IRTF Image Quality Report for April 19, 2001

 

Daniel O'Connor

 

 

Introd.

            Present: Griep, Sears, O'Connor

            Set-Up: TT cam (for wavefronts, ef) on NSFCam (for S&A data)

Data Set: 9 positions on the sky, wavefront data with ef reduction as well as Shift & Add data from NSFCam in K'.

            Storage:

1.) wavefront out of focus images: /benchmark/tiptilt/fits

            (1636.fits thru 1676.fits)

2.)  Ef reduced data, eg zern*.txt /benchmark/wavefront/010419

3.) Shift and Add images /benchmark/image/010419

            (fits images with .bin# extension)

4.) Jpeg images are stored in C:\projects\Image Quality

                                   

Position

Shift & Add

Filename

Ef rms wavefront error (nm)

FWHM from xgfit

(.055"/pix)

3 hrs. North

data0147.jpg /.bin4

400

0.40" (7.32)

2 hrs. North

data0129.jpg /.bin3

380

0.36" (6.58)

Zenith

data0037.jpg /.bin4

540

0.26" (4.84)

2 hrs. South

data0088.jpg /.bin6

660

0.17" (3.15)

4 hrs. South

data0195.jpg /.bin4

500

0.25" (4.62)

30 deg. East

data0106.jpg /.bin5

420

0.43" (7.75)

60 deg. East

data0228.jpg /.bin4

480

0.33" (6.08)

30 deg. West

data0064.jpg /.bin4

360

0.25" (4.72)

60 deg. West

data0185.jpg /.bin4

560

0.28" (5.07)

 

 

Results

            Wavefront errors are those given by `ef' data reduction software.

            FWHM data are from xgfit of `representative' image from Shift & Add.

            (Important note: These FWHM are not what is typically achieved by a long integration of a typical observer. These images are the result taking 1000 images, each with a 0.1 second integration time. We then sort the images by peak height and bin the images into 7 bins. The top bin (ie the bin with the largest average peak height) is then used to form a Shift & Add image. The resultant image formed from the largest peak height represents the situation where the aberrations due to the atmosphere are minimal, and thus is representative of the aberrations in the telescope optical train. It is further interesting to note that the S&A images are very peaky and a fit to a gaussian is perhaps not the best function to choose. 

 

           

            List of files of

                       

                        Zernicke tables - 9 ea text files (could combine into one table)

                        Reconstructed images from ef - 9 ea fits files (could change to jpegs with IDL)

 


 

 

 

 

 

Zenith, 540 nm rms

0.26" FWHM

 

3 hr N, 400 nm rms

0.40" FWHM

 

 

 

2 hr N, 380 nm rms

0.36" FWHM

 

60d W, 560 nm rms

0.28" FWHM

30d W 360 nm rms

0.25" FWHM

30d E, 420 nm rms

0.43" FWHM

 

 

2 hr S, 660 nm rms

0.17" FWHM

 

60d E, 480 nm rms

0.33" FWHM

 

 

 

 

 

 

 

4 hr S, 500 nm rms

0.28" FWHM