Astronomy July 2014

IMAGER PROFILE

With remote observatories in GERALD Namibia and the Alpen foothills, this Austrian imager can lock his lens RHEMANN on any comet or nebula he likes. text and images by imaging from Gerald Rhemann near and far My first encounter with astronomy wasn’t until 1986. Intrigued by the frequent media reports about the return of Halley’s Comet, I decided to have a look through a big telescope myself. I trav- eled to the western suburbs of Vienna — the capital city of Austria and my hometown — where the historic Kuffner Observatory and its 10.6-inch (270 millimeters) refract- ing telescope live. But what I saw through the eyepiece dis- appointed me. Even through this big refrac- tor, Comet 1P/Halley appeared as nothing more than a foggy patch — no evidence of the impressive tails that shone through in photographs. Still, Halley aroused my inter- est enough that a couple of years later, in 1989, I purchased a telescope and mount. I wanted to make images that captured the For several months, the author (pictured above) had same level of detail I had seen in photos of the opportunity to remotely control an astrograph that comet, detail that the eye alone can’t located in Nerpio, Spain. With it, he captured IC 2177, the Seagull Nebula in Monoceros (right). see. Plus, because I was the owner of a pho- This image had 21.9 total hours of exposure — the tography shop, I had ready access to all the longest of any object the author has ever captured. other stuff I needed — cameras, lenses, a (ASA 8-inch f/2.9 hyperbolic astrograph, FLI PL darkroom, and experience. 16803 CCD camera, HαLRGB image with 180, 555, 224, 140, and 217 minutes of exposure, respectively) Comets in the foothills My backyard, however, was not an ideal Austria. Because Jäger and I share an inter- observing spot. Vienna’s light-polluted skies est in taking portraits of the solar system’s didn’t lead to photographic success. Fortu- oldest inhabitants, a deep and lasting friend- nately, I met Michael Jäger, the most experi- ship developed between us. He showed me enced and successful comet imager in his favorite dark-sky sites: observation- friendly spots in the Austrian Voralpen. In Gerald Rhemann has been sky-shooting since these foothills of the Alps, less than an 1989. His work has been featured in scientific hour’s drive from my home, light pollution papers and on NASA websites. is nearly nonexistent.

46 ASTRONOMY • JULY 2014

The author captured Comet Lovejoy (C/2013 R1) on the morning of December 14 from Jauerling, a mountain in the Austrian Voralpen. The CCD’s sensor was sensitive to blue light and therefore accentuated the ion tail structures, whose carbon monoxide causes the hue. The comet was active and powerful enough that its ion tail visibly changed from one day to the next. The image is The region around Antares (Alpha [α] Scorpii) is one of the most amazing and beautiful in the entire sky, a two-panel mosaic. (8-inch f/2.9 ASA hyperbolic containing a complex mix of emission and reflection nebulae, dust lanes obscuring background stars, and astrograph, FLI PL 16070 CCD camera, LRGB im- star clusters. The author took this six-panel mosaic from Namibia over the course of three nights. (8-inch age with 5-minute exposures through each filter f/2.9 ASA hyperbolic astrograph, FLI PL 16070 CCD camera, LRGB image with exposures of 35, 25, 25, and for each panel) 40 minutes, respectively, for each panel)

For imaging bright comets or comets at moves in the field during the exposure — The era of chemical film low altitude under the transparent Voralpen and sometimes its tail structure changes I first imaged deep-sky objects and comets skies, I have portable equipment: an Astro- quite quickly as well — processing observa- through an 8-inch Celestron and later a 5.2- systeme Austria (ASA) DDM60 mount and tions isn’t straightforward. To get both pin- inch Takahashi Epsilon 130 astrograph. an ASA 8-inch f/2.9 hyperbolic astrograph. point star shots and a sharp comet image, I After I became more proficient, I decided to Although trekking out there is a challenge first remove the stars. Then, going back to purchase a Schmidt camera, then the most and requires discipline, especially on a cold the original picture, I remove the comet suitable instrument for comet imaging. winter night, it feels worth the effort when I from the star field, and — finally — I put The camera was a small one, only suit- can capture crisp shots of comet tails them back together again. That might sound able for use with 35mm film, and it was streaming through space. easy, but it is not. tricky to work with: I had to cut the film But creating those pictures is no small My images are so precise that I report and load the pieces into the film holder task. Both the imaging and the processing of positional observations to the International without scratching them or getting any dynamic observations like these are time- Astronomical Union, which has designated dust or moisture on them — and I had to consuming. Because a comet perceptibly my observatory in Eichgraben C14. do this in an improvised darkroom in the

48 ASTRONOMY • JULY 2014 Observing hot spots

Eichgraben, Austria

EUROPE Voralpen, Austria

AFRICA : ROEN KELLY ROEN : Tivoli, Namibia ASTRONOMY

This portrait of reflection nebula IC 4592 also shows IC 4601 in the lower left. (8-inch f/2.9 ASA hyperbolic astrograph, FLI PL 16803 CCD camera, LRGB image with exposures of 55, 30, 20, and 50 minutes, respectively) back of my car. But the hardship provided installed my first CCD camera, a Starlight valuable practice, and I worked myself up Xpress SXV-H9. to a larger Schmidt camera that was suit- Imaging with this camera opened a able for 6x6cm plates. With a focal length of whole new world and new feeling for me. 450mm and a focal ratio of f/2.0, this cam- Because I could immediately see what I was era was fast and produced great images photographing, I could be sure the image across the entire field of view. was in focus and the mount was tracking In those days, commercial film just properly. Moreover, the digital “darkroom” wasn’t ready for astroimaging. We photogra- rendered unimaginable possibilities in pro- phers had to alter it a bit. Using nitrogen gas, cessing plausible, as the throughput we hypersensitized the film to reduce reci- increased enormously. There are always procity failure, which makes the film less trade-offs, though: lots of cables and lots of responsive after a certain amount of expo- electricity — both of which made traveling sure time. We also had to develop and print to observing sites difficult. the film ourselves, which required access to Not one to be deterred, I solved the a darkroom. In view of all these difficulties, problem by building an observatory in the only a few amateurs worldwide attempted backyard of my weekend house in Eichgra- serious astrophotography. With the Schmidt ben, Lower Austria. It has a roll-off roof and camera, however, and doing considerable is fully remote-controlled — I can obtain preparatory work, I obtained several hun- images wherever I am. The observatory has dred images of comets and deep-sky objects. a 12-inch ASA 12N astrograph at f/3.6 on an ASA DDM85 direct drive mount and a Step into the digital age Finger Lakes Instrumentation ML8300 In 2003, I recognized that the time of film CCD camera. had passed, and I switched to CCD astro- The author’s remote-controlled observatory in Eichgraben, Lower Austria, contains a 12-inch ASA photography. Meanwhile I had acquired a Under southern skies 12N astrograph at f/3.6 on an ASA DDM85 mount. 14-inch Cassegrain telescope with a prime Even though I now have many nearby He also observes from the Austrian Voralpen and focus option at f/3.0. On this instrument, I observing options, the summer nights at Namibia, where he has a remote setup.

WWW.ASTRONOMY.COM 49 On an average night, the seeing in Eichgraben is only moderately good. But in spring, it sometimes is decent enough to use the ASA Barlow Corrector to get a longer focal length (2,070mm) with a 12-inch ASA 12N astrograph at f/6.8, as the author did to obtain this image of Bode’s Galaxy (M81). (FLI ML8300 CCD camera, LRGB image with exposures of 240, 110, 70, and 140 minutes, respectively)

In this April 1997 giving visitors like me full access to our gal- image, Comet Hale- axy’s core wonders. Bopp’s (C/1995 O1) tail stretches up to During my 2010 stay in Namibia, I the Double Cluster in installed the same type of equipment that I Perseus (NGC 869/884). have in my observatory in Eichgraben in a The observations were friend’s nearby Southern Hemisphere obser- recorded on Kodak Pro Gold 6x6cm plates. vatory. By 2012, that observatory was fully (225/255/450mm remote-controlled, and I have access to this Schmidt camera, expo- 12-inch astrograph whenever I want. sure of 5 minutes) In the future, I plan to use this telescope for comet searching. The probability of find- ing a new visitor to the inner solar system is much greater in the Southern Hemisphere Austrian latitudes are short and the weather are available — even in the middle of the than in the north, where several professional is unstable. Southern objects are visible at night — and you can have a relaxed stay automatic comet-search programs are low altitudes or not at all. To make up for with like-minded people. already in place. Maybe I will discover a new what my region lacks, I travel to Namibia The farm is on the edge of the Kalahari object as intriguing as the comet that first every two years. My next trip to southwest- Desert, making the climate dry. From May inspired me to put my eye to a telescope. In ern Africa will be my seventh. to September, which is Namibian winter, the that quest, I will sometimes use the South- At the Southern Sky Guest Farm Tivoli, nights last 12 hours and stable high-pressure ern Hemisphere telescope from my Euro- the owners specialize in hosting astrono- systems dominate the weather. Namibia, pean home, but I won’t always stay put. mers. You can rent a telescope, a mount, and twice the size of California, has only 2.5 Distance astrophotography is no substitute an observatory, or you can take your equip- million residents, most of whom live in a for actually being on location and enjoying ment with you and install it for the length of few cities far from the farm. Because transparent skies with my own senses while your stay. The owners adapt everything to Namibia sits on the Tropic of Capricorn, the creating images that enhance what we can the needs of skywatchers. Excellent meals center of the Milky Way transits the zenith, see on our own.

50 ASTRONOMY • JULY 2014 Operating a telescope in Namibia via remote control, the author obtained this image of NGC 2170 in Monoceros. (12-inch f/3.6 ASA astrograph, FLI ML8300 CCD camera, LRGB image with exposures of 230, 140, 140, and 170 minutes, respectively)

Comet Lemmon (C/2012 F6) was mostly visible in the Southern Hemisphere. The author captured it April 21, 2013, by remotely controlling his telescope near Although the transparency of Namibian skies is almost always perfect, the seeing is not. The night the Guest Farm Tivoli in Namibia. (12-inch f/3.6 ASA 12N author obtained this image of NGC 6726, however, the seeing happened to be great, so he used the lon- astrograph, FLI ML8300, LRGB image with exposures ger focal length of the 12-inch ASA 12N astrograph at f/6.8. (FLI ML8300 CCD camera, LRGB image with of 6 minutes through each filter) exposures of 60, 50, 40, and 50 minutes, respectively)

TO SEE A GALLERY OF GERALD RHEMANN’S IMAGES, VISIT www.Astronomy.com/toc.