Our very portable Tele Vue-76 APO refractor has been popular with eclipse-chasers as well as with users that cross over into spotting and birding. With the popularity of small and powerful dedicated imaging cameras, the performance of the Tele Vue-76 is getting noticed by deep-sky imagers on the go. Case in point, Diego Cartes Saavedra is producing outstanding deep-space images from various locations in the southern-hemisphere with this scope. All his images in this blog post were taken from July through November 2018.
Diego’s study of the Tarantula Nebula and surrounding region in the Large Magellanic Cloud examines the area imaged through different filters. The first image is a monochrome version taken in Hydrogen-α light.
The second version is taken through filters that pass wavelengths of Oxygen (OIII), Sulfur (SII) and Hydrogen-α (Hα). This is the “Hubble Palette” that mimics a popular set of filters used by the Hubble Space Telescope to produce “false color images” to unmask processes inside deep-space object . While the camera records each of these wavelengths without color, when the filtered images are combined they are assigned colors. The classic Hubble Palette assignments are Oxygen = Blue, Sulfur = Red, and Hydrogen = Green.
Compared to the first image in Hα only, the addition of of the OIII and SII wavelengths adds a dimensional quality to the clumps, knots, and dashes of dust in this region — all formed from supernova shock fronts and stellar winds of young stars.
The final image in his study combines the wavelengths from the Hubble Palette version with exposures make through Luminance (visible light in monochrome), Red, Green, and Blue filters to produce something closer to what the human eye might see.
In this last and most realistic (full visible spectrum) portrayal of the region, an abundance of hydrogen gas glows red in this very active star-forming region. Stars drizzled throughout the image assume a more natural color. While the image is centered on just a “corner” of the Large Magellanic cloud that contains the nebula, the dense star-region on the top-left of the image indicates where bulk of this little galaxy’s stars lie.
Impressed with his work, we asked Diego how he got involved in astrophotography and he told us in his own words.
My love for astronomy started in my childhood. I had the luck of growing up in a little mining city in the Atacama Desert of Chile, so I had the pleasure of seeing spectacular clear skies almost all year round. Many years later, after I got my law degree, I decided that I wanted to capture pictures to show other people the beautiful objects that are hidden in the night sky. I started with a DSLR camera and the telescopes of my astronomy club. At that time, i frequently took trips to my city, so when I had the opportunity of buying an astrophotography scope, I choose the TV-76, because of its large field of view, and also because it is very easily portable. This later proved to be a very good decision, because I managed to capture nice pictures of M45, the Orion Nebula, the objects around Sagittarius and the Magellanic Clouds, and many more. I have been using my telescope for astrophotography for about 12 years, and I’m still enjoying it!
His next image is the “Helix Nebula” taken with the same filter set as the last Tarantula Nebula image.
The vivid colors of this planetary nebula are the outer layers of a star that were shed at various times in the past. Energy given off by the dying red giant star at the nebula center causes these layers to fluoresce. All this is beautifully captured in Diego’s image.
The Corona Australis Molecular Cloud is one of those regions that those of us that observe from mid-northern latitudes just miss-out on appreciating if trees or structures blocks our southern horizon.
Corona Australis ranks 80th in area among the 88 modern constellations. The image above just frames the northern part of the diminutive “southern crown.” To the upper-right in the photo is NGC 6723 — a globular cluster in neighboring Sagittarius. Almost 2½° along the diagonal, to the lower-left of this wide-field, is alpha Coronae Australis. The image is split along this diagonal by a dense, dark molecular cloud where star formation is taking place. It is a relatively nearby star-forming region at only about 430 light-years distant. The blue nebulae in the upper-right shine by reflected light of hot, young stars.
We wish Diego continued success in his astrophotographic travels.
Tele Vue-76 Details
With a 76-mm diameter APO (Doublet) objective and 480-mm focal length, this f/6.3 refractor combines compact size with apochromatic optical performance. Maximum field-of-view is 5.5° with our 41-mm Panoptic (11.7x) or 55-mm Plössl (8.7x). The 5.0° field-of-view of the 31-mm Nagler (15.5x) is another option for wide-field/ self-finder use.
Available in ivory or green powder coat finish, the optical tube includes: 2″ Focusmate 10:1 dual speed, rack-and-pinion focuser with dual tension adjustment screws on the drawtube and dual lock screws on the end-ring, sliding metal dew shield, screw-on metal lens cover, and soft carry case.
Optional Tele Vue-76 Accessory Package (TVP-3066) adds 3” tube ring- with mounting threads, a telescope balance aid bar that allows for a greater range of shifting the OTA over the mount (great when trying to balance binocular viewers or heavy eyepieces and cameras), 2″, 90° Everbrite dielectric (99%, 1/10-wave) coated mirror diagonal with 1¼” eyepiece adapter and brass clamp rings, and 18.2-mm DeLite eyepiece with 20-mm eye-relief that yields 2.3° true field of view at 26x in the Tele Vue-76.
Our small APO doublet refractors offer a combination of versatility, performance, portability, and build quality unique in the market. We design our own apochromatic objectives to produce startlingly natural images whether it’s the Moon, planets, or birds! High power images are essentially free of detail robbing color fringing at the diffraction limit and contrast is maximized using glass-type specific multi-coatings and dead-flat baffling to control stray light reflections.