Summertime Observing Blues? I Don’t Think So!

We are closing in on that time when visual astronomy is about over for the season. That does not mean there is nothing to do; on the contrary, we have to shift our cosmic interests a bit, to a more solar-system approach of things.

Start with the easiest target in the sky, the Moon: there is everything an amateur astronomer could hope to discover and explore on the lunar surface. All sizes of binoculars, spotting scopes and telescopes can be used for exploring lunar vistas in great detail.

By using a small spotting scope, lunar surface detail as small as 10 kilometres can be seen and, by using an 8- or 10-inch telescope, lunar detail as small as one kilometre can be glimpsed.

Mountain ranges and valleys are some of my favourite regions. By using a good-quality, variable lunar filter, you can reduce the amount of reflected moonlight that washes out fine lunar detail such as the ledges and outcroppings of rock that line crater walls.

The great thing about a variable lunar filter (a.k.a. variable cross filter) is that you can increase or decrease the filtering by simply twisting the rough-edged ring on the outside of the filter.

If you watch the moon’s surface over a period of a couple of days, you will see more detail everyday. At the same time you will notice that some finer detail is washed out by reflective moonlight.

The best viewing of lunar detail is across the Terminator Line, the region between sunlight and darkness. Here you can see, in excellent detail, craters and mountains of all sizes and shapes.

Features such as the Straight Wall are visible only for a few days before they are washed out by moonlight. You can actually see the Terminator Line move as the evening moves onward, revealing more detail.

You can certainly understand the attraction astronomers have for lunar viewing. The moon and planet Mars are the only planetary objects that allow you to see true surface detail – not clouds or rings, but actual mountains, valleys and craters.

If you are looking for something to see and you desire a larger object to view, there is always the Sun.

The local star, the Sun, can offer exciting and ever-changing views. Sunspots are easily visible in small telescopes and larger binoculars, outfitted with special solar filters. By using these special telescopes and filters, you can see solar flares and prominent detail.

This technology was available only to observatories and research facilities in the past. Now, solar telescopes are quite affordable and will show you everything from solar flares and sunspots to actual surface detail. These telescopes are small and simple to set up.

I use a Mylar solar filter that slips over the front of my telescopes. The filter will not let me see solar flares, but it presents an excellent view of sunspots as they cruise across the surface of the sun. These amazing solar filters are also great for solar eclipses and photography.

Extreme caution should be taken when solar viewing: use only equipment and filters made by a reputable astronomy company. I have had an up-close-and-personal experience with bad solar-viewing equipment.

Here is the short version of the story:

A good friend was tossing out an old telescope and its accessories, so we decided to see if it was worth fixing up or tossing it out. Now, this telescope was about 25 years old and came with a most-suspicious-looking solar-viewing kit. We decided that caution was the best policy, and we were right.

When we placed the filters in the appropriate places and double-checked everything, one more time, we then moved the old telescope toward the sun. Suddenly there was a sharp cracking sound.

We quickly moved the telescope off the sun and began a search to find out what happened. Apparently, the solar filter was damaged and the loud crack was the glass elements in the eyepiece as they cracked under extreme heat.

Remember: a telescope amplifies light and also amplifies heat. This was an experience that always reminds me to be “solar safe”.

As for planets, this summer, we will have Saturn in the evening sky. But, by the end of June, Saturn will be falling lower and lower toward the western horizon and disappearing shortly after midnight.

Jupiter, the magnificent cloud-banded planet, will soon be visible low in the southeastern morning sky. This planet offers the best in planetary viewing with cloud bands, a giant storm (the Great Red spot) and four moons easily seen in even the most humble of telescopes.

Yes, Yukon summer nights do make deep-sky targets such as nebulas, galaxies and most star clusters all but invisible to the observer, but this does not mean we have nothing to observe. There is always something of interest in those amazing Yukon Night Skies.

Clear skies, from James “Deep Sky” Cackette.

James “Deep Sky” Cackette can be reached at [email protected]. See his photo adventures on Facebook at Yukon Night Skies.

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