Spirit and Opportunity

The Mars Exploration Rovers Spirit and Opportunity landed on Mars on January 4, 2004 and January 25, 2004, respectively.  Spirit continued operating until contact was lost on March 22, 2010, a total of 2,269 Earth days, which is 2,208 days on Mars (sols)1Spirit operated on the Martian surface 24.5 times as long as its design life of 90 sols.

Even more amazing: Opportunity has been operating on the Martian surface (as of this publication date) for 5,108 Earth days, which is 4,971 sols.   That’s 55.2 times its design life of 90 sols!

Spirit and Opportunity faced their greatest challenge up to that point during the global Martian dust storm of July 2007.  Here is what I wrote about it back then.

Spirit and Opportunity‘s Greatest Challenge (7-26-07)

The intrepid Mars Exploration Rovers Spirit and Opportunity—which have been operating on the surface of Mars over 14 times longer than planned—each carry two 8 amp-hour lithium batteries, and these batteries are charged by solar panels.  Before dust storms began significantly reducing the amount of sunlight reaching the rovers’ solar panels, they were generating about 700 watt-hours of electricity each day—enough to power a 100-watt light bulb for seven hours.  Not much, it may seem, but plenty enough to operate each rover’s internal heaters, motors, scientific instruments, and communication equipment.

In recent weeks, both rovers have seriously been affected by the dust storms, particularly Opportunity which last week was able to generate only 128 watt-hours of electricity on the worst day.  With precious little energy to replenish the internal batteries, controllers have hunkered down the rovers to conserve energy for the most critical need—internal heaters to keep the core electronics warm enough to operate.  Remember, the average surface temperature on Mars is -85° F!

At press time, weather conditions appear to be improving for both rovers, but there are still worries that the rovers could have been damaged by all that dust blowing at them for days on end.


As it turns out, after the global dust storm of 2007 subsided, the rovers benefited from subsequent “cleaning events” where the winds of Mars blew most of the dust off of the solar panels.

There have been no global dust storms on Mars since 2007; however, another one is anticipated later this year.  Hopefully, our intrepid Opportunity will weather the storm and continue to generate enough life-giving power from its precious solar panels .

1A Martian day is called a sol and is slightly longer than an Earth day.  A mean solar day on Earth is 24h00m00s, by definition, but a mean solar day on Mars is 24h39m35.244s Earth time.  To convert Earth days to Martian sols, divide the number of Earth days by 1.0275.

A Better Lotion Bottle

For many of us, winter in the Upper Midwest means dry, cracked hands and nasty splits at the ends of our thumbs and fingers.  The only way to avoid or at least mitigate this is to apply lotion to your hands after every hand washing, because soap removes too much of your skin’s natural moisturizing oils (lipids).

I’m not a big fan of pump dispensers when it comes to lotion.  When the pump has pumped all the lotion it can, there is still a lot of lotion left behind in the bottle.  And most of us don’t want to go through the extra effort needed to get to the remaining lotion, so we throw the bottle out rather than utilizing the remaining lotion and then recycling the bottle.

Wasteful lotion container on the left – Better lotion container on the right

Recently, just to see how much lotion was left in a Gold Bond® pump dispenser (excellent lotion, by the way), we used a razor blade to cut all the way around the midsection of the lotion bottle, separating it into roughly two halves.  Then we used a spoon to scoop out all the remaining lotion in the two halves and put it into a clean plastic tub—formerly a sour cream container.  The amount of leftover lotion is substantial, as you can see in the photograph below.  A many-days supply, to be sure!

Leftover lotion from a seemingly empty pump dispenser

We consumers need to put pressure on pump-dispenser lotion manufacturers to package their lotions in containers that make it easy to extract all the lotion.  Some lotion manufacturers are already doing this, and we should purchase their products.  O’Keeffe’s® Working Hands® is one good example.

You can get all of the lotion out of a container like this

Sometimes, lotion manufacturers package their product in both types of containers—pump dispensers and tub containers—but your local grocery store, pharmacy, or big-box store only carries the less environmentally-friendly pump-dispenser type of container.  Do your research, and meet with the store manager to ask them to carry the tub container alternative instead of—or in addition to—the pump dispenser.

Each and every day we can make choices that are better for our environment.  This is yet another example: use all the product and make it easy to recycle the container.

Welcome to the Zooniverse!

We live in a society where science is little more than a “spectator sport” for most of us who have an interest in it.  Data collection and original research often require substantial investments of time and money, as well as a long-term commitment.  Those of us who are already working full time and, in spite of that, have little discretionary income, often find “participatory science” out of reach, no matter how great our enthusiasm or aptitude.

As today’s scientific instruments increasingly generate enormous quantities of data, the people who “do science” for a living are too few in number to analyze all that data.  Fortunately, this is one area where “citizen scientists” can help.

There are a number of interesting scientific projects that lend themselves well to “crowd sourcing”, and Zooniverse is a portal to many of them.

Here are the currently active Zooniverse projects in the disciplines of astronomy and physics.

Backyard Worlds: Planet 9
Discover new brown dwarfs and possibly a new solar system planet by scrutinizing images from the Wide-field Infrared Survey Telescope (WISE).

Comet Hunters
Discover new comets previously misidentified as asteroids by analyzing deep images taken by the Subaru 8.2-meter telescope in Hawaii.

Disk Detective
Help search for stars with undiscovered disks of dust around them.  These stars show us where to look for planetary systems and how they form.

Exoplanet Explorers
Discover transiting exoplanet candidates in Kepler’s K2 data.

Galaxy Zoo   Galaxy Zoo: 3D
Classify galaxies, many of which have never been studied before, and look for unusual features.

Gravity Spy
Identify and characterize “glitches” in LIGO data to make it easier to identify gravitational wave events.

Higgs Hunters
Help search for unknown exotic particles in data from the Large Hadron Collider (LHC), the world’s largest and most powerful particle collider.

Milky Way Project
Classify images from two infrared space telescopes: the Spitzer Space Telescope (SST) and the Wide-field Infrared Survey Telescope (WISE).

Planet Four
Identify and measure features on the surface of Mars.

Planet Hunters
Discover transiting exoplanet candidates in data from the Kepler spacecraft.

Radio Galaxy Zoo
Search radio images of galaxies for evidence of jets caused by matter falling into supermassive black holes.

Radio Meteor Zoo
Identify meteors through the reflection of radio waves from their ionization trails.

Solar Stormwatch II
Characterize solar storms and their interaction with the solar wind through the analysis of images from NASA’s twin Solar Terrestrial Relations Observatory (STEREO) spacecraft.

Supernova Hunters
Scrutinize the most recent images collected by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) in Hawaii in comparison to reference images to discover new supernovae that can then be immediately followed by ground-based and space-based telescopes.

All of these projects utilize “machine learning” computer algorithms such as neural networks and random forests (artificial intelligence, or AI) to some extent, and in fact citizen scientist participants help “train” these algorithms so they do a better job of finding or classifying or whatever.  For a great introduction to this subject, see “Machines Learning Astronomy” by Sky & Telescope news editor Monica Young in the December 2017 issue, pp. 20-27.

As machine learning algorithms get better and better, they may no longer need citizen scientists to train them.

In the meantime, have fun and contribute to science!

Zodiacal Light 2018

In this year of 2018, the best dates and times for observing the zodiacal light are listed below.  The sky must be very clear.  The specific times listed are for Dodgeville, Wisconsin.

2018 Begin End Direction
Fri. Feb. 2 6:52 p.m. 7:52 p.m. West
Sat. Feb. 3 6:53 p.m. 7:53 p.m. West
Sun. Feb. 4 6:54 p.m. 7:54 p.m. West
Mon. Feb. 5 6:55 p.m. 7:55 p.m. West
Tue. Feb. 6 6:57 p.m. 7:57 p.m. West
Wed. Feb. 7 6:58 p.m. 7:58 p.m. West
Thu. Feb. 8 6:59 p.m. 7:59 p.m. West
Fri. Feb. 9 7:00 p.m. 8:00 p.m. West
Sat. Feb. 10 7:01 p.m. 8:01 p.m. West
Sun. Feb. 11 7:02 p.m. 8:02 p.m. West
Mon. Feb. 12 7:04 p.m. 8:04 p.m. West
Tue. Feb. 13 7:05 p.m. 8:05 p.m. West
Wed. Feb. 14 7:06 p.m. 8:06 p.m. West
Thu. Feb. 15 7:07 p.m. 8:07 p.m. West
Fri. Feb. 16 7:08 p.m. 8:08 p.m. West
Sat. Mar. 3 7:27 p.m. 7:59 p.m. West
Sun. Mar. 4 7:28 p.m. 8:28 p.m. West
Mon. Mar. 5 7:29 p.m. 8:29 p.m. West
Tue. Mar. 6 7:30 p.m. 8:30 p.m. West
Wed. Mar. 7 7:32 p.m. 8:32 p.m. West
Thu. Mar. 8 7:33 p.m. 8:33 p.m. West
Fri. Mar. 9 7:34 p.m. 8:34 p.m. West
Sat. Mar. 10 7:35 p.m. 8:35 p.m. West
Sun. Mar. 11 8:37 p.m. 9:37 p.m. West
Mon. Mar. 12 8:38 p.m. 9:38 p.m. West
Tue. Mar. 13 8:39 p.m. 9:39 p.m. West
Wed. Mar. 14 8:41 p.m. 9:41 p.m. West
Thu. Mar. 15 8:42 p.m. 9:42 p.m. West
Fri. Mar. 16 8:43 p.m. 9:43 p.m. West
Sat. Mar. 17 8:44 p.m. 9:44 p.m. West
Sun. Mar. 18 8:46 p.m. 9:46 p.m. West
Mon. Mar. 19 9:38 p.m. 9:47 p.m. West
Mon. Apr. 2 9:06 p.m. 9:56 p.m. West
Tue. Apr. 3 9:08 p.m. 10:08 p.m. West
Wed. Apr. 4 9:09 p.m. 10:09 p.m. West
Thu. Apr. 5 9:11 p.m. 10:11 p.m. West
Fri. Apr. 6 9:12 p.m. 10:12 p.m. West
Sat. Apr. 7 9:14 p.m. 10:14 p.m. West
Sun. Apr. 8 9:15 p.m. 10:15 p.m. West
Mon. Apr. 9 9:17 p.m. 10:17 p.m. West
Tue. Apr. 10 9:18 p.m. 10:18 p.m. West
Wed. Apr. 11 9:20 p.m. 10:20 p.m. West
Thu. Apr. 12 9:21 p.m. 10:21 p.m. West
Fri. Apr. 13 9:23 p.m. 10:23 p.m. West
Sat. Apr. 14 9:25 p.m. 10:25 p.m. West
Sun. Apr. 15 9:26 p.m. 10:26 p.m. West
Mon. Apr. 16 9:28 p.m. 10:28 p.m. West
Tue. Apr. 17 9:43 p.m. 10:29 p.m. West
Thu. Aug. 9 3:08 a.m. 3:44 a.m. East
Fri. Aug. 10 3:09 a.m. 4:09 a.m. East
Sat. Aug. 11 3:11 a.m. 4:11 a.m. East
Sun. Aug. 12 3:13 a.m. 4:13 a.m. East
Mon. Aug. 13 3:14 a.m. 4:14 a.m. East
Tue. Aug. 14 3:16 a.m. 4:16 a.m. East
Wed. Aug. 15 3:18 a.m. 4:18 a.m. East
Thu. Aug. 16 3:19 a.m. 4:19 a.m. East
Fri. Aug. 17 3:21 a.m. 4:21 a.m. East
Sat. Aug. 18 3:22 a.m. 4:22 a.m. East
Sun. Aug. 19 3:24 a.m. 4:24 a.m. East
Mon. Aug. 20 3:26 a.m. 4:26 a.m. East
Tue. Aug. 21 3:27 a.m. 4:27 a.m. East
Wed. Aug. 22 3:29 a.m. 4:29 a.m. East
Thu. Aug. 23 3:30 a.m. 4:30 a.m. East
Fri. Aug. 24 4:20 a.m. 4:32 a.m. East
Sat. Sep. 8 3:54 a.m. 4:54 a.m. East
Sun. Sep. 9 3:55 a.m. 4:55 a.m. East
Mon. Sep. 10 3:57 a.m. 4:57 a.m. East
Tue. Sep. 11 3:58 a.m. 4:58 a.m. East
Wed. Sep. 12 3:59 a.m. 4:59 a.m. East
Thu. Sep. 13 4:01 a.m. 5:01 a.m. East
Fri. Sep. 14 4:02 a.m. 5:02 a.m. East
Sat. Sep. 15 4:03 a.m. 5:03 a.m. East
Sun. Sep. 16 4:05 a.m. 5:05 a.m. East
Mon. Sep. 17 4:06 a.m. 5:06 a.m. East
Tue. Sep. 18 4:07 a.m. 5:07 a.m. East
Wed. Sep. 19 4:09 a.m. 5:09 a.m. East
Thu. Sep. 20 4:10 a.m. 5:10 a.m. East
Fri. Sep. 21 4:11 a.m. 5:11 a.m. East
Sat. Sep. 22 4:12 a.m. 5:12 a.m. East
Sun. Sep. 23 5:07 a.m. 5:14 a.m. East
Sun. Oct. 7 4:30 a.m. 5:04 a.m. East
Mon. Oct. 8 4:32 a.m. 5:32 a.m. East
Tue. Oct. 9 4:33 a.m. 5:33 a.m. East
Wed. Oct. 10 4:34 a.m. 5:34 a.m. East
Thu. Oct. 11 4:35 a.m. 5:35 a.m. East
Fri. Oct. 12 4:36 a.m. 5:36 a.m. East
Sat. Oct. 13 4:37 a.m. 5:37 a.m. East
Sun. Oct. 14 4:39 a.m. 5:39 a.m. East
Mon. Oct. 15 4:40 a.m. 5:40 a.m. East
Tue. Oct. 16 4:41 a.m. 5:41 a.m. East
Wed. Oct. 17 4:42 a.m. 5:42 a.m. East
Thu. Oct. 18 4:43 a.m. 5:43 a.m. East
Fri. Oct. 19 4:44 a.m. 5:44 a.m. East
Sat. Oct. 20 4:45 a.m. 5:45 a.m. East
Sun. Oct. 21 4:47 a.m. 5:47 a.m. East
Mon. Oct. 22 4:57 a.m. 5:48 a.m. East

On the February, March, and April evenings listed above, you will see a broad, faint band of light extending upwards from the western horizon, sloping a little to the left, and reaching nearly halfway to the top of the sky.

On the August, September, and October mornings listed above, you will see a broad, faint band of light extending upwards from the eastern horizon, sloping a little to the right, and reaching nearly halfway to the top of the sky.

It is essential that your view is not spoiled by nearby streetlights, parking lot lights, or dusk-to-damn insecurity lights, nor any city to the west (Feb-Apr) or east (Aug-Oct).  Give your eyes a few minutes to adjust to the darkness.  Slowly sweeping your eyes back and forth from southwest to northwest (Feb-Apr) or northeast to southeast (Aug-Oct) will help you spot the zodiacal light band.  Once spotted, you should be able to see it without moving your head.

On the February, March, and April evenings listed above, the zodiacal light is best seen right at the end of evening twilight, and remains visible for an hour or so after that.

On the August, September, and October mornings listed above, the zodiacal light is best seen about an hour or so before the beginning of morning twilight, right up to the beginning of morning twilight.

Enjoy!

Mid-Winter Mid-Night Satellite

While video recording the star Tycho 1311-1818-1 in Taurus on a very cold Thursday evening last week (-4° F) in the hope that asteroid 126561 (2002 CF105) would pass in front of it (it didn’t), I was surprised and delighted to serendipitously record a very slow moving Earth-orbiting satellite crossing the field.  Now, in order to see a satellite, it must be illuminated by sunlight.  But to see any satellite during the first week of January only 10 minutes before local midnight, it must be very far from the Earth indeed (more on that later).

Here’s a video of the event showing its complete traversal of the field of view:

Slow-Moving Satellite

I’m hoping that one of the good people that frequent the satellite observers’ forum SeeSat-L will be able to identify this unusual object.  Requisite to that, of course, are two precise positions at two precise times and the observer’s location.

A very useful online tool provided by the Department of Physics at Virginia Tech allows one to input the right ascension, declination, and x-y coordinates of between 4 and 10 known objects, and it does an astrometric solution across the field so you can determine the right ascension and declination of an unknown object.

Using Guide 9.1, Limovie, and this tool, I determined the following:

At 5 Jan 2018 5:42:58.122 UT, the satellite was located at:
5h45m48.14s +21°45’17.5″ (apparent coordinates, epoch of date).

At 5 Jan 2018 5:50:22.931 UT, the satellite was located at:
5h46m53.98s +21°48’06.3″ (apparent coordinates, epoch of date).

Observer Location: 42°57’36.9″N, 90°08’31.1″ W, 390 m.

Using the satellite coordinates above, and the angular separation calculator kindly provided by the Indian Institute of Astrophysics, we find that the satellite traversed just 0.2590° in 0.1236 hours.  That’s 2.095° per hour, or only about four moon diameters in an hour!

Surely, this satellite must be way out there.  How far?  To determine that, I did a couple of what we used to call during my college physics days “back-of-the-envelope” (BOTEC) calculations.  These are rough approximations—using simplifying assumptions—that should get you to an answer that is at least the right order of magnitude.

If we can estimate the orbital angular velocity of the satellite, we can determine its orbital period, and if we could determine that, we can calculate it orbital distance.  Now, we don’t know yet if this satellite is in a near-circular or highly-elliptical orbit.  If the satellite is an a highly-elliptical orbit and we observe it near apogee, its angular velocity will be somewhat slower than the angular velocity of a circular orbit at that same distance.  If we observe it near perigee, then its angular velocity will be somewhat faster that the angular velocity of a circular orbit at that same distance.  First simplifying assumption: let’s assume a circular orbit.

The next simplifying assumptions are that (1) the satellite passes through the observer’s zenith, and (2) the distance to the satellite is large in comparison to the radius of the Earth.  At the time of observation, the satellite was at an altitude between 65° and 66° above the horizon.  Not quite the zenith, but maybe close enough.

First, we need to compensate for the fact that the observer’s location on the surface of the Earth is moving in the same direction (along right ascension) as the satellite is orbiting (eastward) as the Earth rotates.  We need to add the Earth’s rotational velocity to the right ascension component of the satellite’s velocity to get its true angular velocity relative to the center of the Earth.  This of course assumes that the radius of the Earth is small compared to the distance to the satellite.

During the 0.1236 hours we observed the satellite, it moved 0.2743° eastward in right ascension and 0.0469° northward in declination.  We now need to add a portion of the Earth’s angular velocity to the right ascension component of the satellite’s angular velocity.  If the satellite were at the north celestial pole, the amount we would add would be zero.  If, on the other hand, the satellite were on the celestial equator, we would add the full amount.  Since cos 90° is 0 and cos 0° is 1, let’s add the Earth’s rotational angular velocity times the cosine of the satellite’s declination to the right ascension component of the satellite’s angular velocity.

The Earth turns through 360° in one mean sidereal day (23h 56m 04s = 86,164s).  That’s 1.8591° during the 0.1236 hours we observed the satellite.  Taking that times the average declination of the satellite during the observation time, we get 1.8591° cos 21.7783° =1.7264°.  Adding this to the 0.2743° the satellite moved in right ascension, we get new components for the satellite’s angular displacement of 0.2743° + 1.7264° = 2.0007° in right ascension and 0.0469° in declination.  This gives us the “true” angular displacement for the satellite of

This is a motion of about 16.19° per hour, giving us a rough orbital period of 22.235 hours or 80,045 seconds.

Using Newton’s form of Kepler’s Third Law to calculate the orbital semi-major axis, we get (as a very rough estimate):

where G is the gravitational constant, M is the mass of the Earth in kg, and P is the satellite’s orbital period in seconds.

Geosynchronous satellites have an orbital radius of 42,164 km, so our mystery satellite is almost as far out as the geosynchronous satellites.  If it were further, the satellite would have been moving westward across our field of view, not eastward.

Admittedly, this is a lot of hand waving and is almost certainly wrong, but perhaps it gets us reasonably close to the right answer.

Now, let’s consider the shadow of the Earth to give us another estimate of the satellite’s distance.

At the time of observation, the Sun was located at 19h04m23s -22°36’40”.  The anti-solar point, which is the center of the Earth’s shadow cone, was then located at 7h04m23s +22°36’40”.   That is only 18.1° from the satellite.  The Sun’s angular diameter at that time was 32.5 arcminutes.  In order for the satellite to not be shadowed by the Earth, the angular diameter of the Earth as seen from the satellite must be less thanThe distance from the center of the Earth at which the Earth subtends an angle of 18.6° is given bySo, using this method, the satellite must be at an orbital radius of at least 38,905 km to be outside the Earth’s umbral shadow cone.

Now, on to something less speculative: the varying brightness of the satellite.  I used Limovie to track the satellite across most of the field and got the following light curve.

At first blush, it appears the satellite is tumbling with a period of around 51.2s.  But a closer inspection reveals that a larger amplitude is followed by a smaller amplitude is followed by a larger amplitude, and so on.  So the tumbling period looks to me to be more like 102.4s.  The mean (unfiltered) magnitude of the satellite looks to be around 11.8m, but ranging between 10.7m and 13.0m.  Thus the amplitude is around 2.3 magnitudes.  You will find the raw data here.

Update January 10, 2018

Alain Figer, French astronomer and satellite enthusiast, was kind enough to identify this object for me.  Alain writes, “At first glance I noticed, using Calsky, that Falcon 9 rocket, 2017-025B, #42699, might be your satellite…From the MMT data (astroguard russian site) 2017-025B rotation period was measured at 89.55s on 13 OCT 2017.  That figure seems to me in rather good agreement with yours at 102.4s, since the rotation period of this rocket might be quickly lengthening, a rather classical behaviour for such newly launched rockets.”  Alain goes on to say, “For estimating the satellite altitude from your own observations you have to consider its highly eccentric elliptical orbit.”  Thank you, Alain!

After I got home from work this evening, I began thinking, “Hmm, Guide is such an amazing program, maybe it can show me accurate satellite positions as well.”  Turns out, it can!  After downloading the current orbital elements for all satellites and turning on the satellite display, I was able to confirm Alain’s determination that this object is indeed Falcon 9 rocket body 2017-025B.

SpaceX launched the Inmarsat-5 F4 commercial communications satellite from historic Launch Complex 39A at NASA’s Kennedy Space Center in Florida using a Falcon 9 rocket on May 15, 2017.  Here are some pictures and a video of that launch.

The Falcon 9 rocket body currently orbits the Earth once every 23h21m19s in a highly-elliptical orbit (e=0.8358) that ranges from a perigee height of 432.4 km to an apogee height of 69,783 km.  During the time of observation, its range (i.e. distance from me, the observer) went from 64,388 km to 64,028 km.  The semi-major axis of its orbit is 41,481 km which is 3.3% higher than my (lucky) estimate above.  The shadow criterion of > 38,905 km is met as well.

Orbital inclination 25.6 degrees

Meteor Shower Calendar 2018

Here’s our meteor shower calendar for 2018.  It is sourced from the IMO’s Working List of Visual Meteor Showers (https://www.imo.net/files/meteor-shower/cal2018.pdf, Table 5, p. 25).

Each meteor shower is identified using its three-character IAU meteor shower code.  Codes are bold on the date of maximum, and one day either side of maximum.

Here’s a printable PDF file of the meteor shower calendar shown below:

Meteor Shower Calendar 2018

Happy meteor watching!

January 2018
SUN MON TUE WED THU FRI SAT
1
DLM QUA
2
DLM QUA
3
DLM QUA
4
DLM QUA
5
DLM QUA
6
DLM QUA
7
DLM QUA
8
DLM QUA
9
DLM QUA
10
DLM QUA GUM
11
DLM QUA GUM
12
DLM QUA GUM
13
DLM GUM
14
DLM GUM
15
DLM GUM
16
DLM GUM
17
DLM GUM
18
DLM GUM
19
DLM GUM
20
DLM GUM
21
DLM GUM
22
DLM GUM
23
DLM
24
DLM
25
DLM
26
DLM
27
DLM
28
DLM
29
DLM
30
DLM
31
DLM ACE
February 2018
SUN MON TUE WED THU FRI SAT
1
DLM ACE
2
DLM ACE
3
DLM ACE
4
DLM ACE
5
ACE
6
ACE
7
ACE
8
ACE
9
ACE
10
ACE
11
ACE
12
ACE
13
ACE
14
ACE
15
ACE
16
ACE
17
ACE
18
ACE
19
ACE
20
ACE
21 22 23 24
25
GNO
26
GNO
27
GNO
28
GNO
March 2018
SUN MON TUE WED THU FRI SAT
1
GNO
2
GNO
3
GNO
4
GNO
5
GNO
6
GNO
7
GNO
8
GNO
9
GNO
10
GNO
11
GNO
12
GNO
13
GNO
14
GNO
15
GNO
16
GNO
17
GNO
18
GNO
19
GNO
20
GNO
21
GNO
22
GNO
23
GNO
24
GNO
25
GNO
26
GNO
27
GNO
28
GNO
29 30 31
April 2018
SUN MON TUE WED THU FRI SAT
1 2 3 4 5 6 7
8 9 10 11 12 13 14
LYR
15
PPU LYR
16
PPU LYR
17
PPU LYR
18
PPU LYR
19
ETA PPU LYR
20
ETA PPU LYR
21
ETA PPU LYR
22
ETA PPU LYR
23
ETA PPU LYR
24
ETA PPU LYR
25
ETA PPU LYR
26
ETA PPU LYR
27
ETA PPU LYR
28
ETA PPU LYR
29
ETA LYR
30
ETA LYR
May 2018
SUN MON TUE WED THU FRI SAT
1
ETA
2
ETA
3
ELY ETA
4
ELY ETA
5
ELY ETA
6
ELY ETA
7
ELY ETA
8
ELY ETA
9
ELY ETA
10
ELY ETA
11
ELY ETA
12
ELY ETA
13
ELY ETA
14
ARI ELY ETA
15
ARI ETA
16
ARI ETA
17
ARI ETA
18
ARI ETA
19
ARI ETA
20
ARI ETA
21
ARI ETA
22
ARI ETA
23
ARI ETA
24
ARI ETA
25
ARI ETA
26
ARI ETA
27
ARI ETA
28
ARI ETA
29
ARI
30
ARI
31
ARI
June 2018
SUN MON TUE WED THU FRI SAT
1
ARI
2
ARI
3
ARI
4
ARI
5
ARI
6
ARI
7
ARI
8
ARI
9
ARI
10
ARI
11
ARI
12
ARI
13
ARI
14
ARI
15
ARI
16
ARI
17
ARI
18
ARI
19
ARI
20
ARI
21
ARI
22
JBO ARI
23
JBO ARI
24
JBO ARI
25
JBO
26
JBO
27
JBO
28
JBO
29
JBO
30
JBO
July 2018
SUN MON TUE WED THU FRI SAT
1
JBO
2
JBO
3
CAP
4
CAP
5
CAP
6
CAP
7
CAP
8
CAP
9
CAP
10
CAP
11
CAP
12
CAP SDA
13
CAP SDA
14
CAP SDA
15
CAP SDA PAU
16
CAP SDA PAU
17
PER CAP SDA PAU
18
PER CAP SDA PAU
19
PER CAP SDA PAU
20
PER CAP SDA PAU
21
PER CAP SDA PAU
22
PER CAP SDA PAU
23
PER CAP SDA PAU
24
PER CAP SDA PAU
25
PER CAP SDA PAU
26
PER CAP SDA PAU
27
PER CAP SDA PAU
28
PER CAP SDA PAU
29
PER CAP SDA PAU
30
PER CAP SDA PAU
31
PER CAP SDA PAU
August 2018
SUN MON TUE WED THU FRI SAT
1
PER CAP SDA PAU
2
PER CAP SDA PAU
3
KCG PER CAP SDA PAU
4
KCG PER CAP SDA PAU
5
KCG PER CAP SDA PAU
6
KCG PER CAP SDA PAU
7
KCG PER CAP SDA PAU
8
KCG PER CAP SDA PAU
9
KCG PER CAP SDA PAU
10
KCG PER CAP SDA PAU
11
KCG PER CAP SDA
12
KCG PER CAP SDA
13
KCG PER CAP SDA
14
KCG PER CAP SDA
15
KCG PER CAP SDA
16
KCG PER SDA
17
KCG PER SDA
18
KCG PER SDA
19
KCG PER SDA
20
KCG PER SDA
21
KCG PER SDA
22
KCG PER SDA
23
KCG PER SDA
24
KCG PER
25
KCG
26 27 28
AUR
29
AUR
30
AUR
31
AUR
September 2018
SUN MON TUE WED THU FRI SAT
1
AUR
2
AUR
3
AUR
4
AUR
5
SPE AUR
6
SPE
7
SPE
8
SPE
9
DSX SPE
10
STA DSX SPE
11
STA DSX SPE
12
STA DSX SPE
13
STA DSX SPE
14
STA DSX SPE
15
STA DSX SPE
16
STA DSX SPE
17
STA DSX SPE
18
STA DSX SPE
19
STA DSX SPE
20
STA DSX SPE
21
STA DSX SPE
22
STA DSX
23
STA DSX
24
STA DSX
25
STA DSX
26
STA DSX
27
STA DSX
28
STA DSX
29
STA DSX
30
STA DSX
October 2018
SUN MON TUE WED THU FRI SAT
1
STA DSX
2
ORI STA DSX
3
ORI STA DSX
4
ORI STA DSX
5
ORI STA OCT DSX
6
ORI STA DRA OCT DSX
7
ORI STA DRA OCT DSX
8
ORI STA DRA DSX
9
ORI STA DRA DSX
10
ORI DAU STA DRA
11
ORI DAU STA
12
ORI DAU STA
13
ORI DAU STA
14
ORI EGE DAU STA
15
ORI EGE DAU STA
16
ORI EGE DAU STA
17
ORI EGE DAU STA
18
ORI EGE DAU STA
19
LMI ORI EGE STA
20
NTA LMI ORI EGE STA
21
NTA LMI ORI EGE STA
22
NTA LMI ORI EGE STA
23
NTA LMI ORI EGE STA
24
NTA LMI ORI EGE STA
25
NTA LMI ORI EGE STA
26
NTA LMI ORI EGE STA
27
NTA LMI ORI EGE STA
28
NTA ORI STA
29
NTA ORI STA
30
NTA ORI STA
31
NTA ORI STA
November 2018
SUN MON TUE WED THU FRI SAT
1
NTA ORI STA
2
NTA ORI STA
3
NTA ORI STA
4
NTA ORI STA
5
NTA ORI STA
6
LEO NTA ORI STA
7
LEO NTA ORI STA
8
LEO NTA STA
9
LEO NTA STA
10
LEO NTA STA
11
LEO NTA STA
12
LEO NTA STA
13
NOO LEO NTA STA
14
NOO LEO NTA STA
15
NOO AMO LEO NTA STA
16
NOO AMO LEO NTA STA
17
NOO AMO LEO NTA STA
18
NOO AMO LEO NTA STA
19
NOO AMO LEO NTA STA
20
NOO AMO LEO NTA STA
21
NOO AMO LEO NTA
22
NOO AMO LEO NTA
23
NOO AMO LEO NTA
24
NOO AMO LEO NTA
25
NOO AMO LEO NTA
26
NOO LEO NTA
27
NOO LEO NTA
28
PHO NOO LEO NTA
29
PHO NOO LEO NTA
30
PHO NOO LEO NTA
December 2018
SUN MON TUE WED THU FRI SAT
1
PUP PHO NOO NTA
2
PUP PHO NOO NTA
3
HYD PUP PHO NOO NTA
4
GEM HYD PUP PHO NOO NTA
5
DLM GEM HYD MON PUP PHO NOO NTA
6
DLM GEM HYD MON PUP PHO NOO NTA
7
DLM GEM HYD MON PUP PHO NTA
8
DLM GEM HYD MON PUP PHO NTA
9
DLM GEM HYD MON PUP PHO NTA
10
DLM GEM HYD MON PUP NTA
11
DLM GEM HYD MON PUP
12
DLM COM GEM HYD MON PUP
13
DLM COM GEM HYD MON PUP
14
DLM COM GEM HYD MON PUP
15
DLM COM GEM HYD MON PUP
16
DLM COM GEM MON
17
DLM URS COM GEM MON
18
DLM URS COM MON
19
DLM URS COM MON
20
DLM URS COM MON
21
DLM URS COM
22
DLM URS COM
23
DLM URS COM
24
DLM URS
25
DLM URS
26
DLM URS
27
DLM
28
DLM QUA
29
DLM QUA
30
DLM QUA
31
DLM QUA

The Good Old Days of Astronomy…

Those of you who grew up in the 1950s and 1960s as I did will especially delight in reading the July 7, 2007 entry of Uncle Rod’s Astro Blog, courtesy of Alabama astronomer Rod Mollise.  What a hoot!

And here’s a note from Phil Harrington’s website about Celestron’s ads in the 1990s: “It must be good to be an amateur astronomer in California, judging by the ads run by Celestron over the years…Yup, just another typical club star party, right?”  Photo montage by Rod Mollise.

Plastic Recycling

That number you see within the recycling symbol on recyclable plastic is called the “resin identification code” or RIC.  One pet peeve: the recycling symbol and RIC are often too small, not easy to see, or are difficult to find.  Also, some plastics and plastic parts that could be recycled are not labeled.

The seven different types of recyclable plastics are listed below, along with a small subset of initial and recycling uses.  New applications for recycled plastics are being invented all the time!  Perhaps you have some ideas.

Polymer: Polyethylene terephthalate (C10H8O4)n
Other names & abbreviations: PETE, PET, polyester
Common uses: beverage bottles, fibers for clothing
Recycling uses: non-food containers, strapping, carpet fiber

Polymer: High-density polyethylene (C2H4)n
Other names & abbreviations: HDPE, PE-HD
Common uses: milk jugs, food containers
Recycling uses: plastic lumber, parking bumpers, recycling bins, sheds

Polymer: Polyvinyl chloride (C2H3Cl)n
Other names & abbreviations: PVC, V
Common uses: bottles, non-food packaging
Recycling uses: pipes, fencing, flooring, lawn chairs, wire insulation

Polymer: Low-density polyethylene (C2H4)n
Other names & abbreviations: LDPE, PE-LD
Common uses: plastic bags, six-pack rings, containers, snap-on lids
Recycling uses: packaging foam, plastic film, garbage bags

Polymer: Polypropylene (C3H6)n
Other names & abbreviations: PP
Common uses: food containers, medical & lab equipment, pill bottles
Recycling uses: pallets, trays, landscape borders, compost bins, bike racks

Polymer: Polystyrene (C8H8)n
Other names & abbreviations: PS
Common uses: plastic cutlery, disposable razors, CD & DVD cases
Recycling uses: packaging material, insulation sheets, park benches

Polymer: Other Plastics (acrylic, nylon, polycarbonate, etc.)
Other names & abbreviations: OTHER, O
Common uses: plastic lenses, food packaging & bottles, LCD screens, etc.
Recycling uses: plastic lumber, bus shelters, traffic lights, signs, etc.

Big Binoculars

It is often said (and rightfully so) that your first telescope should be a pair of binoculars.  And your second pair of binoculars should be big binoculars on a hands-free binocular mount.  It is amazing how much you can see (and how beautiful it is) at a dark-sky location with 16 x 70 binoculars mounted on an Orion Monster Parallelogram Binocular Mount & Tripod, for example.

And then there’s the realm of binocular telescopes, such as a 6, 10, or 16″ Reverse Binocular Telescope from JMI.  As famed astrophotographer Tony Hallas says in a letter in the July 2007 issue of Sky & Telescope, “Daphne and I have observed…many…deep-sky objects many times over the years using conventional telescopes, including very big ones.  Neither of us ever wants to go back to monocular observing.  Looking with both eyes through twin scopes with fast optical systems enables the brain to absorb so much more information—it’s utterly breathtaking.”

Vacuum Telescopes

The light from a celestial object is bounced and distorted as it penetrates the Earth’s turbulent atmosphere, and this image degradation continues all the way into the telescope.  Currents of air within the telescope tube caused by parts of the tube or optics being at different temperatures can severely degrade a telescope image, particularly in a large telescope.

Nowhere is this more apparent than in a professional solar telescope.  Sunlight entering the telescope heats up the inside of the telescope and optical components, resulting in turbulent air currents that make the images less sharp than they could be.

To solve this problem, some solar telescopes contain a vacuum so there is no air to heat and therefore no image distortion within the telescope.  This requires, however, a rather thick piece of glass (of high optical quality, of course) at the front of the telescope in order to maintain the vacuum within the tube.  A good example of this kind of telescope is the Swedish 1-m Solar Telescope (SST) located on the island of La Palma in the Canary Islands.

A much thinner front lens can be used if the telescope tube is filled with helium rather than evacuated, and though the results are much better than an air-filled telescope tube, they are not quite as good as with a vacuum telescope.

I am not aware of any vacuum telescopes being used for nighttime observations.