Category Archives: Uncategorized

One out of two ain’t bad

I was out this morning, Jupiter and Mars well placed in the south-southeast, but didn’t see the predicted pass of Tiangong2.  The twilight was very bright, but I could still see Arcturus and Jupiter. Here’s this morning’s blue twilight sky with Jupiter barely visible in the photo, about 20 minutes before sunrise.


Canon XS 18mm zoom lens, 1/4 second at f7.1, ISO200.

Since I had been keeping track of where Jupiter was (over that tree), and the sky was clear, Jupiter was easy to see, even though the sky was getting brighter.  Easier than in this photograph.  ( I don’t know how to set this so you can click and enlarge it – it used to be easy in wordpress.)


Oh, Jupiter! And, seeing space stations.

Jupiter is back and its moons are playing their usual tricks.  These are visible in most telescopes.

On Friday morning, the 19th, after Jupiter rises about 2:10am, three of its four brightest moons will be visible. Only Io will be hidden.  From 2:40 to 4:55, Europa’s tiny shadow will be visible on Jupiter’s cloudtops, joined by Ganymede’s shadow starting at 4:43. Europa will blend into Jupiter’s clouds as it moves in front of the planet by 4:56am. Io will reappear from behind Jupiter at 5:08am. The Great Red Spot also crosses the disk, visible an hour or so either side of 5:30am. Sunrise is 7:16am.


Thursday and Friday morning there will be some nice satellite overflights.  In the mornings, the new space station launched by China will pass over us.  Tiangong2 will be overhead on Thursday morning at 6:48am, passing from west to east in a bright sky.  If you can see Arcturus overhead, you should be able to note Tiangong moving across the sky.  On Friday, the pass is earlier, in a darker sky, not overhead, but still high in the sky:


The International Space Station will be visible again, soon, in the evening sky beginning on the 23rd.  The best passes are predicted for the 25th and the 27th.




Heavy Rain at Times Fri./Sat., then Sharply Colder

Watch out for lakes on the highways and backyards today as rain, heavy at times, falls Friday into Friday night.  Temperatures will drop all day Saturday from today’s high forecast in the upper 50s !  With the cold air knifing in under the warmer air with strong winds, late Saturday morning into midday the rain may change to ice pellets (sleet).


The National Weather Service is watching the timing of the precipitation and cold air.

In the Friday morning forecast discussion, the NWS is thinking the rain will end before the coldest air arrives, but watch out for quickly-forming patches of ice:

Cold air then rushes in immediately behind the low center Saturday
morning as it passes through the tri-state area. This would bring
sleet and freezing rain to the NW zones, however PCPN chances
quickly diminish at the same time. Can`t rule out the need for a
winter weather advisory for some of the NW zones, but for now
confidence in the likelihood of PCPN occurring at the time thermal
profiles would support freezing rain is not high enough to issue
one. Another potential issue could be a flash freeze north and west
of the city as cold air quickly filters in as rainfall is ending.

Then waves of low pressure rush down from western Canada (“clippers”) for Tuesday through Thursday with the possibility of brief snowstorms or just snow showers.

Temperatures may be below or near freezing until next weekend.





Lots of Rain Friday, possible end as frozen precipitation Sat Midday?

Forecasts for the NYC area have continued with about two inches of rain for north and east of NYC on Friday into early Saturday.  Local and river flooding are possible.  Tropical moisture just makes it to NYC and points eastward.  Don’t be surprised to hear a rumble of thunder Friday/Saturday night.  Don’t be surprised to see temperatures in the 50s on Friday and watch them drop rapidly by midday on Saturday.  Be ready for fog Friday as the snow cover chills out the moist air mass above it.


Map of total water above the surface. Blue and green are moist and browns are dry.

The cold air is forecast to get here midday Saturday, with a chance of the rain becoming ice pellets or snow before ending early Saturday afternoon.

Then we slide into the freezer again, with below freezing temperatures all day Sunday and Monday.  The next chance for a snowfall is Tuesday.

Wed Morning Jan 10 Moon, Jupiter and Mars in twilight

Here’s some photos from a relatively balmy 20 degrees F dawn in Ardsley, NY.

Click on the photos to enlarge them.

Note some earthshine on the crescent moon in the wide view that includes Jupiter and Mars. Jupiter and Mars are easy to see in a dark sky.

Yes, that may be a 9th magnitude star just below the moon in the shot from the telephoto lens. It wasn’t apparent until I enhanced the photo.

The graphic is the scene Thursday morning, when the moon passes by Jupiter and Mars in our skies.  It’s likely to be cloudy here in the east, so I decided to take the photos today.

Pesky light precip this evening rush hour in the east. Upcoming storms for SoCal and Minn, then the Eastern USA.

The NWS is forecasting light precipitation late this Monday afternoon and evening.  Mostly light snow, but if enough warm air gets in along the coast, there could be some rain that would likely freeze on surfaces, so be careful if you need to travel later today.  Other parts of the east coast, from DC to Phila, as well.

From the NWS forecast discussion for NYC:

Light precipitation out ahead of the frontal system will work
into areas north and west of NYC this afternoon, and then into
the NYC metro and SW Connecticut mid to late afternoon. Farther
east, across Long Island and southern Connecticut, precipitation
will begin very late this afternoon, probably close to sun down.
Vertical temperatures profiles support primarily a light
snowfall event across most of the area, with the possible
exception of coastal locations which could begin as wintry mix.
A dry sub cloud layer will allow for evaporative cooling with
the boundary layer likely cooling to freezing or below. Right
along the coast, temperatures will be at or just above freezing.
Ground temperatures though will likely be below freezing due to
the prolonged period of subfreezing temperatures. Any rain,
especially on untreated surfaces, may freeze in spots. Amounts
will be extremely light with less than a tenth of an inch of
liquid equivalent. Any snowfall across the region will be under
an inch and any ice accretion will be on the order of a
hundredth or two.

Due to the uncertainty of precipitation type at some locations
and the light nature of the precipitation, preference is to hold
off on issuing a winter weather advisory at this time.

Meanwhile – heavy rain is possible in Southern California.  While this is expected in the winter wet season, it will be a problem, especially for areas where wildfires have left the landscape open to erosion.

Minnesota has reached the freezing (melting?) mark of 32 degrees F, but the NWS is looking at the first winter storm of the season for Wednesday night/Thursday.

The medium-range outlook has waves of rain for the NYC area beginning on Thursday, then sharply colder on Saturday.

The system will bring the likelihood of rain Thursday night through
the first half of Saturday. Timing adjustments are anticipated as we
get closer to the event. There may be several waves of rain, first
from warm advection and then as the actual low pressure and cold
front move across. The rain will be accompanied by temperatures
warming into the 50s on Friday and in the upper 40s to near 50 on
Saturday. There is the potential for a widespread 1.5 to 2.5 inches
of rainfall, but this would occur over a long time period. See
hydrology section for more details. Warmer temperatures, snow-melt,
and the rain may lead to areas of fog.

Dry conditions return Saturday night into Sunday as the low moves
away and arctic high pressure builds into the nation from Canada.
Temperatures on Sunday should fall back into the lower 30s.


Indoor / Outdoor Astronomy

First, let’s talk about Outside.  3 degrees Outside. 3 above zero on Mr. Fahrenheit’s scale. It wasn’t so bad; thanks to a lack of wind I lasted for 30 minutes but no more, even though well bundled up.

Jupiter next to Mars made it all worthwhile.  Yes, I could have viewed it from inside (see below), but to get a wider, deeper view, as well as a closer look, it’s better to get out and look without the interference of glass or walls.


Jupiter and Mars to the upper left. Canon XS 35mm zoom lens, 6 second exposure at f/5, ISO 800. Bob King’s recommendation.


Star map for the area in the photo above.


Looking to the upper right of Jupiter and Mars

Let’s take a closer look, using the 250mm zoom lens, at Jupiter and Mars. I’ve cropped this from a larger view to show the details.
IMG_7960 (2)

It’s fun to have captured Jupiter’s moons in this photo of Jupiter and Mars. Jupiter and Mars are overexposed, so don’t show color or details, but the extra exposure helps Jupiter’s four moons come out. 250mm zoom lens at f/7.1 for one second, ISO 800.

Four moons? Yes, there are two pairs of moons, one pair on each side of Jupiter! I had thought, given the 250mm lens is not a real telescope and this is cropped from a larger photo, that two moons were just blurred. wspace
I checked using NASA’s solar system simulator, to see what Jupiter and its moons looked like from Earth – and there they were – two sets of closely spaced moons!  So, not a glitch, but actually what was there.
Astronomy from indoors?
Yes! It’s easier when you have two bright planets close to each other to attract attention. Jupiter and Mars are the two bright ‘stars’ next to each other. Some background stars are visible.
Canon XS on tripod, following Bob King’s recommendation with a 35mm zoom lens working at f/4.5, 6 seconds, ISO 800 shows what you can see from indoors, in a dark room, framed by some nice curtains.   In a warm room.
So, while I was out, here’s a cropped photo of the moon, with the telephoto 250mm lens.
IMG_7964 (2)

Cropped from a much larger photo of the sky including the moon; 250 mm telephoto lens at f/7.1, 1/800 second exposure at ISO 800.

In addition to the various shades of gray in the bright sunshine on the lunar surface, the terminator shows and hints at craters and walled plains visible in the light and dark shadows shown by the low angle of sunlight.