CANOPUS 02/10 - Drakensberg in Winter

Peter Baxter and family	Sean’s 4.5 inch Equatorial
Eric Brindeau	12 inch f/7 Equatorial
Val Fraser	6 inch f/8 Dobsonian
Bert van Winsen and family	10 inch f/6 Equatorial. SBIG CCD camera

The cold weather is something of the past as we look forward to the upcoming warmer months. But it is also a time for some of us to reminisce about our excellent outdoor adventures and astronomy of what must be one of South Africa’s best-kept secrets – winter astronomy experienced from our breath-taking landscapes.

We know our winter months offer observations of some of the best constellations and a vast array of astronomical targets. With Sagittarius soaring high above, we focus on the centre of the Milky Way’s expanses of dark patches and bright luminous bands, wondering what it hides. When faced with exposure to the frigid elements, our obvious choice is that of warmth and comfort. It is only with great determination and promise of adventure that we can face the challenge of observing during cold winter nights.

Our society has long been organising events to take full advantage of enjoying astronomy from dark locations and the excellent skies of winter. Past trips like visits to the Boyden observatory in Bloemfontein and Swinburne dark sky site in the Drakensberg were timed accordingly. In fact, it was such a trip that made a group of us go in search of challenging astronomical and outdoor thrills. In July 1997, our society planned a star party to Swinburne, which had all the right elements in place (Canopus – June 1997, "Diaries of an Astro-amateur by John Maher"). Unfortunately, us late stragglers couldn’t make bookings in time, and it was then decided to head for the mountains in the same area. With the full range of the Drakensberg available to us, all we had to do was pick a spot. It is to this most fascinating and beautiful mountain range that we have been making an annual star party pilgrimage.

Our dark sky trips are almost always camping related. Roughing it is one of the best ways of escaping the daily routine of our lives and enjoying a different experience and camaraderie. Camping brings one in touch with nature, simplifying our lifestyle, following the rhythm of sunrise to sunset. Appreciating the night sky, we are able to view the heavens, just like our ancestors would have done. Members of our group all share a passion for the outdoors and actively partake in birding, photography, exploring and hiking.

The secret of winter observing in the Drakensberg is not only the promise of dark skies. It is the warm winter days, almost deserted resorts and wonderful hot showers! Although the nighttime temperatures can drop well below freezing, the days are pleasant and make any outdoor activities enjoyable. The number one rule for any star party is to try to find a resort or campsite relatively free of any ambient lighting. This hindrance can come from both nearby campground facilities or fellow campers. Our first dark sky trip to the beautiful Mahai campsite in the Royal Natal Park turned out to be a disaster. The neighbours must have been from Gauteng, as several had outside security lights! We had fun sneaking around in the dark in a feeble attempt at covering the lights with plastic bags and whatever else was on hand. Over the years we have tried various places and enjoyed a variety of scenery. This year in the Central Drakensberg, we were just about the only souls in the entire campsite for five days. With experience, we have learned to plan our trips in order to give us an opportunity of several nights of viewing in case we encounter some cloudy weather. Apart from the massive cold fronts, winter is also notorious for plumes of smoke from veld fires in the area, which has ruined some of our observing sessions.

It gets cold, very cold. But this only adds to the experience. We have been lucky up until now, where the window period of the July new moon has not coincided with the closing of Van Reenen’s Pass due to snow. Mostly the snow is only visible on the highest mountain peaks. I visited Canada a few years ago and managed to enjoy some astronomy with locals in mid-winter. While crunching around in the snow and ice, where the mere act of removing a glove to handle eyepieces or equipment can be most hazardous, I realised that the winter here is not that bad. Our misfortune is not having access to the warm gear the Canadians do. Safety and comfort is of utmost importance. I found an excellent Sky & Telescope article on "Keeping Warm Under Winter Stars" (S&T February 1993), which I use as a handbook and pass it on to anyone about to join us.

According to the article, the first principle of cold-weather dressing is to wear layers. Studies by the U.S. Army have found that it doesn’t matter if you have the most hi-tech or common material, only how many inches you put on. The second principle is to cover your whole body evenly, covering both the legs and upper body. The third principle is to cover your extremities. Fingers, toes, nose and ears freeze first. Wear a scarf and beanie, as most heat is lost through the head. With preparation and experience, it is possible to have a comfortable viewing evening in freezing temperatures.

This year the cold seemed to be particularly debilitating. A steady icy breeze swept down the mountain valleys through our observing area, forcing us to retire soon after midnight. One night, I was woken up by the sound of horses roaming the campsite. Running around in the dark, my attempts at chasing them away by waving my Mini Maglite like a Jedi lightsabre seemed useless. A tree branch proved more useful, but then I realised I was standing on thick frost in my bare feet! Packing up one evening, my frozen state did not help the agility needed while reaching to put on the dew cap, which smashed to the ground.

We are all in some way graduates of the society’s telescope making class, and most of our trips provide a testing ground for new equipment and techniques. Several telescopes have seen "first light" on these trips – Val’s 6 inch, Peter’s 10 inch, and my refurbished 8 inch (commercial optics). Gerhard Koekemoer has always been entertaining us with new electronic drive systems and telescope mount designs for his 8 inch dobsonian. Bert has gone to great lengths in producing high quality astro photos, first capturing the light from deep sky objects on emulsion, then advancing to CCD’s.

Bert is the most advanced astronomer among us. His 10 inch telescope is the embodiment of his determination to find a perfect drive system. He reminds me of astronomer Jim Gunn in Richard Preston’s novel "First Light", creating everything from available materials, programming his own computer chips and customising software. While the rest of us survive the rat race, Bert manages to log the hours night after night, continuously improving his techniques of Periodic Error drive Correction (PEC) and refining his stunning astro photographs. While contemplating the physical aperture of his 10 inch as being a major disadvantage, he decided to advance onto CCD photography, unlocking an entire new universe. Although his telescope is permanently housed in his own observatory (Canopus - August 2002, "A unique little observatory"), he can quickly dismantle it for trips to dark sites. He has cleverly constructed a portable observatory for these away trips to reduce wind turbulence, an essential requirement for accurate CCD recording. For the rest of us it is a place to escape the breeze and catch up on what he is up to. From the comfort of his "desk", he can control the entire operation with hand-held paddles. CCD photography is a time-consuming process and requires dedication and patience for accurate scope tracking and alignment. There is nothing more exciting than seeing the successive images download to the laptop screen, all layers combining to create stunning deep sky images.

Moving from the warm campfire, the night sky pulls you in. For a while you are disoriented and stare in silence. You search for the familiar, but patterns don’t match. The normally bright Alpha and Beta Centauri are almost lost in the Milky Way. Star hopping proves even more difficult as your finder is filled with a sea of stars and you are not sure which direction to go. We spend time reacquainting ourselves with the constellations and identify a few new ones not accessible from our light polluted backyards. The skies here are the darkest I have experienced, matched only by the night sky I have seen in Namaqualand and the Kalahari on Trevor Gould’s meteorite trips.

There was plenty of excitement as we had a new scope to test. Prior to the trip, much effort was spent by our group to help get Val’s 6inch reflector together (Canopus - August 2002, "First Light"). Murphy’s Law had its way with an overcast sky when we first tested it from Peter’s garden. This was "first light" for her scope. There’s an incredible rush as you enjoy the sky with something self-made. I hopped through all my favourites and challenging objects, the scope performing excellently. Open clusters, globular clusters, galaxies, planetary nebulae and expanses of nebulous clouds were all on the list. For the test, close double stars proved too difficult as the atmospheric seeing was not perfect, but other challenging objects like Peter Baxter’s Planetary (NGC 6563) at magnitude 13.0 (finder chart in Canopus – August 1999, "Southern Sky Star Hopping"), the faint haze of Barnard’s Dwarf Galaxy (NGC 6822) in Sagittarius and the dim wisps of the Running Chicken Nebula (IC 2944 complex) near Crux were no problem.

Although most of the time was spent enjoying the familiar, we did take the time to find several new objects. Val was able to point out Dave Gordon’s "guitar" (NGC 6234) in Scorpio (Canopus - August 2001, "A Cluster Hop Around the Body of Scorpion"), something Peter and I had failed to see from the city. On my list was a selection of the most challenging, obscure globular clusters from various Sky & Telescope deep sky articles that I had been collecting. Using Sky Atlas 2000 as a guide and Millennium Atlas for detailed charts to star hop, I found a few, some taking over an hour to locate. Of all the obscure globulars, Djorgovski 2 in Sagittarius was the finest. This globular was only discovered as recently as 1987, and appears as an extremely faint haze lying in the dense star field next to the spectacular "Ink Spot Nebula" B86. I was able to share the galaxy cluster Abell 3574 in Centaurus with the group using the DSS image I prepared (Canopus – August 2002,"Using the Digitized Sky Survey for Serious Deep Sky Observing"). We were able to count eight galaxies almost in the same field of view. By far the most challenging object of the trip in the 12 inch was hunting down the 14.5 magnitude planetary nebula Abell 70 ("Diamond Ring Planetary" – The Best Abell Planetary Nebulae – S&T May 2002), on the border of Aquilla. It was just visible in a Lumicon Oxygen III filter. I took time out to share my little corner of the sky with everyone, the "Eric" cluster. Lying inside the borders of Crux, the open cluster NGC 4439 looks very much like an "E". But it soon turned out to be quite a joke as everyone teased me, offering several interpretations from an "M" to a "B" for Baxter or Bert!

With Peter’s experience in tracking down difficult deep sky objects, he helped locate a bi-polar nebula in Norma (NGC 6164/5), not plotted in Millennium (not surprising, as there are still many errors in the charting of southern objects). Visually we could see the brighter of two arcs, and Bert later imaged it with his CCD to make sure we were on target. The inspiration for this object comes from my favourite deep sky website, www.blackskies.com. Dedicated to planetary nebulae, this site has some very interesting information on targets for southern observes.

In the early hours of the morning, with Cygnus the Swan soaring above the horizon, we exercised our yearly ritual of tracking down the Veil Nebula in the "northern cross" constellation. The Cygnus Loop is one of the largest and closest supernova remnants known. We had always thought this massive object was only accessible to the northern hemisphere, until one year when Bert was adventurous enough to try to find it. This is a definite showpiece, and tracing the large arcs and knots of nebulosity is a breathtaking experience.

So ended the chapter of another brilliant winter trip. We were exhausted and exhilarated after enjoying four nights of astronomy and hiking in the mountains and forests during the day. Next year, on the July new moon, you will find us somewhere in the Drakensberg…