Optical fabrication of the camera elements has begun. Elements 7 & 8 are generated and first-cut spherical surfaces are completed. They are being analyzed for acceptability. Early in the next quarter, work on the aspheric surfaces will begin.
The optical profile of the collimator was measured both with the profilometer and with a null lens. The tests suggest that fabrication of the collimator mirror was complete. A full report has been prepared by Terry Mast and David Hilyard and is being analyzed. The center "plug" that was glued into the mirror still needs to be removed. Once removed the mirror will be mounted in its cell, and further testing will be done to confirm that the cell support structure is working as designed.
The junior Optical Lab Optician resigned during the quarter, leaving all the optical fabrication of the DEIMOS camera elements to David Hilyard until a new optician can be hired. However, even if a suitable new optician is not hired in time to work on DEIMOS, it is anticipated that David can finish the camera elements by mid next year, not affecting the projected delivery date of the instrument.
A test cell was successfully completed with CaF2 and flint elements to test camera lens mounting and the retention of fluid couplant between the lenses. The lens elements are held in the cell with RTV and the lenses are optically coupled with Dow Corning 200 fluid. Mechanical stability tests are planned next quarter.
A mini-review of the structure (cylinder, drive disk, drive undercarriage) was held in mid May prior to the start of major fabrication. A report on this review is attached. The review was held in two parts, the first with members of the mechanical design team for the Gemini Multi Object Spectrograph and the second with Dan Fabricant, Frank Melsheimer, Jerry Nelson, and Terry Mast. The major change was a simplification of the drive disk that minimizes deformations transmitted to the grating, camera, and slit mask mounts. Following the review, the cylinder was contracted to L&F Industries in Los Angeles. When the modified design of the drive disk is complete, L&F will be asked to bid on this part also. Materials for the undercarriage have been delivered to Lick. The possibility of having L&F fabricate this part is also being explored.
The grating mount is giving us a considerable challenge. A prototype has been constructed complete with kinematic mounts, but testing revealed that the motion on the mounts is many times greater than allowed. On the positive side, the stiffness of the grating drive mechanism itself is well within specification. This topic is covered further in the section on Mechanics.
The DEIMOS software effort since the PDR in late March has been extremely productive and has concentrated on acquiring the tools and developing the infrastructure at UCO/Lick needed to support DEIMOS software development and CDR preparation under both the Solaris and Digital Unix (OSF) operating environments. Considerable effort has also been directed towards developing several proofs-of-concept for our keyword and database models of the global DEIMOS data flow, and towards assisting CARA in starting to develop the infrastructure at Keck needed to support the database applications we intend to deliver as part of the DEIMOS software. Clarke and Allen have developed a "universal FITS keyword database" (which will also benefit ESI), from which we hope to generate documentation, test data, and source code at considerable labor savings to the project. In addition, Allen has defined all of the coordinate systems and transforms needed to map between points on the sky, slit masks, focal plane, and detector pixels and developed mechanisms for documenting these transforms within DEIMOS FITS headers. We have also begun addressing many of the recommendations of the Software PDR Review Board. All of these items are covered in greater detail in the software section (2.4) of this report.
Work continues at Orbit Semiconductor on a new wafer run of DEIMOS design CCDs. These new wafers should be available for testing near the end of July. The Lick Observatory CCD thinning effort is close to achieving its initial goals and expects to have a working, thinned CCD before the end of July.
Flexure Control is still largely on the back burner. One change is that we are now considering moving either the detector head or the chip inside the dewar to provide flexure compensation in the direction perpendicular to dispersion. We previously were considering moving the entire camera/detector group, but the currently preferred methods involve far less moving mass.
Jim Burrous, who has several years of experience at Mt. Hamilton, is joining the Technical Facilities group at Lick. He will work with the labs personnel to integrate assemblies into DEIMOS and will be taking on the responsibilities of documentation of the instrument. One of our goals will be to expand the present software documentation on the Web to include all other areas of the project.
2. Reports on Specific Areas
2.1 Optics
2.1.1 Collimator Mirror
Data produced from the null test of the collimator mirror was analyzed by Terry Mast and compared to the profilometry data. The two sets of data were in excellent agreement and summarized in a report in April. The center plug needs to be removed, final documentation completed, and fiducials marked. The report still needs to be reviewed for a final buyoff on the collimator surface quality.
2.1.2 Camera
The doublet made up of Elements 7 and 8 has been started, the spherical sides being worked first. Both spherical surfaces have been finished, and the aspheric surfaces on the two lenses have been fine ground to the optimum initial sphere radii. All three aspheric plunge tools for the camera have been initially cut on the CNC lathe and grooved. Measurements will be made of the tools and corrections made to the profiles before plunge grinding begins. Both Element 7 and Element 8 aspheres will be processed together, stepping along in parallel.
The first of the three calcium fluoride lenses (Element 5) has arrived, generated by Optovac, and will be the next lens to be worked on. Element 2 is expected in mid-July and Element 3 by September.
2.1.3 ORA Contract
ORA was not able to finalize their planned reports to us on camera fabrication and general tolerances. They did provide enough short-term guidance to allow us to start camera fabrication with Elements 7 and 8 above. Faber visited Mike Rodgers in Pasadena and together they settled on the exact optical configuration (grating, wavelengths, field angles, etc.) to be used in the tolerance analysis and subsequent design rebalance during fabrication (if needed). Faber also investigated a variety of possible filter recipes and gathered realistic filter indices of refraction to be entered into the design.
2.2 Mechanical Design
We had a double mini-mechanical review in mid-May (see attached report). Since then, most of the work has been integrating the suggestions made by the review committee at that time. We have produced fabrication drawings for the main DEIMOS structures, and fabrication at L&F has begun.
2.2.1 Cylinder
The design changes that came out of the design review have been integrated into the design. These include adding gussets to the front mounting flange, making the interior surface flush, extending the bulkhead flanges to attach to the longerons, and changing the hatch edge details.
2.2.2 Drive Disk
The drive disk design is quite different from what we had before May. We have modelled in detail several ideas that arose from the May mini-review. The biggest change is that the disk is now a single part with a groove at 35 inch radius on both sides. The single piece should simplify fabrication and give us the right stiffness where we want it. The drawings have been sent to L&F Industries for a quote which has not yet been received.
Collectively, the gussets (between the cylinder and outer flange of the drive disk) and the groove in the disk itself appear to solve what had been a major design problem of the disk. Slight misalignments between the edge of the drive disk and the friction drive rollers are expected to exert axial forces (parallel to the cylinder axis) of up to 200 pounds at each roller on the edge of the disk. These loads were causing the edge of the disk to warp and the center portions to tilt, thus tilting the grating and camera mounts objectionably. Adding the outer gussets has stiffened the edge considerably, and the groove at 35 inches further isolates the tilt of the inner portions from the outer parts. Formerly we had envisioned a two-piece construction to achieve this isolation, but the problem is now solved with the groove more simply and cheaply with just a single piece of steel. A report describing our FEA analysis of the drive disk will be provided with Quarterly Report #9.
2.2.3 Carriage
The carriage design had to be modified to clear the gussets that were added to the cylinder. Also, the locations of the kinematic mounts were moved farther apart to accommodate the wider-spaced rails preferred by NIRSPEC. The drawings for the carriage were also sent to L&F for a quote. We had originally thought that we would build the carriage in house but are now considering having L&F build it so that they can do the integration of the entire structure assembly. They have the machines to correct any problems that we may find in the assembly process. Also, having the carriage built at L&F will allow us to have the large front mounting plate machined flat after it is welded in place. This was a suggestion of Frank Melsheimer that will give us an accurate datum surface from which to layout the entire instrument.
2.2.4 Kinematic Mounts
The design for the kinematic mounts between the carriage and the Nasmyth deck has not changed since the design review. As was mentioned before, we have moved the locations of the front two mounts farther apart (outside the Nasmyth platform rails) to eliminate an interference with the framework on NIRSPEC (the IR instrument that will share the Nasmyth platform with DEIMOS).
2.2.5 Camera
The test doublet for the camera cell has been completed. The preliminary results look good as there are no visible signs of leaks. We are in the process of designing further tests of the cell to check for thermal stresses, flexure, etc. We are preparing a technical report which will give a detailed cook-book account of its design and assembly.
2.2.6 Grating Assembly
A full prototype of a grating cell, drive, and kinematic mount was constructed and mounted (with clamps) on our rotating DEIMOS model. The two-stage stiffness of the grating tilt drive was measured to be 6 x 106 in-lb/radian. We measured this by applying a torque directly to a dummy 8 by 12 grating with a spring scale. The resultant motion of a clutch-driven arm mounted to the grating cell stub axle was measured with a sensitive LVDT (Mahr gage), as per suggestion by Frank Melsheimer. The grating packaging does not allow for a counterweight, and so the native drive stiffness is all that prevents rotation as the instrument rotates. This imbalance produces 2" of grating tilt in use, which is a motion of 0.5 px. This is quite small and within our ability to live with or correct via flexure compensation. The Galil motor was locked during this test. The torque applied was 2 pounds at 4.82 inches. The displacement was 0.00001 inch at 6.12 inches. The Mahr gage can resolve 0.000001 inch. We feel that our measurement tolerance is easily below 10%.
The kinematic locators for positioning and holding the grating drive and cell within DEIMOS have not worked out as hoped, and a re-design is in progress. The previous plan used a classic kinematic mount (ball-in-cone, ball-in-vee, etc.) to both locate and hold the grating assembly in place. It appears that the high Hertz contact stresses of the ball-in-vee prevented us from pressing hard enough to hold the 100 pound assembly in place. We used 255 pounds, which produced 500,000 psi compressive stress at the ball-in-vee interface. During one instrument rotation, we measured 200" of motion in the plane of the grating, or "roll". This is 200 times more than budgeted for this system. The obvious thing to do is to increase the ball diameter so that higher clamping forces can be used. We went to 2.5 inches in radius, and the clamping forces can now be 1500 pounds if necessary. We have also had to redesign the locating mechanism and are trying a taper pin in conjunction with other mounts. The results will be available soon.
2.3 Detectors
In the last Quarterly Report, we stated that we released two DEIMOS design CCD wafer runs for fabrication at Orbit Semiconductor. After further consultation with Orbit personnel, we decided to be a bit more conservative and to permit just one of these runs to go forward. This gives us a chance to make further fabrication modifications should the need arise. This delay in the start of the second run will not affect the DEIMOS schedule. The run that was released for fabrication will probably be completed by the end of July. We will then test all of the devices on the wafers and will probably select some of them for further work in the CCD thinning project.
The CCD thinning effort at Lick is close to producing its first thinned device. We expect to have images from a thinned CCD before the end of July for presentation at the July SSC meeting. Once these are ready, we will have achieved the goal of demonstrating the ability to produce thinned CCDs. This portion of the effort has been funded mostly by the SSC and CARA, and not by DEIMOS funds.
Lincoln Labs is reported to be working on thinning some devices in their CCD development effort. However, no new details are available. We have also heard that SITe is now taking orders for 2K x 4K chips that are nearly flat enough to meet our specifications. We will be looking further into their product as part of the process to select a final DEIMOS CCD, which will start ramping up next quarter.
2.4 Software
At the start of this quarter we received the Software Review Board's report for the DEIMOS Software PDR that was held on March 22. The Review Board was generally satisfied with the preliminary design and the completeness of most of the material presented. The Board had specific recommendations in a number of areas, and our efforts during the last quarter involved several of these: budget and schedule, CCD readout hardware and software, early prototyping of user interface software, software tools for quick look image display and reduction, coordination with CARA, especially with respect to TV guider, allocation of effort towards general software infrastructure, and generation of simulated DEIMOS data.
A full reply to the Review Board's report is in preparation, but the following summary is a listing of their major recommendations and our planned response.
2.4.1 CCD readout hardware and software
This was identified as the highest risk area for the DEIMOS software effort, and the Board recommended focusing on development of DSP and low-level code for the second generation Leach II CCD controller as soon as possible. We agree with this recommendation, and will commence work on the prototype DSP software as soon as we receive the beta-test version of the second-generation CCD controller boards from SDSU. This hardware was successfully tested at SDSU during a Gemini-related review held on May 23, and it achieved a per-pixel readout time of 2.4 microseconds/pixel reading out a 1K x 1K CCD. Subsequently some manufacturing problems were discovered involving the reliability of chip sockets and the soldering of surface mount components. SDSU is working with the board manufacturers and assemblers to resolve these problems. Expected delivery of this hardware has now slipped approximately one month, from mid-August to mid-September. Should this delivery slip further, we will likely begin preliminary tests of our fall-back plan of using the first-generation SDSU CCD controller hardware (Leach I). The test CCD dewar should be completed well before software testing begins, and several engineering grade thick 2K x 4K CCD Orbit CCD chips are available for testing in that dewar. Significant effort on the design and prototyping of the DEIMOS CCD controller software will thus commence near the end of the next quarter.
2.4.2 Early prototyping of user interface software
The Board recommended putting more effort into early prototyping of DEIMOS user interfaces. We agree and have begun assembling software toolkits for this effort. We plan to use TCL/Tk-based tools for UI prototyping, and numerous TCL/Tk related tools have been acquired (ported where necessary), installed, and tested under Solaris 2.4.5. To support tests of these UI prototypes using existing Keck-style hardware and also to support the eventual development of the actual DEIMOS control and UI tasks, Clarke succeeded in porting the Keck Task Libraries (KTL), the complete HIRES keyword libraries, and Lupton's KTL-TCL to Solaris 2.4.5. (The latter was also ported to TCL version 7.5.) This porting effort proved to be much harder than anticipated due to a number of serious difficulties with the existing Keck I style make/build procedures provided by CARA as part of the KTL distribution, as well as the use of non-portable programming constructs within the KTL sources. As a result, we intend to develop alternative make/build procedures that will be easier to maintain and to use and which will be portable between different operating systems, compilers, and hardware architectures. We also plan to follow the recommendation of the Review Board and convert to using CVS rather than sccs for source code management. Sccs is currently used for KTL and other Keck I software, and this divergence from past Keck practice will need to be resolved with CARA. However the advantages of CVS are large, and we have decided to follow the Review Board's advice to facilitate long-term ease of maintenance.
To confirm the integrity of this porting effort and to provide a proof-of-concept for using these TCL/Tk-based tools to build GUIs for instruments, Clarke successfully used this ported software to develop a working, albeit rudimentary, GUI for the HIRES Image Rotator. This GUI was used to operate portions of the actual rotator hardware currently in Santa Cruz (awaiting shipment to Keck). The DEIMOS software team has also reviewed the existing HIRES rotator GUI (specified by Tytler and implemented at CARA using the commercial GUI-builder software "Dataviews") and identified a number of aspects that can be improved for the DEIMOS GUI that will be used to control instrument rotation.
2.4.3 Software tools for quick look image display and reduction
The Review Board expressed some concerns regarding our plan to use IRAF-based packages as our primary software for DEIMOS quick-look reduction and display and suggested that we at least investigate other alternatives such as IDL. We prepared a questionnaire to better gauge the needs and preferences of prospective DEIMOS users, as well as the anticipated availability and support for IRAF and IDL at those users' sites. This questionnaire was distributed via e-mail at the end of the quarter to approximately 150 DEIMOS users at UC, CIT, UH, and NASA. The final date for the return of these questionnaires is August 1. (As of July 14, we had received 35 responses, but these have not yet been tabulated.)
We have also carried out a series of image display and quick look reduction tasks on large images using IRAF and have nearly completed corresponding benchmarks with IDL. Preliminary results do not indicate significant performance differences that would recommend one package over the other.
2.4.4 Coordination with CARA
The Review Board identified the need for close coordination between the DEIMOS team and CARA software developers with respect to several key areas:
During this past quarter, we put considerable effort into item 3). Clarke and Kibrick visited CARA for several days in late April to work with CARA software staff on various DEIMOS related issues and to develop a proof-of-concept of the utility of using a database package (i.e., Sybase) for managing and archiving both science images as well as engineering/environmental data. Clarke also watched Faber's LRIS observing run and submitted a report to Faber in May describing various problems with the existing GUIs and observing procedures. Clarke developed and installed a working prototype for ingesting the FITS headers from existing Keck science (and guider) images into a operational database. This tool proved sufficiently successful that it has been adopted by CARA as operational software, and the FITS headers of all of the HIRES, LRIS, and NIRC images that have been saved to Exabyte tape over the last several years via the STB backup software have now been stored into this new database; headers for newly acquired images are being added to the database as part of the STB backup procedure. Using this database, relatively complex queries regarding the FITS headers of Keck images taken to date can now rapidly be answered.
Clarke also implemented and installed a prototype database for managing the HIRES engineering/environmental data, and all of these data for the last few years have been ingested. In addition, Clarke installed several TCL/Tk-based GUIs to allow non-expert users to construct database queries to the FITS header database, and a prototype Web-based UI for querying the database of HIRES engineering/environmental data. These tools have been well received at CARA, although the Web-based UI needs further refinement.
These database prototypes represent a subset of the database implementation that we plan for DEIMOS. Their successful installation, operation, and reception at CARA serve to validate both the feasibility and utility of using database packages (such as Sybase) for managing data from astronomical instruments and represent the first step in developing at CARA the necessary infrastructure for supporting such database applications as we intend to deliver as part of the DEIMOS software.
2.4.5 Allocation of effort towards general software infrastructure
The Review Board recommended that we allocate sufficient effort early on towards defining and constructing an adequate software infrastructure to support DEIMOS software development. We agree, and during the past quarter considerable effort was devoted to acquiring, building, installing, and testing not only the GUI development tools noted in section 2.4.2 but also general-purpose software development tools including compilers (e.g., gcc), debuggers (e.g., gdb, ddd), source code utilities (e.g., tkdiff), code maintenance software (e.g., RCS and CVS), and Sybase-related tools. In addition, in response to the Review Board's recommendation that we not develop our documentation directly in HTML (as was done for our PDR documents), several documentation tools (tex, latex, latex2html) were installed which will allow us to develop documents using latex, which can then be translated automatically to HTML for posting to the web. CARA will also be providing to DEIMOS a version of the Frame package, including an option for generating HTML from Frame documents. Many of these general-purpose tools were subsequently used for the porting and building efforts described in section 2.4.2. All of these tools are now operational under Solaris 2.4.5, and many are also operating under Digital Unix (formerly OSF) on the DEIMOS Dec Alpha test-bed machine, radec. Porting/installing the remainder of these tools to Digital Unix is planned for the next quarter.
2.4.6 Generation of Simulated DEIMOS Data; FITS Keyword Database
The Review Board recommended that we generate and experiment with simulated DEIMOS data early on. We agree, and plan to start generating such data towards the end of the next quarter. Generating simulated data means not just the generation of 8K by 8K images but also the mosiacing scheme in software for those images, plus the entire DEIMOS FITS header. In preparation for this task, as well as to support the overall design and documentation effort, Clarke designed and implemented a database for managing the large number of Keck keywords that will be used to control and document the operation of DEIMOS, and has developed an exhaustive specification of legitimate FITS keyword syntax. As a proof-of-concept, this database was successfully used to model all of the existing HIRES keywords. This database will be used to automatically generate HTML documents of keywords, as well as code to generate sample DEIMOS FITS headers. In parallel, Allen has designed and documented all of the coordinate transforms needed to map between sky coordinates, focal plane coordinates, and both spectral and imaging pixels of the detectors of the mosaic. The FITS keywords and associated FITS extension tables for representing these transforms have been defined, and the means for representing these within the keyword database have been designed. Allen has also worked to finalize the coordinate system labeling and detector/amplifier numbering conventions, and was worked with Osborne to insure that the consistent use of these conventions on all DEIMOS engineering and mechanical design drawings. Abstracts for two papers, which describe the keyword database and the coordinate transform designs, are being submitted for the Astronomical Data Analysis and Software Systems (ADASS) conference scheduled for late September.
The above FITS keyword database will enable a new level of automated software generation and documentation control that was not previously possible. With the keywords fully described and characterized in machine-readable format, it will now be possible to generate large amounts of DEIMOS instrument control software fully automatically. Software documentation can also be generated similarly. As an example, we plan to prepare essentially all documentation for the upcoming Software CDR this way. Formerly such lengthy documentation consisted of text files entered by hand, but the new plan will generate the great bulk of it under software control. The new approach will, we hope, solve the problem that CDR documentation rapidly becomes out of date because the labor of maintaining the text files is prohibitive. In the new system, it will be possible to generate new documentation automatically with each new make/build of the system.
The above examples are only a few of the ways in which the FITS keyword database will have impact. Other applications will be discussed at the CDR.
2.4.7 Plans for the next quarter
We anticipate that Clarke, Allen, and Phillips will continue working on DEIMOS at roughly the same level of effort during the next quarter. Clarke will be concentrating on overall data-flows and global design issues, definition of database schema, and GUI prototyping. An internal software review of the data-flows and database schema is scheduled for July 30.
Allen will begin software prototyping of the coordinate transformations and their representation in FITS image headers with the goal of generating simulated DEIMOS FITS images that include all of the relevant DEIMOS keywords and header extension tables (including the mosaic representation scheme). These simulated data will be used to evaluate various quick image display and data reduction alternatives. Allen and Clarke each plan to present a paper at ADASS.
Phillips will continue his efforts on slit mask design software and will begin work on integrating the coordinate transform and FITS header mechanisms that Allen has defined. Phillips will also spend some time evaluating the capabilities of IDL (and the user-contributed IDL astronomy libraries). We plan to arrange for Phillips to visit with at least one astronomy research group which conducts optical observations at Keck and which uses IDL as its primary quick look reduction tool. With assistance from this group, Phillips will test the ability of IDL and existing IDL astronomy packages to perform typical quick look image display and data reduction functions on existing LRIS multi-slit data.
The availability of Kibrick and Tucker to the DEIMOS software effort will be significantly constrained during the next quarter due to vacations, HIRES image rotator installation and commissioning, several Keck AO CDRs (for which Kibrick is serving on the review board), and commissioning of the Lick Prime Focus Camera (PFCAM) on the Shane 3-meter in late September. DEIMOS CCD software design and prototyping is now anticipated to commence near the end of the next quarter, coincident with the expected delivery of the beta-test second-generation (Leach II) SDSU controller hardware. DEIMOS-specific motor control software effort will also commence at that time, building on common motor controller software developed for PFCAM.
During the next quarter, we anticipate purchasing (partially with DEIMOS funds) an additional 4 GB of disk to support Solaris-based software development for DEIMOS, as well as a laptop computer (running Linux). We are currently obtaining pricing Dec Alpha memory with the goal of adding an additional 256 MB to the DEIMOS test-bed machine, radec, to support tests on simulated DEIMOS images. We plan to complete our formal response to the PDR Review Board report during the next quarter following the tabulation of results from our IRAF/IDL questionnaire and Phillips' evaluation of IDL capabilities.
2.4.8 Software Budget and Schedule
The scheduling of the DEIMOS software effort since the PDR has been primarily short-term, based on relatively close day-to-day coordination among the DEIMOS software staff. While we are pleased with the progress since the PDR, it is clear that long-range planning of the DEIMOS schedule is still needed and that close coordination with the ESI software scheduling is also required. Toward this end, Bigelow and Kibrick have met twice to iterate on the ESI schedule, and Kibrick and Faber have several meetings scheduled for late July to refine the DEIMOS software schedule. An updated long-term software schedule for DEIMOS will be released following those meetings. We are still planning on holding the software CDR near the end of 1996 and will try to have the actual date established by the end of the next quarter.
2.5 Electronics
Some of the details of the manual paddle control design for the DEIMOS motor controllers were refined because of software concerns by Dean Tucker. The grating tilt mechanism was wired and tested and is working well. The barcode scanner for reading the slit masks has arrived and will be evaluated for functionality and performance.
As a result of working on a new interconnect board for the Prime Focus Camera, some wiring and grounding issues have been discovered between the Leach controller and the CCD electronics box. Though these are not "critical" for the Prime Focus Camera, they will be for DEIMOS due to its faster CCD clock rates. This has led to investigating new cable assemblies for the DEIMOS Leach controller.
Preliminary design has started on a revised CCD pre-amplifier to accommodate the faster clock rates of the new Leach controller, while maintaining the same low noise figure.
We conferred with CARA and agreed on the number of cables to be used for flat-field dome calibration lamps on Keck II. We ordered some sample lamps for the internal calibration lamps to conduct brightness tests.
2.6 Flexure Compensation
We are now studying the possibility of moving either the dewar or the chip within the dewar to achieve flexure compensation perpendicular to the direction of dispersion. Previously, this component of motion was to be achieved by rotating the entire camera-detector assembly, but the new approach reduces the moving mass. Brian Sutin calculated raytraces to show the effect of moving the field flattener off the camera axis. Any such motion is unacceptable, and we must therefore either move the dewar behind the FF or move the chip within the dewar. A 100m motion stage supplied by Physik Instruments may be suitable. This stage is driven by a piezo electric actuator, and available versions are vacuum compatible. A decision is not required until the fall, when design of the dewar is planned to begin.
A report on the end-to-end flexure control system was planned to be complete by the end of the next quarter but will probably be slightly delayed because of Faber's effort needed to get the optical design of the camera under control following the departure from the project of Harland Epps and the effort required to start the software effort earlier in the year. We plan to have this report completed before the design of the dewar system (which is planned to begin in October 1996). Terry Mast has been working on aspects of the error budget, and this work will be included.
3. Report from the PI's
All PI activity this quarter was covered in the previous sections.
4. Budget
To the end of June 1996, $1,547,110 has been expended on the project, including $774,190 on labor and $772,920 on materials and supplies. Table 1 is a summary of the budget, and the details are shown in Table 2.
During this quarter $156,883 was spent on labor and $82,910 on materials, supplies and services. Mechanical engineering is in full swing, with two engineers working almost full time on the project. The optical fabrication of the camera elements is also moving along nicely with David Hilyard spending most of his time at this task. Software is now well under way with almost double their total time on the project during this quarter.
Significant expenditures were for the fabrication of the structure ($38,500) and for optical materials ($21,500). During the quarter we also collected approximately $5,000 in expenses related to the structural and software reviews.
At the end of this quarter we reviewed and revised the budget to better reflect our understanding of where expenditures would occur. Some activities are now complete and we have final costs, particularly for the expenditures for the optical glass/crystals and the collimator mirror. The results of this revision are summarized in Table 3, which reviews the contingency activity. This table will be a regular feature of all future quarterly reports. The first column of figures is the old amount allocated to a particular category. The second column is the change in that category we now envision, with positive changes representing cost growth over budget and negative numbers (gray text) indicating savings. The third column is the new amount allocated. Typically, cash expenditures are handled separately from internal labor hours, which are held in a separate account (labor hours are recognizable because they are not preceded by a $ sign).
The last through review of the budget occurred in October 1995, so the present changes to the contingency reflect activity over an eight month period. The bottom line is that the cash contingency account of $491,298 has been drawn down by $45,940, leaving a new contingency of $445,358. This is 13% of unexpended funds. Labor hours have been reallocated among the various accounts, and no net increase is projected to the total labor hours at this time. A review of completed items (last column) indicates that the labor estimates in the original budget were adequate, though a few items, such as the gratings, are overrunning.
Major unanticipated expenditures include the need for $30,000 to contract to ORA plus 1200 hours for in-house optical research because Harland Epps is no longer participating in the project. We also substantially increased the time and expenditures required for reviews. The number of external mechanical reviews is larger than originally planned, owing to our decision to conduct more, smaller, focussed reviews on particular subsystems.
A substantial amount of the estimated internal labor cost to fabricate the frame and structure was transferred to an external expense in light of our decision to contract this portion of the fabrication to L&F Industries. We reduced the estimated cost of the guide camera system, as the currently estimated cost of a guide camera is about $30,000 less than originally estimated.
5. Schedule
Figure 1 shows a summary of the project schedule. At the end of the quarter we are still anticipating that we will be able to commission the instrument in the first quarter of 1998. However, optical fabrication of the camera elements is on a critical path to this anticipated date. David Hilyard is doing well with his estimates of fabrication time, and so far a slip in the project schedule due to optical fabrication is not expected. The critical path is shown as Figure 3.
Figure 2 shows the activities planned for the next year in more detail.
Two following areas of activities have less than a month of float in their estimated time to complete, and could become critical. These are the development of the detector / dewar systems and mechanical engineering of the instrument. We are planning a meeting in August to review the status of the detector system. Some mechanical engineering activities have been re-assigned to reduce the possibility that engineering will come onto the critical path. However it depends on our success in the design of the grating system which is proving a very difficult and time consuming design task.
The following is a list of milestones from the last Quarterly Report, together with the progress made on them:
1. The DEIMOS mini-structural review was held as planned, but construction of the cylinder and undercarriage were slightly delayed, to the next quarter. A contract for the cylinder was let to L&F Industries as planned. The undercarriage and drive disk contracts will be let next quarter.
2. The RTV/fluid test cell was completed as planned.
3. The optical fabrication of the camera elements started as planned.
4. The fabrication of the CCD test dewar started as planned.
5. The tolerance analysis report from ORA was not received. It is expected shortly.
6. The slit mask insertion mechanism design did not start as planned because Jack Osborne is still occupied with the grating assembly. Eric James has now been assigned to this task.
7. The first grating assembly prototype was completed and tested. The drive is stiff enough, but the kinematic mounting scheme has unacceptable flexure and is being reworked.
8. No progress was made on the error budget.
Milestones for the next quarter:
1. Complete fabrication of the cylindrical structure and drive disk.
2. Start design of the slit mask insertion mechanism.
3. Complete the spherical surfaces of camera Elements 7 and 8 and begin the aspheric surfaces.
4. Begin polishing CaF2 Element 2.
5. Complete the CCD test dewar and install thick 2K x 4K Orbit test chips.
6. Receive the tolerance analysis and fabrication reports from ORA.
7. Put the optical design on the Engineering Group's Zemax laptop computer.
8. Review the collimator report and decide on final buyoff.
9. Prepare an alignment plan.
10. Complete the reworked grating mount prototype and test it.
11. Continue the grating slide design.
12. Finish testing the RTV/fluid test cell and verify the thermal design.
13. Arrive at a semi-final TV guide camera optical layout with vignetting estimates and FOV. Adopt a TV manufacturer and strawman sensor and coordinate with CARA.
14. Prepare a formal response to the March Software PDR report.
15. Finalize the software budget, schedule, and priorities list.
16. Receive beta-test Leach II controller boards and begin DSP software development. If this slips past mid-September, start testing fall-back plan using Leach I controller.
17. Conduct an internal review of the global data design plan.
18. Continue instrument GUI prototyping.
19. Achieve full simulated mosaic images with FITS headers.
20. Begin motor-control software.
21. Evaluate IRAF vs. IDL and make a decision.