Astro-Physics 155mm f7 Starfire EDF Apochromatic Refractor Telescope, Model 900 GTO
Equatorial Mount with Pier, and other accessories and optics. Will accept Money Orders or
Cashiers Checks. Buyer pays for shipping.
Email me for any questions : mailto:Bobbyduckworth@cs.com
Click on pictures to expand
Descriptions and specifications (Material derived from Company Seven Website, distributor for Astro-Physics) :
I. Astro-Physics 155mm f7 Starfire EDF Apochromatic Refractor with 4" Focuser and 4" Field Flattner Lens
The objectives are APOCHROMATIC, meaning images are essentially free of false color, both
photographically and visually. The selected Super ED is the heart of this optical design because
of its excellent light transmission and superior correction of all the monochromatic and
polychromatic aberrations. Super ED is a more advanced glass than the more common varieties
used in commercialrefractors allowing Astro-Physics to use crown rather than flint for the outer
elements. Normal ED (FK01) and even Fluorite doublets use flint glasses as the leading element,
causing the color correction to be less than perfect, especially in the violet region of the spectrum.
These flints introduce false color that can be seen as purple halos around bright objects, or purple
fringing along the Lunar edge and at the edges of bright craters. This color error can cause brighter
stars to bloat on long exposure photographs.
Their relatively compact arrangement makes the EDF series of telescopes truly one man manageable
instruments; affording spectacular views unmatched by any other telescope systems in terms of field
of view, detail, color fidelity, contrast and clarity. One of the important advantages of a short focal
length is that the mounting can be relatively smaller, lighter and more compact than longer telescopes
The result is a highly portable refractor system with superior imaging qualities, ideal for a wide
variety of astronomical work from high-magnification lunar/planetary to deep sky astrophotography.
This 155mm f7 StarFire EDF (6.1" aperture) was designed to be the ultimate astrograph while
providing uncompromising visual performance. Outstanding photographs published in Sky &
Telescope, Astronomy and various international astronomy magazines can only hint at the
detail of the original prints and negatives. Photographic spot diameters measure 15-20 microns
over a 5 degree field (4" circle). The fast f7 focal ratio captures elusive and faint deep-sky objects
easily with incredible detail. This lens has outperformed mirror type astrographs twice its size,
as we had predicted.
The EDF is superb as a visual instrument as well. It is easily capable of high-power observations of
the moon and planets. Secondary spectrum is nearly absent at any power. Deep-sky views are
equally impressive due to the very high transmission of the three glass types.In the astrographic
configuration, the lens is a 5-element design in 2 groups (3 elements in front, 2 in rear). The heart
of the front triplet apochromatic lens is an ED glass and 2 crowns. This combination totally
eliminates all secondary spectrum, coma and spherical aberration. The rear lens is a 2ement field
flattener that eliminates astigmatism and field curvature. In the visual configuration, the rear
2-element lens is removed andreplaced with a standard visual adapter. This adapter allows all
our usual accessories to be attached, as well as all standard 2" and 1.25" oculars.
The Astro-Physics giant 4" focuser is truly versatile, allowing coverage of medium format films with
minimal vignetting. In the hands of knowledgeable astrophotographers, these instruments can
produce superb, professional astrophotographs of all your favorite deep-sky objects. Images are
so sharp, it requires enlargements of up to 30" x 40" to resolve the finest details. The 4" ID of the
drawtube will allow maximum coverage of the Pentax 6 x 7 cm negative for medium format
photography. The inside of the drawtube has a series of knife-edge baffles for maximum contrast.
When you wish to use your 35mm camera with the Astro-Physics telecompressor for even faster
exposures (f5.2), you can attach the 2.7" reducer and you are ready to go. The 2" and 1.25"
adapters (Included) will allow you to use all of our standard accessories to maximize your visual
and photographic applications.
Specifications of Refractor:
· Clear aperture 155mm (6.1")
· Focal length: 1085mm (43") efl
· Color correction Less than 0.01% focus variation from 405nm to 706nm (r to h
wavelengths)
· Resolution: 0.74 arc second
· Coatings: Multi-layer, overall transmission greater than
97% in peak visual wavelengths
· Magnification range 20x to 600x
· Tube assembly: White, 6.5" aluminum tube, baffled, flat black interior
· Focuser type: 4.0" I.D. Astro-Physics rack & pinion focuser, 4.5" travel,
2.7", 2" and 1.25" adapters, 2.5" extension
· Telescope length 1041 mm (41 ") with dewcap fully retracted
· Tube weight: 27 lbs.
· Field Flattener: 4" diameter 2-element with multi-coatings
· 35mm Photographic field: 1.3 x 1.8 degrees @ f7 at Prime Focus
1.7 x 2.4 degrees @ f5.2 with Telecompressor
0.6 x 0.9 degrees @ fl4 with 2x Barlow
· 6 x 7 cm Photographic field: 3.2 x 3.7 degrees @ f7 at Prime Focus
· Maximum Photographic Field: 5 degrees, 4 inch circle
1. Finder scope 8X50
2. Finder scope Mounting ring with quick
release bracket
3. Photo guide scope 80mm X 900mm
4. SBIG ST-4 Auto-guide and imaging CCD
5. 2 “” Diagonal Maxbright
6. Barlow Lens/Convertible
7. Camera Adapter, Prime Focus & Eyepiece
projection (Nikon Body)
8. Gelatin Filter Holder for 4 inch Field Flattner
9. Foam-fitted, vinyl-covered plywood case, standard carryimg case for
Telescope Tube Assembly
10. Telecompressor, Photo-Visual for 2.7 and 4 inch focuser, Flat Field 0.75x for 35mm
The 900 GTO Equatorial Mount is designed for solid stability under a variety of observing
conditions. At the same time, the mount is truly portable so that it can be transported to your
favorite dark-sky site and set up quickly and accurately. The mounting break down into
manageable sizes, but when set up, is an extremely rugged and steady platforms.
Astro-Physics has also developed a very accurate worm gear set and state of the art
electronics technology to insure smooth, effortless tracking of celestial objects for all
visual and photographic purposes, and a high degree of durability and reliability.
The basic mounting configuration was engineered with proper vibration and strength of
materials criteria. As in a good building design, all loads are channeled into massive
load-bearing cross sections to their final destination - the ground. This is engineered in
a manner that minimizes mass and size while maximizing rigidity. For examples of this,
study the tension rods on the piers, and the thrust bearings on the polar and declination
axes that transfer a tremendous amount of load in relation to their size. To these mechanics
is added a drive that is accurate and sophisticated enough for the most demanding
application, featuring a custom-manufactured fine-pitch worm gears driven by a Servo
motor with an advanced hand held controller. This makes the tracking of celestial objects
a snap, even for beginners.
Benefits of Servo Motors:
Zero-cogging servo drive motors are more accurate than steppers,
even when steppers are in the "microstep" mode
Servo motors require less power to run, and therefore extend battery operating times
Servo motors offer improved torque at high slewing rates.
The input commands to the GTO system are entered either via a keypad or an optional
personal computer with the DigitalSky Voice control software. If the computer is equipped with
a speaker and microphone, all control functions can be performed by simply speaking the
commands, which are repeated by the computer to confirm your command.
Specifications of Equatorial Head :
Counterweight Shaft (removable) of 1.875" diameter. weight is.
All precisely machined mounting made from aluminum, brass, and stainless steel bar stock
Dual Axis servo motors with 12 Volt quartz micro-drive controller choose either
Polar and Declination axes dovetailed to come apart quickly for light-weight easy handling and transport
Polar and Declination axes set in precision Ball Bearing races
Fine altitude and azimuth adjustment mechanisms for quickly and accurately zeroing in on the Pole in the
field
R.A. Setting Circle Porter Slip Ring design
Declination axis gear allows full 360 degree continuous rotation; can move through zenith for
photography
R.A. axis shaft threaded for included optional detachable polar scope for quick, accurate alignment in
the field
One 6 volt power output for optional camera (Pentax 6x7cm-Not Included)
Motors and electronic components fully enclosed
Ready to go with our optional (Included) SBIG Star Tracker Auto-guider / Imaging CCD System
· R.A. worm wheel: 7.2 inch, 225 tooth aluminum
· Declination worm wheel: 6 inch diameter, 225 tooth aluminum
· Worm gear material brass
· Latitude range 19 to 68 degrees with polar scope; low latitude wedge available
· Setting circles Porter Slip Ring design
· Declination Shaft: 1.75 inch Diameter
· Declination Thrust Surface: 6.0 inch Diameter
· Right Ascension Shaft 2.2 inch Diameter
· R.A. Thrust Surface: 7.0 inch Diameter
· Weight of equatorial head: 38 lbs. Disassembles into two manageable pieces:
Right Ascension Polar axis weight is 22 lbs.
Declination axis weight is 16 lbs.
The GTO Mount basic
functions that are included are:
· Low current draw, reversible servo motor drive system on both the Right Ascension and Declination
· Contains a Telescope Interface Connector ("TIC") socket for CCD Star Tracker/Imaging Camera Systems
· Drive Rates: King, Lunar, Sidereal, Solar
· Guide/Slew rates: 0.25x, 0.5x, 1x, 8x, 64x Sidereal
· Maximum Slew Rate: 5 Deg./Sec. (1200x Sidereal)
· Periodic Error Memory correction; user programmable to correct for worm induced periodic errors.
· Periodic Error Memory correction retains correction data - no need to reprogram each night out.
· User selectable Declination Backlash control.
· Adjustable voltage output for accessories such as a guiding eyepiece illuminator.
Specifications of the
GTO keypad controller:
·
low temperature display
· Display Type: Red LED backlit alphanumeric
· Display Screen: Vacuum Fluorescent Display (VFD)
· Display Arrangement: 4 line, 20 character display
· Directional N-S-E-W control buttons
Features of Digital Sky Voice control software:
· Extensive object database includes: Messier, IC, NGC, ADS (Aitkens Double Star) and planets.
· Voice control as easy as saying "M1", or "Find the Cocoon Nebula".
· Voice control preserves night vision by eliminating need to view a computer screen.
· Guides you through polar alignment and all functions of the program.
· Provides extensive information about the object you are viewing.
· Timer: lets you know the time remaining during an exposure.
· Advises when the object that you selected has reached the desired position in the sky.
· Informs you of favorite objects that are visibe within constellations that have risen.
· Easy two star polar alignment.
· User can add objects to the database.
· User can store up to three observing site locations in memory to facilitate future set up.
· Will advise you when you ask to go to an object that is below the horizon.
· Night Vision Mode display
· Can use with Software Bisque astronomy planetarium program "The Sky" version 4.0 (not included).
Options included
1. Polar Finder scope
2. 18 lb counterweight
3. 10 lb counterweight
4. 15” Dovetail Plate
5. 15” Slide bar
6. Low Latitude Wedge
7. Set of 6.5” Mounting rings
8. 8” X 54” Portable Pier
III. Other Products included with this system
1. Kendrick Power Pack (Battery 12v 33 amp hours)
LED state of charge indicator (voltage)
Four Cigarette Lighter output power sockets
Outputs on individual breakers (two 10 amp & two 5 amp)
Nominal Working Voltage 11.88 volts DC
Weight of 32.5 lbs
Includes Soft Shell carrying case
2. Thtee Eyepieces
Tele Vue 9mm Nagler
Tele Vue 5 mm Radian
Tele Vue 22 mm Nagler Type 4
3. 12 Volt Regulated Power Supply
Pyramid Model PS-14KX
Input 115 Volt AC 270 watt
Output 13.8 Volts DC
DC output 12 Amp Constant/14 Amp Surge
4. Lumicon 2 " Premium Deep Sky Filter
5. Pentax 6 V DC Power Cord
7. Float Charger for Power Pack
Deltran "Battery Tender"
12 volt DC/6 amp
Charges fully discharged battery in 5 hours
Storage trickle charge
Visit the following websites (Company Seven, distributor for Astro-Physics & Astro-Physiocs, manufacturer)
for more complete details and specifications:
http://www.companyseven.com/astrophy/products.html
http:/www.astro-physics.com