Try your hand at this quiz about the summer sky, space exploration, anniversaries and astronomical events. What are some of the highlights of the time between the June solstice and the harvest festival of Lammas on August 1st?

Summer Solstice to Lammas – Quiz

Summer Solstice - St John's Day
Each day for six months after the winter solstice, the Sun rises a bit higher in the sky. It reaches the maximum height at the summer solstice, the longest day. Evidence of rituals and festivals at the times of the solstices goes back thousands of years.

I would still love to be on the river in one of the valleys in Austria where Sommersonnenwende (summer solstice) is celebrated with lights on the river and on the hills plus fireworks. I found there was a broken link in my article, so have found a new picture of the Wachau Valley on Sommersonnenwende.

But of course the solstice has long past now and we're nearing the equinox.

Bonfires on the beach are a big feature of Catalan celebrations of the feast of St. John (San Xoan) in Spain. Much of the tradition leans heavily towards summer solstice celebrations.

Did you know that St Brigid's Day is associated with Groundhog Day? It falls on a cross-quarter day, i.e., a day midway between an equinox and a solstice. In the Celtic tradition, this is where most of the major festivals were celebrated.

February second is Groundhog Day, a day that's a mystery to people outside North America. Even in the USA and Canada, it's more a bit of fun than a holiday. Yet however superficial it is now, it's the offshoot of traditions that began in Europe thousands of years ago.

Groundhog Day

Here's an annotated photo of the Summer Triangle over the Great Wall of China. Even against the starry background of the Milky Way, the three stars of the Triangle stand out - especially Vega!

In 1054 there suddenly appeared a bright star in the sky that was described by Chinese astronomers. In fact, the stellar explosion that had caused it had happened around 6500 years before, but it took several thousand years for the light to travel the long distance to Earth.

This is a composite image of the Crab Nebula (M1), the remnant of a supernova. The image was created by combining data from five telescopes spanning the electromagnetic spectrum from radio waves to X-rays. This means most of the colors are false colors, because they represent wavelengths of light that are invisible to our eyes.

The telescopes involved are the Karl G. Jansky Very Large Array, the Spitzer Space Telescope, the Hubble Space Telescope, the XMM-Newton Observatory, and the Chandra X-ray Observatory. We are used to seeing the iconic Hubble image of M1, but adding other wavelengths to it tells astronomers a good deal about temperature and structure that is otherwise invisible. And it makes a very appealing picture.

What would Messier think if he could see this!

Image Credit: NASA, ESA, NRAO/AUI/NSF and G. Dubner (University of Buenos Aires)

Comet Shoemaker-Levy 9 broke into fragments in May 1994. Hubble got this image of 21 icy fragments stretched across 1.1 million km (710 thousand miles) of space.

Phooto Credit: NASA, ESA, and H. Weaver and E. Smith (STScI)

In mid-July - past US Independence Day - the fragments started hitting Jupiter. The brown spots in this photo show eight of the impact sites of comet Shoemaker-Levy.

Photo Credit: Hubble Space Telescope Comet Team and NASA

The Tunguska event of June 30, 1908 flattened about 2000 square kilometers of Siberian forest. Something exploded over the area - an asteroid or comet - releasing around 200 times the energy of the Hiroshima atomic bomb.

This photo shows the devastation caused by the Tunguska event. It was taken 20 years after the event by Leonid Kulik.

The Crab Nebula is M1 and the Andromeda Galaxy is M31. Over a hundred deep-sky objects with "M" numbers are listed in the Messier Catalogue. Charles Messier, 18th-century comet hunter, is known today less for his comets and more for his catalog of things that aren't comets.

Charles Messier - Comet Ferret

Charles Messier, born June 26, 1730, was not only a keen comet hunter, but so successful at finding comets that the King of France nicknamed him "the comet ferret". While looking for comets, Messier encountered nebulae, which were also fuzzy objects in the sky. This inspired him to begin his catalogue of nebulae so that they wouldn't trip up other astronomers.

Caroline Herschel was an intelligent young woman trapped in domestic servitude by her mother. Her brother William rescued her and trained her as a singer. After he discovered the planet Uranus, the two of them ended up forming a great partnership whose work revolutionized the study of astronomy.

Caroline Herschel

Born on March 16, 1750, Caroline Herschel discovered eight comets and a number of other "nebulae" (star clusters, nebulae & galaxies). This was a significant number of comets for anyone, but for about 150 years Herschel held the record for greatest number of comets discovered by a woman.

The record was finally surpassed by American astronomer Carolyn Shoemaker who has found 32 comets (unless she's found some more since I last looked). She was one of the discoverers of comet Shoemaker-Levy 9 that broke up in Jupiter's gravity and plunged into the planet.

Lick Observatory lies high on a mountaintop overlooking Silicon Valley. Known for major contributions to astronomy, it also has some unusual features. Its benefactor James Lick is buried under the Great Refractor, and the observatory's original seismogram of the 1906 San Francisco earthquake is on display.

Lick Observatory - 10 Fascinating Facts

The Great Refractor was once the largest telescope of its kind, and today it's still the second largest. A refracting telescope focuses incoming light using two lenses. The disks for the Lick Refractor were made in France, but made into lenses by Clark & Clark in Massachusetts. They then traveled to California by rail and up Mount Hamilton by horse and carriage. One of the lenses broke in transit, and it took nearly two decades to get a replacement.

The 100-inch Hooker telescope at Mt Wilson Observatory was, for a time, the largest in the world. It was also of historical importance because of the discoveries that Edwin Hubble made with it. A few decades later it was eclipsed by the 200-inch Hale telescope at Palomar Observatory.

Palomar Observatory
A mile above the California desert stands Palomar Observatory. Its 200-inch mirror was officially impossible to make, but George Ellery Hale's vision inspired a nation in the grip of the Great Depression and it became the jewel in the crown of astronomy for the second half of the twentieth century.

Telstar didn't itself change our lives, but it was the beginning of a revolution that has changed the way we live. Satellites make possible mobile phones, GPS, the Internet and live broadcasting from around the world. They also allow better weather monitoring, data about resources, surveying of natural events, and many astronomical uses.

Hard to imagine - or remember, if you're old enough - what things were like before then.

The first Sputnik certainly changed the world. It was the first triumph of the space race between the USA and the USSR. And, more practically, it was the first of many satellites in orbit. What would we do without them now? Sputnik 1 was launched sixty years ago today on October 4, 1957.

Forty years after launch Voyager 1 is still sending back data, though the amount of data has deiminished considerable. It's been headed out of the Solar System for some time, but has a very long way to go before it passes the Oort Cloud and is away. However on September 13, 2013 NASA announced that the spacecraft had crossed a boundary and was now in interstellar space where the Sun's influence doesn't prevail.