Photo of the International Space Station’s Trail Across the Sky

I love an advertisement that pokes fun of the company it’s advertising.  Actually, I love funny ads in general!

One in particular.  The copy read, “Here’s a glorious, full-sized color photo of the Goodrich blimp!”  It was a photo of a (blank) blue sky.  Goodrich was a rubber tire company, but not the one (Goodyear) that had the blimps. 🙂

So, you know where this is going.  I kinda missed the ISS’s (ISS’?) overflight last night.  It’s hard to focus the camera without bright stars, there were too many streetlights, yada, yada, yada.

As I was focusing on the Big Dipper, I noticed the very bright dot of the ISS at the bottom of my frame.  Here is the photo:

Upside-down Big Dipper between a roof gutter and a tree.
The track of the ISS is that bright dash leaving the bottom of the photo.
Five-second exposure Canon XS 18mm zoom lens at f/4, ISO 800.
No processing.

The ISS, in the sunlight 432km right above me, was brilliant!

I re-aimed the camera and tried twice more, each with the two-second delay to decrease camera shake, and the same five-second exposure time. If I take a shorter exposure, the stars don’t show up, but the ISS makes a dot like it looks in the sky, not the streak we see in timed exposures.

Hope you had better luck! Share your story in the comments.

May 16 2020: Gulf of Mexico to Gulf of Maine International Space Station Overflight Tonight

The ISS will fly over the eastern United States during twilight tonight, crossing New Orleans, Washington (DC), New York and Boston. You’ll be able to see the ISS crossing directly overhead between 8:38pmCDT for New Orleans and other places in the Central Time Zone, 9:42pm EDT for the folks from Washington, DC and the Eastern Time Zone.

Map for the overflight, centered on Washington, DC, so you can see the path over the eastern United States. forecast of ISS ground track for Saturday, May 16th.
Time hacks in eastern daylight time.
Example sky plot for ISS over Washington, DC.
This map will be similar for most locations near the ground track.
A couple of minutes earlier for locations to the southwest, later for places to the northeast.

For many locations, the track of the ISS through our skies will take it in front of the handle of the Big Dipper! The stars of the tail of the Great Bear may be hard to pick out of the bright twilight. I’ve found them easier to see after the ISS goes by, as the eye has something distant to focus on.

This fly-over is not a planned event specifically for the Eastern United States – it’s a consequence of orbital mechanics of the many loops the ISS takes around our planet.

Update! Mid-May 2020 Swan Song, ISS all-night, Venus/Mercury, Morning Planets

  • Summary:
  • Is Comet Swan going to re-brighten?. It’s low in the northeast just before sunrise. Also later in the month low in the northwest right after sunset.
  • This week, try for as many ISS overflights as you can see in a night – every 90 minutes or so for a few nights, then just in the evening sky. Check or the NASA site for times.
  • Venus stands bright, but getting lower, in the west-northwest. Watch for Mercury’s pop-up appearance, arcing above Venus later next week. The very thin Moon joins them in twilight on the 24th/25th.
  • Jupiter and Saturn are still outstanding low in the southeastern sky before sunrise. Check out their moons! Mars socially distances to the left.

Comet SWAN: Another one falls to dust (I think there is a song there!). It may be showing signs of re-brightening. Best resource for SWAN is Astro Bob (no relation) at .

ISS overflights! The night of the 15th /16th has as many as six (!) overflights, some better than others. Here’s a list from for White Plains, NY. This is also a great night of ISS viewing for the northeast and middle-atlantic states of the USA. See heavens-above for times for your location. The ISS has a “high beta angle” near the summer solstice for the northern hemisphere. This year beta season is very early and here’s a link to why. Thanks to space station guys for the reference!

15 May-2.420:51:2310°S20:53:5420°SE20:56:2610°Evisible
15 May-2.822:27:1210°WSW22:30:2749°NNW22:33:4510°NEvisible
16 May-0.700:05:4010°NW00:07:5216°NNW00:10:0410°NNEvisible
16 May-0.501:43:4010°NNW01:45:4115°N01:47:4310°NEvisible
16 May-2.203:20:0110°NW03:23:1137°NNE03:26:2210°Evisible
16 May-2.804:56:5810°WNW04:59:5327°SW05:02:4810°SSEvisible
Times you can see the International Space Station from the NYC metro area.
Thanks to !

The best overflight over NYC is on the 16th, overhead, across the Big Dipper, about 9:43pm. After the 19th, the overflights are after sunset through mid-night.

At Four-so-early-in-the-morning (Daylight Time), see the outer planets. (Pluto’s location marked for completeness. Not visible.)

4:30am Local Daylight Time sky May 16th. Good for rest of May
(However, the Moon will move on each day toward new moon on the 22nd.)

Cute break for today: When I wear my Planetary Society shirt, My two-year old grandchild points to the tiny dots at the bottom of the shirt, out beyond Neptune, and says “planets”. I guess she’s in favor of Kuiper-Belt objects as planets!

Week of May 6-13, 2020 Sahara Dust Episode in Puerto Rico

  • 12Noon EDT/AST update on Thursday, May 7th:
  • Visibility at San Juan Airport varying between 8 and 9 miles this morning in haze in all directions.
  • US Naval Research Laboratory’s NAAPS model predicts dust will move on (toward Florida) by Saturday.
  • For more updates, follow the links at the bottom of the post!

Visibility is dipping to less than 10 miles in Puerto Rico this week and may last through the weekend. The tropical skies in Puerto Rico are often crystal clear, at least when it’s not raining. You can see more than 10 miles most of the time in Puerto Rico, despite the high humidity commonly occurring in this tropical locale. But when the aviation weather observation occasional says “HZ ALQDS” (haze in all quadrants), dust from the Sahara Desert is likely the cause.

Below is a list of today’s observations since midnight local time at the San Juan International Airport on May 6th : Visibility was as low as 8 miles. Despite some nearby power plants, due to a relative lack of combustion emissions, and good dispersion in trade winds, there is not much sulfate that causes the white summer haze seen here in the eastern United States.

TJSJ 070056Z 09007KT 10SM CLR 27/23 A3002 RMK AO2 SLP164 T02720233
Example decoded, below:
TJSJ 062356Z 08007KT 10SM FEW033 27/23 A3000 RMK AO2 SLP158 T02720233 10333 20272 53013
TJSJ 062256Z 12007KT 9SM FEW034 FEW150 29/22 A2999 RMK AO2 SLP153 HZ ALQDS T02940217
TJSJ airport 06 May, 22:56Z is 6:56pm May 6th 9 miles visibility, few clouds at 3,400 feet, few clouds at 15,000 feet, temperature 29C, dew point 22C, altimeter setting 29.92 inches Remark about automated sensing, sea level pressure 1015.3mb, haze in all directions, temperature more precisely at 29.4, dew point at 21.7.
TJSJ 062156Z 14006KT 9SM FEW036 SCT150 31/21 A2997 RMK AO2 SLP148 HZ ALQDS T03060211
TJSJ 062056Z 15009KT 9SM FEW038 SCT130 32/21 A2996 RMK AO2 SLP145 HZ ALQDS T03170206 56007
TJSJ 061956Z 15012G17KT 9SM SCT040 SCT130 32/21 A2997 RMK AO2 SLP146 HZ ALQDS T03220206
TJSJ 061856Z 12009G16KT 9SM SCT044 SCT130 33/22 A2996 RMK AO2 SLP145 HZ ALQDS T03280217
TJSJ 061756Z 09016KT 9SM FEW042 SCT050 SCT130 31/23 A2998 RMK AO2 SLP152 HZ ALQDS 60001 T03110228 10333 20283 58019
TJSJ 061656Z 14009G17KT 9SM FEW045 BKN130 33/21 A3000 RMK AO2 SLP158 HZ ALQDS T03330206
TJSJ 061556Z 12010G19KT 9SM FEW037 SCT050 SCT090 32/22 A3003 RMK AO2 SLP167 HZ ALQDS T03170222
TJSJ 061456Z 09018G21KT 8SM FEW031 SCT041 SCT090 32/23 A3004 RMK AO2 SLP170 HZ ALQDS T03170228 50004
TJSJ 061356Z 09017KT 8SM FEW028 FEW130 31/23 A3004 RMK AO2 SLP171 HZ ALQDS T03110228
TJSJ 061256Z 09014KT 8SM FEW026 FEW120 30/23 A3003 RMK AO2 SLP168 HZ ALQDS T03000228
TJSJ 061156Z 10007KT 8SM FEW026 FEW120 28/23 A3002 RMK AO2 SLP166 HZ ALQDS T02830228 10283 20244 53015
TJSJ 061056Z 14003KT 8SM FEW024 26/22 A3001 RMK AO2 SLP159 HZ ALQDS T02610222
TJSJ 060956Z 12004KT 10SM FEW033 FEW085 26/22 A2999 RMK AO2 SLP153 T02560222
TJSJ 060856Z 00000KT 10SM FEW032 SCT080 26/22 A2998 RMK AO2 SLP151 T02560222 55001
TJSJ 060756Z 00000KT 10SM FEW030 SCT050 SCT075 26/23 A2997 RMK AO2 SLP149 T02560233
TJSJ 060656Z 00000KT 10SM SCT022 SCT075 26/23 A2998 RMK AO2 SLP149 T02610228
TJSJ 060556Z 09004KT 10SM FEW025 SCT075 26/23 A2999 RMK AO2 SLP153 T02560228 10272 20256 56008
TJSJ 060456Z 12004KT 10SM FEW024 FEW060 27/23 A2999 RMK AO2 SLP155 T02670228

The US Navy uses computer models to predict the transport of dust and other particles that can reduce visibility. It would seem to me the US Navy’s interest in haze and dust is the Navy doesn’t like the idea of not being able to see in all directions, in case they need to protect themselves from potential attackers. It’s good to know when low visibility might allow foes or even landmarks or other ships to be hidden. Thus, one of the many projects at the Naval Research Laboratory is the sensing and measurement of particles in the atmosphere, where they are and they the come from.

Here’s the NRL’s forecast for sulfates, dust, and smoke for 1200 UTC on May 7th.

From the US Naval Research Laboratory web site.

This map predicts dust concentrations of over 80 micrograms per cubic meter over Puerto Rico, denoted by the light blue color on the ‘dust’ map in the lower left quadrant. The health standard for particulate matter less than 10 microns is 150 micrograms per cubic meter. Particles of Saharan Dust are left after traveling across the Atlantic Ocean are typically between 2 and 5 microns in size.

The dust is lofted into the air in sandstorms in the Sahara Desert. Most of the strong winds come from the downdrafts of large thunderstorms or when large pressure gradients produce high wind speeds. This dust gets lofted into the middle of the troposphere and gets pushed out over the Atlantic Ocean by tropical trade winds. Because of the stable layer caused by the hot, dry air from the desert, over moist, cooler air at the ocean’s surface, this dust can travel thousands of miles, only slowly falling out of the sky. Over land, more mixing occurs and the dust is brought near the ground, creating the low visibility conditions.

Here’s some quick links to weather information, so you can track this Sahara Dust episode:

Latest San Juan Airport Weather observations:

Latest satellite photo:

Local National Weather Service forecast discussion for Puerto Rico and the Virgin Islands:

More information is at my other blog post with some more sources of data at

Almost Full Moon – 2 hours before perigee

Just took a Canon XS snapshot of the not-quite-Full-Moon. Great view in binoculars. The relief from the Sun rising over the craters on the southeastern limb of the Moon (from Earth’s point of view) was fantastic as the Moon’s South Pole was tipped toward us. So, I popped the camera on the tripod and used the 250mm lens and got a good focus using the 10x live view.

250mm lens at f/7.1 1/800 seconds at ISO200.
Sharpened a bit and increased the brightness and darkness
in Photoshop Elements 15, from RAW file, saved as factor 7 jpeg.
A ‘murderer’s row’ of craters along the lunar sunrise line.
IDL TIFF file converted to jpg by PE15 for wordpress use.
From NASA’s Scientific Visualization Studio.

Moon Data: 97% full just two hours before it was at perigee at 223,532 miles from Earth – the sixth closest monthly lunar perigee of the year. Luna will be further away from us at Full Moon, 32 hours from tonight’s perigee. I think that will be the third closest Full Moon of the year. I was lucky to have been able to see it tonight, instead of the farther awaySUPERMOON” (say that in Movie Announcer Voice) on the night of May 6/7. The South Pole of the Moon was tilted 6 degrees toward us. It makes the northern features look a bit shifted toward the northern horizon.

The Moon was even better in my 8×25 image stabilzed binoculars than this photo and saved the task of hefting the 43-pound scope outside.

Zoom-ing across the skies

Last night, I spent most of an hour after sunset with a local Girl Scout Troop. Via video conference for the Westchester Amateur Astronomers.

I thought I’d write it down in case it helps others who are trying to do remote astronomy.

Me, with the 8-inch dob, getting ready for our Girl Scout zoom conference.

They enjoyed it and were thankful for some directions as to where to look in the sky. We had a 3/4 full Moon which gave us a great, very bright, starting point. A quarter turn to the right and we were looking at Venus. As twilight faded, Venus stood out more and more, amazing our guests. They spotted stars as they ‘came out’. Castor and Pollux in Gemini were noted early, since they were between the Moon and Venus. Some with a good western horizon saw a red star, likely Aldebaran. (Taurus and Orion were blocked by trees at my house.) I pointed out Leo would become visible, jumping over the Moon, by the time they finished their campfire after our star party.

Advanced planning helped. The Troop Leader acquired copies of the National Geographic guide to the stars. They got a hold of small binoculars. I sent the latest map for May. I had my eight-inch Orion Dobsonian telescope out. I took some photos of the Moon and of Venus before we started. I took them on my Android Tablet at the eyepiece and they came out pretty well. I wasn’t able to show the view through the scope live on the video call, so I pointed my iPhone at the photos on the tablet and the Scouts were able to see them. (They are included, below.) The brightness was too great to see details when I held the iPhone to the eyepiece during the call. I’ve taken photos at the eyepiece with my iPhone before, so I know the phone can do it, but when the video call was using the camera on the iPhone, the Moon overwhelmed the details and Venus was lost in the twilit sky.

I talked about how to get started with bright objects, like the Moon and Venus. Then, the light and dark areas on the Moon and how and when they came to be. Why Venus was a crescent. Where Polaris, the North Star, would be. How the Milky Way wouldn’t be seen, even in darkness, because it was on the horizon tonight. Our Galaxy was spread around us like two paper plates taped together and we are on the outer part of that disk looking sideways across the Galaxy. And tonight, looking upward, we are looking out of the top of the Galaxy into intergalactic space.

Here’s the photos of Venus and the Moon. Android Tablet held up to eyepiece. 2-inch eyepiece at 40x in the 200mm dobsonian reflector. I’ve cropped the Venus view to show the crescent better.

Good luck with virtual star parties!