revised September 1997

compiled by: Bruce Cantor, University of Toledo

Robin Dalrymple, George Hassel, and Harry Augensen, Widener University

In Trailer

• Turn on switch on power strip at entrance next to telescope control (TC) computer
• Make sure Pegasus computer (Sun workstation) is on ; it should be left on for the entire run unless lightning storms are expected
• Log into URSA computer (Gateway)
• Turn on filter wheel switch on tower to right of Pegasus computer
• On TC computer (amber monitor) next to door, type: ne <epoch> (i.e., for stars with epoch 2000 coordinates, type: ne 2000)
• On gray box next to TC computer turn telescope command over to the dome

In Dome

• Turn on main power switch behind telescope pier.
• Fill dewar with liquid nitrogen. Note this takes several minutes, so if nitrogen seems to drip fairly soon after start of fill-up turn down the flow of nitrogen to the dewar to eliminate the dripping. If dripping persists then dewar is full. Dewar should be refilled once more, probably around midnight or shortly thereafter.
• Open dome while dewar is filling.
• After hose connection to dewar becomes warm enough, remove it. Then on telescope control computer type: cr (cover remove)

On URSA Computer (in Trailer)

• Click on Configure button
• Type in: observer name(s)

institution

beginning sequence number of files (click Apply)

image name root (click on Apply)

• Click on Close Configure Button
• On Observing Control panel on bottom of screen, type in for Image Title: bias
• On gray box next to TC computer, switch telescope command back over to trailer
• On xtool window flip image upside-down (click third button on top right) and turn panner off (click on first button)
• Take a test object by clicking on Test button and hitting <Enter> key.

Note: Wait for chip to cool to -110 degrees Celsius; then you are ready to take bias (zero exposure), flat, and dark frames:

Helpful keyboard commands on URSA (Gateway):

• F5 key - puts windows up in front on the screen
• F7 key - closes windows
  

Taking BIAS (Zero) Frames

• Settings:
  • Number to take : 10
  • exposure time : 0 seconds
• Click on Zero button to start biases
• Take about 30-50 bias frames during the night
  

Taking FLAT Frames

On the telescope control computer, turn on the tracking by typing: tr

• Select Calibrate Filter Wheel button
• Select first filter
• Change Image Title to: flat
• Around sunset, take a test flat. If mean count is about 10,000-15,000 and maximum count is less than 20,000, then you can begin taking flats.
• Settings:
  • Number to take: 5 per filter
  • Exposure time: ~1 second for B,V,R filters, ~2 seconds for I filter
• Click on Flats button to start flats

Note:

• If I filter does not seem to work, just click on the Calibrate Filter Wheel button again and select I filter again. This will fix the I filter problem.
• Do not use exposure times shorter than 1 second for flats.
  

Taking DARK Frames (not absolutely crucial since T = -110 C)

• Change Image Title to: darks
• Settings:
  • Number to take: 3
  • Exposure time: <maximum exposure time for target objects>
• Click on Darks button to start darks

When the sky becomes dark enough and before imaging your target stars, you will need to focus the telescope.

Determining the Focus Setting in Each Filter

• On telescope control terminal, make sure tracking is on. Then type: sa
• The computer will search the SAO catalogue for a bright star to determine focus. You will be prompted whether you want to search for a star near the current telescope position. If so, type: t
• When prompted for a magnitude range, hit <Enter>
• At the prompt, type: a. Note: If star chosen is ok then hit <Enter> key, otherwise type: a again until a suitable star choice is given. Then hit <Enter> key.
• choose B filter
• do a Test object (exposure time: 1 sec)
• center star in middle of CCD using observing control panel options:
  • click mouse on Center Frame
  • place mouse cursor on middle of star and hit <space bar>.
• set scale maximum to 500-1000 above maximum pixel value in the test image
• set scale minimum to 500-1000 below maximum pixel value in the test image
• take another Test object
• click on Update Focus (use exposure time = 1 sec)
• focus on star by using focusing buttons on telescope control box. A star is in focus when its image is round and small. Note values in TC computer screen.
• To stop and check focus: click Stop Focus option.
• Then click Inexamine option

Note: Inexamine gives you the PSF(Point Spread Function) for the star's image. If PSF is less than about 5.0, then image is in focus.

• Read focus number off TC monitor and record on log sheet. This will be input into URSA shortly.
• Next choose the V filter and repeat the focusing procedure.

Note: Focus setting for R and I filters will be exactly the same as for the V filter.

• Once this is done click on Configure option. In Configure window type in the newly determined Focus number for the different filters. Don't forget to click on the Apply button for each filter. Once this is done, click on Close Configure button.
• The focusing should now be completed.

On Telescope Control (Move) Computer

• type : co (for coordinates)
• terminal will prompt you to type in the RA and DEC of the target star:
  • RA : <hr min sec> (leave a space between hr, min, sec)
  • DEC : <deg min sec> (leave a space between deg, min, sec)
• terminal will tell you how far the telescope has to slew. If it is more than 2 degrees then someone must be in the observatory to watch the telescope. This is a precaution so that no cords or cables connected to the telescope get tangled and snagged.
• hit <Enter> key to have telescope slew to target star.

On URSA Computer

• Change to first filter. If doing standard B,V,R,I photometry, start with B filter and continue in order V,R,I.
• Change Image Title to : <target star's name>
• Set exposure time
• Do a Test Object
• Center star on CCD, using Center Frame option. (Note: Centering only has to be done once per object.)

Now you are ready to take observation.

• Click on Object option

When finished, repeat procedure for other filters:

• change Filter
• change Exposure time
• click on Object button

Repeat observing procedures outlined above for each target star.

What to Do If URSA Crashes

• If observing program freezes up in the middle of the night, hit Ctrl-C, then type: flprc
• For a computer crash during the night, hit Ctrl-C to main menu. Then click on NURO, go to menu, click on: start ice. This will reboot the observing program. Important: all data must be re-entered!

In Trailer

• On TC computer, type: tr (turns tracking off)
• Switch telescope control over to dome

In Dome

• On dome computer, type: cr - this will allow you to put cover back on telescope
• Type: ho - sends telescope to home position
• Rotate dome so that large black marks line up
• Close dome: flip switch on wall to close and press green button until dome is closed
• Turn off CCD and power pack behind telescope base
• Turn off all lights and lock up dome

In Trailer

• Switch telescope control back to trailer
• Turn off filter wheel switch on tower to right of Pegasus
• Turn off power to TC and URSA computers,
• Turn off monitor to Pegasus, but leave computer on
• Clean up your mess in the trailer, turn off the lights and lock up.

Good Work! Go home and get some sleep.

Data should be transferred from the URSA terminal throughout the night.

**Transfer will be incomplete if data is being taken - - be sure to wait for URSA to be idle.

Objectives

• To copy image (.imh) files into a temp directory
• Convert these files to .fits files
• Copy converted files into your school's directory
• Clear the temporary directory

Steps for Data Transfer

1. Open an xgterm window.
2. Log into URSA by typing:

rlogin ursa.lowell.edu

password: (provided by Brian Taylor)

1. Change to home directory by typing: cd
2. Start IRAF by typing: cl
3. Change to data directory by typing: cd data
4. Copy image files to temp directory by typing: imcopy *.imh temp
5. Change to temp directory. Type: cd temp
6. Create an image list. Type: files *.imh > image.list
7. Enter the text editor. Type: vi image.list
8. Type the following exactly:

:g/imh/s/.imh/.fit

:w fit.list

:q!

1. Type: wfits @image.list fits_files=@fit.list
2. Open another xgterm window.
3. Type: ftp ursa.lowell.edu
4. Type: prompt
5. Change to temporary directory. Type: cd data/temp
6. Type: mget *.fit
   

Clearing Temporary Directory

1. Click onto first xgterm window.
2. Change to temp directory. Type: cd temp
3. Type: imdel *.imh
4. Type: del *.fit
5. Type: del *.list
6. These commands delete all image files, fits files, and lists.

*Repeat from step 3 throughout observing session to transfer additional data.

**If the second xgterm window should close, type: open ursa.lowell.edu at command prompt.

To Copy Data from Hard Drive to Tape

1. Load tape cartridge onto tape drive device.
2. Change to directory on hard drive where files are stored (eg, cd/data/widener/summer97)
3. To advance tape to end of last data files stored, type: mt eom (only if tape is partially filled)
4. To begin transfer of data to tape, type: tar -cv *
5. To get tape out, type: mt rewoffl. Tape will automatically eject.

To Copy Data from Tape to Hard Drive

1. Load tape cartridge onto tape drive device.
2. Change to directory on hard drive where files are to be stored (eg, cd/data/widener/summer97)
3. To begin transfer of data to hard drive, type: tar -xv
4. To get tape out, type: mt rewoffl. Tape will automatically eject.
5. If desired, may rewind tape by typing: mt rewind
   
   

1. On Physics computer in outer office, start Linux and log in as usual.
2. At prompt, type: ftp pegasus.lowell.edu (may need to use !ftp)
3. Screen will respond with "connected" or something similar, then will prompt you for your username: Type in your username and hit <Enter>.
4. You will next be prompted for the password, which you should type in and hit <Enter>.
5. To find out where you are, type: pwd, which should show /lowell/myhome/pegasus/observer/
6. Change to subdirectory where data files lie: cd/data/widener/summer97
7. To see what files are in the subdirectory, type: ls -l |more
8. To transfer files, type: mget <filename.ext> (e.g., mget rvtauri*.fit.Z), then <Enter>.
9. If there are more than one file, the system will continue to prompt for each one. Continue to hit the <Enter> key for each. To save time, at the beginning you can simply hit <Enter> the number of times corresponding to the number of files to be transferred.
10. When done, type: quit twice, first to logout of the site and again get out of >ftp.
11. To logout of the local system, type: logout
    
    

To compress files

1. Go to the subdirectory where the files you which to compress are located.
2. To compress the files and run compression in the background, type: gzip -9 <filename.ext> &. (E.g., to compress all files in the directory, type: gzip -9 * &)
   

To uncompress files

1. Go to the subdirectory where the files you which to uncompress are located. They should have an extension .Z or .gz.
2. To uncompress the files, type: gunzip <filename.ext>

(E.g., to uncompress files rvtauri0001.fit.Z through rvtauri0199.fit.Z, type: gunzip rvtauri*.fit.Z)