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   Go here for links to software used for astronomical image acquisition and processing.

  Go here to see 3-D Curvature maps of different optical system and camera combinations.

August 2007 observatory set-up at Sierra Remote Observatories:

RCOS 12.5 inch f/9 RC, Paramount ME, RCOS PIR, Astrodon Monster MOAG, ST-402 off axis guider, Apogee filter wheel and Apogee U16M CCD camera.

July 2007 Temporary set-up at Sierra Remote Observatories:

  RCOS 10 inch f/7 RC Astrograph telescope, Paramount ME and the STL-11000M on loan from CSUF Physics Department (thanks Fred).

Optical Set-up, Winter 2006:

Shown above:

 

The Takahashi BRC-250 is a 10 inch f/5 astrograph.  The BRC-250 uses a hyperbolic (non-spherical) primary and secondary mirror which is the definition of a Ritchey-Chrétien telescope.  It also uses an internal Baker lens system to achieve f/5 over a very large and flat image circle.   Hence the name, Baker Ritchey-Chrétien (BRC).  The short focal length of only 1,268 mm offers a up the opportunity for wide field imaging for this aperture scope.  The Finger Lakes Instrumentation (FLI) Precision Digital Focuser (PDF) allows remote digital focusing of the CCD camera.  Custom CNC tube rings have been made by Leon Aslan.  The SBIG STL-11000M CCD camera is on loan from California State University Fresno campus observatory.  Thanks to Dr. Fred Ringwald for letting me test drive this camera.

Characteristics of the Ritchey-Chrétien (RC) design are its ability to eliminate spherical aberration and coma with only two mirrors.  Because all pure RC optical systems still have a small degree of inherent field curvature and astigmatism, the optical system needs to have an internal lens corrector to generate fast focal ratios and very flat fields..  The Takahashi BRC-250 employs non-spherical surfaces for both the primary and secondary mirrors.  When they are combined with a two element Baker type internal lens system, the problems of spherical aberration, coma, field curvature and astigmatism are virtually eliminated.  This optical configuration produces a fast focal ratio of f/5 with a 100mm 5°Ø image circle.  This is a step forward when compared to other state-of-the-art RC manufacturers that produce optical systems with focal ratios of f/8 or f/9.  This makes the BRC-250 a well suited astrograph for the unforgiving demands of large format CCD imaging.

 

 

Optical Set-up, Summer 2005:

Shown above:

Losmandy G-11 with Gemini Goto

Nikon 150mm aperture 600mm focal length f/4 with attached SBIG CFW-8A and ST-10XME

Losmandy Dovetail Side by Side mounting plate and additional counter weights

Meade 10-inch f/6.3 SCT OTA with attached Optec TCF-S focuser and a SBIG Self Guiding Spectrograph with attached ST-7XE CCD camera (Property of CSU Fresno Physics Department).

The Pier, Completed June 12, 2005:

The Pier is constructed from 6-inch schedule 40 black-pipe with a welded steel cap.  Ken Lehman fabricated the laser-cut round 5/16 inch steel cap piece, thanks Ken!  The concrete base is isolated from the rest of the patio.  The base is made from 650 pounds (dry) of concrete and 39 feet of concrete reinforcing bar (rebar).  The pier is filled with concrete and rebar and extends two feet below the slab surface.  A Losmandy Meade Field Tripod Adapter is bolted to the steel cap on top of the pier.  The pier has been painted black.  Construction was completed on June 12, 2005.

Optical Set-up, Spring 2005:

Shown above left:

Meade 10-inch f/6.3 LX-200 classic on a Milburn Wedge

Losmandy Dovetail plate piggyback and 12.5 pounds of counterweights

Nikon 107mm aperture 300mm focal length f/2.8 with attached SBIG CFW-8A and ST-10XME CCD camera

Optec TCF-S focuser with attached 2-inch diagonal and Pentax XL 40mm eyepiece

Shown above right  (Photo by Kirsten Ellis):

Nikon D70 attached to the Nikon 300mm f/2.8

SBIG AO-7 placed between the ST-10XME and focuser

Meade 0.63x focal reducer placed between the AO-7 and CCD camera

Equipment List: 

Meade 10-inch LX200 classic f/6.3 SCT

Nikon 300mm ED IF f/2.8

Nikon D-70 DSLR

Nikon Wide Field adapter by Steve Mandel

Nikon 2x teleconverter for the 300mm lens

SBIG ST-10XME CCD camera

SBIG CFW-8A color filter wheel and filter set

SBIG AO-7 adaptive optics high-speed guider

Optec TCF-S digital focuser

Meade 0.63x reducer / field flattener

Meade 0.33x reducer / field flattener and adjustable coupler

Standard Milburn Wedge made by Ken Milburn for the 10" LX200

Losmandy dovetail rail system to piggyback the Nikon 300mm

Losmandy counterweight system with one 2.5 lbs. and two 5 lbs. weights

Meade counterweight system with 1, 2 and 3 lbs. weights

Lumicon SCT thread to 2-inch F adapter

Lumicon 2-inch M to T-thread adapter

Lumicon T-thread to Nikon camera adapter

Optec TCF-S to Meade 3-inch rear cell threads

Lumicon 2-inch F to Meade 3-inch mirror cell threads

JMI SCT thread to 2-inch M adapter

Meade 2-inch diagonal

Meade 10-inch metal dew shield

SBIG 12VDC Power Supply for the CCD camera

Pentax XL series eyepieces: 2 inch 40mm and the 1 ¼ inch 14mm, 7mm and 5.2mm

2 inch to 1 ¼ to inch adapters for the eyepieces

Celestron 20x80 binoculars and tripod mount

Bogen / Manfroto #3036 tripod and ***** tripod head for the binoculars

Celestron 12.5mm illuminated astrometric reticle

Meade series 4000 Super Plossil 12.4mm used for eyepiece projection

USB red light, with a long flexible neck, for the computer keyboard given to me by Kevin Hansen

3-in-1 accessory shelf for the LX200 tripod

Orion Vibration foot pads for the LX200 tripod

JMI NGF-SE manual, zero shift, Crayford focuser for visual work (equivalent to the NGF-C)

JMI adapter for the NGF-SE to Meade 3-inch rear cell threads

RS-232 serial DB 9 M to USB adapters

USB repeater cables

USB Hub, non-powered

Filters:

Custom Scientific 1 ¼ inch 3nm Hydrogen-Alpha filter

Schuler 1 ¼ inch 10nm Hydrogen-Alpha filter

Schuler photometric V filter

Orion Sky Glow Broadband filter for visual work only

Thousand Oaks Optical type III full aperture solar filter for the Nikon 300mm

*** full aperture solar filter for the 10" LX200

SBIG RGBC color filter set 1:1:1.6

Custom made parts:

Light Box for image flat field calibration, made by Kevin Hansen (thanks Kevin)

Digital focuser stepper motor assembly and drive belt for remote focusing of the Nikon 300mm

Variable eyepiece projection unit that fits inside the Optec focuser terminating in SCT threads

Parfocal ring for the 40mm Pentax XL eyepiece

SCT thread to 2-inch M adapter with extensive anti-reflective internal baffling

SBIG D-block to SCT thread adapter, for use of a focal reducer between the AO-7 and CCD camera

1 ¼ eyepiece extender tube to allow for parfocality of an eyepiece and CCD camera chip

12VDC power supply bus that powers all the hardware

Equipment I have used in conjunction with the California State University Fresno, Department of Physics, Campus Observatory:

Meade 16-inch LX200 classic f/10

SBIG ST-8

SBIG SGS Self Guiding Spectrograph

For a complete list of all the equipment available at the CSUF campus observatory, click here.

Optical System Configurations:

Taking images with the Meade 10-inch LX200 in combination with other accessories can produce different field scales, f/ ratios and corresponding fields of view.  Although I have the Meade 0.33x focal reducer, I do not use it the same way as the 0.63x reducer.  Since the scope is already a f/6.3 instrument, the 0.33x reducer causes too much distortion near the corners of the ST-10 to be of much use.  The Nikon 300mm A IF f/2.8 lens is used piggyback on the LX200 for wide field images.  This lens can be used with either the Nikon D-70 DSLR or in conjunction with the CFW-8A and ST-10XME with the Nikon adapter made by Steve Mandel.  The aperture is 107mm and it has 8 elements to deliver a flat field over a 35mm format.  Star images are slightly smaller and sharper when this lens is set at f/4 for imaging.  The Nikon D-70 is really wonderful for taking images of a total lunar eclipse and the like.  Anything that is relatively bright like the moon and sun and even the planets and bright comets can be shot with the D-70 DSLR.  Here is a table that outlines the equipment / optical train and its affect on the final image.

Equipment / Optical train                                        Field scale   f/ratio      Field of View

                                                                 arc seconds                arc minutes

                                                                 per pixel               

Nikon 300mm f/2.8 > Nikon D-70                                   5.37           2.8         268.9 x 178.8

Nikon 300mm f/2.8 > CFW-8A > ST-10XME                            4.67           2.8         170.1 x 114.7

Nikon 300mm f/2.8 > 2x teleconverter > Nikon D-70                2.68           5.6         134.4 x 89.4

Nikon 300mm f/2.8 > 2x teleconverter > CFW-8A > ST-10XME         2.34           5.6          85.1 x 57.4

LX200 > Optec TCF > 0.63x reducer > Nikon D-70

LX200 > Optec TCF > Nikon D-70

LX200 > Optec TCF > 0.63x reducer > CFW-8A > ST-10XME            1.15           4.82         41.7 x 28.1

LX200 > Optec TCF > AO-7 > 0.63x reducer > CFW-8A > ST-10XME     1.07           5.16         39.0 x 26.3

LX200 > Optec TCF > CFW-8A > ST-10XME

LX200 > Optec TCF > AO-7 > CFW-8A > ST-10XME                     0.73           7.58         26.5 x 17.8

LX200 > Optec TCF > 0.33x > CFW-8A > ST-10XME                    1.81           3.04         66.0 x 44.5

LX200 > Optec TCF > AO-7 > 0.33x > CFW-8A > ST-10XME             1.68           3.29         61.1 x 41.2

Digital focuser Optec TCF-S:

The Optec TCF-S is a Crayford style, zero shift two-inch focuser that is attached to the backplate of the 10-inch LX200 three-inch threads with an Optec adapter #17455.  This RS-232 serial device allows for very accurate and repeatable software control of the focus of the optical system.  This device is also a temperature-controlled focuser.  When calibrated, the focus will change proportionally with the ambient temperature.