******************************************************** ** ** ** IIII NNN NN GGGGG ** ** II NNNN NN GG GG LA PALMA ** ** II NN NN NN GG ** ** II NN NN NN GG GGG INFORMATION ** ** II NN NNNN GG GG ** ** IIII NN NNN GGGGG BULLETIN ** ** ** ** ** ** DATE: 1 April 1994 ** ** NUMBER: 2 ** ** ** ******************************************************** >>>>> ISAAC NEWTON TELESCOPE <<<<< Derek Jones The prime focus autoguider has been made more reliable and failures caused by dome rotation are now infrequent. The filter wheel mechanism has been provided with stops to protect the Hall effect transistors. Redesign of the Direct Memory Access circuits has effectively eliminated the transfer fault which corrupted many large images in the past. The same modification has been made to the JKT. The door to the prime focus filter wheel has been replaced by a light-tight hatch. During the December/January Prime focus run the Intermediate Dispersion spectrograph was dismounted, the camera shutters replaced and all the mechanical moving parts serviced. The performance of the Ford (Loral) chip has been disappointing. Since a successful run in 1993 September when it was used to discover two new Kuiper belt asteroids, it has not been reliable enough to offer to visiting observers. The engineering grade chip worked well on a discretionary night which suggests that it may be the science grade chip itself which is at fault. It is hoped to commission the TEK 3 chip in May. On 1994 January 20 there was a lightening strike close to the telescope which damaged the computers and some other electronics. It is believed that all the damage has now been repaired. The limiting zenith distance for full illumination when the the lower dome shutter is down has been re-determined and found to be 57 degrees. >>>>> JACOBUS KAPTEIJN TELESCOPE <<<<< Phil Rudd Two recent enhancements to the JKT Instrument Control System are high capacity 2Gb SCSI disks, and the installation of a DAT drive in addition to the existing Exabyte. The new disks offer a three-fold increase in capacity over the old disks, being capable of storing approximately 400 full-frame EEV CCD images. The DAT tapes have the advantage that it is now possible to append files to the same tape, as well as having higher capacity, in excess of 800 EEV images. This will reduce the number of C-tapes required by observers, although D-Tapes should be limited to around 300 files, to reduce access times from the ING Data Archive. >>>>> IMAGING POLARIMETRY <<<<< Vik Dhillon As described in Gemini 42, imaging polarimetry with ISIS is now available as an option to all users. To change to imaging mode it is necessary to replace a grating with a plane mirror, use a special Savart plate and dekker mask located in the multislit unit and mount standard broad or narrow band filters in the below-slit ISIS slides. These new items are used in conjunction with the existing half or quarter wave plates to give a field of approximately 1 arcmin-squared. The final commissioning runs and first observing run were performed during January and February 1994. During this time we finalized the focussing and acquisition procedures, measured numerous polarized and unpolarized standard stars and tested the system on two extended sources -- R Mon and NGC1068. The system proved to perform extremely well, despite a number of teething problems. The system is now fully operational and a draft user guide is available. For further details on the ISIS imaging polarimetry facility, please contact Vik Dhillon or Rene' Rutten on La Palma. >>>>> ISIS DICHROICS <<<<< Rene' Rutten We now have the follwong set of new dichroics for ISIS: Slide pos 0 pos 1 pos 2 ------------------------------------ 1 clear flat 7500 (limited field of view) 2 clear flat 6100 3 clear flat 5700 4 clear flat 5400 5 clear prism 4500 Reflectivity and transmission curves are available. >>>>> QUALITY CONTROL <<<<< Rene' Rutten Our quality control program is now in full operation on our main instruments. The purpose is to regularly check the performance of the instruments using simple and quick bench-mark tests, in order to find possible faults or gradual degradation at an earliest possible stage. The observers are invited to browse through the quality control folder which may contain useful information for planning observations. >>>>> NEW CCD READOUT SPEEDS AT WHT <<<<< Rene' Rutten The new CCD readout speeds which were reported in the previous ING Bulletin have now been implemented in the ICL software on the WHT. The list below gives and overview of the basic CCD characteristics in the different read-out modes (information from D. Ives, Nov. 93). For each entry three numers are given: the gain [e-/ADU], noise [e-] and the readout time [sec] : readout EEV3 EEV6 TEK1 TEK2 GEC5 mode --------------------------------------------------------- standard 0.8 1.1 1.3 1.2 1.8 3.0 4.1 4.3 4.5 7.4 108 108 90 90 17 quick 1.1 1.4 1.8 1.7 2.5 5.4 4.3 4.3 6.3 8.5 53 53 51 51 9 turbo 1.7 2.1 2.8 2.6 3.8 6.4 5.4 7.8 8.5 13 38 38 36 36 6 non-astro 3.0 3.7 4.9 4.4 6.6 7.8 11 13 13 16 23 23 20 20 4 Note that the above numbers are guide lines. Consult your support astronomer for more, and more recent details, or when you would like to use a readout speed other than `standard' speed for you science observations. >>>>> IMPROVED DEAD-TIMES AND ACCURATE UT'S ON THE WHT <<<<< Vik Dhillon In addition to the new CCD readout speeds, which give a wider range of choice in selecting dead-times, a fast-clearing option has been installed on each of the 4 large WHT chips (TEK1, TEK2, EEV3 and EEV6) and is now the default setting on system startup. Using fast clearing, the time taken to clear a full chip is reduced from 15s to approximately 1s. This is achieved by `turning on all of the clocks', ie. by clearing all of the rows simultaneously instead of one by one. Care should be taken not to super-saturate the chip since the fast option does not clear as efficiently as the slow option. Another time-saving technique which has recently been implemented on the WHT CCD's is fast-skipping to windows, so that the CCD controllers do not clear any unwanted pixels if a window has been defined in the middle of a chip. A major improvement for high-time resolution spectroscopy has been the recent implementation of accurate UT's on the CCD controllers and hence accurate shutter opening times in the file headers. This has been achieved by regularly synchronizing the CCD controller clocks to the WHT time service. >>>>> CCD TRAPS IN TEK1 AND TEK2 <<<<< Rene' Rutten Note the following [x,y] positions of electron `traps' on our TEK1 and TEK2 CCDs. TEK1 [808,102] [560,280] [374,692] [377,688] [403,657] [204,912] [150,1001] [460,963] [468,949] TEK2 [564,843] [316,939] [751,434] [745,434] [721,466] [920,212] [664,164] [656,173] [974,124] >>>>> WHO-IS-WHO FOR INSTRUMENT RESPONSIBILITIES ON SITE <<<<< Contact the following persons if you have queries about specific instruments (usernames given in brackets): WHT - Chris Benn (CRB) / Vik Dhillon (VSD) INT - Emilios Harlaftis (EHH) / Phil Rudd (PJR) JKT - Phil Rudd (PJR) Imaging - Reynier Peletier (PELETIER) / Phil Rudd (PJR) WHT prime - Reynier Peletier (PELETIER) INT prime - Reynier Peletier (PELETIER) / Emilios Harlaftis (EHH) ISIS/FOS2 - Rene' Rutten (RGMR) / Vik Dhillon (VSD) UES - Nic Walton (NAW) TAURUS - Nic Walton (NAW) LDSS - Mike Breare (BREARE) IDS/FOS1 - Emilios Harlaftis (EHH) RBS - Phil Rudd (PJR) PP - Vik Dhillon (VSD) / Phil Rudd (PJR) MPF - Rene' Rutten (RGMR) GHRIL - Vik Dhillon (VSD) / Mike Breare (BREARE) >>>>> ASTRONOMY PERSONNEL CHANGES <<<<< Derek Jones will leave the island beginning of April. Although he will retire he may be contacted at RGO Cambridge. >>>>> SERVICE REQUESTS NEEDED FOR UES <<<<< Nic Walton We invite people to submit service applications for UES. The following list gives the dates of forthcoming UES service nights. Latest draft UES user guide can be found on the ING Gopher service. >>>>> SERVICE NIGHTS COMING UP <<<<< The following service and discretionary nights are scheduled for the current semester 94A: WHT Apr. 3 - full night LDSS May 2 - full night ISIS May 17 - half night ISIS May 23 - full night UES May 24 - full night ISIS/UES June 1 - full night ISIS June 8 - half night ISIS June 23 - full night UES June 30 - full night UES July 3 - full night ISIS July 4 - half night ISIS July 14 - full night ISIS July 23 + 24 - full night UES INT Apr. 28 - full night prime focus May 16 - half night prime focus May 21 + 22 - full night prime focus May 23 - 25 - full night prime focus / IDS May 31 - full night prime focus June 1 - full night prime focus June 17 - full night IDS June 30 - full night IDS July 1 - full night IDS July 7 - full night IDS July 11 + 12 - full night IDS July 15 - full night IDS July 19 - 21 - full night IDS JKT Apr. 5 - full night imaging Apr. 19 - half night imaging May 25 - full night imaging May 26 - half night imaging June 10 - half night imaging June 24 - full night RBS June 28 - full night RBS July 6 + 7 - full night imaging July 15 - 20 - full night imaging To apply for service time send you e-mail service application to SERVICE@MAIL.AST.CAM.AC.UK, or to SERVICE@ING.IAC.ES >>>>> CONTACTING La Palma <<<<< La Palma can best be reached through INTERNET address: user@ING.IAC.ES And through SPAN: 29146::user >>>>> NEXT patt APPLICATION DEADLINE <<<<< September 30, 1994 (for observations between Feb. 1 and Jul. 31, 1995). NOTE: for Dutch applications, according to the latest information, the deadline will be September 15, 1994. Note also that applications are now required to have instrumental setup specified using the Instrument Scheduling Form. ============================================================================== This information bulletin was prepared at the Isaac Newton Group of Telescopes. Distribution is by e-mail only. For free subscriptions send your Internet or JANET address to: >>>>>>>>>>>>> BULLETIN@ING.IAC.ES <<<<<<<<<<<<<<<< Or, for UK users, to: >>>>>>>>>>>>> DXC@MAIL.AST.CAM.AC.UK <<<<<<<<<<<<<<<< Suggestions regarding content are appreciated. ==============================================================================