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.

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.

Lunar Limb - Daylight Observation

Date: 24 August 2008

Time: 17:18 - 17:33 U.T.

Telescope: 80mm f/5 achromat

Magnification: 70x

Filter: Polarizing

Seeing: Fair - Good

NELM: Daylight

Temperature: +85F (+29C)

Wind: Calm

Transparency: Very Good (cloud-free sky


The above sketch shows two lunar mountains that were silhouetted against the darker sky background. North is up. Lunar East (preceding) is to the left in this mirror-reversed view. The sketched region is at 90 degrees west longitude and approximately 12 or 14 degrees south latitude. The moon was a fat, waning crescent at the time of the observation.

Not shown in the sketch is Lacus Aestatis which was seen as a dark patch to the left of the lower mountain peak beyond the sketched region. A very rough, larger scale sketch was made to facilitate finding this region on a lunar map. That sketch showed Lacus Aestatis, Cruger, Grimaldi, and Riccioli all as dark patches.

The sun was still spotless today. I used the 80mm refractor at 24x. A glass, white-light solar filter covered the front of the telescope. The filter gave the sun a soft, golden, peachy color. There was something aesthetically pleasing about observing a spotless sun through a telescope with one's own eyes.

Shooting the Moon

Shown above is a 'snapshot' of this evening's gibbous moon. It was taken under poor seeing conditions with a DSLR camera attached to a 102mm Schmidt-Cassegrain telescope (about 700mm focal length). This was one of two experimental images I took of the moon. The telescope's tripod was set up on my south porch - not the most stable of platforms, but sufficient for experimental purposes.

The Perseid Meteor Shower should be near its peak after the moon sets later tonight. If you read this early enough (Monday night - very early Sunday morning), have adequate sky conditions, and can affort to lose the sleep (a lot of 'ifs') you might want to spend some time lying back, staring at the sky, and counting meteors.

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.

Maskelyne (lunar crater)

Date: 25 March 2007 U.T.

Time: 3:19 - 4:05 U.T.

Telescope: 30cm Newtonian

Magnification: 145x

Filter: Moon-SkyGlow

Seeing: Fair to Poor

NELM: 5.6

The above sketch shows Maskelyne, an oddly-shaped, 24km wide crater in the south-central portion of the Moon's Sea of Tranquility.

This is my first lunar observation with the MSG filter. The filter appeared to remove the yellow color from the Moon, creating more of a black and white landscape; but I didn't notice any improvement in visible detail.

Lunar Eclipse

Date: 4 March 2007 U.T.
Time: 1:03 - 1:26 U.T.
Telescope: 102mm SCT
Magnification: 34x
Seeing: Bad
NELM: Bright Twilight
Temperature: +37 F (+ 3 C)

The rising Moon was spotted in the trees at 1:03 U.T. -- just nine minutes before the end of the umbral phase of the eclipse. The Earth's shadow along the Moon's eastern limb was obvious in the telescope as well as to the unaided eye.

The seeing was very unsteady. Rapidly moving undulations were in constant motion along the limb as well as over the face of the Moon.

Colors: The Moon was a golden, yellow-orange color outside the umbra. No colors other than shades of gray were noticed near and within the umbra.

Observational Highlights: As occasionally happens in this hobby, I started out with the objective of observing one thing (the final phase of an eclipse) and ended up with a bit more. Due to atmospheric refraction the rising Moon appeared noticeably 'squished'. It appeared shorter along its vertical axis than along its horizontal axis. But of greater interest were the colors (due to atmospheric refraction) hugging the lunar limb. From top to bottom along the lunar limb the colors were: blue, green, yellow, orange, and red. As the Moon rose higher in the sky these colors became less noticeable.

The Penumbra and Clouds: An attempt was made to observe how long the Earth's penumbra could be positively distinguished on the Moon after the umbral phase of the eclipse had ended. Unfortunately, at 1:25:30 U.T. a thin cloud began covering the Moon. Up until that point in time it was possible to distinguish (with telescope as well as with the unaided eye) the effect of the penumbra of the Earth's shadow on the Moon. It seemed ill-advised to continue the observation with the complicating effect of clouds.

Hercules & Atlas

Date: 25 January 2007 U.T.
Time: 21:08 - 22:00 U.T.
Telescope: 102mm SCT
Magnification: 72x
Filters: Polarizing
Seeing: Fair to Good
NELM: Daytime
Temperature: +51 F (+11 C)


The above sketch shows the region around Hercules (bottom) and Atlas. North is to the upper right; and west is to the lower right in this mirror-reversed sketch. This sketch is the actual 'at-the-telescope' sketch. A polarizing filter helped to improve contrast for this daytime observation of the first quarter Moon.

Daytime observations have some advantages over night observations. There's no need to use artificial lighting for note taking and sketching. The temperature is more comfortable; and it's often possible to catch the object at a higher altitude in the sky.

Day observations also have disadvantages: Contrast is lower for lunar features; and care must be taken in regards to the Sun.

Theophilus - Revisited

Date: 24 January 2007 U.T.
Time: 21:15 - 22:08 U.T.
Telescope: 102mm SCT
Magnification: 72x
Seeing: Good
NELM: Daytime
Filters: Polarizing
Temperature: +52 F (+11C)

The above sketch Shows the ring mountain Theophilus which is 100km (62 miles) in diameter. Nearby is the 28km (17 mile) diameter crater Madler. North is toward the upper right. West is toward the lower right in this mirror-reversed view. The approximate location on the Moon is 11 degrees south latitude, 28 degrees east longitude.

I'm somewhat more pleased with this sketch than I've been with my other recent lunar sketches. Sometimes it doesn't take much practice to make a difference; but usually it takes more than the few (lunar sketches) that I've made this year!

I was surprised at the temperature! Several years ago I could expect temperatures in the neighborhood of minus 20 degrees F. for a week or two at some point in the December through February time-frame. Temperatures in the 50s at this time of year are kind of scary! Of course, the temperature could still drop like a rock at any time . . .

Lunar Observation - Atlas

Date: 23 January 2007 U.T.
Time: 00:01 - 00:28 U.T.
Telescope: 102mm SCT
Magnification: 94x
Seeing: Fair
NELM: Evening Twilight
Temperature: +37 F (+ 3 C)



The above sketch shows the 87 kilometer (54 mile) diameter lunar crater, Atlas. North is to the upper right. West is to the lower right. The sketch shows the mirror-reversed telescopic view. I'm still not very happy with my lunar sketches; but the only solution is more practice.

My weather this evening was (according to the Clear Sky Clock) supposed to be: Bad Seeing, Poor Transparency, 30% cloud cover, and strong wind; but the sky was clear. So I took out a small telescope for a quick lunar session.

Last night I set up the 30cm Newtonian (or as Ann referred to it: "The Big Gun") shortly before sunset; but the weather worsened and I ended up bringing the frost-covered scope back inside after several hours of waiting. The weather proceeded to improve afterwards; but by that time it was too late. I decided to get some sleep.

Theophilus - Lunar Observation

Date: 07 January 2007

Time: Centered around 12:00 U.T.

Telescope: 80mm f/5 refractor

Magnification: 65x

Seeing: Fair-Good

NELM: 5.1 or better

Temperature: +20 F (-7 C)

The above sketch shows Theophilus (the large formation) and the nearby crater, Madler. West is toward the upper right. South is toward the lower right in this mirror-reversed view. Some of the surrounding details were very hastily rendered, resulting in a more inaccurate sketch. I really need to start using my larger refractor, on it's sturdier (tracking) mount while I sketch comfortably seated. The at-the-telescope sketch that the above was based on was made while standing. The telescope was on a homemade alt-az mount that was set up on a porch -- not the best of situations! Nevertheless, I wanted to continue with a bit of lunar observing and sketching.

Bailly -- a Lunar Observation

Date: 02 January 2007 U.T.
Time: 4:30 - 5:00 U.T.
Telescope: 80mm f/5 refractor
Magnification: 65x
Seeing: Good
NELM: 4.5
Temperature: +15F (-9C)



The above sketch is 'mirror reversed' -- the way things look when a simple, mirror diagonal is used with an astronomical refractor. East is roughly up. North is roughly to the right. The moon was a little more than one day away from being in its full phase.

At 65x the entire moon was visible in the refractor's FOV. Yet, the sketch shows a very small fraction of the moon's visible surface. The largest feature in the sketch is the walled-plain "Bailly." Bailly is the largest walled-plain on the Earth-facing side of the Moon. Its position on the Moon is: 66.8 degrees South latitude, 69.4 West longitude. The three large craters shown above Bailly are, from left to right, Kircher, Bettinus, and Zucchius. Those craters are each roughly 70km (44 miles) in diameter.

The sketch was fairly quickly executed and is the first lunar sketch I've made in quite a long time. A quick comparison of the above sketch with the actual 'at the telescope' sketch reveals that Bailly appeared more foreshortened with a narrower floor and walls than depicted in the sketch above. Perhaps I'll use the original for a somewhat more accurate sketch at some later date . . .

As I worked on this observation I found myself wishing I had set up a larger, higher quality telescope. Nevertheless, the sketch gives some idea of what can be seen on the moon with a small, relatively inexpensive telescope.

The telescope was set up on a porch. My fully shielded porch light (which is almost always turned off) was turned on to provide brighter (than that provided by moonlight alone) illumination on my clipboard.