International Space Station Sails Overhead

At 8pm, a decent time of night, the International Space Station passed almost overhead here just north of New York City. (And many locations along the eastern seaboard of the United States, as seen in this graphic from

I took some iPhone video live on facebook. Just because. I don’t see stars in the video, so there’s no reference point for someone to see how the ISS is moving. (I’ll do better next time. I wonder if nightCAP video can go straight to facebook?)

Here’s some photos from my Canon XS on my trusty Manfrotto tripod:

ISS moving toward the horizon. 4 seconds worth of motion at f/3.2 ISO 800 with a 50mm Canon lens.

ISS path in an 8 second exposure at f 3.2, with the handle of the Big Dipper including Alcor/Mizar pair. And an aircraft. Longer exposure, more trail of light from the ISS, more stars show up on the photo.

It’s hard to get a photo that shows the ISS as you see it in the sky – a dot, not a streak. Here’s a one second exposure with the lens wide open for more light at f/2. The ISS is entering the frame from the bottom as it passes between Orion on the left and Taurus on the right.


Sat. Mar. 23. Aurora possible. ISS pass earlier in the evening

Nope. Not a peep. It must have missed us. I wouldn’t have made a deal about a possible aurora at G1/G2, a significant, but not a high geomagnetic activity level, but near the equinox, small storms can produce over-performing aurora. But, not if it misses us! Not too many chances during this quiet time of solar minimum. The ISS pass was fantastic. Did you see them wave? (Me neither.)

11am update: All quiet so far. K-index is 1. But the forecast has not changed for a possible geomagnetic storm tonight that could produce aurora visible low in the northern sky as far south as the northern United States. The solar plasma ejection has not reached Earth yet, so the low K-index does not mean it won’t get here.

There is actually a chance for an aurora to be seen this far south Saturday evening. A solar storm will arrive late in the day on Saturday. There are rarely seen this far south, but solar particles can be more likely to slip through the Earth’s magnetic protection field during the equinox.

Forecast for Friday midday. See web sites for updates.

Here’s forecasts for Saturday night for NYC metro: Clear but windy and cold: Saturday, March 23 at 8pmTemperature: 38 °F Dewpoint: 14 °F Wind Chill: 29 °F Surface Wind: NW 17mph Sky Cover (%): 13% Precipitation Potential (%): 0% Relative Humidity (%): 37% (As of Noon Friday. Check link for updates.)

ISS overflight almost directly overhead at 8pm. Get out a few minutes earlier to see it approach from the (See attached chart, which you can use as a star chart for the evening sky.)

Sunset 7:10pm Really dark by 8:43pm. Moon rise 10:29pm. To try to see an aurora, get outside between when it gets really dark and moonrise. Get to a dark place where you can see the sky, out of lights (and out of the wind). Give yourself 15 minutes to get used to the darkness. Look generally toward the north, or overhead, if the view to the north is blocked. An aurora usually lasts for a while, so don’t worry if you take some minutes to look at the wonderful winter constellations. No optical aid needed. Aurora are often subtle and fickle, so enjoy the rest of the sky, in case you don’t see it.

Updated aurora forecasts at: and

Good articles at and (thanks to Charlie)…

Which planet is closest to Earth most often?

Mars? No. Venus? You’re getting warmer. Mercury. Yes, Mercury!

Mars gets lots of fuss at its closest approaches, but Venus comes closer to Earth. Since we can see surface detail on Mars and it’s visible in the middle of the night, not just before sunrise and after sunset like Venus, its closest approaches are well publicized.

A new paper, reported in Physics Today, ran calculations for 10,000 years. The researchers found Mercury was the planet closest to Earth on average.

From the paper:

“Indeed, when Earth and Venus are at their closest approach, their separation is roughly 0.28 AU—no other planet gets nearer to Earth. But just as often, the two planets are at their most distant, when Venus is on the side of the Sun opposite Earth, 1.72 AU away.”

(AU is the average distance from the Earth to the Sun, about 92,955,807 miles.)

I read about this in Sky and Telescope some time ago and mention it from time-to-time in my monthly Heads UP! So, to show an example, I ran calculations from the Jet Propulsion Laboratory’s Horizons Web Interface to get distances from Mercury, Venus and Mars to Earth to plot on a graph. Here’s the graph for a two-year period centered on March 2019.

Distance from Earth to selected planets, plotted every ten days in units of Earth to Sun average distance (AUe). March 2018 through April 2020.

During this time, Mercury is the closest planet to Earth from February through December 2019, about 11 months. That’s more often than Venus or Mars. Note that Venus is makes the closest approach during this time. Mercury is the closest planet to Earth, not so much because it swings so close to Earth, but because Mars and Venus spend half their orbits further away than Mercury ever gets from Earth. Note: if you do this chart for different ranges of dates, Mercury won’t most often be the closest planet. But, on the whole, Mercury takes the prize. Is that why the authors ran the simulation for thousands of years?

Solar System
Planets in our Solar System, March 2019, from Note Mercury, the inner-most planet is closest to Earth this month (insert to upper left).

Monday’s storm: Updated 8pm Sunday

Quite a storm. Fast moving storm. Gaining strength rapidly.

NWS has to go for large snowfall amounts.

If they wait until the storm shows its cards, it’ll be too late to warn us.

8pm Update: The NWS says the high resolution model (HRRR) has been doing well with the rain/snow line in southern NJ.

In their words:

Made slight adjustments to the forecast this eve, mainly based
on the latest HRRR, which has been handling the snow/rain
transition area very well across southern NJ last few hours.
Based on this, mixed p-type should remain confined to southern
portions of Nassau county and NYC`s south boroughs, Suffolk
County and extreme SE CT. This has impacted snow totals slightly
with up to an inch more accumulation, mainly across SE CT.

Otherwise, Winter Storm Warning remains in effect with a
widespread 5 to 9 inch snowfall expected for the entire region,
highest amounts over the western half of the forecast area
between now and shortly after midnight, and the eastern half of
the area during the second half of the night.

Sunday evening it’s over the southeastern USA, Monday morning it’s all over in NYC. Five to nine inches in NYC and inland, but the rain line could move further inland if the storm wobbles a little left of the rain / snow ‘benchmark’ at 40 degrees north, 70 degrees west. Yes, Rutgers applied meteorology fans, they still use that as a factor for rain vs. snow for the NYC metro area.

Small variation in path will make a big difference in snow amounts.

Lots of moisture, warm air streaming up the coast. Heaviest snowfall after midnight for NYC metro, earlier or later to the south and north east, respectively.

From the National Weather Service forecast technical discussion for NYC from 4:30 Sunday afternoon:

Main uncertainty is with the rain/snow line as models indicate heavy snow just north of it with trends farther north or south with this line making a difference with snowfall amounts. Trends farther north with the low and its warmth aloft will lead to a little less snowfall especially across the coasts whereas a trend farther south, keeps precipitation pretty much all snow with potential for slightly higher snow amounts. The jet stream exhibits phasing of polar and subtropical jets this afternoon into tonight. This is really key with the upcoming system. . . . . [Best forcing] particularly second half of this evening through midnight from Western Long Island and SW Connecticut to farther west. Thereafter that best forcing shifts towards SE Connecticut and Eastern Long Island for overnight through around 4am local time
. . . .
[Short version: Showers and thunderstorm where the storm forms in the southeast USA add energy to the storm, getting stronger rapidly near Long Island. Local NYC area gets more rising air and heavier rain or snow after midnight. - Original, more detailed discussion continues below: ]

At the surface, low pressure develops in the Southeast US early this evening. There will be a lot of convection down there and that convection allows for latent heat release which will cause subsequent downstream ridging and upstream troughing. The overall effect is to increase baroclinicity with noticeable decreasing wavelength in height patterns aloft. The low is set to deepen by late evening along the Carolina coast and then move northeast offshore of Long Island overnight, eventually settling to a point SE of Cape Cod by early Monday morning. The models deepen the low 10-15mb from 7pm tonight to 7am Monday morning. The 12Z NAM indicates a low track inside of 40N/70W but is also less with the deepening of the low. The result here allows more mid and low level warming for Eastern Long Island with even some rain possible whereas others keep Eastern Long Island colder with more sleet mix with snow as well as some freezing rain. Looking at mesoscale, 12Z HREF indicates a high likelihood of snowfall rates exceeding one inch per hour late this evening through the start of the overnight across the forecast region. This is about the same time the 850-700mb 2-D Frontogenesis maximizes across the whole region as well which is a forcing factor for lift. It shifts east of the region after 4am local time. Still some indications from models of some enhanced lift 4-7am for Southeast Connecticut and Eastern Long Island. Therefore, kept end time of 7am for the Winter Storm Warning.

Heads UP! for March 2019

First – a limited time offer!  Mercury is sinking in the western sky right after sunset.  The innermost planet had a good showing in late February. It’s not very far from our Sun in the sky, but hanging right above where the sun set, so it’s been a good apparition for the northern hemisphere.  By the 5th, Mercury is only five degrees above the horizon 45 minutes after sunset.  It’s dimming as it drops, so after the 5th, binoculars are needed.

Evening sky, facing west, just where our Sun set.
Mercury, looking like a moderately bright star only five degrees above the horizon 45 minutes after sunset through the 5th.

Jupiter and Saturn are fleeing from the solar glare, low, but are well into the dark morning sky. Venus still blows the rest of the planets away with its brightness, but it’s getting so low, low down among the streetlights.   Around mid-month, the three pose equally spaced across the southeastern and southern skies.

The morning sky, looking southeast to south, to the right of where our Sun will rise in 45 minutes.

The label for Saturn is harder to find than the label for impossible-to-see Pluto.

Take advantage of the darker skies in the morning to get your telescope out and see what Jupiter looks like to you.  Any size telescope is good for aim at the banded planet.  What do its bands look like this month?  Typically, Jupiter has two darker bands, one north and one south of its pudgy equator.  One year, bright ammonium sulfate clouds formed over one band, so it looked like Jupiter only had one stripe. Early reports says the equatorial region has darkened.  What do you see?  Let us know! During one of your mornings with Jupiter, you might see one or two of Jupiter’s moons making shadows on the planet.  The moon itself may appear to be out to the side of the planet at that time because we get a bit sideways with Jupiter, a condition called ‘quadrature’.  The Canadian Almanac says two shadow transits at once will occur in the early mornings of March 18th and 25th.  You may need three inches or more of telescope aperture to see these satellites’ shadows.  

Prediction of how Ganymede and Europa’s shadows could look on Jupiter around 5am EDT, Monday, March 25th, 2am PDT. Ganymede are Europa are off the the left of Jupiter in this rendition. Many telescopes will invert this scene. In a telescope, west is the direction Jupiter will move, providing a guide to which way the cardinal directions are in your telescope.

Mars leads the passage of the bright winter stars across the evening sky.  Going to daylight time makes Orion and the other constellations seem to take a step backwards.  In the fall, the switch back makes the stars seem to rush for the exits sooner. 

Screenshot of the evening sky for mid-month. Our Moon’s location will be further to the right earlier in the month and further left after this date.

Guy Ottewell, in his Astronomical Calendar at, points out our Moon, Saturn and Pluto will appear to be within a tight circle on the 2nd.  If you are spending a spring break in Cancun later in the month, you can point out where Pluto is on the 29th, when Pluto is passing near or just behind our Moon around that day.  Earlier, our Moon will occult Saturn for folks in southern Africa.   

Speaking of unobservable events, our Moon approaches various clusters each month.  Many almanacs use our Moon as a pointer to interesting objects.  For its pass by the Beehive on the 17th, the waxing gibbous Moon will make the bees hard to see without optical aid, defeating the purpose.  However, it is fun to use a telescope and find the hidden bees even though our bright Moon is so close by. 

The pass of solar system objects by our Sun in our skies should be a classic unobservable event, but the SOHO solar coronal viewer at makes it possible.  Mercury, Neptune and minor planet Vesta pass through the C3 frame this month.  The United States’ Navy Research Laboratory has a finder chart for these passes is at .  Our WAA folks have confirmed it’s safe to access this site, despite our browser’s warnings.

If you don’t want to go there, I have a summary of the SOHO site’s information at

The International Space Station is visible in the dawn sky through the 18th, and for the rest of the month in the evening.  Have you seen the United States Air Force space plane OTV-5?  It’s visible to the unaided eye, but it’s not very bright in our skies.  Based on long-range projections, mid-month will be the best time for evening sky viewing.  See it to get astronomical and spy tech bragging rights.  Changes in solar ‘wind’ strength and its effects on our Earth’s tenuous but tenacious upper atmosphere can change satellites orbits with time. Check or your favorite satellite spotting app for updates. The Air Force launched the OTV-5 in September 2017, and the Air Force changes OTV’s orbit from time to time and could bring it back to a gliding landing at any time.

This month’s full Moon is on the 20th, just 25 hours after lunar perigee.  It’s not a very close perigee, as our Moon is 1,500 miles further away than February, with our Moon made its closest approach for the year. March’s full Moon is 3,400 miles further away than last month’s ‘supermoon’ full Moon.

Daylight time begins Sunday morning, March 10th.  It moves the sunrise forward an hour by the clock, making our morning planet-viewing time more accessible to everyone.  Look out for some clear mornings after the time shift!  Plan ahead by reviewing long-range forecasts or computer models for when a big high-pressure system may settle over us, or, even better (but typically briefer), when a tropical warm front brings stable, but perhaps hazy, air our way. 

Using SOHO to see the impossible scene

The passing of solar system objects near our Sun in our skies should be an unobservable event, but, you, intrepid reading of blogs, may already know our secret for actually viewing these events; we can ‘cheat’ by using the Solar and Heliospheric Observatory. SOHO is designed to look for faint solar wind phenomena near our Sun, which is exciting all by itself. The pages with the SOHO solar viewer is at .

The SOHO spacecraft is a million miles from Earth in the direction of the Sun, and doesn’t have to deal with pesky things like atmospheric turbulence or our Moon photobombing the shot. This kind of photo is hard to take from Earth, unless you have a total solar eclipse (next in the USA in 2024!), which is a good kind of lunar photobombing.

In March 2019, Mercury, Neptune and minor planet Vesta pass through the widest viewing frame, known as C3.  The United States’ Navy Research Laboratory has a finder chart for these passes (for some reason, the site is not listed as secure by our browsers, so you may want to skip following this link until we find out what’s going on there): . But, I’ve borrowed the graphic for 2019, right here:

Field of SOHO’s C3 camera, marked with where and when solar system objects will pass through in 2019.

A recent example of using the SOHO viewer, to see when Saturn passed near our Sun from our point of view, is at:

Happy hunting – report results in the comments, if you like!

Heads UP! for February 2019

We start today with a new moon, and we’ll wait a few days for the banana moon to appear and ripen.  In the meantime. . .

The early morning sky looks like someone pulled the fire alarm.  Jupiter is soaring out to the upper right of Venus bailing to the exit to the lower left.  Saturn is staggering in from the lower left, as if bewildered.  It’s all happening low in the southeastern sky, to the right of where the sun will rise.  Folks further south will have a better view of the proceedings.  The sunrise time will keep moving later, more rapidly as the month progresses, so it’s a good idea to check this scene out while you’re still starting your day in the dark.

The best evenings to see the International Space Station flying over the tri-state area will be on the 7th and the 8th.  The ISS will appear to pass almost overhead on those dates.  On the 10th, the ISS will pass near the Moon and Mars just before 6pm.  The sky will be pretty bright at that time.  Get out early and find our Moon, then Mars, then watch that area for the ISS.  That’s likely to be the best strategy for stalking the station that night.  Go to for a full list of sightings and to get details on the path the ISS will take through our evening twilight skies. The evening passes end on the 12th.  The ISS joins the morning fun starting the 20th

The International Space Station sails past Mars and the Moon on the evening of Sunday, Feb. 10th, just before 6pm EST.

Mars still stands high in the evening sky, like a party guest that has nothing much to offer (it’s hard to see any details in most of our telescopes), but refuses to leave.  The Moon comes by on the 10th to remind Mars of better days.  See how early after sunset you can find Mars with our Moon as a pointer.  Mars makes itself useful by passing a degree from Uranus on the 13th.  Uranus appears about half the width of Mars in a telescope and the color contrast – reddish/blueish – could be very nice.

Mercury doesn’t get far from the Sun, but in contrast to the shallow sky in the morning, its trip up from the horizon is almost vertical.  It’ll be Mercury’s best evening sighting for the year for the northern hemisphere.  Greatest elongation is on the 26th at 18 degrees east of (following) the Sun.  After that, Mercury appears to tail off the right as it swings back toward the solar glare.  Get a preview of Mercury in the SOHO spacecraft’s C3 view now through the 9th.

More about the morning – From the 17th though the 20th, Saturn tries to recreate the super sight of January’s view of Jupiter with Venus.  Saturn is 2½ magnitudes dimmer than Jupiter, so the Saturn/Venus conjunction will not be quite as spectacular as Jupiter/Venus was.  Our Moon, Venus and Saturn group up in the morning sky in early March. In the meantime, see if you can get a selfie with the Jupiter/Venus/Saturn planetary arc, especially later in the month.  

Due to the way the IAU set the boundaries of the constellations, Jupiter is not in a zodiac constellation this year – it’ll be in Ophiuchus (I pronounce it ‘that harder-to-see constellation above Scorpius’).

Make sure you get a look at the superest Moon of 2019!  The closest Full Moon of the year occurs on the 19th just four hours after the closest lunar perigee of the year about 5am.  This should make for some great photos of the setting Moon that morning.