Uploaded October 2011 | Updated September 2026, 2 weeks ago
The 5th anniversary of the launch of the NASA STEREO mission (twin spacecrafts) grows near (Oct. 26). We will be posting a sample of STEREO's selects gallery of many great observations and discoveries of the next few days.
Solar Eclipse, STEREO Style - Feb. 25, 2007
There was a transit of the Moon across the face of the Sun - but it could not be seen from Earth. This sight was visible only from the STEREO-B spacecraft in its orbit about the sun, trailing behind the Earth. NASA's STEREO mission consists of two spacecraft launched in October, 2006 to study solar storms.
The transit started at 1:56 am EST and continued for 12 hours until 1:57 pm EST. STEREO-B was about 1 million miles from the Earth, 4.4 times farther away from the Moon than we were on Earth. As the result, the Moon appeared 4.4 times smaller than what we are used to. This is still, however, much larger than, say, the planet Venus appeared when it transited the Sun as seen from Earth in 2004.
This alignment of STEREO-B and the Moon was not just due to luck. It was arranged with a small tweak to STEREO-B's orbit in December 2006. The transit was quite useful to STEREO scientists for measuring the focus and the amount of scattered light in the STEREO imagers and for determining the pointing of the STEREO coronagraphs.
The Sun as it appears in these the images and each frame of the movie is a composite of nearly simultaneous images in four different wavelengths of extreme ultraviolet light that were separated into color channels and then recombined with some level of transparency for each.
NASA SDO will see a Lunar transit early next year too. And then in June the Venus transit. Stay tuned...
Credit: NASA STEREO
The 5th anniversary of the launch of the NASA STEREO mission (twin spacecrafts) grows near (Oct. 26). We will be posting a sample of STEREO's selects gallery of many great observations and discoveries of the next few days.
Solar Eclipse, STEREO Style - Feb. 25, 2007
There was a transit of the Moon across the face of the Sun - but it could not be seen from Earth. This sight was visible only from the STEREO-B spacecraft in its orbit about the sun, trailing behind the Earth. NASA's STEREO mission consists of two spacecraft launched in October, 2006 to study solar storms.
The transit started at 1:56 am EST and continued for 12 hours until 1:57 pm EST. STEREO-B was about 1 million miles from the Earth, 4.4 times farther away from the Moon than we were on Earth. As the result, the Moon appeared 4.4 times smaller than what we are used to. This is still, however, much larger than, say, the planet Venus appeared when it transited the Sun as seen from Earth in 2004.
This alignment of STEREO-B and the Moon was not just due to luck. It was arranged with a small tweak to STEREO-B's orbit in December 2006. The transit was quite useful to STEREO scientists for measuring the focus and the amount of scattered light in the STEREO imagers and for determining the pointing of the STEREO coronagraphs.
The Sun as it appears in these the images and each frame of the movie is a composite of nearly simultaneous images in four different wavelengths of extreme ultraviolet light that were separated into color channels and then recombined with some level of transparency for each.
NASA SDO will see a Lunar transit early next year too. And then in June the Venus transit. Stay tuned...
Credit: NASA STEREO
