Deep Sky PhotographyGetting the Images

The author's portable photographic setup at the dark-sky site near Caliente, NV with the six-inch Astrophysics f/7 EDF Refractor mounted on the Byers Series II

Go HERE to find out about the photographer.

Go HERE to see a photograph of me with other Las Vegas astrophotographers.

Description of Photographic Site, Equipment & Techniques

  A brief glance at a satellite photograph of the United States at night quickly reveals that the darkest skies in the country are located in the Southwestern deserts. Of these areas, central Nevada is undoubtedly the very darkest. This fact, combined with the exceptionally dry air and abundant mountain ranges, makes for exceptional conditions to photograph the night sky. It is no coincidence that the U.S. Military chooses these areas to carry out ultra-secret is extremely remote and therefore a great distance from urban or even rural population centers. I have taken advantage of the dark desert skies of South-Central Nevada to produce color images of very faint nebulae, many of which I had never seen photographed in color before.

All equipment is portable and is transported to the remote photography site. The site is located at Oak Springs Summit and is accessible via a dirt road off of the Great Basin Highway about 100 miles northeast of Las Vegas. Driving time from Las Vegas is about 2.5 hours. The altitude is 6,500 feet and the site is situated on top of a gently sloped mountain covered with small pine trees and shrub ground cover. These mountains are very much like ‘islands’ rising above the desert ‘sea’. The altitude, dry desert air (relative humidity anywhere from 10 to 25 percent) and topography of the site make for excellent transparency and seeing. The Milky Way visible to the unaided eye actually corresponds to the isophotes which appear on sky atlases. Stars overhead are very steady two hours after sunset. Furthermore, the site is well protected from wind. At night stars are bright to the horizon and the sky is free from man- made sky-glow for 360 degrees around. There is a very faint glow from Las Vegas to the Southeast spiking skyward less than 10 degrees since the absence of moisture in the air dramatically reduces light scattering. It is not uncommon to spend an entire weekend at this site and not see or hear any human activity. Even commercial air traffic over the area is infrequent due to the proximity of Area 51 and the restrictions to air travel near these military installations.

My photographic equipment includes a 6 inch f/7Astrophysics EDF refractor with a 4-inch focuser (recently sold), an Optical Guidance Systems 14.5 inch f/7.65 (f.l. 2875mm) Ritchey-Chretien, a Celestron-14 f/11 SCT used with a Lumicon Giant Easy Guider and focal reducer to f/7, and a 300mm f/2.8 Tamron telephoto lens. The three telescopes are mounted via heavy-duty aluminum rings, custom-made by Edward Byers, on a Byers Series II mount (11.3 inch drive gear).  The mounting sits on a heavy-duty custom tripod fashioned from aircraft quality aluminum I-beams. The set-up is quite massive and holds up to moderate wind gusts. An SBIG ST-4 autoguider guides the exposures through either a 3 inch guidescope (which is mounted with separate rings atop the refractor), or through a Lumicon Newtonian Guider (low profile) when photographing with the Ritchey-Chretien. I use a Pentax 6X7 camera with 120 format film when photographing through the refractor and a 35mm Olympus OM-1 when using the Tamron lens, the RCT or the C-14. During exposures using the Pentax camera and medium format film, dry nitrogen gas is flushed into the camera chamber via a small hole in the bottom of the camera which opens up about an inch in front of the film plane. The nitrogen is slowly infused during the entire exposure. This serves to prevent film creep, or swelling, of the dry hypered film during long exposures and assures pin-point star images across these large negatives. When photographing a large area of the sky on medium format film, very accurate polar alignment is required to avoid field rotation. A close approximation to the pole is quickly achieved by using a calibrated polar finder scope which is secured to the side of the mounting. I then use the drift method until there is no visible movement in declination of a star at the celestial equator on either the eastern horizon or meridian after 15 minutes using a 3mm eyepiece with the refractor.

Most of the images presented cannot be seen visually in the camera viewfinder. To facilitate acquision and framing of the subject, I print out a starfield of the area to magnitude 9 using a computer program called Megastar. I can print the view to exactly the field size and image orientation as it will appear in the camera viewfinder. In this way I am able to obtain precisely the field I wish to photograph. Focusing is achieved as follows: After composing the shot and acquiring a guidestar in the guidescope, a nearby star is chosen to focus on. Best results are obtained with a magnitude 3 star. Stars of mag 1 or brighter are too difficult to use. The star is placed on the ground glass of the focusing screen in the Pentax camera such that it lies between the inner and outer circles of the ‘doughnut’ in the center of the screen. Using a 20X achromatic loupe with an acrylic base (purchased from Edmund Scientific) the star is carefully focused, directly on the surface of the focusing screen, with the rack and pinion focusing knob. Care must be taken to first focus the magnifier on the ground glass to the user’s eye in daytime lighting and then to secure the magnifier at this point.   Focussing in achieved when using the Cassegrain telescopes with a Spectra Sure Sharp knife-edge focuser.

Many of the images presented here were obtained using the discontinued Fuji Super HG 400. The film was hypered for 7.5 hours in forming gas at 50 degrees C, 6 psi after outgassing the film for 30 minutes with a 2-stage vacuum pump prior to introducing the gas. Some of the more recent images were taken using Kodak PPF (Pro 400). The Kodak PPF is hypered for only 2.5 hours under the same conditions. The film is always hypered spooled onto a plastic film reel, either unwound from the film cannister, in the case of 35mm film, or unwound and separated from the paper back in the case of 120 format film. After hypering both film and paper, the 120 film is rolled back up with its paper back. The film is transported to the site under a vacuum and kept on ice up until its exposure at the telescope. It is transported back the same way and promptly processed.

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