Sunspot - 29 April 2007

Date: 29 April 2007 U.T.
Time: 15:50 - 16:20 U.T.
Telescope: 102mm SCT
Magnification: 90x
Filter: Baader Solar Filter (Objective)
Seeing: Fair
Transparency: Thin (Cirrus) Clouds
Temperature: +71 F (+22 C)

The above sketch shows the same sunspot that was observed two days earlier. North is up. Preceding is to the left (mirror reversed image).

A comparison of the this sketch with the previous sketch will give an idea of how quickly the appearance of a sunspot can change. Even during the thirty minute's it took to make this observation minor changes could be noticed.

Sunspot - 27 April 2007

Date: 27 April 2007 U.T.
Time: 18:56 - 19:12 U.T.
Telescope: 102mm SCT
Magnification: 90x
Filter: Full Aperture, Baader, White-Light Solar Filter
Seeing: Fair
Transparency: Mostly Clear with Scattered Clouds
Temperature: +67 F (+19 C)


The above sketch shows the sunspot that was near the Sun's following limb on this date. The view is mirror-reversed. North is up. Preceding is to the left.

A mild wind was blowing during this observation; but the curved wall of the "Colosseum" blocked most of it. Clouds briefly blocked the Sun a couple of times during the observation.

Venus & Saturn with ST-80

Date: 25 April 2007 U.T.

Time: 2:31 - 4:42 U.T.

Telescope: 80mm f/5 refractor

Magnification: 105x

Filters: #58 Green, #12 Yellow

Seeing: Good

NELM: Bright Twilight (later 5.3)

Temperature: +45F (+7 C)

Above is Venus as seen with the small refractor from 2:31 until 2:36 U.T. North is up. Preceding is to the left. A 90 degree, mirror diagonal was used, resulting in a mirror-reversed image. A #58 Green filter was also used for this observation.

The planet's phase was slightly gibbous, almost quarter. The sunlit limb of the planet (to the left) appeared to be a little brighter than the rest of the planet. Two darker regions were suspected as shown in the above sketch.

Above is Saturn with Titan to the upper right. This observation was made from 4:22 until 4:42 U.T. As with Venus, north is up; and preceding is to the left. A #12 Yellow filter was used for this observation. (The Venus and Saturn sketches are not to the same scale!)

Visible features include the C-ring where it crosses in front of the planet, the shadow of the planet on the ring system, the Cassini Division (appearing as ill-defined, somewhat darker arcs near the outer edges of the ring system), and the South Equatorial Belt (the subtle, dark 'band' running parallel to the planet's equator (and ring system) in the planet's southern hemisphere.

After observing Saturn I took a look at Earth's Moon, which was near Saturn in the sky. A tremendous amount of detail was visible at 105x. Some of the lunar mountains were casting long, pointed shadows. I was tempted to sketch the crater Cassini; but instead decided to end the session early.

Two Galaxies and a Planet

Date: 17 April 2007 U.T.
Time: 1:50 - 5:50 U.T. (with breaks)
Telescope: 30cm Newtonian
Magnifications: 150x (Venus)
160x (M81)
250x (M82)
Filters: Moon-SkyGlow & #58 Green (Venus)
None (Galaxies)
Seeing: Fair to Poor
NELM: Bright Twilight (Venus)
6.5 (Galaxies)
Temperature: +43 F (+6 C)

Venus was observed and sketched near sunset. The planet's gibbous (approaching quarter) phase was obvious. Subtle markings were difficult to pin down due to relatively poor seeing conditions. Nevertheless, I was able to complete a rough sketch.

M81, a bright, spiral galaxy in Ursa Major was observed and sketched at 160x. This galaxy had a small, bright, central region surrounded by a fainter, oval glow. Upon closer inspection one of the galaxy's spiral arms became evident on the north following side of the galaxy's nucleus. Other arms were suspected as glimpses were caught of darker regions within the faint glow of M81's outer regions.

M82 is a bright, irregular galaxy near M81 in Ursa Major. A few brighter and darker regions were seen without much difficulty in this interesting, cigar-shaped galaxy.

Green Venus & More

Date: 14 April 2007 U.T.
Time: 1:50 - 2:06 U.T.
Telescope: 30cm Newtonian
Magnification: 150x
Filters: Moon-SkyGlow & #58 Green (simultaneously)
Seeing: Fair to Poor
NELM: Bright Twilight
Temperature: +45 F (+7 C)


The above sketch gives a better idea of how Venus looks when using a Green filter (with or without an MSG filter). In the sketch, South is up and Preceding is to the left. Seeing conditions were a little worse than they have been for most of my earlier observations of this planet. The cause might be related to warmer daytime temperatures. Seeing conditions seemed to have improved later in the night when I targeted other objects.

Using words, the south polar region of the planet seemed to have a bit more white than elsewhere on the planet. A large dusky region was suspected in the mid-southern latitudes. A smaller dusky region was suspected in the mid-northern latitudes. The limb region away from the terminator appeared somewhat brighter than the rest of the planet.

The highlight of this night's observing were my later, deep-sky observations. Seeing conditions improved, and transparency proved to be very good some time after the Venus observation. Careful observations and sketches were made of NGC 3242 (The Ghost of Jupiter) at 250x and NGC 4565 (The Needle Galaxy) at 120x. Both objects were nicely shown by the 30cm Newtonian.

By the time I had completed the above observations (6:07 U.T.) with a break between each, I had grown rather fatigued. At one point I had decided to attempt to stay awake until Jupiter reached my south meridian; but fatigue ended up the winner of that battle and I eventually called it a night.

A Brief Binocular Session

Date: 13 April 2007 U.T.
Time: 4:00 - 4:30 U.T.
Binoculars: 20x80 (hand-held)
Seeing: Good
NELM: 6.4 (or better)
Temperature: +29 F (-2 C)

Three relatively bright non-Messier objects were targeted this evening. The first was NGC 2403. This galaxy was very easy to see with the large binoculars. It looked like a small, distinct patch of nebulosity and was more readily visible than many of the Messier galaxies.

Next was NGC 3242 "The Ghost of Jupiter". This object is a small, but very bright planetary nebula. Through the binoculars it resembled a slightly bloated, slightly fuzzy star. The detailed charts in the Uranometria Atlas allowed for easy identification via the surrounding star field.

Last on my list was NGC 4565 "The Needle Galaxy". This well-known, edge-on, spiral galaxy was visible in the binoculars as a small, faint, elongated glow with a somewhat brighter middle.

For whatever reason, I found myself looking in the vicinity of M81 with the unaided eye. I noted the nearby star pattern as plotted on atlas charts. All of the nearby stars plotted in the Cambridge Star Atlas (2nd edition) were visible to the unaided eye. In particular, I noted 24 Ursae Majoris and the unlabeled star between 24 and M81. At times I suspected a tiny, faint glow at the exact spot where M81 was supposed to be.

I'm not positive that I saw M81 with the unaided eye on this evening; but I'll try to remember to look for this relatively bright galaxy from time to time (with the unaided eye) when conditions are favorable.

M 104 (The Sombrero Galaxy)

Date: 8 April 2007 U.T.
Time: 5:17 - 5:40 U.T.
Telescope: 30cm Newtonian
Magnifications: 250x and 120x
Seeing: Fair to Poor
NELM: 6.5
Temperature: +22 F (-6 C)

The Sombrero Galaxy is a beautiful object! It consists of a small, bright, central core surrounded by an elongated (east-west), fainter glow. The glow is widest in the central region, growing progressively narrower further out. Just south of the core a narrow, dark, dust-lane was visible running the length of the galaxy. The galaxy's glow to the south of the dust lane was considerably fainter than the glow to the north. The galaxy appeared to be slightly brighter along its western extension than along its eastern extension.

The overall shape of M 104 was similar to that of two saucers with their rims in contact with one another -- viewed edge-on.

A magnification of 250x was used for most of the observation and sketching. Later I dropped the magnification down to 120x. It may have been possible to see the faint, outermost glow of the galaxy a little better at the lower magnification; but details showed up better at the higher magnification.

Venus (08 April 2007)

Date: 8 April 2007 U.T.
Time: 1:55 - 2:10 U.T.
Telescope: 30cm Newtonian
Magnification: 150x
Filters: Moon-SkyGlow and #58 Green (simultaneously)
Seeing: Fair
NELM: Bright Twilight
Temperature: +29 F (-2 C)

The gibbous disk of Venus was sharply defined. Suspected, subtle darkenings on the planet's disk were sketched. The planet appeared to have a bright, featureless, narrow rim around (just inside) its limb everywhere excepting the planet's terminator. The largest suspected dusky marking was in the planet's southern hemisphere. A possibly connected, smaller, dusky feature was suspected in the planet's north-preceding quadrant. Two subtle, dark 'notches' were suspected along the planet's terminator. One was near the center of the terminator. The other (slightly larger) notch was a bit more to the north.

It's difficult to be certain of suspected features in the Venusian clouds. The planet appears to be almost without visible markings. The suspected markings mentioned above may or may not be actual features in the Venusian atmosphere.

My typical procedure (and the one followed on this evening) is to set up the telescope prior to sunset after the wall of my open-air observatory is casting a high enough shadow to place the telescope's lower section (containing the large, primary mirror) in shade. Sunlight shining on that section of the telescope might prolong cool-down of the mirror. (The telescope has a built in cooling fan; but I've never felt a need to use it.) The observation of Venus began shortly after sunset, after the telescope had been outside for over an hour.

Venus (27 March 2007)

Date: 27 March 2007 U.T.
Time: 1:30 - 1:50 U.T.
Telescope: 80mm refractor
Magnifications: 20x, 40x, 67x
Filters: None, #56
Seeing: Fair
NELM: Bright Twilight
Temperature: +53 F (+12 C)

Tonight's observation was made using a relatively simple, 80mm, f/5 achromatic refractor. Such telescopes are occasionally used by individuals just starting out in amateur astronomy. More experienced amateurs sometimes use such instruments as quick-look, grab-and-go telescopes or even as finders for larger telescopes.

I chose this particular telescope this evening for the following reasons: Predictions called for bad seeing, wind, and increasing clouds. I wanted to see what Venus looked like through a small and relatively low quality telescope on a relatively poor night.

At 20x Venus looked like a tiny blob of bright light surrounded by a substantial, mostly purple glow. Yellow-green light was occasionally also seen around the planet. These colors were due primarily to the telescope's achromatic objective lens. Such objectives fail to bring all colors to the same focus; but often, particularly when looking at much less brilliant objects, this defect can go unnoticed. At 20x the planet's disk could not be made out with any degree of certainty.

At 40x the planet's disk was clearly visible. It was difficult, but possible to discern the planet's gibbous phase. False color surrounded the planet just as it did at 20x. The planet's normally white disk appeared somewhat yellowish due to the 80mm achromat's chromatic aberration.

At 67x the planet's disk was clearly visible; and its gibbous phase was clearly discernable. The wind was strong enough to shake the telescope a little; but it wasn't strong enough to compromise the observation. The false color extended outward from the planet in all directions a distance of at least three planetary diameters. The disk of the planet was only mildly discolored (like it was at 40x).

At 67x with a #56 Light Green filter the planet looked much better. Green was the only color visible with the filter. For all practical purposes the filter effectively eliminated the achromat's false color. The purple glow around the planet was gone and replaced by a much weaker greenish glow. The seeing conditions caused the planet to jiggle a little as if it were made of jello; but the jiggling was quite mild. The planet's gibbous phase was well defined and obvious.

Moon - Unaided-Eye

Date: 27 March 2007 U.T.

Time: 1:15 U.T.

Instrument: Unaided-Eye

Temperature: +55 F (+13 C)

As the above sketch shows, a telescope is not always necessary in order to make observations of other worlds. North is up and lunar east is to the right in the sketch.

Predictions called for bad seeing, wind, and increasing clouds; but meanwhile the sky was mostly clear so I decided to skip out on setting up a large telescope and instead make a quick, unaided-eye observation of the Moon. After all, it's often said that one can see more on the Moon with the unaided-eye than one can see on Mars with the aid of a telescope.