WIYN ODI User manual

The WIYN One Degree Imager
User Manual
Version: 4.1 Generated: February 27, 2017 SVN Rev: 183
c
 2012-2016 WIYN Consortium, Inc.

ODI-MAN-1001 ODI User Manual
DRAFT Version 4.1, Expires n/a
Summary:
This is the ODI Operating Manual and is a recommended read for anybody using or operating
the ODI instrument.
Signo for Version 2:
WIYN ODI Scientist Daniel Harbeck July 1 2014
Revision History:
Version Date Author Changes
1 5/30/2013 D. Harbeck First public release.
2 9/11/2013 D. Harbeck Updated GUI gures, include bin-
ning, misc.
3 6/1/2014 D. Harbeck & Wilson
Liu Update on calibration stability, guide star prediction, pointing cor-
rection. Overall update.
4 July 2015 D. Harbeck Work in progress for 5x6 ODI.
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ODI-MAN-1001 ODI User Manual
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Notes:
1. no notes available at this time
Title picture:
A 5 millisecond exposure of the moon observed by 5x6 ODI.
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Contents
1 Instrument Overview 7
1.1 InstrumentWalk-Through.............................. 8
1.1.1 InstrumentBody............................... 8
1.1.2 Major External Components & Infrastructure . . . . . . . . . . . . . . . 10
1.2 TheODIFocalPlane................................. 11
1.2.1 OTADetectors................................ 11
1.2.2 pODI with 13 detectors (2012 - 2014) . . . . . . . . . . . . . . . . . . . 11
1.2.3 ODI with 30 detetctors (2015- ...) . . . . . . . . . . . . . . . . . . . . . . 12
1.2.4 Coordinate Systems in ODI . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.2.5 Understanding ODI Images - A directory of FITS les . . . . . . . . . . 13
2 ODI Detector & Imaging Performance 17
2.1 ImageQuality..................................... 17
2.1.1 Sensitivity................................... 17
2.1.2 Read Noise, Gain, Full Well . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.1.3 Amplier and Pass Transistor Glow . . . . . . . . . . . . . . . . . . . . 20
2.1.4 DarkCurrent................................. 20
2.1.5 Crosstalk ................................... 21
2.1.6 Persistent Charge / Ghost Images . . . . . . . . . . . . . . . . . . . . . 21
2.1.7 Fringing.................................... 22
2.1.8 Charge Transfer Eciency of Lot 6 detectors . . . . . . . . . . . . . . . 22
2.1.9 Vignetting................................... 23
2.1.10ImagingQuality ............................... 23
2.1.11 Linearity & Photometry . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.1.12Astrometry .................................. 26
2.1.13 Calibration Stability and Artifacts . . . . . . . . . . . . . . . . . . . . . 29
3 Observing with ODI 35
3.1 Understanding the data ow in guided & OT corrected images . . . . . . . . . 36
3.1.1 Open-Loop OT Correction vs. Closed-Loop Telescope Guidance . . . . . 37
3.2 OverviewofODITools................................ 38
3.3 TheODIMenu.................................... 38
3.4 Launching Observations with the ODI GUI . . . . . . . . . . . . . . . . . . . . 39
3.4.1 TheLoginScreen............................... 39
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3.4.2 Adhocobservations ............................. 40
3.4.3 Standard Dome Calibrations . . . . . . . . . . . . . . . . . . . . . . . . 45
3.4.4 DitherPatterns................................ 47
3.5 Manual Filter & ADC Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3.5.1 FilterOperation ............................... 48
3.5.2 ADCOperations ............................... 48
3.6 TheODIFileBrowser ................................ 48
3.6.1 Image Actions and Image Display . . . . . . . . . . . . . . . . . . . . . . 50
3.7 TheOTAListener................................... 51
3.7.1 OverviewImage ............................... 53
3.7.2 Single OTA Display & Guide Star Selection . . . . . . . . . . . . . . . . 53
3.7.3 Correcting the Telescope Pointing Zero Point . . . . . . . . . . . . . . . 53
3.8 Telescope Guider Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.8.1 Non-siderealtracking............................. 56
3.9 WhereareMyData?................................. 57
3.9.1 QuickReduceData.............................. 57
3.9.2 Obtaininghelp ................................ 58
4 ODI Observing Strategies & Hints 59
4.1 Starting to Observe: A Walkthrough . . . . . . . . . . . . . . . . . . . . . . . . 59
4.1.1 Afternoon................................... 59
4.1.2 Evening .................................... 60
4.2 GuideStarSelection ................................. 61
4.2.1 Automatic Guide Star Selection . . . . . . . . . . . . . . . . . . . . . . . 61
4.3 ExposureTimeCalculator.............................. 63
4.4 Dithering ....................................... 63
4.5 Telescope Guiding & OT Corrections . . . . . . . . . . . . . . . . . . . . . . . . 63
4.6 Filters......................................... 64
4.7 PointingosetsforODI ............................... 64
4.7.1 Correcting Telescope Pointing using ODI . . . . . . . . . . . . . . . . . . 64
4.8 ObservingOverheads................................. 66
5 Afternoon Calibrations and the ODI Standard Calibration Plan 67
5.1 Summary of standard calibration plan observations . . . . . . . . . . . . . . . . 68
A Software Operations & Known Issues 71
A.1 KnownIssues..................................... 71
A.1.1 Stargrasp Controllers GH become unresponsive . . . . . . . . . . . . . . 71
A.1.2 Readout stalls for a while, but resumes . . . . . . . . . . . . . . . . . . . 71
A.1.3 Readout stalls and does not nish, with error messages such as DAC busy. 72
A.2 Walkthrough: Bringing up the ODI Observing Environment . . . . . . . . . . . 72
A.3 Starting and Shutting Down the ODI Computer System . . . . . . . . . . . . . 74
A.3.1 Restarting the JBOSS Application Server on odiweb ........... 74
A.3.2 Restarting the JBOSS Application Server on odiserv .......... 75
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A.3.3 Starting the ODI Database System (Oracle) . . . . . . . . . . . . . . . . 75
B Starting Observations on the Command Line 77
C When Images Look Wrong 79
C.1 Flat Field: The Tertiary Mirror at Wrong Port . . . . . . . . . . . . . . . . . . 79
C.2 Condensation on Dewar Window . . . . . . . . . . . . . . . . . . . . . . . . . . 80
C.3 VacuumIonGaugeenabled ............................. 80
C.4 Residual Charge in Detectors I: After Powering On . . . . . . . . . . . . . . . . 81
C.5 Residual Charge in Detectors II: Darks . . . . . . . . . . . . . . . . . . . . . . . 81
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Chapter 1
Instrument Overview
Telescope & Port WIYN 3.5m telescope, permanently mounted at f/6.3
Nasmyth port
Field of View pODI (2012-2014): 240×240
ODI (2015- ... ): 400×480
Optics 2-element eld attener & atmospheric dispersion
compensator
Detectors pODI (2012-2014): 13× STA OTA CCDs
ODI (2015- ... ): 30× STA OTA CCDs
full design: 64× STA OTA CCDs
Pixel Scale 12 µ m, 0.11  / pixel
OTA Cell Size 480 ×494 pixels; 5200 ×5400 on sky
Gaps between cells x: 28 pixels (3"); y: 11 pixels (1.3")
Gaps between OTAs about 21
Fill Factor per OTA 90%
Read noise ≤10 e
−
, 8.5 e
−
typ.
Gain typ. 1.1−1.6 e
−
/ADU, varies by cell
Dark Current 0.006 e
−
/sec/pixel typical
Exposure time Minimum ∼5 ms. Maximum limited by OTA amplier
glow. Linear from 20 ms to 60 min.
Filters Full size lters: g' r' i' z'
compatible w/ KPNO Mosaic lters w/ smaller FoV
Readout time ≤30 seconds sustained bias to bias
Humidity range ≤70%
Table 1.1: ODI in a nutshell.
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1.1 Instrument Walk-Through
ODI consists of the instrument body that is mounted to the Nasmyth port of the WIYN
telescope plus supporting infrastructure throughout the WIYN facility. In this chapter we will
discuss the major components of the instrument hardware, the properties of the detectors and
how they are arranged on the focal plane, and the support infrastructure for ODI.
1.1.1 Instrument Body
The instrument main body is divided into three major components:
The Forward Corrector Element that mounts into the Nasmyth port. Its sole purpose
is to position the rst optical element of ODI, the forward corrector (also called Lens 1, see
Fig. 1.1 (a)).
The Instrument Support Package (ISP) (bolted to the forward corrector element) is the
backbone of the instrument and hosts the following elements (see Fig. 1.1):
1. Two rotatable prisms that constitute an atmospheric dispersion compensator. Each
prism is driven by a stepper motor and has end switches.
2. Nine lter arms that move into the telescope beam like a semaphore. The lter arms
are mounted to three supporting posts (labeled A, B, C). On each post there are three
lter arms mounted (labeled 1, 2, 3, where 1 is the one closest to the telescope). Each
lter arm has its own stepper motor and gear box.
3. The Bonn shutter.
4. Temperature sensors and a temperature multiplexer box.
The dewar is mounted to the ISP. Its main component is the vacuum vessel with the focal
plane. The dewar window is also an optically powered element, and forms the eld attener
in conjunction with the forward corrector lens. The focal plane with up to 64 OTA detectors
is cooled by four closed-cycle helium cryo-heads that are capable of removing 200W of heat
from the focal plane ( ≈120 W for a full set of 64 OTA detectors, plus about 60W radiative
load). You will also nd a turbo-molecular vacuum pump permanently mounted to the dewar.
The CCD controllers (IfA Stargrasp controllers) are mounted on two opposite sides of the
dewar, and each side drives one half of the detector array on the focal plane. Since the
CCD controllers dissipate a signicant amount of heat (1.2kW), they are enclosed in isolated,
glycol-cooled boxes to avoid creating a turbulent air ow in the dome (and thus diminishing
the seeing).
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Figure 1.1: Cut through ODI Model. Light enters from the telescope (right) through the forward
corrector lens (a), then passes the two prisms of the atmospheric dispersion compensator (b) and one
of the nine lters (c). Following the lters the shutter (d) is mounted just in front of the dewar window
(e); note that the dewar window also has optical power. In the dewar the detectors are mounted on
the focal plane (f). Noticeably mounted on the sides of the dewar are the two golden Stargrasp CCD
controller boxes (g). The hex panel and cable wrap (h) are mounted on the back of the instrument.
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On the backplane of the dewar the hex-panel is mounted. The hex-panel is the interface for
various cable, glycol, dry air, and helium connections that are routed through a cable warp to
a boom hanging over the instrument.
1.1.2 Major External Components & Infrastructure
ODI depends on external infrastructure and components that either could not be mounted on
the instrument body due to weight constraints, or for other practical considerations. These
components are in particular:
1. ISP control computer : The ISP Control Computer is mounted to the telescope fork.
It controls the helium cryo-heads, the thermal regulation and heating of the focal plane,
overall instrument temperature telemetry, ADC prism and lter arm motors. The box
also provides power for the shutter and monitors the shutter's state. While not critically
dependent on cooling, the ISP box is glycol cooled for thermal management.
2. The Stargrasp Power Supply Box provides the electrical power to the Stargrasp
CCD controllers. Since the power supplies also dissipate a signicant amount of heat, it
is also linked to the glycol cooling system. Indeed, the control node for the glycol system
is located in that box. In order to keep the lines short, the main power lines are routed
directly from the power supply box to the hex panel, bypassing the cable wrap.
3. Heat removal from the instrument is achieved through the ODI Fluid Chiller & glycol
heat exchanger system. This system consists of the uid chiller in the WIYN utility
room, and a heat exchanger outside the WIYN building.
4. The ODI helium compressors in the WIYN utility room supply the cryo heads on
the ODI dewar with pressurized helium to cool the focal plane. The waste heat from the
helium compressors is dissipated in a heat exchanger unit outside the WIYN building.
Helium lines are routed through the telescope pier to the instrument.
5. The ODI data acquisition computer rack & network switches are located in the
WIYN computer cabinet. A dedicated 10-Gigabit switch routes data coming from the
32 Stargrasp ber pairs to the ODI data acquisition computer.
6. The ODI Observer Computer is a Mac Pro computer with two 30 inch displays,
located in the WIYN control room.
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