Image of the Month
Equipment
THE PRIMARY INSTRUMENT in use at the observatory is an 11-inch (280mm) aperture Celestron Schmidt Cassegrain telescope of 2800mm focal length (f/10 focal ratio). The C-11 Optical Tube is mounted on a Mountain Instruments MI-250 German Equatorial Mount. This mount features 7.5 inch gears with matching diamond-lapped worms on both the RA and DEC axes. Tracking accuracy is + or - 4 arc seconds. Load capacity of the mount is 75 pounds. The optical tube is attached to the mount via a Casady precision tip-in saddle. In this photo, the telescope is set up for digital imaging at f/2 using a HyperStar III corrector lens mounted in place of the normal secondary mirror. Mounted on the HyperStar lens is a ZWO ASI 2600MC CMOS digital imaging camera. This camera has a SONY IMX571 back-lit 23.6 X 15.6mm sensor with 3.76 micron pixels (26 megapixels). When using the HyperStar imaging system this gives a 2.5 X 1.5 degree field with a resolution of 1.76 arc seconds per pixel. Also used with this system is a Starlight Express SXVR H694C Color CCD imager and a ZWO ASI 071MC camera.
Also visible in this photo are the 80mm (3.1")
ORION guiding telescope and the 80mm (3.1") ANTARES erect-image finder scope.
The MI-250 mount is controlled remotely from the adjacent control room using N.I.N.A (Night time Imaging 'N' Astronomy) software by Stefan Berg, in conjunction with the GEMINI I controller shown in the photo just below the mount.
ASTRO IMAGING EQUIPMENT
The photo to the right is a closer view of the hardward used for guided astro imaging at the observatory.
The 80mm (3.1") ORION ED 80 Apochromatic guiding refractor is mounted atop the C-11 OTA using Losmandy heavy duty dovetail base and rings. Attached to the guiding telescope is a ZWO ASI 174MM CCD guiding camera, which sends guiding corrections to the MI-250 mount via an RS-232 connection.
Also shown is the MICRO-TOUCH stepper motor
focuser, which provides precise focus adjustment. Each motor step moves the focusing screw 1/3000th of a revolution.
During an imaging session, both the imaging camera, guiding camera, and MI-250 mount are controlled remotely from the CONTROL ROOM, via underfloor cabling, using N.I.N.A (Nighttime Imaging 'N' Astronomy) software running on an HP 15-dh-1054 OMEN 5gHz laptop computer.
Below is a closeup of the MICRO-TOUCH stepper motor focuser on the C-11.
Pictured below is the ZWO 174mm Mini guiding camera
THE CONTROL ROOM
Shown at right is a photo of the desk in the control room at LAND OF OZ OBSERVATORY.
To the right ofthe HP Laptop Computer is the hand pad for the MICRO-TOUCH DIGITAL FOCUSER for the C-11 and the hand pad for the JMI MOTORIZED FOCUSER for the 80mm guide scope.
Below is a photo of the laptop screen during an imaging
sequence. The N.I.N.A screen is open, showing the down-
loaded image, the camera control box, the guiding graph, which is showing excellent guiding with very small corrections, and the sequence progress & focus boxes.
Setting up for an evening of imaging: The photo to the left shows the C-11 telescope on the MI-250 equatorial mount with the HyperStar imaging system and the Starlight Express SXVR-H694C color CCD imager mounted. Also shown is the 80mm f/7.5 guiding telescope. This photo taken by Dave Hudgins in July of 2018.
New ZWO ASI 2600MC Pro Camera (Below)
September, 2021: (at right) A new imaging system installed at Land of Oz Observatory. After nine years of imaging at f/2 using the Starizona HyperStar III system installed on the "top end" of the C-11, we are going to try our hand at Cassegrain focus imaging, using the Starizona Reducer/Corrector SCT III .63X focal reducer along with the new ZWO ASI 2600MC Pro one-shot color CMOS camera. This camera has the latest Sony IMX571 APS-C format back-illuminated 26 mega-pixel sensor. This sensor has native 16 bit ADC and 3.76 micron pixels. Using the .63X focal reducer will yield a focal length of 1760mm versus the 560mm of the HyperStar setup. This, and the smaller pixels will yield greater resolution on smaller galaxies and nebulae. The image field of view is 45 X 30 arc minutes.
