescope. I might upload a sketch later . . .

Pythagoras is a large, 130km wide lunar crater. It was prominent (and greatly foreshortened) along the terminator of this evening's gibbous moon. Pythagoras's central peak was very obvious, standing out as a bright notch in the non-illuminated portion of the crater. The nearby 144km wide crater Babbage, with Babbage A within its border, aided in positively identifying Pythagoras.

I have only one 0.965 O.D. eyepiece -- the size that fits the 60mm refractor's diagonal. Therefore I'm currently restricted to using only one magnification (28x) with this telescope.

Venus - 02 February 2009

The above sketch of Venus depicts the general appearance of the planet on 02 February 2009 at 0:40 UT at about 30x with a 60mm f/11 achromat. West is to the lower left. North is to the upper left. Of course, at 30x the planet didn't look as large as it appears above, but the fat crescent was none the less sharply defined and easy to see.

Interestingly, a 60mm f/11 achromat is virtually free of false color at 30x. Venus as well as our own crescent moon were sharply defined with little false color (chromatic aberration). Galileo would have loved to use a telescope like this!

It was unnecessary to provide any specific cool-down time for the small refractor. The outside temperature was about 40 degrees (F) cooler than the inside temperature. Yet the image was sharp and crisp when I looked into the eyepiece. Smaller telescopes have some disadvantages, but they also have their advantages!

Polar Doubles Revisited

Last night I re-observed the double stars listed in my previous blog entry. The seeing was a bit better this time around. Sketches, with north carefully noted, were made of all five double stars. A magnification of 135x was used for all of the double star sketches.

Prior to the double star observations I trained the scope on Jupiter -- as an object to focus on prior to adjusting the scope in its cradle. Balance is more sensitive for my home-made alt-az mount than it is for my equatorial.

As the bright twilight gradually faded, more stars popped out in the vicinity of Jupiter. A sketch was made at 43x of Jupiter, its moons, and some of the background stars. The seeing varied from poor to extremely poor at this point in time, but it had improved noticeably by the time I trained the 13cm refractor on the double stars.

My work schedule prevents me from making a more detailed post or refining and uploading sketches at this point in time.

Saturday Evening: Venus in the West

After a cloudy day with intermittent, light precipitation I was greeted by a mostly clear sky after sunset. The tiny point of light near the bottom center of the image is Venus. Clicking on the image will reveal a somewhat enlarged view.

Venus and Mercury in Evening Sky

For the past three evenings I've managed to see these two planets low in the western sky shortly after sunset. Brilliant Venus has been the easier planet to spot. Dimmer Mercury has been between one and two degrees to the lower right of Venus.

Binoculars seem to be better suited for catching these two planets than a telescope. The sky has been too bright at prime observing time for Mercury to be seen with the unaided eye.

This evening I set up a small, 80mm f/5 refractor on the porch. Venus was easily visible, but trees blocked Mercury from view. From nearly the same location I managed to see both planets with 20x80 binoculars. This was primarily because my eye level with the binoculars was a little higher than the telescope -- just enough to bring Mercury above the trees.

On the previous two evenings I viewed the two planets with 8x42 binoculars as well as with the 20x80s. Mercury was easier to see with the 20x80s. Venus showed up easily with either pair of binoculars. Once I knew where to look, Venus could also be seen with the unaided eye.

On all three evenings I had to look thru thin clouds when observing Venus and Mercury. The clouds appeared to have formed near the time of sunset low in my western sky. They showed up as horizontal bands of varying thickness, but not thick enough to block the planets from view with binoculars.

Meanwhile, Jupiter shines brightly in the south-southeast. Jupiter and its brightest moons are not difficult to see with either tripod-mounted or steadily held binoculars.

What is a planet?

What is a planet? In my opinion any astronomical body that's essentially massive enough to maintain a spherical shape, but not massive enough to trigger a self-sustaining fusion reaction (becoming a star) should be considered a planet.

Looking over the known bodies in our solar system, it seems that a reasonable cut-off at the low end would be 10e20 (one with twenty zeros) kilograms. Some solar system bodies with a mass in the 10e19 range are reasonably spherical, others are not. Since it's desirable to have an unambiguous definition (based solely on mass - which is one of the most easily determined properties of solar system bodies) it seems reasonable to fix 10e20 kilograms as the lower limit for planetary status.

The upper limit would be more flexible (as far as mass goes). The primary criteria here is that the body in question is not a star - that is, it does not generate a self-sustaining fusion reaction. For objects otherwise similar to those in our solar system, this limit would likely lie within the 10e28 kilogram mass range.

Planet Classes can now be designated as:

Class 0 -- with masses in the 10e20 kilogram range

Class 1 -- with masses in the 10e21 kilogram range

Class 2

Class 3

Class 4

Class 5

Class 6

Class 7 -- with masses in the 10e27 kilogram range

Class 8 -- with masses in the 10e28 kilogram range

Jupiter would be a Class 7 planet. Earth would be a Class 4 planet. Pluto would be a Class 2 planet. Tethys (one of Saturn's moons) would be a Class 0 planet.

Bodies with masses less than 10e20 kilograms could be referred to as "subplanetary" and designated as lying within Subplanetary Class -1, Subplanetary Class -2, etc. for masses in the 10e19 and 10e18 kilogram ranges respectively.

Note that the location of an object is not relevant in this system. The object is classified the same regardless of whether it orbits a star or a planet. A Class 5 planet, for example, could even be adrift in interstellar space.

Jupiter's Family via 25x100 Binoculars

Shown above are two sketches of Jupiter and its brightest moons as observed on 1 August 2008 U.T. The uppermost sketch was made at 3:15 U.T. The lower sketch was made at 7:25 U.T. The lower star at the far left is an actual star, not one of Jupiter's moons. Europa was in transit across Jupiter's disk (and not visible in the large binoculars) at the time of the first sketch, but by the time I had started working on the second sketch it had reappeared off Jupiter's preceding (western) limb.

Jupiter's North and South Equatorial Belts (the dark bands running parallel to Jupiter's equator) were visible in the tripod-mount 25x100 binoculars. Seeing conditions were rather poor on this night. Jupiter's moons and the various field stars appeared to twinkle due to earth's unsteady atmosphere. A haze (most likely from forest fire smoke) seemed to fill much of the sky as well.

Binocular & Small Telescope Session

Date: 13 January 2008
Time: 3:05: 3:25 U.T.
Binoculars: 8x42 & 20x80
Telescope: 80mm f/5 Achromat
NELM: 6.0 to 6.5

Comet Holmes was visible to the unaided eye, but it was significantly better with the binoculars. A crescent moon was above the horizon to the southwest, but appeared to have little if any adverse effect on the evening's viewing. Clouds were approaching from the west.

Mars looked like a tiny, yellow-orange disk in the ST-80 at 105x without filters. Markings on the planet were difficult to see with the small telescope, but they became easier when the planet's brightness was reduced and contrast was increased via the use of a #23A Light Red filter. The #23A filter transformed the color of the planet to a orange-red. Normally I wouldn't consider using such a small telescope on Mars, but I was curious concerning what could be seen with minimal optical aid. Without any filters, the ST-80 is likely to disappoint just about anyone when viewing Mars. With filters, a fair amount of patience, a bit of observer experience (and a good solid mount!) it's possible to conduct some regular study of Mars when the planet is near opposition, but I would strongly suggest that any interested observer use a larger, higher quality telescope.

Surface markings were ill-defined and difficult to pinpoint in location due to the telescope's small aperture, the relatively low (for Mars) magnification, the less than perfect (achromatic) optics, and the somewhat uncooperative, home-made mount (One of these days I should add a friction adjustment to the mount's altitude axis).

After Mars I lowered the magnification to 22x using a wide-angle eyepiece. I took quick looks at the Great Orion Nebula, the Andromeda Galaxy (and its two nearby satellite galaxies), M33, and Comet Holmes. The ST-80 and its home-made, alt-az mount seem to perform at their best when used for such low magnification purposes. All of these objects were very pleasing in the small, short telescope. Comet Holmes looked like a fairly bright, diffuse (amorphous) cloud occupying approximately one-third of the 3.34 degree field of view.

In the course of the evening's short session I never felt any need to uncap the telescope's finder. It was easy enough to point the telescope at Mars, etc. with the 22x eyepiece in place prior to switching to higher power.

I brought the telescope and mount inside, leaving the tripod out in case I decided to try out a 102mm (4-inch) SCT on Mars. Later, when I went back outside, I discovered a cloud covered sky and frost on the tripod. It was clearly time to bring the tripod inside and wait for another clear night.

Jupiter 11 Sept. 2007 U.T.

Date: 11 September 2007 U.T.

Time: 1:35 - 1:47 U.T.

Telescope: 13cm refractor

Magnification: 138x

Seeing: Very Poor - Fair

NELM: Twilight

Temperature: +68 F (+20 C)

Shown above is my rough, at-the-telescope sketch of Jupiter. North is up. Preceding is to the right. As part of an experiment a 1.25 inch, 90-degree, erect-image diagonal was used. Also in use was a new filter wheel; but no filters were used during the making of the above sketch. The filter wheel was loaded with various filters for deepsky use; but the planned observing session was cut short due to clouds and high humidity.

Jupiter's North Equatorial Belt was the darkest feature on the planet. It had a subtle, somewhat rusty color. The other belts on the planet appeared to be blue-gray in color. The following limb of the planet was somewhat darker than the preceding limb due to the sun angle (a phase effect).

At times the seeing was very bad, leaving nothing more than the NEB visible on the planet. At other times the seeing was fair, approaching good. The seeing was both, worse at times and better at times than it was for my previous Jupiter observation; but for the most part it was better.

Jupiter & Lambda Ophiuchi

Date: 03 September 2007 U.T.
Time: 2:03 - 2:15 U.T. (Jupiter)
Telescope: 130mm refractor
Magnification: 138x (Jupiter)
Filter: Moon-SkyGlow (Jupiter)
Seeing: Poor to Fair
NELM: Twilight (Jupiter)
Temperature: +83 F (+28 C) (Jupiter)

The above rough (at the telescope) sketch of Jupiter has North up and Preceding to the left.

Due to poor seeing conditions small-scale, moving "ripples" were constantly visible around the limb of the planet. The "star" to the upper right of the planet is Io, one of Jupiter's moons. A little later in the evening Io was seen in transit across the planet's disk. The following limb of the planet was slightly darker than the preceding limb due to the sun angle (a slight phase effect). At times more detail was visible; but under the circumstances (poor seeing and a relatively quick observation and sketch) some of the details shown may not be particularly accurate.

The planet's North Equatorial Belt (the darkest belt on the planet) appeared brownish-red in color. Other features had colors that were too subtle to differentiate from shades of gray.



After completing the Jupiter observation I observed and sketched Lamda Ophiuchi A&B, a close double star. The above sketch (greatly enlarged from the telescopic view) shows this double with North up and West to the left. A #82A Light Blue filter sharpened the view a bit under the relatively poor seeing conditions. The "A" star appeared to have a yellow or yellow-orange color while the "B" component appeared bluish. A narrow gap was visible between the two stars during intervals of somewhat improved seeing conditions. A weak, broken, diffraction ring was also visible at times around the two stars. A magnification of 218x was used for this observation.

Venus - 13 July 2007

Date: 13 July 2007 U.T.

Time: 2:50 U.T.

Telescope: 80mm f/5 achromat

Magnification: 85x

Filter: #56 Light-Green

Seeing: Fair

NELM: Bright Twilight

Temperature: +80 F (+27 C)

The above (mirror-reversed) sketch has North up and Preceding to the left. It shows the basic appearance of Venus as seen in a small telescope.

As the planet's phase changes from full to quarter (half) to crescent to new the planet's disk appears larger and larger. When Venus's phase is near full the planet is on the far side of the Sun. When the planet is a crescent it's on the near side of the Sun. These changes have a dramatic effect on the apparent size of the planet as seen in a telescope.

Currently Venus is moving closer to Earth as it orbits the Sun. As a result it's appearing increasingly larger as seen in a telescope and its phase is becoming a thinner crescent.

Venus is currently visible in the evening sky in the west immediately following sunset. It's by far the brightest object in that area of sky and readily visible to the unaided eye.

Venus & Saturn - Together

Date: 2 July 2007 U.T.
Time: 2:40 - 3:40 U.T.
Telescope: 80mm f/5 (ST-80) refractor
Magnifications: 22x, 24x, 39x, 54x
Seeing: Fair
Transparency: Good
NELM: Bright Twilight
Temperature: +77 F (+25 C)

Venus and Saturn shared the same low to medium powered telescopic field this evening. Venus was a brilliant, white crescent while Saturn appeared roughly half as large and much fainter. At all of the listed magnifications it was possible to observe both planets simultaneously in the same field of view.

Venus was visible to the unaided eye prior to sunset; but Saturn proved difficult in the telescope until after the sun had set. Later, in a darker sky both planets became easily visible to the unaided eye in the western, evening sky.

A sketch was made of the relative sizes and orientations of the two planets, but in order to show both together, as they appeared in the telescope it would be necessary to render the planets as very tiny objects.

The small, portable telescope was set up on my north porch for this evening's observation.

Venus - 19 June 2007

Date: 19 June 2007 U.T.
Time: 22:40 - 22:50 U.T.
Telescope: 102mm SCT
Magnification: 72x
Seeing: Poor - Fair
Transparency: Partly Cloudy (thin clouds)
NELM: Daytime observation
Temperature: +86 F (+30 C)

The above is my rough, at-the-telescope sketch. North is up. Preceding is toward the left. Disk details are questionable under the seeing conditions; but the south cusp was suspected to be somewhat brighter than the north. The limb was brighter than the terminator. The planet appeared white against the blue daytime sky.

I went outside around 4:00 pm local time, looked up, saw the Moon, looked a few degrees west of the Moon and spotted Venus with the unaided eye. Afterwards I set up the telescope and made the above observation.

Observational Slow-Down:
Lately a combination of factors have slowed down the frequency of my astronomical observations. Among those factors is increased activity in my other (long neglected) hobby - chess. If my renewed interest in chess continues long enough I may start an additional blog devoted to that interest.

Sharing the View

Date: 3 June 2007 U.T.
Time: 3:00 - 5:00 U.T.
Telescope: 13cm refractor
Magnifications: 35x, 90x, 170x, 240x
Filters: #56 and #58 Green (for Venus only)
Seeing: Good
Transparency: Bright and darkening twilight

After many cloudy or otherwise missed nights everything fell into place for a good evening. The telescope was set up on on an equatorial mount with an electric RA drive. The motorized tracking simplified sharing the view with two guests.

Venus was our first target, and for a long while our only target. The seeing was very steady with the refractor -- one of the benefits to using a relatively small telescope. The planet's sharply defined quarter (or 'half-moon') phase was easily visible to everyone present.

The green filters helped cut down the brightness of the brilliant, white planet to a more tolerable level. We took turns studying the planet at 90x. Through the use of questions and answers, it looked like the guests may have been able to perceive some of the subtle markings in the Venusian atmosphere.

Eventually the sky darkened enough for the younger guest to spot Saturn in the twilight sky. We shared views at 35x and gradually worked our way up to 240x. Titan was immediately noticed near the ringed planet. After the sky had darkened a bit more we saw three more of Saturn's moons. The two moons between Titan and the planet, one above the other, were later identified as Tethys (to the north) and Rhea (south of Tethys). Just off the north-following limb of the planet was Dione.

At the higher magnifications the ring was visible in front of the planet. The guests also noticed Saturn's South Equatorial Belt (SEB). Cassini's Division presented a challenge for the guests, but they eventually succeeded in seeing this division between Saturn's A and B rings -- at least on one side of the ring system. The shadow of the planet on the ring system proved to be a bit more of a challenge for the guests.

After Saturn we took a look at the globular cluster, M13 in Hercules. Next was the Ring Nebula (M57) in Lyra. The final object was Albireo (Beta Cygni) -- one of the northern hemisphere's "showpiece" double stars.

Twilight had still not quite ended by the sessions end. Nevertheless, part of the summer Milky Way was seen. We also saw at least one meteor, an airplane and at least one satellite.