NIRSPEC Quick Start Guide

Logging in

NIRSPEC is unlike most other instruments at Keck in that it does not use numbered accounts for observing. Please see your support astronomer for the proper login name and password. Once you have these, login to hanauma, the Sun workstation with 3 monitors that is closest to the Polycom in Remote Ops II. Keck uses the open windows window manager that is recognized in the instrument accounts by a pale blue background. Right click in the blue background to view the openwin menus.

Instrument Released?

After logging in, please open a web browser (Netscape for now) via the background menu. The NIRSPEC home page should be the home page for this Netscape account. In the NIRSPEC home page, click on the Instrument Status link to see whether NIRSPEC is ready for your use. Typically, NIRSPEC will be released around 2 pm, but occasionally summit work or testing delays this release until 4 pm. If NIRSPEC has not been released by 4 pm, please contact your support astronomer to coordinate with the summit for the release of NIRSPEC.

Starting the NIRSPEC Control System

Once NIRSPEC is released, you may start up the software by right clicking in the blue background and selecting NIRSPEC Control Menu then Start NIRSPEC Control Software . A window with yellow text on a black background will open and echo messages to the screen. This window will prompt you to retrieve or set new observers, start the software in daytime or night-time mode (please select daytime mode), and whether you wish to initialize the motors. PLEASE NOTE!!!: Do NOT initialize the motors via this prompt when recovering from a server crash and you need calibrations in your current instrument setup.

Upon startup, you should see these windows:

Left Monitor	Middle Monitor	Right Monitor (8-bit display)
XNIRSPEC (light path) XNIRSPEC (SPEC control) XNIRSPEC (SCAM control)	NIRSPEC format simulator (EFS) Quicklook (SPEC) Quicklook (SCAM)	Nothing automatically, provides space for: guider evesdrop FACSUM XMET

SPEC and SCAM alive?

Now is a good time to see if the SPEC and SCAM detectors are reading out correctly. SCAM typically reads out one test frame during the startup. On the middle monitor, the SCAM Quicklook display should display an image with a blue color scheme. If not, press the TEST button on the XNIRSPEC (SCAM control) to take another image. At the same time, press the TEST button on the XNIRSPEC (SPEC control) to take a SPEC image. This should display in the SPEC Quicklook display with a red color scheme.

If anything seems amiss, check the troubleshooting webpage or contact your support astronomer.

Nighttime Mode

Once the telescope has been released (typically between 4 and 4:30 pm), you may enable nighttime mode for NIRSPEC. This connects NIRSPEC to the Real DCS (the telescope), sets a default nod size for SNAPI imaging, and starts the Rotator GUI and Slitnod widget. To enable nighttime mode, select NIRSPEC Control Menu --> Enable Nighttime Mode from the pull-down menu.

Before continuing, you will need to select IROT then Tracking On on the XNIRSPEC GUI and then press the Set button in the Physical column of the Rotator GUI.

A note about server crashes

NIRSPEC is much less prone to server crashes than before. Occasionally, they still happen. If you suffer a server crash, quick crash recovery is available via the recover script. If you have recovered from a server crash and you have not taken calibrations for your current setup, do NOT initialize the motors when prompted within the script started via Start NIRSPEC Control Software on the blue background menu. This can move the echelle and/or grating and lead to incorrect wavelength calibrations. Instead, initialize only the motors that are necessary for calibrations using XNIRSPEC. On the upper XNIRSPEC window (light path), select the Engineer button, then Motors, and finally Init. This will open a window in which you can select which motors you wish to initialize. Initialize as few motors as possible, such as the Cal. Cover and Cal. Mirror, take your calibrations, then fully initialize NIRSPEC.

Gotchas

Please note that this is a very abbreviated list. Futher help can be found on the troubleshooting webpage.

SCAM not updating

The SCAM Quicklook display polls the disk for a new image at 1 Hz. If the product of your SCAM itime and coadds is not greater than 1 second, Quicklook may miss your image. For example, if you are taking a 0.3 second image with 1 coadd, up the coadds to 4 to ensure Quicklook will catch the image. More info is available on our Quicklook trouble webpage.

Array Linearity

The SPEC array is an Aladdin-3 that is linear to 18,000 DN; however, please try to limit the counts in a single co-add to 8,000 DN or less. This is due to a charge persistence problem with the SPEC detector when exposed to close to its linear limit. N. B. that Quicklook sums the counts in images with multiple co-adds such that peak counts of 15,000 DN in 3 co-adds is really 5,000 DN per co-add and well within the safe range.

Charge persistence

If you notice charge persistence or have just looked at a bright source (flat, standard star, etc.), you can issue the flush or flush2 commands from a waimea prompt for the SPEC and SCAM detectors respectively. More information can be found on our Charge Persistence webpage.

Observing

Nod Sequence

NIRSPEC has several built-in nod sequences that automatically nod the telescope for background subtraction. Most observers use the ABBA sequence which yields 4 images. After a nod, NIRSPEC will pop-up a message asking if the nod was ok before taking the image. Be careful not to leave remote ops if you just start a nod sequence as the instrument will just be sitting there. If you find nodding to be good and wish to disable this feature, type wait4center off from a waimea prompt.

Integration Times

For most sources, background emission limits the length of your integrations. Shortward of 3 microns, the limit are the OH night sky lines. Longward of 3 microns, the limit is the thermal background from the telescope/dome/sky. Before starting long integrations, take a short test image to ensure you will not put too many counts on the detectors. Keep in mind that sky conditions in the IR can change over timescales of order minutes such that an ok integration time now, may be too long in 30 minutes. Check your raw images periodically throughout the night.

Lamps Only

On the NIRSPEC format simulator, there is an option for a lamps only sequence. This sequence takes 3-4 images: an internal flat; a lamps off for the flat; and (low-res): a Neon lamp and an Argon lamp; or (high-res): a Ne+Ar+Kr+Xe lamp. Integration times and co-adds are set automatically based on filter and resolution mode. If you wish to take your own calibrations, please check out our exposure recipes page.