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Home > Astronomy > Telescope Operator Notes > Working with Integral

WORKING WITH INTEGRAL

INTEGRAL is mounted at the GHRIL Nasmyth platform, and is a multi fibre interface instrument for WYFFOS to use for spectra-imaging of extended sources (galaxies, nebulae etc.) Look in INTEGRAL USERS MANUAL for further reference.
Known problems

The rotator has only 355 degrees of travel and the TCS will often complain about limits. Watch this carefully. We have seen the TCS only checking the short way and not the long way to reach a specific sky PA when slewing. In this case you can lead the rotator specifying the approximate mount PA.
Startup

TCS:
Check that Nasmyth turret is set to GHRIL
  • USER> STATION GHRIL_ROT
  • USER> INSTRUMENT INTEGRAL
  • USER> AGSELECT INTEGRAL
  • USER> ZEROSET AZ and ALT ABS
Before zerosetting the rotator, ensure that the mount PA is around 180. It is important to visually inspect that the rotator is in the correct position (i.e. with the 0 mark on the plate far away from the top). The rotator limits are: 32;-387 degrees of motion of MOUNT PA.
  • USER> ZEROSET ROT ABS
  • USER> CAL LAST
  • USER> FOCUS 98.15.
LAST PARAMETERS
Telescope
Focus
Autoguider
TV
Rotator
center
Instrument
center
DATE
98.15
AG5 on WHTDAS18
AG2 on WHTDAS17
559.3,514.2
516.5,487.6
15/04/13


New uDAS Autoguider:
The autoguider has got two fibre bundles mounted on a single moving probe for acquiring a guidestar; Inner & Outer probe. Each bundle has a FOV of 18 x 18 arcsec and the total area available for guiding is 30 arcmin squared.

The SDSU Autoguider software is started on the relevant DAS machine using 'obssys', 'startobssys' and 'startag AGX', where X is the AG camera number, see table above. Then select 'INTEGRAL', option 4.

GSS2 is used for finding guide stars. Select 'WHTIntegralInner' or 'WHTIntegralOuter' to find the probe postions required to centre a guide star in each of the fibre bundles. The guide probe is moved using

  • TO@Taurus> ISA X Y
where X and Y are the coorinates from GSS. GSS still displays these coorinates as 'Radial' and 'Theta', this is incorrect.

We do not use the 'prag' command for INTEGRAL.

The AG camera displays the two guider bundles side by side as shown below (DS9 Invert X). The most recent region file can be loaded from INTEGRAL_AG_20130415.ref. These regions have their size, and location locked in the individual region's preferences.

 
inner probe                












outer probe


New uDAS TV:
The TV is used to centre a target in the acquisition fibre bundle. The SDSU TV software is started on the relevant DAS machine using 'obssys', 'startobssys' and 'startag AGX', where X is the TV camera number, see table above. Then select 'INTEGRAL', option 4.

The regions file containing the last rotator centre (red) and instrument centre (green) can be found in INTEGRAL_TV_20130415.reg. As for the AG regions, the size and location of the regions have been locked in the individual region's preferences

Preparation

Telescope focus:

At the begin of every night focus INTEGRAL by visually inspecting the image of a faint star on the acquisition TV system.

Determine rotator centre:

After an instrument change you are supposed to determine the rotator centre and to run the 7 star calibrate procedure, this takes about 20 minutes. Slew to a faint pointing star and move the SWING PLATE to acquisition bundle viewing:

  • SYS@Taurus> ISP ACQ OBS

Measure the star position on the TV screen (x,y), then rotate 180 degrees and measure again. Calculate the midpoint, this is your rotator centre.

Calibrate procedure:

Calibrate is done on the rotator centre with the rotator tracking turned off

  • USER> ROT MOUNT XXX
Determine aperture offset:

The science fibre bundles are designed such that the centre fibre will coincide with the rotator centre. This is not necessarily true for the acquisition bundle due to the manufacturing process. Therefore an aperture offset is present with respect to the acquisition bundle. Centre a star on the RC (acquisition bundle), move to the science bundle and take an exposure. The SA then can tell you which way to move the telescope in RaDec. Check what this means in the XY system (Handset) used for aperture offsets and apply the value as Aperture 0.

Handset alignment (XY and APOFF):

       +------+          +----------------+
| | |AG TV |
| | | | |
| v | | ^ Y |
| | | | |
+------+------+------+ | | |
| | | | | | |
| <-- | ^ | --> | | +----> X |
| | | | | | |
| | | | | |
+------+------+------+ +----------------+

Sky directions (PA=0 and PA=90):

+----------------+    +----------------+
|TV | |TV |
|PA=0 | |PA=90 |
| N | | E |
| ^ | | ^ |
| | | | | |
| | | | | |
| E<--. | | .-->N |
| | | |
| | | |
+----------------+ +----------------+

Autoguider field (arrow shows direction in which star moves):

outer              inner
+---------------+ +---------------+
| | | |
| - | | - | size: 18"x18" each or
| ^ | | ^ | 4000x4000 units
| Y | | | Y | |
| | | | | |
| v | | v |
| + | | + |
| X | | X |
| + <------> - | | + <------> - |
| | | |
+---------------+ +---------------+

Observing

Acquisition:
When slewing to a new object watch out for limits in rotation and azimuth.
Acquisition is done with the acquisition bundle at the rotator centre. If necessary, perform a blind offset from a reference star to the science target.
After locking onto the guide star the observer will move the swing plate to one of the science fibres. Note that from this point onward you will no longer be able to see the object on the TV!

Autoguiding:
The uDAS Autoguider looks at both autoguider bundles. Before locking on the guide star make sure the star isn't too close to the fibre bundle edge.

To check the guiding bundles are properly mounted, do the following:
- Locate the slide unit at (65237,0).
- Align a star at the rotator centre at Sky PA 0.
- Applying an offset of 212 (386) arcsec south the star should appear at the centre of inner (outer) guiding bundle.
If no star appears, the slide unit might need zerosetting. Use the DATUM option on the Integral Engineering Mimic.

The probe is moved by commands from the ICL or the engineering mimic. The ICS command are IXA and IYA (to move x and y separately) or for both:

  • SYS@Taurus> ISA XXXXX YYYYY
Data Handling

You can write DVDs on WHTDRPC2 (in the control room) or WHTPC1 (in the terminal area). When you put a blank DVD in either machine it will be automatically recognised and you will be given the option to 'Create data DVD with K3b'. Select this, the software is very easy to use and needs no explanation. Spare DVDs can be found in the astronomy office.

Miscellaneous

ICL:
ICL>ISP STD1 CAL - puts standard fibre bundle 1 into calibrate position.
ICL>ISP ACQ OBS - puts acquisition bundle to acquire object.
ICL>ILA CUNE ON/OFF - switches on/off the CuNe calibration lamp.
ICL>ISA 65000 13000 - move the autoguider probe to X=65000 (0..130000) and Y=13000 (0..26000).

ICL>WCHANGE - Changing WYFFOS grating.
ICL>WCENWAVE - Set central wavelength in Angstroms.

Eliminating WYFFOS Messages:
If there is a stream of annoying WYFFOS errors coming from the ICL window then you can use the following procedure as a work around to divert these errors to another window:

  • hh:mm:ss> kill wyffos
  • Start another decterm window on the vaxstation.
  • In the new window type 'lpvg', and log on to lpvg as observer.
  • Type 'y' to questions about disk space and news file.
  • Type 'n' when asked whether you want to run the observing system.
  • $> icl
  • hh:mm:ss> load wht_wyffos_dir:wyffos_define
  • hh:mm:ss> wyffos_load
  • hh:mm:ss> wyffos_begin
All done. This will restart the wyffos tasks in the new decterm window.


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Last modified: 15 April 2013