Space Station Transits Sun | 11 Jun 2017

A few days ago I received an email notice from CalSky that the International Space Station would pass directly in front of the Sun for my location. The station moves about 5 mi/sec. The duration of the transit would be 0.67 sec to cross the full disc of the Sun. Here it is. Don’t blink.

This view is slowed down to 1/4 as fast and is much easier to see. Do you hear the birds in the background?

Here is a composite of the station position each tenth of a second.

Strawberry Moon | Micromoon | 9 Jun 2017

Moonrise for me last evening was 8:42 pm. I went out at 9:10 to see if the sky to the east was clear giving a view. Saturn was supposed to be positioned close to the right of the Moon. It was very hazy. The Moon was not bright and Saturn was not visible to me. I went back in the house for the camera and tripod. These two photos are at 9:20 and 9:21 with the Moon framed by some trees low to the horizon.

9:20 pm CDT

9:21 pm CDT

I went back inside to wait for the Moon to rise above some of the haze. When I returned at 9:59, the conditions were better. There was still a hazy glow near the Moon. I liked the effect. How about you?

9:59 pm CDT

Timing is everything, so I’ve heard. This moon coincides with the ripening of strawberries. Hence the name Strawberry Moon.

Much has been written in recent years about super-moons. That occurs when the Moon is at its nearest distance from Earth at full moon. This time, the Moon was at its farthest from Earth when full. The term mini-moon or micro-moon has been applied by some for this event. For more information about this full-moon, follow this link to The following image compares a super to a micro moon. See this link for details.

Astronomy Picture of the Day | Catalin Paduraru

Double Iridium Satellite Flares | 13 May 2017

Iridium is a global network of communications satellites. The system was originally a product of Motorola. Iridium’s 66 satellites provide wireless mobile communications as they move in polar orbits at altitude of 485 mi (781 km). They are able to provide global coverage from pole to pole.

This brief video illustrates the ability of the constellation of satellites to receive a ground signal, pass it to other satellites, then deliver it to the ground in another part of the world.

The original Iridium satellites carry three highly reflective antennae as shown in the image below. Because of their mirror-like surfaces being positioned much of the time in intense bright sunlight, they sometimes reflect a bright spot of light to the ground. The ground track of the reflections is known precisely. If you happen to see it in the sky above, it grows in brightness over a few seconds and can be many times more intense that Venus and then it fades away. They are most easily seen just after sunset and before sunrise. They can also be seen in bright daylight if you know where to look.

Wikimedia | Cliff

I received an email earlier in the week telling me such a reflection, or Iridium flare, was to pass right over my house going south. In fact, another Iridium satellite in nearly the same orbit was to also flare me only 24 seconds after the first. The sky was clear the night of 13 May as I set up for a time exposure photograph.

About 45 seconds before 9:22:14 pm, I started the exposure using NightCap Pro on my iPad 2. The flare maximum occurred as predicted right on time. Coming right behind it was the next one. It passed and peaked at 9:22:38 pm. After 90 seconds I ended the time exposure.

Taken with NightCap Pro | ISS mode | 89.05 sec

How does one know when and where to look? I subscribe to a service called CalSky. It emails me when significant events like this are to occur. It offers many options and services but is not the easiest to use. There are others which are simpler. The best in my opinion for the general user is Heavens Above. In these services, you need to input your location. Heavens Above makes it easy to do by clicking on a map for your location.

Using the CalSky interface, I produced the sky chart of where the Iridium flares were going to pass. It gave this chart making it easy to know where to point my camera.

CalSky Chart

Jupiter | Three Galilean Moons | 7 May 2017

The clear evening sky offered a view of our Moon with Jupiter nearby as shown at left. Near sunset we set up the telescope and camera on tripods for closer looks. Good seeing allowed a photograph of Jupiter showing a few cloud bands as well as 3 of the 4 Galilean Moons. Ganymede was at the upper right. Europa and Io were to the lower left. Callisto was visible farther to the lower left in the telescope view. But, it didn’t show in this photo.

Usually, setting the exposure for Jupiter detail underexposes the Galilean moons and makes them not visible. Setting exposure to show the Galilean moons overexposes Jupiter. This time was a compromise.

Canon PowerShot SX60HS, ISO = 100, Shutter = 1/25s, Raw

Screenshot view via Stellarium


Venus | Inferior Conjunction | 2017

Venus is closer to the Sun and orbits faster than Earth. Earth takes just over 365 days. Venus orbits in just under 225 Earth days. During the recent few months, Venus was bright and easily visible in the evening sky as it caught up to and passed Earth. In doing so, it came closer and appeared larger when viewed with a telescope or binoculars. This animation from a desktop program illustrates their motions. Mercury is not shown in order to simplify the view. The sizes are exaggerated.

Show me more…

Venus | Morning View | 24 Mar 2017

I got my first morning view of Venus this spring at 6:45. There was a layer of high clouds to the east dimming the view quite a lot. Binoculars helped locate it for a photograph. Thanks to Scott at Scott’s Sky Watch for pointing out Venus is now visible both in the evening and the morning if the sky is clear enough. He called it a double dose of Venus.

Looking slightly north of east through high clouds.

Clouds made the image a little hazy.

There was another bonus this morning. Looking to the southeast, the waning crescent Moon shined through a clear break in the clouds.