Monday, March 29, 2010

Review: Human Vision and the Night Sky

Human vision and the night sky
By Michael Borgia

This great little book has much to recommend it. Not since reading Astronomy Hacks have I come across such a good list of observing projects. 

While the deep sky projects are worth persuing, it is in the extensive set of solar system projects where this book excels. 

As one example, nowhere else have I seen such good descriptions of finding the smaller moons of Jupiter and Saturn.

Published in 2006 as part of the Patrick Moore Practical Astronomy Series, the book is a little out of date on the most recent Hubble findings. It is full of observing notes that would have been mote interesting before 2010 and I think most of it was written about 2003-4. . 

The photographs and photographic techniques seem pretty old and out of date. They do not represent techniques of 2010. 

But the approach to simple visual astronomy will speak well for many years to come.

My thanks to Matt and Tina Rottman for letting me read their copy of the book. I think I will attempt to find the book on used book shelves. 

Sunday, March 21, 2010

Moon in Pleiades


Last night, I had a nice time watching the moon glide through the Pleiades. I had set up my binocular chair, with a pair of Celestron 20x80 tubes mounted on the A-frame above my seat.

It first seemed to me that the moon might occult Merope, but as the moon began to cross the open star cluster, it soon became clear that Merope would glide past the north pole of the moon without being covered. That meant that all the major stars would be spared the embarrassment of being covered by our moon -at least as seen from San Antonio, Texas.

Further south, it is possible that some of the sisters may have been covered by the moon. However, further north, the stars would have been even further north of the Moon.

Attached to this blog is a Cartes du Ciel image of the Occultation from about 930 PM. It is about the same time as a fellow San Antonio Astronomer took a great photo of the passage. She had that photo published on the Space Weather.com website today.

Wednesday, March 17, 2010

Messier Marathon II


The new moon near the end of March is the best opportunity to take a tour through the Messier objects. At this time of year, the small slice of sky occupied by the sun is placed so that none of the 110 Messier objects are obstructed by Sol. Last year, I ran the list of Messier objects with my 10 inch reflector scope. While I was doing so, John E, a fellow club member at our local club ran the list with his large binoculars. We each saw almost all the objects

When I experienced the Couch Potato Telescope (CPT) rotating support for binoculars at the Texas Star Party in April 2009, the concept of observing all the Messier objects with binoculars began to grow on me. I built a CPT from a kit the same weekend that I came home from the TSP. Then, this last fall, I purchased a large binocular. The Celestron 20x80 pair was stable and easy to handle on the CPT. The plan was coming together.

This last weekend, Diane and I joined friends at Ft McKavett, north of Junction, Texas for a weekend of astronomy. It had been a dreary week, but as the weekend drew closer, the weather cleared after a cool front passed.

So, after a year of thinking, building, and dreaming about a Binocular Messier Marathon, it came to me sitting in my CPT on a cloudless evening about 130 miles away from the nearest large city.

The evening stars began to pop out of the darkening sky. Mars was first to make an appearance. Then Sirius, Rigel, and Betelgeuse. Before long, the guide stars of the western horizon became visible. Cassiopeia made her appearance in the northwest, and then the pointer stars of Andromeda. Finding M31 was easy, but M110 was not yet visible. I could not yet see M33 or any sign of the more difficult M74 and M77.

I swung the chair toward Orion and plucked the two objects from his sword and one from just above his belt. Yep! even that blush of nebula above Alnitak was now visible as the sky darkened.

Before I forgot it (again) I swung by the Pleiades and enjoyed the placement of that cluster in my binocular.

A check of M74 and M77 again revealed nothing. I rotated the chair further north and looked again at M31. AhHa! M32 was clearly visible now. And even M110 was now visible. M33 shone as a ghost out of the darkening sky as well. Overhead, the Milky Way was beginning to be visible.

I knew where M74 and M77 should be, and their locations were drawing closer and closer to the horizon. Fortunately, the sunset horizon was flat and unobstructed. A quick check of M77's location was fruitless. Same for M74. I went back to M77's nest and looked at my charts again. I gently tapped my binocular to see if I could use motion and non-central vision to catch a glimpse of the object. Yes! is that it? Yep! It sure is. M77 is in the bag.

Now back to the M74 location. Not there. How about scanning left and right and coming back? Do I see it? Hmm. Maybe. Come on - its not for sure. Scan back to M110 and M33. Then back to M74's location. [I am remembering that M74 was the only object I was not able to identify last year.] What! I think that IS it. Quick! Scan away... then back. It is there! Good! Great! M74 is in the bag.

OK. The hard evening objects are done. Now begins the more leisurely approach to the objects in CAS, PER, AUR, GEM, and the rest of the first shift of objects. Then it is time to get up from the chair and see how Diane is doing with our 16 inch Looking Glass. She seems to be having a ball. Good. Others on the observing star field are having fun. At least three other friends are trying to make something of a Messier Marathon. They are doing well too.

Then after a drink of water, its back into the chair. Leo has risen far enough, and the sun has dropped into the night deeply enough, to attempt the Leo galaxies. The Zodiacal light shines all too bright all the way to the zenith, making it harder to see the really dim fuzzies. The two groups of Leo galaxies are spotted and bagged. The obvious clusters in Cancer are also remembered. (I forgot the Beehive one night!) Rotating my chair toward the big Dipper, the larger group of Messier galaxies in and about UMA are found one (or two) at a time.

It is finally time for bed and a nap at about 1030 PM. Everything that is reasonable has been tagged. Spica is just up over the eastern horizon and the Virgo cluster of galaxies is too low to work on right now.

At 1230 AM, I am up. It is getting cold, but there is still not a cloud in the sky and the slight breeze is keeping dew from forming. I wrap up tightly, put a hand warmer in each pocket, and go out to work my way through the torturous path of the Virgo cluster. I warm up on the two outliers to the east of the main cluster and then enter from the tail end of Leo.

The work I have done this year with my 16 inch scope on the Herschel list really pays off now! Last year, I might not have been able to see these faint blushes of stardust that make up some of the Virgo cluster Messier objects. I know that there are many other objects in here that I can see with more aperture, but with my binocular I am nearly at my limit for some of the galaxies. However, I am able to walk my way from galaxy to galaxy by using my chart and the stability that the CPT gives me. It is really nice to have the binocular pointed at a galaxy and be able to drop my eyes to a chart and then go back to the same spot in the sky!

After an hour of observing, I have gotten through the newly available objects and go back to bed for another two hour nap.

All too soon, it is 330 AM. The early morning objects are coming into view. To top of Scorpius is poking its head out of the horizon. M4 is visible. The swan and the lyre are up. 45 minutes of chilly observing lets me go back to bed to warm up next to Diane for another hour.

Then it is 5 o'clock. I put a hand warmer in each sock and wear gloves with a hand warmer in each palm. Sagittarius is fully up and the full trail of objects in the steam of the Milky way is visible. The little globulars in the base of the teapot are not much more than star sized points, but at least the horizon is free of clouds and the dew is being kept away by the cold breeze.

I find the kite of Terabellium 1 and 2 that allows me to find M55 and M75. M72 and M73 are finally seen. The remainder of the Morning objects come into view and are seen as I move my chair a little further out into the field to bring the horizon down a little.

Finally, I find myself looking exactly at the right spot to see M30, the last of the Messier object to see for the night. The sun is brightening the eastern sky by the moment. Hope is lost. It will not be seen. The Marathon began a little too easily with the evening objects too high in the sky to make the last morning object visible.

A sense of accomplishment washes over me. I really did quite well in this binocular marathon. 109 is not shabby at all! Along the line I saw Venus, Saturn, Mars, and the very very old moon with lots of earth shine. I shared the starfield with friends and had a good time with my wife as she observed a lot of the sky on her own.

But, as the sun began to rise ever more strongly, it was time to lie down for a nap until breakfast!

Sunday, March 7, 2010

Effectively Sharing the Sky

Two examples of sharing the sky came to my notice this last week. They have some similarity and remind me of lessons I want to remember about helping others.

The first example was a friend who is relatively new to finding sky objects. He bought a telescope this week and was having fun under a clear sky with a first light celebration. I was trying to figure out (again) where the guide stars are in the western sky for the beginning of the Messier Marathon. So I was only listening to the excitement in the background.

My friend was getting help from enthusiastic knowledgeable friends. But I heard him say something about how he wanted to start from the beginning and find the object himself. And he did. object after object.

Another friend visited his grandchildren in another state. They had received a telescope gift from grandfather and had (I'm sure) all the problems of a new astronomer. It was an important moment. Either they were going to figure out how to see something or they were going to pack the telescope in the back of the closet. I've seen it many times before. It happened to me twice in my life.

This wise grandfather had the kids do most of the work of selecting some objects to look for in the clear night sky. They developed a short list of beautiful objects appropriate to the scope and the sky. M42, a double star, and a star cluster would do nicely for such a list. Practicing putting the scope together in the warm living room and in the light would make that chore less frustrating outside in the dark and the cold.

Then grand-dad watched as the kids toted the scope outdoors and set it up themselves. They were able to find the objects with a planisphere or atlas in the night sky, and then aim the scope at the objects they wanted to look at. As the earth rotated, they moved the scope themselves to follow it.

This business self directed exploration is such an important goal! In much of my public star party sharing I have given folks the opportunity to be wowed by sky objects. But only infrequently have I had the opportunity to go the next step and help someone through the necessary steps of becoming an independent sky observer.

These examples are fresh in my mind. I really need to do something about them while they still weigh on my consciousness.

Dark Skies! And may we all learn something new this month...