1. 1.8 m Adaptive Optics Telescope 1.1 m Wide Field Telescope at PARI
Plans for a
1.8 m Adaptive Optics Telescope
and a
1.1 m Wide Field Telescope at PARI
J. D. Cline, M. W. Castelaz (Pisgah Astronomical Research Institute)
AAS 200th meeting, Albuquerque, NM, June 2002 Wednesday, June 5, 2002, 10:00am-7:00pm. Session 64.08

2. Radio and Optical Observatories at the Pisgah Astronomical Research Institute (PARI)
PARI is
a not-for-profit public foundation
dedicated to providing research and educational access to radio and optical astronomy for a broad cross-section of users
PARI is located on 200 acres in the Pisgah Forest west of Asheville, NC
The site is relatively free of light and radio interference

3. Aerial View of the PARI CampusN
26-m East
Optical Ridge
26-m West
12-m
For use by Visiting and Resident scientists:
Two 26-m radio telescopes, one 12.2 m radio telescope, one 4.6 m radio telescope, several dedicated optical telescopes
Locations for future telescope development
Lab and Office Space

4. The Radio Telescopes
Two 26-m radio telescopes with 1.42, 4.8, 6.7, and 12.2 GHz receivers are shown here. The telescopes slew, set, guide, and track. They can be operated together (300 m near E-W baseline) or separately.
26 m West
26 m East

5. The 4. 6-m radio telescope feeds include 1. 42, 4. 8, 6. 7, and 12
The 4.6-m radio telescope feeds include 1.42, 4.8, 6.7, and 12.2 GHz. This telescope is used for education/public outreach through the School of Galactic Radio Astronomy (SGRA; this meeting Session 47.03).
4.6-m
The 12.2-m antenna is available for consortium sponsorship and use at frequencies up to 60 GHz.
12.2-m prime focus feed

6. The PARI Optical Ridge
Aerial Image of the Optical Ridge. At an altitude of 910 m, the ridge runs East-West with steep sloping sides to the North and South. The highest point on the horizon is 5 degrees, with an average of 2 degrees. The 1.8 m and 1.1 m locations are shown (red), along with existing telescopes (blue).
Lat: 35d m N, Long: 82d m W Altitude: 934

7. Telescopes Other Than the 1.8 m and 1.1 m on the PARI Optical Ridge
Questar (18 cm, f/14.3, 81.2 arcsec/mm), 2k x 2k 13 um/pix CCD 36 arcmin FOV), UBVRI filters
Solar/Lunar 12.7 cm telescope with SBIG STV, live video feed to Internet
All-sky fisheye 24 hour telescope
Polaris continuous photometry telescope
Atmospheric Seeing/Transparency 24-hour monitoring 12.7 cm telescope and SBIG STV
0.2 m telescope for Galactic Plane Survey, operating since October 2000
0.28 m telescope for gamma ray burst afterglow

8. Plans for a 1.8 m Adaptive Optics Telescope
4 cm Thick Fused Silica Adaptive Optics Mirror
F-Ratio = 1.5
Spherical Surface Figure
Wavefront Errors = l/50 (l/30 allotted to steady state operational dynamics)

9. Characteristics of the 1.8 m Adaptive Optics Primary Mirror Cell
Three Flexural Supports
40 Actuators to a Back Structure
Cell Weight = 1400 lbs
Mirror Weight = 550 lbs
Mirror
One of the actuators is shown. The back of the mirror is coupled to the actuator through a glass block for thermal insulation.
Glass Block
Actuator

10. Telescope Uses and Designs under consideration:
Telescope Definition
Telescope definition is an open issue and depends on input from the astronomical community. Suggestions for use and design beyond those listed below are welcome. Please feel free to contact us ( or leave a note here for us to contact you..
Telescope Uses and Designs under consideration:
Large Field Prime Focus Camera for
Gamma Ray Burst Afterglow Photometry
Supernova Search
Near Earth Object Search
LIght Detection And Ranging (LIDAR) for atmospheric research
High Resolution (0.01 A/pix) Spectrometer

11. Plans for a 1.1 m Wide Field Telescope
The telescope will be field corrected prime focus camera with a 1.73 degree diameter field of view.
The primary mirror is a 1.1 m f/4.4 fused quartz (honeycomb) substrate, coated
Scale 41.5 arcsec/mm
Conic constant – /
The Primary Mirror

12. Characteristics of the Field Corrector at Prime Focus
We have set the condition that image quality in the focal plane will not be limited by telescope optics, rather by seeing and mechanical effects. To meet this condition, a 3-element field corrector, will be used to focus a 15 cm diameter focal plane. The table below summarizes the properties of the corrector. All lenses are made of BK7 glass. Lens 1 is nearest to the primary mirror at a distance of cm, and Lens 3 is 7.16 cm from the focal plane.
Lens
Curvature of Lens
Radius of Curvature (cm)
Diameter (cm)
Distance from Previous Lens
(cm) 1
Simple positive convex
225.49
34.113
--- 2
Achromatic convex-concave
70.58
29.614
70.411 3
Simple positive convex-plane
80.07
7.163
17.462

13. Schematic Showing the 3-Element Field Corrector

14. Prime Focus Optical Layout
The prime focus is formed by three lenses comprising a corrector. Shown here is the third of the lenses, along with the shutter, and two guide cameras. Light in the center 10 cm square field (1.15o) is the science field. Two guide cameras are located 180o apart in the fields formed by the 15 cm diameter field and chords along the science field. A third chord area will hold several fiber optics for a future spectrograph.

15. With the field corrector, the RMS wavefront error is less than the diffraction limit to the edge of the 15 cm focal plane.
Figure below shows spot diagrams within 1 arcsec boxes on the optical axis and at the edge of the 15 cm focal plane, respectively.
The image size approaches one arcsecond at the very edge of the field of view.
The science field is a 10 cm square, so the optics produce less than one arcsecond images in the entire science focal plane.
Spot diagrams based on the prime focus corrector for the 1.1 m telescope. The boxes are 24 microns, or 1 arcsec on a side. a) The spot diagram on the optical axis, b) the spot diagram 7.65 cm from the optical axis.

16. Telescope Assembly
The open structure optical tube telescope mount we plan to use is the DFM Engineering equatorial mount, shown above. The DFM 1.27 m polar axle and support telescope mount will be customized for the 1.1-m mirror.

17. Atmospheric Seeing and Transparency Measurement Instrumentation
Weather Station: probes for temperature, humidity, pressure, wind, rain.
All-Sky Camera: Live video of the sky through a fisheye lens.
Polaris Telescope:
Continuous 24-hour monitoring of atmospheric transparency and seeing conditions
0.25 m telescope with CCD plus UBVRI filters; 81 arcsec/mm or 0.60 arcsec/pixel
Bright Star Telescope:
Robotic 12.7 cm f/10 telescope with CCD
Measures flux of bright (V<2.5) stars 24 hours a day
Software automatically points telescope, images, does photometry and outputs stellar magnitude and sky brightness
outputs seeing measure based on area bright stellar image covers on CCD chip
outputs transparency measure based on ratio of stellar/sky surface brightness.

18. The Bright Star Telescope is seen in its clear dome
The information from the Bright Star Telescope and the other seeing/transparency instruments build a database of atmospheric conditions accessible to other telescopes of the PARI Observatories and observers using the telescopes remotely.

19. Don Cline (dcline@pari.edu) Or Michael Castelaz (mcastelaz@pari.edu)
We are open to new consortia to develop projects at PARI, or an established consortium to enhance their research and education opportunities with projects at PARI including development and support of existing or new telescopes at PARI.
Contact:
Don Cline Or Michael Castelaz
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC
Internet:
Office: FAX: Internet: