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Featured researches published by J. Julian.


Astronomical Telescopes and Instrumentation | 1998

GatirCam: Gemini mid-infrared imager

Charles M. Telesco; Robert K. Pina; Kevin T. Hanna; J. Julian; David B. Hon; Thomas M. Kisko

The University of Florida is developing the mid-IR imager, called GatirCam, to be used primarily, but not solely, at the southern hemisphere Gemini telescope at Cerro Pachon, Chile. Key features of GatirCam are its fully reflective optics, its very high mechanical rigidity, and the fact that the associated electronics are very similar to those is in use successfully on similar instrumentation. Design studies for GatirCam indicate that it will meet or exceed all critical requirements of image quality and performance. A low-resolution spectroscopic mode is also currently under consideration for implementation in GatirCam.


Astronomical Telescopes and Instrumentation | 2003

CanariCam: a multimode mid-infrared camera for the Gran Telescopio CANARIAS

Charles M. Telesco; David R. Ciardi; James French; Christ Ftaclas; Kevin T. Hanna; David B. Hon; J. Hough; J. Julian; Roger Julian; M. Kidger; C. Packham; Robert K. Pina; Frank Varosi; R. Glenn Sellar

The University of Florida is developing a mid-infrared camera for the 10.4-meter Gran Telescopio CANARIAS. CanariCam has four science modes and two engineering modes, which use the same 320 x 240-pixel, arsenic-doped silicon, blocked-impurity-band detector from Raytheon. Each mode can be remotely selected quickly during an observing sequence. The pixel scale is 0.08 arcsec, resulting in Nyquist sampling of the diffraction-limited point-spread-function at 8 μm, the shortest wavelength for which CanariCam is optimized. The total available field of view for imaging is 26 arcsec x 19 arcsec. The primary science mode will be diffraction-limited imaging using one of several available spectral filters in the 10 μm (8-14 μm) and 20 μm (16-25 μm) atmospheric windows. Any one of four plane gratings can be inserted for low and moderate-resolution (R = 100 - 1300) slit spectroscopy in the 10 and 20-μm regions. Insertion of appropriate field and pupil stops converts the camera into a coronagraph, while insertion of an internal rotating half-wave plate, a field mask, and a Wollaston prism converts the camera into a dual-beam polarimeter.


Astronomical Telescopes and Instrumentation | 2003

Performance of the FLAMINGOS Near-IR Multi-object Spectrometer and Imager and Plans for FLAMINGOS-2: a Fully Cryogenic Near-IR MOS for Gemini South

Richard Elston; Steven N. Raines; Kevin T. Hanna; David B. Hon; J. Julian; Matthew Horrobin; Charles F. W. Harmer; Harland W. Epps

We report on the performance of FLAMINGOS, the worlds first fully cryogenic near-IR multi-object spectrometer. FLAMINGOS has a fast all refractive optical system, which can be used at telescopes slower than f/7.5. This makes FLAMINGOS a very efficient wide-field imager when used on fast small aperture telescopes and a high AW spectrometer using laser machined aperture masks for MOS spectroscopy. FLAMINGOS uses a 2048x2048 HgCdTe HAWAII-2 array by the Rockwell Science Center. The array is readout through 32 amplifiers, which results in low overheads for observations. We describe both the operating characteristics of the HAWAII-2 array and of the array controller and data acquisition system. FLAMINGOS has been in operation for about 1.5 years and is now in routine use on four telescopes: The Kitt Peak 4-m and 2.1-m, The 6.5-m MMT and the 8-m Gemini South Telescope. We will describe the operating characteristics of FLAMINGOS on each of these telescopes that deliver fields-of-view from 21x21 arcminutes to 2.7x2.7 arcminutes and pixels from 0.6 arcseconds to 0.08 arcseconds. While providing a large AW product for fast telescopes (i.e. f/8), FLAMINGOS becomes progressively less efficient on slower telescopes. Since nearly all large telescopes have fairly slow optical systems (f/12 or slower) the combination of large aperture and slow optical systems makes FLAMINGOS ill suited for optimal performance on current large aperture telescopes. Thus, we are beginning construction of FLAMINGOS-2, which will be optimized for performance on the f/16 Gemini South 8-m telescope. Similar to FLAMINGOS, FLAMINGOS-2 will be fully refractive using grisms, laser machined aperture masks and a 2048x2048 HgCdTe HAWAII-2 array. FLAMINGOS-2 will provide a 6.1 arcminute field-of-view with 0.18 arcsecond pixels. FLAMINGOS-2 will also be designed to except an f/32 beam from the Gemini South MCAO system.


Proceedings of SPIE | 2006

The Canarias Infrared Camera Experiment (CIRCE): optical and opto-mechanical design and manufacture

Michelle L. Edwards; Stephen S. Eikenberry; Antonio Marin-Franch; Miguel V. Charcos-Llorens; M. Rodgers; J. Julian; Nick Raines; C. Packham

We report on the design status of the Canarias InfraRed Camera Experiment (CIRCE), a near-infrared visitor instrument for the 10.4 meter Gran Telescopio Canarias (GTC). In addition to functioning as a 1-2.5 micron imager, CIRCE will have the capacity for narrow-band imaging, low-and moderate- resolution grism spectroscopy, and imaging polarimetry. CIRCEs all-reflective aspheric optical design offers excellent throughput and image quality. We present an analysis of the optical layout and the progress of the opto-mechanical design and manufacture.


Proceedings of SPIE | 2008

Optical-mechanical operation of the F2T2 filter: a tunable filter designed to search for First Light

Erin Mentuch; Alan Scott; Roberto G. Abraham; Elizabeth J. Barton; Matthew A. Bershady; Joss Bland-Hawthorn; David Crampton; René Doyon; Stephen S. Eikenberry; Michael D. Gladders; Karl Glazebrook; Joe Jenson; J. Julian; Roger Julian; Jean-Paul Kneib; David Loop; Nick Raines; Neil Rowlands; J. D. Smith

The Flamingos-2 Tandem Tunable filter is a tunable, narrow-band filter, consisting of two Fabry-Perot etalons in series, capable of scanning to any wavelength from 0.95 to 1.35 microns with a spectral resolution of R~800. It is an accessory mode instrument for the near-IR Flamingos-2 imaging-spectrograph designed for the Gemini South 8m Observatory and will be fed through the upcoming Multi-Conjugate Adaptive Optics feed. The primary science goal of the F2T2 filter is to perform a ground-based search for the first star forming regions in the universe at redshifts of 7 < z < 11. The construction of the F2T2 filter is complete and it is currently in its calibration and commissioning phases. In this proceeding, we describe the calibration and performance of the instrument.


Proceedings of SPIE | 2008

Day-one science with CanariCam, the Gran Telescopio Canarias multi-mode mid-infrared camera

Charles M. Telesco; C. Packham; Christ Ftaclas; J. Hough; Margaret Marie Moerchen; Kevin T. Hanna; J. Julian; Frank Varosi; Roger Julian; Greg Bennett; Charles H. Murphey; Francisco Reyes; Craig Warner

CanariCam is the facility multi-mode mid-IR camera developed by the University of Florida for the 10-meter Gran Telescopio Canarias (GTC) on La Palma. CanariCam has four science modes that provide the GTC community with an especially powerful research tool for imaging, grating spectroscopy, coronagraphy, and dual-beam polarimetry. Instrument commissioning in the laboratory at the University of Florida indicates that all modes perform as required, and the next step is on-telescope commissioning. After commenting on the instrument status, we will review key features of each of these science modes, with emphasis on illustrating each mode with science examples that put the system performance, particularly the anticipated sensitivity, into perspective.


Archive | 2010

CIRCE: The Canarias InfraRed Camera Experiment

Miguel V. Charcos-Llorens; A. J. Cenarro; Michelle L. Edwards; Stephen S. Eikenberry; Kevin T. Hanna; J. Julian; N. M. Lasso Cabrera; A. Marín-Franch; C. Packham; S. N. Raines; M. Rodgers; Frank Varosi

The Canarias InfraRed Camera Experiment (CIRCE) is a near-infrared (1–2.5 μm) instrument for the Gran Telescopio Canarias (GTC) 10.4 m telescope. CIRCE has an off-axis aspheric all-reflective optical system that offers both excellent throughput and image quality. Observational modes include broad/narrow band imaging and low-resolution spectroscopy. High time-resolution data acquisition and polarimetry are available in both cases. We present an overview of the instrument and the current status of design and fabrication.


Proceedings of SPIE | 2008

The Canarias InfraRed Camera Experiment (CIRCE): Progress of the Opto- and Cryo- mechanical Design and Manufacture

Michelle L. Edwards; Stephen S. Eikenberry; Miguel V. Charcos-Llorens; A. Marín-Franch; N. Lasso; Steven N. Raines; J. Julian; Kevin T. Hanna; C. Packham; M. Rodgers; Reba M. Bandyopadhyay

We present the current status of the Canarias InfraRed Camera Experiment (CIRCE) an all-reflective near-IR, imager, spectrograph, and polarimeter for the 10.4-meter Gran Telescopio Canarias (GTC). In particular, we review the progress of the opto- and cryo- mechanical design and manufacture, focusing on the custom filter, lyot, and grism wheels, lightweight optics, and mirror brackets. We also outline our progress with the optical bench. Finally, we discuss a number of CIRCEs features that both complement and augment the planned suite of GTC facility instruments.


Proceedings of SPIE | 2008

Characterization and testing of FLAMINGOS-2: the Gemini facility near-infrared multi-object spectrometer and wide-field imager

Steven N. Raines; Stephen S. Eikenberry; Reba M. Bandyopadhyay; J. Julian; Kevin T. Hanna; Craig Warner; Roger Julian; J. Greg Bennett; Curtis N. DeWitt; Skip Frommeyer; Anthony H. Gonzalez; Michael D. Herlevich; Charles H. Murphey

FLAMINGOS-2 is a near-infrared wide-field imager and fully cryogenic multi-object spectrometer for Gemini Observatory being built by the University of Florida. FLAMINGOS-2 can simultaneously carry 9 custom cryogenic multi-object slit masks exchangeable without thermally cycling the entire instrument. Three selectable grisms provide resolving powers which are ~1300 to ~3000 over the entire spectrograph bandpass of 0.9-2.5 microns. We present and discuss characterization data for FLAMINGOS-2 including imaging throughput, image quality, spectral performance, and noise performance. After a lengthy integration process, we expect that FLAMINGOS-2 will be in the midst of commissioning at Gemini South by the fall of 2008.


New Astronomy Reviews | 2006

FISICA: The Florida image slicer for infrared cosmology and astrophysics

Stephen S. Eikenberry; Richard Elston; Rafael Guzman; S. Nicholas Raines; J. Julian; N. Gruel; Glenn D. Boreman; Jeff Hoffmann; M. Rodgers; Paul Glenn; Greg Hull-Allen; Bruce Myrick; Scott Flint; Lovell E. Comstock

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M. Rodgers

Science Applications International Corporation

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