Auto-Guiding System for Cquean (Camera for Quasars in Early Universe)

Kim, Eunbin; Park, Won-Kee; Jeong, Hyeonju; Kim, Jin‐Young; Kuehne, John; Kim, Donghan; Kim, Han Geun; Odoms, P. Samuel; Chang, Seunghyuk; Im, Myungshin; Pak, Soojong

doi:10.5303/jkas.2011.44.4.115

Cited by 15 publications

(19 citation statements)

References 10 publications

(9 reference statements)

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“…The tracking error along Dec. turned out to be very small: −0.0001 /sec. This value is consistent with the estimation of Kim et al (2011). Meanwhile, the values along RA are about 0.03 /sec for Sections 1, 3, and 5, and 0.02 /sec for the other sections.…”

Section: Exposure Time Requirementsupporting

confidence: 78%

“…From this condition, we can estimate the cycle time of the guide camera that will produce a tracking error less than 0.3 . Figure 1 in Kim et al (2011) shows that telescope drift along the Dec. direction is more or less constant up to 2000 seconds. We estimated from Figure 1 that the drift along declination direction will be about 0.3 for a 3000 second cycle time and along RA direction about 0.3 for a 10 second cycle time.…”

Section: Exposure Time Requirementmentioning

confidence: 99%

“…Figure 1 shows the drift of the target center on the CQUEAN images along the RA, aligned with the X axis of the CCD chip, and Dec., Y axis of the chip, without the auto-guiding system. Kim et al (2011) showed that there is a misalignment of the worm gear in the OST mount that causes a periodic error of about 2 minutes. The different direction of tracking offset labeled as Sections 2 and 4 are caused by this misalignment of the gear.…”

Section: Exposure Time Requirementmentioning

confidence: 99%

“…Because CQUEAN is installed in the cassegrain focus (f/13.65), which has a characteristic of high magnification and small field of view (FOV), a focal reducer was developed in order to reduce the focal length and result in a larger FOV (Lim et al 2013). In addition, Kim et al (2011) made an auto-guiding system specifically for CQUEAN, because other existing auto-guiding systems for the OST could not be adapted for CQUEAN. The auto-guiding system made by Abbott (1990) was not suitable for long time exposures, and the one for the Sandiford Echelle Spectrograph cannot be used for other instruments.…”

Section: Introductionmentioning

confidence: 99%

“…The pixel size of the guide CCD camera is 24µm × 24µm, and its pixel scale is 0.17 /pixel, with a FOV of 2.97 × 2.97 . The guide camera is held by an arm that can rotate around the optical axis of the telescope to find a guide star in the off-axis fields (Kim et al 2011). The auto-guiding software, agdr, originally developed for the 2.7-m telescope in the McDonald Observatory, was modified to be used for CQUEAN and the OST.…”

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confidence: 99%

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A New Auto-Guiding System for Cquean

Choi¹,

Park²,

Lee³

et al. 2015

Journal of The Korean Astronomical Society

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We develop a new auto-guiding system for the Camera for QUasars in the EArly uNiverse (CQUEAN). CQUEAN is an optical CCD camera system attached to the 2.1-m Otto-Struve Telescope (OST) at McDonald Observatory, USA. The new auto-guiding system differs from the original one in the following: instead of the cassegrain focus of the OST, it is attached to the finder scope; it has its own filter system for observation of bright targets; and it is controlled with the CQUEAN Auto-guiding Package, a newly developed auto-guiding program. Finder scope commands a very wide field of view at the expense of poorer light gathering power than that of the OST. Based on the star count data and the limiting magnitude of the system, we estimate there are more than 5.9 observable stars with a single FOV using the new auto-guiding CCD camera. An adapter is made to attach the system to the finder scope. The new auto-guiding system successfully guided the OST to obtain science data with CQUEAN during the test run in 2014 February. The FWHM and ellipticity distributions of stellar profiles on CQUEAN, images guided with the new auto-guiding system, indicate similar guiding capabilities with the original auto-guiding system but with slightly poorer guiding performance at longer exposures, as indicated by the position angle distribution. We conclude that the new auto-guiding system has overall similar guiding performance to the original system. The new auto-guiding system will be used for the second generation CQUEAN, but it can be used for other cassegrain instruments of the OST.

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Section: Exposure Time Requirementsupporting

confidence: 78%

Section: Exposure Time Requirementmentioning

confidence: 99%

Section: Exposure Time Requirementmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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A New Auto-Guiding System for Cquean

Choi¹,

Park²,

Lee³

et al. 2015

Journal of The Korean Astronomical Society

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Camera for Quasars in Early Universe (CQUEAN)1

Park¹,

Pak²,

Im³

et al. 2012

Publications of the Astronomical Society of the Pacific

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We describe the overall characteristics and the performance of an optical CCD camera system, Camera for QUasars in EArly uNiverse (CQUEAN), which is being used at the 2.1 m Otto Struve Telescope of the McDonald Observatory since 2010 August. CQUEAN was developed for followup imaging observations of red sources such as high redshift quasar candidates (z 5), Gamma Ray Bursts, brown dwarfs, and young stellar objects. For efficient observations of the red objects, CQUEAN has a science camera with a deep depletion CCD chip which boasts a higher quantum efficiency at 0.7 − 1.1 µm than conventional CCD chips. The camera was developed in a short time scale (∼one year), and has been working reliably. By employing an auto-guiding system and a focal reducer to enhance the field of view on the classical Cassegrain focus, we achieve a stable guiding in 20 minute exposures, an imaging quality with FWHM ≥ 0.6 ′′ over the whole field (4.8 ′ × 4.8 ′ ), and a limiting magnitude of z = 23.4 AB mag at 5-σ with one hour total integration time.

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Color Variability of HBC 722 in the Post-Outburst Phases

Baek

Pak

Green

et al. 2015

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We carried out photometric observations for HBC 722 in SDSS r, i and z bands from 2011 April to 2013 May with a Camera for Quasars in Early uNiverse attached to the 2.1m Otto Struve telescope at McDonald Observatory. The post-outburst phenomena were classified into five phases according to not only brightness but also color variations, which might be caused by physical changes in the emitting regions of optical and near-infrared bands. A series of spectral energy distribution (SED) is presented to support color variations and track the time evolution of SED in optical/near-infrared bands after the outburst. Given two years of data, possible periodicities of r, i and z bands were checked. We found out three families of signals around ∼6, ∼10 and ∼1 days in three bands, which is broadly consistent with Green et al. (2013). We also examined short term variability (intra-day and day scales) to search for evidences of flickering by using the micro-variability method. We found clear signs of day scale variability and weak indications of intra-day scale fluctuations, which implies that the flickering event occurs in HBC 722 after outburst.

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Auto-Guiding System for Cquean (Camera for Quasars in Early Universe)

Cited by 15 publications

References 10 publications

A New Auto-Guiding System for Cquean

A New Auto-Guiding System for Cquean

Camera for Quasars in Early Universe (CQUEAN)1

Color Variability of HBC 722 in the Post-Outburst Phases

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