ISS This Morning

   This morning at approximately 5:42 am CST the International Space Station had a brief 3-minute flyover of my part of the world. It first appeared high over the northwest horizon and quickly passed the bowl of the Big Dipper coming close to Merak, the bottom front star making up the Big Dipper’s bowl. Look closely at the next to last line from the right. That is the stars of Coma Berenices (Berenice’s Hair), a small constellation named after Queen Berenice, one of the wives of Ptolemy III, of ancient Egypt.
   Less than a minute later, if that much, the ISS was setting in the southeast as it passed by Jupiter.
   Each picture is a stacked composite of several pictures. Camera was set to ISO 1600; F5.6; 3.2 seconds; 18mm.


Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

NSTA @ Nashville

   I’m in Nashville Tennessee for the next several days at the NSTA national conference. Planets and stars will still be in the skies but not as easy to see from downtown Nashville as it is where I live. On the morning of April 1st the waning waning crescent Moon will be within a few degrees from Dwarf Planet Pluto. Too dim to be seen without a large telescope it is, nonetheless, a neat idea that when you look toward the Moon you are also looking in the direction of Pluto. It’s out there!
   And here is a sequence of graphics showing the pre-sunrise morning sky at 5:30 am EDT for each day during the conference, and one night view on April 1st showing Jupiter. Both Pluto and the Moon are located just above and to the left from the handle of the teapot asterism for Sagittarius the Archer.


Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Venus-Jupiter Conjunction – Behind the Scenes

June 30

June 30

   Have you been following the motions of the Venus and Jupiter in the evening over the western horizon. The two planets, one an inner planet (Venus) and the other an outer planet (Jupiter), have moved noticeably closer to each other with the closest on Wednesday July 1st at 2 UT. For my time zone, CDT, this was at 10 pm CDT on Tuesday June 30th. At that time they were separated by about 0.5o, about the diameter of the full Moon, or your finger held out at arm’s length. As the days passed the two planets moved apart.

rotating-earth_at-night   So what is happening?
Several things, all involving the motions of Venus, Jupiter, the Earth and the Sun’s apparent motion, and of course the Earth’s rotation. The latter, Earth’s rotation, is the cause of the apparent east to west motion that all celestial objects follow across your skies. Other than being aware of the setting times this sky motion is not a major part of the conjunction between Venus and Jupiter.

   Starting with the Sun we can see over time that the Sun appears to move eastward at a rate of nearly 1o each day, which is the result of the Earth’s orbital motion, aka revolution, of nearly 1o each day. Keep this daily rate in mind because the other planets each move eastward at their own respective daily rate based on distance from the Sun. Venus as an inner planet takes 224.7 days to orbit the Sun so 360o / 224.7 = 1.6o; Earth takes 365.25 days to orbit the Sun so 360o / 365.2 = 0.98o; Jupiter takes 4331 days to orbit the Sun so 360o / 4331 = 0.083o.
Planetary Fact Sheet from NASA.

   What the preceding paragraph boils down to is that Venus and the Sun will catch up with slower moving Jupiter and pass by Jupiter. Venus as a Sun orbiter will move out away from the Sun toward the East and at some point will curve around and head back toward the Sun. Jupiter as an outer planet only moves eastward (excluding when it or any outer planet is in retrograde motion). So the Sun will catch up with Jupiter coming between the Earth and Jupiter, officially on August 26th when Jupiter is at solar conjunction. Venus will also catch with Jupiter but due to Venus being an inner planet it will pass Jupiter twice – east bound and then west bound which is currently the direction Venus is moving. Venus will pass between the Earth and the Sun around the middle of August putting Venus at inferior conjunction.

   This animated graphic shows the sky at the same time and illustrates how the sky shifts toward the west due to Earth revolution as well as the changing positions of Venus and Jupiter. Were you to measure how much the sky shifts daily, by carefully observing the altitude of Regulus, for example, above the horizon and measuring this altitude each evening at the same time from the same location, you would see that Regulus has shifted westward about 1o daily. You may also noticed that Regulus was at its previous days position 4 minutes earlier. So the net effect is that as each day passes the two planets are lower and lower above the horizon, and setting closer and closer to the time of sunset.

   See some pictures of the two planets taken nearly daily since June 19th.


Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Comet ISON Simulator

Click on graphic to see it full size.

Click on graphic to see it full size.

   Here is a really neat interactive online Comet ISON simulator showing the path of Comet ISON from a space view of the inner solar system, and an Earth view – a Planetarium-like view of the horizon and starry sky where the comet is located. The simulator has a timeline along the bottom that highlights various points along the comet’s path including when it is predicted to become naked-eye visible.

Click on picture by Damian Peach to see it full size.

   The comet has brightened considerably as it approaches perihelion in less than two weeks. Here is a beautiful picture of the comet from yesterday by Damian Peach.

   Thanks to Universe Today and editor Fraiser Cain for the heads up on this Comet ISON addition to the online Solar System Scope simulator.

Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Tracking Satellites: An App

   As a followup to my posting from yesterday I thought it would be worthwhile to do sort of a review of the things I use for planning photo opportunities for the ISS and Iridium Satellites. You have seen some of what is possible with them so the review will be more of a description and how I use it. So watch for these reviews over the next week or so.

ISS Detector Pro

ISS Detector Pro

   My posting yesterday included the App ISS Detector Pro, one of the programs I use for setting up a photo opportunity for the International Space Station, or Iridium Satellites specifically. This particular App is available for Android phones and Android devices such as what I use, a Kindle Fire HD. With that in mind I can only describe how it works on my ‘handheld’ device. (By handheld I mean web enabled and capable of running Apps or software – like cell phones, tablets, or other small screen device held in the hand as opposed to the typical laptop or notebook type of computer.)

bottom bar   An additional couple of features are located at the bottom of the locator display screens. Tap or click on the left button to go online with your default web browser to a web site describing the particular Iridium satellite or the ISS. The button on the right side brings up a map showing the current location for the satellite or the ISS and a plot of the orbital path relative to the Earth’s surface as the banner picture on the top of the page shows.
Top Bar   At the top of the locator display are some other things you could do with the information shown on the display. The 3 dots icon takes you where you could share by e-mail, or by social media sites, for example. You could add the event to your Google Calendar; the 3 vertical dots take to a configuration page where you have control over a variety of things.

   The slideshow below cycles through 3 screen shots from the ISS Detector Pro App: The Home page showing any sighting opportunities for the ISS and Iridium satellites; a locator for the Iridium flare; and a locator and path for the ISS.

   Click here to read about and see additional pictures of the ISS and Iridium flares.

                              Move the cursor over any picture to bring up the controls.

This slideshow requires JavaScript.

   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Preview August Issue of Qué tal

voki   As the subject line states, the August preview issue of Qué tal in the Current Skies is now online and available at this temporary web address:
   It will be at its regular web address in a few days.

   Thank you for your support and encouragement.
   Clear Skies…
   Bob Riddle

   Click here to go to the Qué tal in the Current Skies web site for more observing information.

June Solstice

Sun's Apparent Motion Along the Ecliptic

Sun’s Apparent Motion Along the Ecliptic – from Taurus to Gemini

   Northern hemisphere spring comes to an end and its summer begins at 12:04 am CDT (05:04 UT) on 21 June as the Sun ‘reaches’ the celestial coordinates of 23.5oN and 6 hours right ascension. With respect to the Earth’s surface the Sun is described as over the Tropic of Cancer, 23.5oN of the Earth’s equator. At this same time the Sun is still within the boundaries of the constellation Taurus the Bull – but just barely. Interestingly 9 hours later, (9:00 am CDT – 14 UT), the Sun ‘will move’ into the region of Gemini as it crosses the boundary between Gemini and Taurus.
   We know that it is the Earth’s orbital motion around the Sun giving rise to the sun’s apparent eastward motion amongst the stars in the background. This is how the Sun ‘reaches’ a celestial coordinate, how it ‘crosses’ the boundaries between constellations, or how it is ‘in‘ a constellation.
   With respect to the southern hemisphere this is the end of their summer and start of their fall season so thinking globally my preference has been to use the name of the month to designate the season change. Hence the use of the term June Solstice rather than the limited to northern hemisphere term summer solstice.

   Follow the seasons by observing how vegetation changes during 1 year. The video below was produced by an Earth orbiting satellite operated by the NASA/NOAA Suomi National Polar Orbiting Partnership (NPP). It is a really interesting narrated tour of the Earth from orbit over a variety of geographic features and landscapes.

Just had to include this!!

Just had to include this!!


   Click here to go to the Qué tal in the Current Skies web site for more observing information.