Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://www.mrao.cam.ac.uk/~jsy1001/dimmwit/finder/userman.html
Дата изменения: Wed Oct 27 23:46:15 2004 Дата индексирования: Tue Oct 2 10:46:54 2012 Кодировка: Поисковые слова: п п п п п п п п п п п п п р п р п р п р п р п |
...Using the window manager menu (COAST finders)User Interface Layout
...From an xterm (COAST finders)
...From an xterm (DIMMWITs)
File MenuThe Panel Controls and Indicators
View MenuOpen Config...
Save Config
Save as...
Data Parameters...
Connect Telescope
Disconnect Telescope
Exit
ToolbarCCD Menu
Statusbar
Tracking MenuConnect CCD
Disconnect CCD
Fullscreen
1D DIMM Mode
2D DIMM Mode
Transverse DIMM Mode
Help MenuSelect Target
Select Region
Subframe
Start Tracking
Stop Tracking
Manual Control
Save Movie
Stop Recording Movie
About...
CCD Readout
BinningVideo Display
Exposure
Clear Charge
Stretch ContrastStatus
Correct Gamma
Fast 1D Grid
Fast 2D Grid
Fast Trans Grid
Show Scale
X and Y Offset Signals
Telescope Secondary and Beam Splitter Status
Progress Bars
Status Bar
ssh coast@dimmwit finder
The single board computer at each telescope contains a configuration file that lists aspects of finder operation that are unique to that telescope. Finder running on each telescope configures itself according to this file. The contents of the file are described in more detail here .
Open Config...
The default file name is "finder.conf" but with this menu item the user can choose to load a different configuration as long as it has a " .conf" suffix.Saves the current configuration under the filename finder.conf . NOTE: If the crosshair position changes while finder is running, finder will automatically update finder.conf when quitting
Save Config
Save as...
Saves the current finder configuration under a new name. This might be useful if the user wants to record the current crosshair position before doing experiments where it will be temporarily changed.
Invokes the data file dialog, which tells finder (or DIMMWIT) how to save files when the "
Data Parameters... Shift+P
Save Movie " action (in the tracking menu) is chosen. The file format depends on whether finder or DIMMWIT is in 1D DIMM mode or not. Normally, the file is a 3D FITS file with the image stored in the x and y dimensions and successive images in time in the z dimension. In 1D DIMM mode, the file is a 2D FITS file with spatial information in x and successive snapshots in time in the y axis. See "
Save Movie " and "
1D DIMM Mode" for more information.
![]()
In the file parameters section:
In the FITS parameters section:
- Under "Base file name" you can enter the path and file name you want to save files to. On COAST finders, the default directory is recommended as it is NFS mounted to oberon and has much higher capacity than the local silicon hard drive. On DIMMWITs you should choose a directory that is NFS mounted on your computer, again because the local silicon hard drive capacity is limited (information on how to NFS mount your computer's hard drive on DIMMWIT can be found here).
- If you choose "Insert date/time in filename when saving" the base filename you have specified above will have the current date and time (down to the millisecond) inserted. Hence even if you just keep pushing the "
" button over and over, each file you make will have a unique file name. Note that this option is forced on if you want to acquire more than one file on a single trigger.
- The "On trigger acquire" allows you to specify how many files to sequentially acquire and how many frames each one should have.
- This allows you to save up to 99 files sequentially without having to manually initialise the acquisition of each one.
- If you want a simple 2D FITS file, specify one file with one frame.
- Be aware that a frame can take several seconds to acquire if you are in full screen mode so a large series will take a while in that case.
- On the other hand, each image in the DIMM modes only takes a few milliseconds to acquire so you can take large numbers of frames.
- NOTE: The maximum number of frames in 1D DIMM mode is 131072 ( 217 ). In 2D and transverse mode it is 65536 (216). You do not have to remember these numbers, if you type in a larger number than 131072 it will be automatically reduced to this maximum and if you try to acquire a 2D DIMM file with more than 65536 frames you will be warned and the number will again be reduced to the allowed maximum.
- 131072 frames is just over 4 minutes 22 seconds in DIMM 1D mode, 65536 frames is just over 3 minutes 16 seconds in 2D DIMM mode.
- The "Acquire until stopped" item is deprecated and has been disabled.
- You can record a brief description in each of the fields provided or leave them at their default settings. This information will be written into a standard FITS header when finder saves the file.
(NOTE: This command will not work with DIMMWIT unless it is on the COAST network.)
Connect Telescope Shift+T
Connects this finder to the telescope controller via local ethernet. If the connection is successful the "Disconnect Telescope" menu item and button will become available, otherwise there will be an error dialog and you should refer to the troubleshooting guide for suggestions as to what to do next.
The telescope controller IP address and the port number to use are determined by the configuration file . The port number is important because the telescope controller uses it to distinguish which finder it is talking to. The appropriate port numbers are here . It is important to get the port number right, as it is otherwise possible to have a finder feeding signals back to a different telescope!
NOTE: If finder can't find or does not understand its configuration file, it will default to port 2700 (the centre telescope). So if a finder is unexpectedly communicating with the centre telescope, look for a missing or broken finder.conf.Disconnects finder from the telescope controller. If finder is connected to the telescope controller and the latter program forces disconnection (for example, by quitting), finder now also disconnects gracefully .
Disconnect Telescope Shift+D
Exit Ctrl+Q
Quits finder. If the configuration has changed (new crosshair position) finder will inform you before exiting.
NOTE: Finder is reasonably robust when told to quit unexpectedly while connected to everything and tracking. However, it is best not to tempt fate and to shut it down gracefully:
- Click on the "
" to disconnect from the telescope.
- Click on the "
" to disconnect from the CCD.
- Select "Exit" from the "File" menu.
Toolbar
Hides/shows part of the toolbar. Of limited use.
Statusbar
Turns status messages (at the bottom of the display) on/off.
Connects finder to the CCD controller. If all is well, readout will begin immediately. If not, you will be informed and should refer to the troubleshooting guide for ways to rectify the problem.
Connect CCD Ctrl+C
NOTE: If the camera head does not have power (for example, a telescope beam splitter is out) the display will remain dark.
Disconnects finder from the CCD controller. If you try to quit finder before doing this you will see an error message asking you to disconnect first.
Disconnect CCD Ctrl+D
Causes finder to start reading out the entire CCD. The following operations are cancelled if they were running:
Fullscreen Ctrl+F
This is a good button to press if something has gone wrong, as all feedback is cancelled and the entire field of the CCD is displayed.
- Subframing.
- Tracking.
- Either DIMM mode.
Initiates high speed CCD readout in a way that is suitable for one-dimensional DIMM measurements.
1D DIMM Mode Alt+1
1D DIMM mode tries to maximise readout rate for seeing measurements:
Note:
- Readout is initiated by a periodic USB interrupt to the microcontroller.
- Firstly, 64 lines of CCD charge are clocked into one line, the readout register.
- Secondly, 64 pixels from the readout register are each clocked out and digitised.
- The results from the readout are sent to the single board computer over the USB link.
- The cycle repeats every two milliseconds.
- The result is spatial information in the horizontal dimension at 500Hz.
- Because there is no charge clearing, charge produced anywhere on the CCD will eventually be read out. Hence:
- There are many 64x64 regions on the CCD besides the corner that are also useful.
- These regions are marked out when the "Fast 1D Grid " check box is ticked.
![]()
1D DIMM mode also differs from normal readout in other ways:
Dropouts in acquisition files can occur if acquisition is disturbed. Hence:
- The display changes to display the 64 pixel line of charge.
- Most controls are disabled.
- 1D DIMM mode can be stopped by selecting "
Fullscreen".
- Selecting "
Save Movie" produces a 2D "strip chart" FITS file:
- The horizontal dimension is spatial.
- The vertical is time in 2ms increments.
- Up to four minutes of data can be saved.
- Data is saved in finder computer memory and saved to file after the event.
- Don't move the mouse or interact with the display in any way while saving movies.
Initiates high speed CCD readout in a way that is suitable for two-dimensional DIMM measurements.
2D DIMM Mode Alt+2
NOTE: This mode works with both MX516 and HX516 cameras whether they have had the the hardware modification described above or not.
2D DIMM mode tries to maximise readout rate for seeing measurements:
Note:
- Readout is initiated by a periodic USB interrupt to the microcontroller.
- A 64x32 pixel region is read out. It is binned 4x4, so the result is a 16x8 array of data.
- The cycle repeats every three milliseconds.
- The result is spatial information in the horizontal dimension at 333Hz.
- Because there is no charge clearing, charge produced anywhere on the CCD will eventually be read out. Hence:
- There are many 64x32 regions on the CCD besides the corner that are also useful.
- These regions are marked out when the "Fast 2D Grid " check box is ticked.
2D DIMM mode also differs from normal readout in other ways:
Dropouts in acquisition files can occur if acquisition is disturbed. Hence:
- The display changes to display the 16x8 rectangle of charge.
- Most controls are disabled.
- 2D DIMM mode can be stopped by selecting "
Fullscreen".
- Selecting "
Save Movie" produces a 3D FITS file just like those produced during ordinary readout, except that:
- The time interval between frames is fixed at 3ms.
- The maximum number of frames is 65536 (about 3 minutes 16 seconds of data).
- Data is saved in finder computer memory and saved to file after the event.
- Don't move the mouse or interact with the display in any way while saving movies.
Transverse DIMM mode also differs from normal readout in other ways:
Dropouts in acquisition files can occur if acquisition is disturbed. Hence:
- The display changes to display the 8x16 rectangle of charge.
- Most controls are disabled.
- Transverse DIMM mode can be stopped by selecting "
Fullscreen".
- NOTE: Sometimes this does not work.
- If this happens:
- Go into 1D DIMM mode by clicking on "
".
- Select "
Fullscreen" again.
- Selecting "
Save Movie" produces a 3D FITS file just like those produced during ordinary readout, except that:
- The time interval between frames is fixed at 4ms.
- The maximum number of frames is 65536 (about 4 minutes 22 seconds of data).
- Data is saved in finder computer memory and saved to file after the event.
- Don't move the mouse or interact with the display in any way while saving movies.
Changes the cursor into the target selection shape. If it is then clicked in the video display area:
Select Target Alt+A
If you are using a COAST telescope finder, the crosshair marks the position on the CCD image plane that the telescope controller will guide stars to.
- The target crosshair moves to the clicked position.
- The cursor changes back to its default shape.
- To move the crosshair again, choose "
Select Target" again.
- It is functionally equivalent to the crosshairs on the old finder system.
- When finder is tracking the telescope will try to guide stars to the crosshair position.
- Hence the crosshair position should be set optically congruent to the autoguider.
- As with the old system, this is normally done by setting the crosshairs to the image position of the artificial star return beam from the telescope flat/corner cube.
Changes the cursor into the region selection shape. To select a region in the CCD image:
Select Region Alt+R
In normal use a region is selected around the image of a star that is to be acquired. When that region is later subframed it reads out much more quickly than the full CCD field. The region can also be used to exclude stars that are not of interest.
- After choosing this option, move the cursor to one corner of the region you want to select.
- Hold the left mouse button down.
- Move the cursor to the opposite diagonal of the region. A green bounding rectangle will change shape as the cursor moves.
- Let the left mouse button go.
If a region has been selected, this action initiates subframing - that is, only the region of the CCD that has been selected is read out. Tracking is not initiated.
Subframe Alt+U
Subframing improves the readout rate, as less time is required to clock the CCD and to transfer the data over the USB cable. This is useful in situations where visual real-time feedback is important, or as a precursor to tracking or acquisition of 3D DIMM files.
If used on a COAST telescope finder, this is the action used to automatically steer a star image to the crosshairs and hence hopefully within autoguider range.
Start Tracking Ctrl+T
If a region has been selected, this action initiates subframing (if that is not already occurring) and tracking. Tracking consists of the following actions:
Hence, as the star image moves the subframe region moves with it. The star can be tracked across the entire field without resorting to slow full frame readout. Subframing in this way also allows the user to exclude stars that are not of interest.
- Subframe readout of the selected region begins.
- The position of the brightest pixel in the region (such as a target star image) is recorded:
- Relative to the region boundary.
- Relative to the target crosshair.
- As the brightest pixel position changes, the subframing region moves to maintain its initial spatial relationship with the pixel.
- The error relative to the crosshairs is displayed.
- On COAST telescope finders (with finder connected to the telescope controller):
- Once a second, the position of the brightest pixel relative to the crosshair is sent to the telescope controller.
- The controller tries to steer the star image to the target crosshair (if it has been told to).
- If the star is close to the crosshair position, finder tells the telescope controller that the star is acquired.
Stops any ongoing tracking. The most recent subframe region is retained and continues to be read out. However, no valid data is sent to the telescope controller. To recommence tracking:
Stop Tracking Ctrl+S
- If the object of interest is still in the field, select "
Start Tracking".
- If it is not, select "
Fullscreen", select a new region and then start tracking.
If the finder is connected to a COAST telescope, this action allows the user to make manual adjustments to the telescope pointing by clicking and dragging on the star field. To use it:
Manual Control Shift+C
All this action really does is send a fake error signal to the telescope, which then tries to correct it using pointing changes. As with a real error signal, a conversion is done by the telescope controller into Az and El components. Hence dragging vertically should result in image motion that also appears vertical.
- Select "
Manual Control".
- Move the cursor into the video display area and to some arbitrary position. The cursor changes into a hand.
- Hold the left mouse button down.
- Drag the mouse cursor in the direction you want the star field to go.
- Moving further away from your starting point makes the telescope pointing change faster.
- Let go the left mouse button when the field is where you want it.
- The cursor changes back to its default shape.
Initiates the saving of a sequence of one or more consecutive FITS files, each consisting of a set of one or more consecutive images. To change the file saving parameters invoke the data file dialog using "
Save Movie Shift+M
Data Parameters" first.
The files you get after you select this option depend on whether you are in 1D DIMM mode or not.
If you are acquiring normally or are in 2D or transverse DIMM mode:
If you are in 1D DIMM mode:
- The files are 3D FITS files.
- The X and Y dimensions are the binned pixel dimensions of the frame, or the region if subframing was active at the time.
- Each pixel has depth 16 bits.
- The Z dimension is time (3ms between frames in 2D DIMM mode, 4ms in transverse DIMM mode) and of depth as specified in the data file dialog.
In either case:
- The files are 2D FITS files.
- The X dimension is 64 unbinned pixel intensities.
- Each pixel has depth 16 bits.
- The Y dimension is time in 2ms increments.
- Hence the files are strip charts.
- Finder should be left undisturbed while acquiring, otherwise there may be dropouts in the data.
- When you start saving the movies:
- The "
Save Movie" icon is disabled (greyed out).
- The "
Stop Movie" icon is enabled.
- You can interrupt movie saving by selecting "
Stop Movie".
- You can tell when movie saving is completed:
- The "
Save Movie" icon becomes re-enabled.
- The "
Stop Movie" icon becomes disabled.
- The computer beeps.
Interrupts the recording of a sequence of FITS files.
Stop Recording Movie Shift+H
NOTE: Using this button is not recommended:
You may be able to recover the saved data manually:
- The file that is interrupted will be shorter than its FITS header says.
- Your FITS file viewer will probably complain.
- DIMM mode acquisitions will not be interrupted until the current file has finished acquiring (or sometimes the next one).
- Look at the file length and FITS header to work out how many records were actually saved.
- Manually edit the FITS header to agree with this.
About...
Displays a brief message about Finder.
Binning
Changes the amount of charge binning in the X and Y directions.
Binning is the adding together of charge from neighbouring pixels prior to readout.
Binning can be changed "on the fly" even while subframing or tracking.
- As there is a fixed noise associated with readout, increasing the binning can improve the signal to noise ratio at the cost of resolution.
- Refresh rate is also increased as less data is transferred via the USB cable to the finder computer.
- A full unbinned frame can take several seconds to read out. Recommendation: subframe the region of interest before reducing the binning.
The binning parameter is ignored in either DIMM mode.
- The change in resolution is accounted for in display and tracking signals.
- However, reducing binning can be dangerous while tracking:
- The first new frame has low signal (possibly the previous binning has cleared the charge).
- Mistracking errors may result.
- Recommendation: if tracking, reduce binning one step at a time.
Exposure
Sets the exposure time between frames.
- Use long exposures for faint targets.
- Exposure length can be changed "on the fly" even while subframing or tracking.
- The true exposure time depends on whether "Clear Charge" is set, see below.
- Exposure time is ignored in either DIMM mode.
Clear Charge
This option clears CCD charge prior to an exposure.
Unchecking it reduces readout time. However, image artefacts are also introduced:
- The CCD charge readout channels are not light sensitive.
- If charge clearing is on, the readout time does not have to be factored in to the exposure time.
- If charge clearing is off, the CCD is exposing and reading out at the same time.
- If the CCD is subframing, the clocking mechanism can move charge from other parts of the chip into the readout region.
- This charge is interpreted as part of the image.
- Hence only uncheck this option if the rest of the field is reasonably dark or you are doing full frame readout or you wish to exploit this charge transfer property in some way.
- "Clear Charge" is ignored in either DIMM mode.
Stretch Contrast
This option linearly maps the scale of intensities in the image to the full range of the display:
- Images are 16 bits deep but the display is (usually) 8 bits deep.
- High dynamic range images are compressed for display.
- Low dynamic range images (of faint sources) are expanded for display.
- Recommendation: Do not compare source intensities between running finders while contrast stretching is on.
Correct Gamma
Corrects for the nonlinear intensity response of a cathode ray tube display. Hence a linear relationship between photon flux and displayed intensity is produced.
Turn this option off if you have a linear display (such as an LCD monitor) or your display hardware already compensates for monitor gamma (if you are using a Silicon Graphics computer, a Macintosh or some PC display adaptors).
Fast 1D Grid
Displays a red grid in the video display area that marks the fast readout regions useful in 1D DIMM mode . As long as all star images in a DIMM set are in the same valid rectangle of the grid and are separated horizontally, useful data will be obtained.
![]()
Fast 2D Grid
Displays a blue grid in the video display area that marks the fast readout regions useful in 2D DIMM mode. As long as the star images in a DIMM image set are in the same rectangle, useful data will be obtained.
Fast Trans Grid
Displays a blue grid in the video display area that marks the fast readout regions useful in Transverse DIMM mode. As long as the star images in a DIMM image set are in the same rectangle, useful data will be obtained.
![]()
Show Scale
Displays the angular sky scale on the video display area.
Not yet implemented and disabled.
X and Y Offset Signals
Display of the offset being sent to the telescope controller (if it is connected to finder).
- The offset is the distance in unbinned CCD pixels between the brightest pixel being tracked and the crosshair target position.
- The numbers become more approximate as binning is increased.
- The telescope controller tries to move the bright spot towards the crosshairs by adjusting telescope pointing (if it is connected and has been told to).
Telescope Secondary and Beam Splitter Status
When finder is connected to the telescope controller, the positions of the telescope secondary mirror and beam splitter are displayed:
- These panels are arranged to look like a ray-trace of the light through the telescope.
- They cannot be used to move telescope optics.
- Their appearance is as follows:
Status
Secondary
Beamsplitter
Out
![]()
![]()
Moving
![]()
![]()
In
![]()
![]()
Progress Bars
Data Saved
- During movie saving, this indicator displays how much of the current movie has been saved so far.
- This indicator is inactive when movies are saved in any of the DIMM modes.
Max Flux
- During acquisition, this indicator indicates as a percentage:
- The intensity of the brightest pixel in the most recently acquired frame, divided by...
- The maximum intensity possible. For the HX516 and the MX516, this value is 65535.
- The intention is to provide quantitative feedback for the user regardless of the status of the Stretch Contrast option.
Status Bar
At the lower left of the finder user interface, messages to the user are sometimes displayed.