Monday, November 12, 2018

Idaho Skies Transcript for November 16th, 17th, and 18th

RACHEL
Welcome to Idaho Skies for November 16th, 17th, and 18th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
On the evening of the 16th, the third quarter moon forms a triangle with Mars and Fomalhaut.

PAUL
The moon just left the presence of Mars on the 15th. That means Mars now appears to the right of the moon. You can’t misidentify Mars, it’s relatively bright and yellowish-orange in color. While binoculars can’t show you detail on Mars, they are useful for viewing the cratered surface of the moon. The lunar southern hemisphere is where you’ll see most of your craters. Especially along the terminator, or boundary between day and night.   

RACHEL
Fomalhaut is the only star appearing to the moon’s lower left corner. The star is among the brightest star in the sky, but its position makes it appear much fainter. That’s because the light of Fomalhaut must travel through much more atmosphere when it’s that close to the horizon. Not only does air absorb starlight, it also scatters it. So Fomalhaut will usually twinkle more than other bright stars.

PAUL
Fomalhaut is a first magnitude star. Greek astronomers classified the apparent brightness of visible stars on a magnitude scale that runs from 1st to 6th. To the Greeks, first magnitude stars were the brightest and 6th magnitude were the faintest stars visible to the unaided eye. Modern astronomers have put this magnitude scale on a firm mathematical scale and now the brightest stars are magnitude zero or even negative numbers.   

RACHEL
The apparent magnitude of a star depends on two factors, a star’s intrinsic brightness and its distance away. Fomalhaut is over 16 times brighter than the sun and 25 light years away. If the sun were as far away as Fomalhaut, we could still see it, but only in dark skies. The sun at 25 light years away would appear around 4th magnitude, which is impossible to see from downtown Boise. 

PAUL
That’s Idaho Skies for the 16th, 17th, and 18th of November.

RACHEL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for November 14th and 15th

PAUL
Welcome to Idaho Skies for November 14th and 15th. We’re your hosts, Paul…

RACHEL
…and Rachel.

PAUL
Venus and Mars are making appearances on this episode of Idaho Skies.

RACHEL
First, there’s Venus. The Morning Star is slowly sailing past Spica for the next few days. Stargazers going outside at around 7:00 AM will find Venus and Spica close together in the low east-southeast. If checked every day or two, their apparent motions relative to each other will be quite easy to see. A pair of binoculars will come in handy making this observation. 

PAUL
Next up in the batter’s box is Mars. Mars is an evening planet this fall and winter. Meaning stargazers don’t have to get up early to see it. Because of our planet’s smaller orbit, Earth is speeding ahead of Mars and putting some distance between it. But Mars is still very bright. If you’re uncertain where Mars is located, or want confirmation, then look for the moon on the evening of the 15th.

RACHEL
Mars appears to the upper left of the moon. Their distance apart is two degrees. For a sense of perspective, the moon appears to be half a degree across. So the distance between the moon and Mars is four times larger than the moon’s apparent diameter. Since most binoculars have a field of view of 7.5 degrees, both the moon and Mars will appear together in your binoculars.   

PAUL
Mars, Venus, and Earth make up the solar system’s three terrestrial planets with atmospheres. Interestingly, they have a near geometric progression in their atmospheric densities. Earth’s atmosphere is 142 times greater than Mars’ and Venus’ atmosphere is 92 (times) greater than Earth’s. Both Mars and Earth have variable surface wind speeds because of the extreme difference in t heir surface temperatures. Since Venus is uniformly hot day and night, its surface winds are always very light.     

RACHEL
That’s Idaho Skies for the 14th and 15th of November.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul…

RACHEL
…and Rachel.

PAUL
Dark skies and bright stars.

Idaho Skies Transcript for November 12th and 13th

RACHEL
Welcome to Idaho Skies for November 12th and 13th. We’re your hosts, Rachel…

PAUL
…and Paul.

RACHEL
Venus is the Morning Star this month.

PAUL
The planet Venus was named after the Roman goddess of love and beauty. But little did the Romans know the true nature of this planet. Had they known, they might have named the planet Pluto after the god of the underworld. Astronomers last century knew that Venus is just a bit smaller than Earth. It’s so close to Earth in properties that they thought its surface might be covered with swampy life forms.   

RACHEL
Venus is a terrestrial planet, so it has a solid surface made of rock. The surface is volcanic and primarily basalt like we have in Idaho. Curiously, there are very few craters on the surface of Venus. Compare this to the moon, which is packed with craters, especially in its Southern hemisphere. Astronomers use crater density measurements to estimate the age of a surface.   

PAUL
The more craters per square mile, the older the surface. That gives a relative age for the region, or a way to determine that one region is older than another. Since the rate of crater formation is known, absolute ages can be estimated. In other words, how long a region has sat undisturbed can be estimated from the number of craters visible on its surface.

RACHEL
Unlike the old surfaces of Mercury, the moon, and Mars, Venus has very few craters. So astronomers estimate that its surface was covered over in extensive, planet-wide lava flows only 300 to 600 million years ago. This could be common on large planets that don’t experience plate tectonics. So instead of earthquakes and mountain building, massive amounts of lava may instead erupt and completely cover the planet’s surface.   

PAUL
That’s Idaho Skies for the 12th and 13th of November.

RACHEL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com

For Idaho Skies this is Rachel…

PAUL
…and Paul.

RACHEL
Dark skies and bright stars.

Sunday, November 11, 2018

UAVSonde Data for NearSys Station, 11 November 2018

The UAVSonde was launched at 14:00 MST today to collect data. Images indicate the visibility is at least 50 miles. The tilt in the images, especially east-looking one indicates there was a lot of wind at Flight Level 4. The upper troposphere is becoming more humid on account of the increasing amount cirrus clouds and the longer contrails present.

Conditions at the surface were,
Temperature: 54.5 degrees
Relative Humidity: 24.6%

At Flight Level 4:
Temperature: 53.2 degrees
Relative Humidity: 22.4%

East

North

South

West

24-hour Temperature and Relative Humidity for NearSys Station, 10 November 2018

In the chart below, it can be seen where the sun shield for the datalogger was blown over between noon and 4:00 PM. This means the datalogger was exposed to direct sunlight During this time. During this time frame, NearSys Station experienced partly cloudy skies which gave rise to the fluctuations observed in the temperature.

Saturday, November 10, 2018

24-hour All-sky LED Photometer for NearSys Station, 10 November 2018

The LED Photometer required two repairs before it could start collecting data again. So there have been no reports since May. I finally had time and inclination inclination to troubleshoot and repair it. Below is the proper output from the working photometer. It can be seen that between 2:00 and 3:30 PM MST NearSys Station experienced partially cloudy skies.

Unlike past reports, the photometer now includes red data. However, the photometer still operates from a four "AAA" alkaline cell pack. So I plan to switch it and the UV-B Photometer over to a 5V rechargeable battery pack. Then perhaps place them inside the weather-proof can I partially 3D designed and built. Then assemble the GPS recorder for the buoy???


Monday, November 5, 2018

24-hour LED Photometer for NearSys Station, 5 November 2018

The LED Photometer is finally working again. But I still need to find out what's going on with the red LED, it's not producing an output. Perhaps it's a bad trace.

From the chart below, it's apparent that we had partly cloudy skies.