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WHT: 

Optics:

the following information, which agrees with the 1994 users guide, was
forwarded to me by Sue Worswick on January 5, 1998

 Primary curvature 20879 mm asphericity -1
 Secondary curvature 6231.38 asphericity -2.53287
 Primary to secondary separation 8034.961 mm
 Secondary to Cassegrain focus 10534.75 mm
 Clear aperture of primary 4180 mm
 Diameter of central obstruction 1210mm

 Field diameter at Cass (no vignetting) 15'
 
Mechanical Mounting (at Cassegrain):

from 1994 users guide, p 185

 reference point is outer FLANGE of WHT A&G unit (the A&G unit is
 attatched to the instrument rotator at the top and to the instrument via
 the FLANGE)

 this FLANGE has 
	16 x 16.5mm diameter holes on a 1200 mm PCD
  	12 x M10 tapped holes on a 457 mm PCD
  	12 x M10 tapped holes on a 635 mm PCD

 the focus of the telescope is 150 mm below the FLANGE (p39)

 maximum mass attached to FLANGE 1000 kg
 maximum moment on FLANGE 1600 kg m
 clearances measured from FLANGE are
	3500 mm diameter and 2000 mm length

 After lengthening V18 by 60 mm to accomodate the dichroic the clearance
at the WHT is 118 mm (John Hart, email 4/9/98)

CCD availability:

Email Kuijken 19/1/1999 confirming that the TEK ccds or 2k x 4k EEV ccds
are available and should do the job. 
 
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 TNG (Galileo):

  the following information is from the document 
 "TNG Instrument Plan" by Fusi Pecci and Stirpe (3/1992)

 Primary curvature 	-15400 mm  	K = -1.023818	F/2.2
 Secondary curvature 	-4416.7 mm	K = -2.452659	
 Position of exit pupil  10443 mm before image plane
 Diameter of exit pupil	 949.3 mm
 Radius of curvature of image plane  1898 mm
 Focal Length		38502 mm
 Overall focal ratio	F/11

 Following is derived by NGD from figure 1 on p24
  
 Primary to secondary separation 	5933.3 mm
 Secondary to Nasmyth focus		8833.9 mm

 Instruments can be attached to a flange provided with
 48 holes M10 on a diameter of 1580 (p28). The
 focal plane is 500 mm outside this flange.


 from Dario Mancini and/or Valentino Zitelli 

 mechanical limit on the derotator flange
 is 2000kg, 400nm unbalanced torque.

 Nasmyth area is about 4m x 7m in extent

 the Nasmyth field is 10' x 10' but exhibits
 some curvature; autoguiding is available
 via the telescope software if a bright star
 is located near the edge of the field


 From Sperello
 di Serego Alighieri

 "The optical data about the telescope are the nominal ones and are correct.
  The primary mirror conical constant has actually been measured by Roberto
  Ragazzoni and is:   K_1 = -1.0245 +/- 0.0007."

 
 Other notes:
 
 Direct imaging is scheduled to begin 3/98, the
 Low Dispersion Spectrograph is scheduled for 1999

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Status required on following items for WHT and TNG:

Email Nigel to Koen and Magda (Jan 13, 2000):

1.  storage of the instrument

2.  status of the project from the observatory's perspective (e.g. 
deadline(s) for requesting time, availability of focal station etc etc)

3.  which (and how many) CCDs are available and their characteristics
(Q.E., pixel number and size, reflectance of the chip in connection with
ghosting)

4.  which spectral lamps are available, will they illuminate the full
area of our focal plane and do we or do we not need to add screens or
mirrors to deflect and/or diffuse the light? will these lamps give two
(preferably three) lines for each of our [OIII] filters?

5.  same thing for white light lamp

6.  we will (probably) operate the instrument from a PC linked via a
long cable to a rack-mounted box located near the telescope (but not
attached to the instrument).  Thus, unless some spare internal
connections are available, we will need to link the rack-mounted box to
the instrument with loosely-hanging cables and these cables will need to
follow the instrument as the telescope tracks.  How long would they need
to be? Are there any spare internal connections at the telescope which
link the focal station to (say) the control room?

7.  (just double-checking!) is it absolutely certain that the telescope
acquisition and guidance function will not be interfered with by the
PN.S?

8.  do we have up-to-date drawings of the plate to which the PN.S has to
be attached, and where are these drawings, and do we know where the
focal plane is with respect to this plate?

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Document date: 13 Jan 2000