OSIRIS Top Stories

May 9, 2008

The following is a email sent to all known OSIRIS users regarding the March 2008 service mission.

Dear OSIRIS users,

There have been significant changes to OSIRIS since March 2008 and we want you to know about the changes. If you have received this email in error, please accept my apologies.

  1. In early March we serviced OSIRIS to add new K-band filters with built-in pupils for the 100 mas scale. These new filters are called Kcb, Kc3, Kc4, and Kc5 and are identical to the Kbb, Kn3, Kn4, and Kn5 filters respectively. Both sets of K-band filters are in the instrument. To make room for these new filters, we removed the Open, Zn2, Zn3, and Zn5 filters. The new KcX filters are meant to be used only with the 100 mas plate scale. For all other plate scales, please continue to use the original K-band filters. We have engineering time in June to measure the difference in background between the old and new filters. All operational software has been updated to reflect the changes. Observers may wish to download new versions of the Manual, OOPGUI, and DRP from the OSIRIS Toolbox web page.
  2. During this mission, we fixed a mechanical issue with the OSIRIS handling cart that prevented the instrument from defining in the proper location. Since the mission, we can now measure the focus offset among the 4 SPEC plate scales and the Imager.
  3. We have developed software to automatically correct for the focus offsets among the 4 SPEC plate scales and the imager. This software is transparent to the observer, but there are important things to note:
    1. If you are taking simultaneous SPEC and IMAG frames, sky frames will be focused for the imager, object frames will be focused for the spectrograph.
    2. If you are taking SPEC frames only, object and sky frames will be focused for the SPEC plate scale.
    3. If you are taking IMAG frames only, object and sky frames will be focused for the Imager.
  4. We have converted OSIRIS over to use the kvnc suite of software developed for mainland observing. OSIRIS will no longer use the osiris server as its VNC server; rather, it will use svncserver2. The change should be transparent for Waimea observers and mainland observers will no longer have to hand-edit a script to start the proper VNC viewer.
Please contact with any questions and thank you!

jim

Dated Entries

April 28, 2008

OSIRIS will now automatically account for the focus offset among the scales when scripts are run via the GUIs.

April 28, 2008

The OSIRIS Rectification Matrices Webpage has been updated with the new "Kc" filters under the "v4.0" heading. Except for the new "Kc" filters, all other matrices are identical to "v3.0".

April 28, 2008

Links for the OSIRIS Manual and for software on the Tools Page have been updated.

March 7, 2008

OSIRIS was serviced yesterday by Keck and UCLA personnel. We had two goals for the service: investigate and correct the global and relative focus jumps; install new K-band filters for the 100 mas scale.

We found that the OSIRIS handling cart was stopping too far from the AO bench. This seemed to prevent the instrument from defining correctly. We adjusted the switch on the handling cart to allow it to move closer to the AO bench.

Inside the dewar, we found the locking mechanism on the lens barrels for the 35- and 100-mas scales to be loose. Unexpectedly, we found the 50-mas lens barrel to be secure. We tightened the locking mechanism for all scales and adjusted the 50-mas to more closely align to the 20-mas scale, which is our reference point. OSIRIS is still warm so testing has not started.

We removed the Opn, Zn2, Zn3, and Zn5 filters and replaced them with filters equivalent to the Kbb, Kn3, Kn4, and Kn5 filters. These new filters also have 9-m pupils installed that will significantly reduce the background observed in the 100-mas scale. These new filters are named Kcb, Kc3, Kc4, and Kc5, where the 'c' is for coarse. These filters are intended only for the 100 mas scale. Software has been updated and tested.

March 5, 2008

Recent fiber testing with OSIRIS has confirmed that the 4 OSIRIS plate scales are no longer parfocal. This accounts for part of the image quality problems observers have seen in the 50 mas scale. An OSIRIS service mission starts tomorrow which will attempt to correct the problem.
Scale (mas) Focal shift (mm)
20 0
35 -0.25 ± 0.25
50 -1.75 ± 0.25
100 0

August 21, 2007

Recent fiber testing with OSIRIS has confirmed that the 4 OSIRIS plate scales are no longer parfocal. This accounts for part of the image quality problems observers have seen in the 50 mas scale. Most likely, the 2006 earthquake or subsequent service mission caused the focal shift. We are investigating ways to correct or compensate for the focal shift.
Scale (mas) Focal shift (mm)
20 0
35 0.50 ± 0.25
50 1.00 ± 0.25
100 0

August 2, 2007

The OSIRIS rectification matrices are now online and available for download.

August 1, 2007

Jim Lyke has produced a DRP Cookbook to help users get started in reducing data.

July 26, 2007

Recently, we've noticed some image quality issues related to the 50 mas scale of OSIRIS. We are investigating the cause. Possiblities include:
  1. We have an incorrect offset to the center of the 50 mas scale such that we are vignetting the beam slightly.
  2. There is a focus offset for the 50 mas scale.
  3. Something on the AO bench changes with OSIRIS spec scale

In a possibly related note, some observers have recently described problems in offsetting from the center of one scale to another. This could indicate an incorrect offset value for the 50 mas scale.

We need the AO bench to investigate this issue. OSIRIS will next be in AO between August 5 - 22, 2007.

June 6, 2007 note to observers from James Larkin

Dear OSIRIS users,

We have just released the latest version of the pipeline, quicklook2, and OSIRIS manual (version 2.0). There have been significant improvements and changes to the pipeline, we highly recommend that all users refer to the manual for your reductions. In addition we have included a new interactive data reduction pipeline gui (ODRFGUI) which allows users to easily operate and generate pipeline files. This new GUI should be run with the latest version of the pipeline (version 2.0). All of this can be downloaded from the

Keck OSIRIS Toolbox or the UCLA OSIRIS webpage.

IMPORTANT: It was discovered that all calibration scans taken in March 2006 for K and H broadband and narrowband 100 mas scale modes were saturated. If you had observations with these modes from March 2006 - May 2007 please contact the for new calibration files for your reductions. For more information please see the new OSIRIS Updates page.

List of Major Changes to the Pipeline

  1. Added new module "Correct Dispersion" - corrects for atmospheric dispersion and chromatic dispersion from the AO bench and should be performed on all OSIRIS cubes after "Assemble Data Cube" in the final reduction processes (GUI puts this in the correct order).
  2. Added a new module "Extract Star" - extracts 1D spectrum of a stellar object from an OSIRIS cube, typically for telluric extraction.
  3. Added a new module "Remove Hydrogen Lines" - takes a 1-D spectrum and attempts to remove absorption lines due to hydrogen. The primary purpose is to remove hydrogen absorption lines from telluric standard stars before dividing them into science exposures.
  4. Added a new module "Divide by Blackbody" - divides a 1-d, 2-d or 3-d spectrum by a blackbody of a specified effective temperature (Kelvin). This is primarily useful to fix telluric spectra, and accepts different wavelength ranges.
  5. Added a new module "Divide by Star Spectrum" - Divides cube by 1-d stellar spectrum. This is primarily useful for telluric correction.
  6. Fixed wavelength solution to resolve small ~0.1 A shifts between each lenslet wavelength solution.
  7. The "Mosaic Frames" module now updates the RA and DEC header in the output file when multiple frames are mosaiced together.

Happy Reductions!

Best,

James

Feb 27, 2007

An updated version of the OSIRIS Manual v1.1 (PDF - 1.8 MB) is available.

Feb 14, 2007

OSIRIS was damaged in the October 15, 2006 Earthquake. One of the G-10 A-frames that support the primary optical plate broke, causing a thermal touch-off within the dewar. James Larkin and our team at Keck opened OSIRIS in late December. We diagnosed and fixed the broken A-frame. Subsequent calibration and on-sky data have shown that the alignment of the optical elements within OSIRIS is the same as before the earthquake. There appears to be no change to the wavelength calibration nor to the spatial recitifcation of data.

Feb 22-23, 2005

OSIRIS achieves first light! The 22/23 February run is the first of 5 runs planned for the instrument commissioning. In the following months, all the instrument modes and operations with AO, both with Natural Guide Star and Laser Guide Star, will be tested.

OSIRIS Installation on Keck II

Check the picture gallery at UCLA.