Hōkū Ke‘a Observatory: The Facility

This section presents some detailed technical information on the telescope, instrumentation, dome and observatory site.


The telescope is a state-of-the-art PlaneWave Instruments CDK700 observatory system, with an aperture of 0.7 meter (28") and a focal ratio of F/6.5. The mirrors are made of fused silica glass with a very low thermal expansion. The Corrected Dall-Kirkham (CDK) optical design provides an optimal field of view of 70mm at the focal plane. The mount is of an alt-az design with direct-drive motors and high-precision encoders. Two instruments are available, each installed on a field de-rotator at both Nasmyth focii. Switching from one instrument to the other is done by moving the tertiary mirror and is very quick (~ 10 seconds). The telescope can be operated in a classical, remote or robotic mode from anywhere with Internet access.

For more detailed information on the telescope, please click here: CDK700 Telescope 

FLI           eShel              filters   

The first generation of instruments for Hōkū Ke‘a includes a CCD camera with a set of broad and narrow bandpass (50mm square) filters, and a fiber-fed echelle spectrograph. The CCD camera is an electronically cooled FLI 16803 ProLine camera, with 4096 x 4096 pixels and a pixel size of 9 microns. As a result, the imaging pixel scale is 0.41"/pixel and the field-of-view is 28' x 28'.  The filters include the typical UBVRI set, a Sloan set, a LRGB set and several narrow-band (30 or 50 Ang. wide) filters centered on some of the main nebular lines. These filters are mounted in two FLI CenterLine CL-1-10 filter wheels, each wheel containing 10 filters (2 free apertures).  The Shelyak Echelle spectrograph (eShel) includes a fiber-fed module, a cross-dispersor, internal calibration lamps, a guiding module, and operating software. The detector is an Apogee Alta 2k x 2k U230 CCD camera. Typical spectral resolution is 10000, covering 450-700nm.  Both Hōkū Ke‘a instruments are available at a given time on each Nasmyth port and can be selected by quickly rotating the tertiary mirror.

UH Hilo also has a long-slit Shelyak spectrograph with diffraction gratings that could be made available later on for Hōkū Ke‘a. We are also planning to install a Celestron C925 equipped with a Hyperstar system in piggyback to the main telescope to obtain wide-field (~2 x 2 degrees) images. We are also working with IfA-Hilo on the development of a small robotic Adaptive Optics system.

For more detailed information on the FLI CCD Camera, please click here: FLI Camera
For more detailed information on the HKO Filters, please click here: HKO Filters
For more detailed information on the eShel spectrograph, please click here:
eShel Spectrograph


The Hōkū Ke‘a telescope and its instrumentation are hosted within an AstroHaven 18-foot dome. The dome is of a "clamshell" design so there is no rotation. The sleeves can be fully open to give access to the entire sky, or partly open to protect against strong winds. The dome can be operated remotely or robotically, from the original control software, or from the telescope control software.

For more information about the AstroHaven dome, please click here: HKO Dome


No permanent site for the Hōkū Ke
a has not been identified yet although we have several good options. We hope to have a definitive choice made in the coming months.