Filter=Open - 3.4c 70%

2/01/2000 20:24:12
You will note that this is similar to the display appearance at power up but now the date and time are shown and the temperature of the CCD will probably be lower than when you first turned on the power.
You can enter the SETUP menu at any time by pressing the Setup button on the STV control panel. The Setup menu contains a number of items in addition to the date and time. The STV will remember some of the items the next time you power up the camera but the date and time information will be saved only as of the time the camera was turned off. This is why there is also a separate prompt to enter the date and time at power up. The items contained in the Setup menu are as follows:
MAIN MENU Date/Time CCD Temperature Grid Night Vision Filter Units Focal Length Aperture Diameter Telescope Magnitude Corr. Site Beep Adjust Filter Video VIDEO MENU Mode Date/Time Test Pattern Gray Scale VALUES Set month, day, year, hour, minute, second Set temperature to a given value greater than -50 (degrees C). On / Off (displays a grid overlay in image mode for manual guiding) On / Off (turns the video image predominantly red) Yes / No (rotates an internal filter over the CCD for ~20x attenuation of light) Inches / cm Enter your scope's focal length (0.01 to 600) Enter your scope's aperture diameter (0.01 to 600) Refractor / Reflector (a Schmidt-Cassegrain is a reflector) Enter correction factor for calibration of magnitudes (+5.0 to -5.0) Enter site ID number from 1 to 255 for inclusion in the image header On / Off Adjust the threshold value for the filter wheel opto sensor [takes you to the VIDEO SETUP MENU] VALUES NTSC / Internal PAL / External PAL / Off (set video format or turn it off) On / Off (turns the date/time display on the video screen on or off) [displays a test pattern for adjustment of an external video display] [displays a gray scale for adjustment of an external video display]
In the same way that you set the Date/Time when you powered up the STV, once you have pressed the Setup button, you can scroll through the setup menu items by pressing the Parameter button or by turning the rotary know directly under the Parameter button. Likewise you may select or change the value for any given men item by pressing the Value button or by turning the rotary knob directly under the Value button. For illustration let us assume you wish to use the Night Vision Mode for the video display. You press the Setup button to enter the setup mode and then scroll through the menu items using the Parameter button or the rotary knob directly under the Parameter button until you see the following display:

Having set the date and time and other setup items you are now ready to start capturing images. The first thing you need to do is focus the camera. Enter the Focus mode by pressing the Focus button once. You will see a focus setup display similar to the following:

FOCUS SETUP Sensitivity

You can adjust the initial sensitivity by pressing the Value button or turning the rotary knob directly under the Value button. Select a sensitivity value between 1 and 16 and press the Focus button again. Now you will see a display similar to this:

FOCUS Norm

.10s 1x
The focus display shows the following information:
FOCUS = you are in focus mode 1 Norm = zoom level is normal (Normal, Zoom, Wide) 1.10 s = exposure time is.10 seconds (1ms to 2.5 seconds) 1x = the camera gain is set to 1x (1x, 2x, 4x, 8x, 16x) Full = the image size is full (Full or Partial)
In focus mode, both of the rotary knobs perform the same function: to increase or decrease the exposure time and gain of the camera. The range of exposure times is 1 millisecond to 2.5 seconds with a zoom setting of Normal.1 The gain is increased or decreased only when the exposure time is at.25 seconds. Try turning either of the rotary knobs and watch the resulting change in exposure times and sensitivity. Also note that when you have increased the exposure time to.25 seconds and the gain to 4x the display adds some additional information:

x Px= y=.10s 1x

Px = peak value of brightest pixel on the CCD (maximum 1023 with zoom set to Normal)2 x y = X and Y coordinates of the brightest pixel on the CCD (e.g., 154, 265)
Because it takes some processing time to display this additional information, it is not displayed at exposure times shorter than.25 seconds in order to keep the video screen updates as rapid as possible for visual focusing. However, this information is particularly helpful when using the STV as a stand alone autoguider without any video display. In this case, when the video screen is set to "Off" in the Video Setup menu, the peak value and location of the brightest pixel are displayed at all exposure times. _______________________________________________________________________________

IMAGE PBright

Norm,Exp=0.1s ContrastQ
In Image Capture Mode (unlike focus mode) the rotary knobs do not change the exposure time of the image. Rather, the exposure time is selected in the Image Setup Menu and the rotary knobs control the brightness and contrast of the image. The display shows small circular arrows prompting you to adjust the Brightness and Contrast to suit your monitor. Pressing the Parameter button in Image Mode will toggle through the zoom levels. Pressing the Value button has no effect in Image Mode. Each of the Image Setup Menu Items and Values are explained in detail below:
Exposure: Set the exposure time from 0.001 seconds to 600 seconds. Gain: Set the gain of the camera 1x or 2x. In general, use 1x for bright objects like the moon and use 2x for dim objects like galaxies. Zoom: Set the initial zoom level to Zoom, Normal or Wide. The zoom mode can also be toggled between Zoom, Normal or Wide by hitting the Parameter button during continuous updates while in Image mode without having to return to the setup menu. Changing the zoom level will automatically adjust the exposure time to compensate for the difference in sensitivity (See Tech Note on page 11). Dark Subtract: Yes or No. If set to No the STV does not take a dark frame. When taking short exposures (e.g., less than one or two seconds) it will speed up the video rate if you do not take a dark frame. For longer exposures, a dark frame is recommended. When set to Yes, the STV automatically takes a dark frame by rotating the internal shutter to the closed position and taking an image. The STV will then automatically subtract the dark frame from each subsequent light frame that is of the same exposure time and zoom setting. Changing the exposure time or zoom setting will cause the STV to automatically take a new dark frame. Mode: Continuous, Snap, Track&Accum, Mosaic (Lg), Mosaic (Sm), Best Sharp, Best Peak, Auto Grab: Continuous: The STV will continuously take and display images. The actual frame rate is somewhat slower than normal video and (depending on the mode and exposure time you select) you will notice the frames updating on the video monitor. Using a short exposure time, no dark subtract, zoom mode will give the fastest video updates for focusing and planetary observations. Snap: The STV will take a single image.

Track&Accum (Track & Accumulate - US Patent 5,365,269): The STV will automatically take, register and co-add a series of images. You see the image density and brightness build up on the video monitor in real time as each subsequent image is added to the accumulated composite of all the previous images. This mode is a useful alternative to guiding because the STV will register each new frame on a common reference star of your selection in the original frame. Small shifts caused by telescope drive errors are compensated for by this process and the resulting Track & Accumulate image is nearly as good as a long single guided exposure. When you take a Track & Accumulate series, the STV automatically closes the shutter and takes a dark frame at the beginning of the sequence. This dark frame is stored in the STVs internal memory and it will be subtracted from each subsequent light frame in the sequence. After the dark frame is captured, the shutter rotates to the open position and the first light frame is captured. The first light frame is displayed and the brightest star is highlighted with a shrinking box. The display will look similar to this:
IMAGE Norm,Exp=50ms Select Guide Star Next
It is usually OK to use the guide star that is automatically selected by the STV. However if the brightest star happens to be near the edge of the image or very near another star you should manually select a bright star that is located away from the edge of the frame so that it is not lost during the sequence. You can select a different guide star by moving the highlighted box around the image using the STVs rotary knobs. When you are ready to start the sequence, select Next by pressing the Value button on the STV control panel. As each light frame is captured during the Track & Accumulate sequence, the STV will co-add the frame to the accumulated image seen on the video monitor. You will see the composite image build up after each exposure. When you are satisfied with the density of the image press the Display button to stop the process and examine the result. You can also save the image by pressing the File Ops button and selecting Save from the File Ops Menu. Mosaic (Lg): The STV takes a series of 6 images, each cropped to the central 104 x 98 pixels and arranges the result is a mosaic of a single frame of two rows and three columns. Mosaic is useful for taking planetary shots where a wide field of view is not so important and momentary changes in seeing are difficult to anticipate. By automatically taking a series of exposures your chances of capturing one or more during a moment of best seeing are increased and you may later crop the mosaic to keep the best of the lot. There must be at least one empty memory slot available to take a mosaic image. The time each image is taken is saved in a text file for reference. Mosaic (Sm): The same as Mosaic (Lg) mode except that the STV takes a series of 40 images, each cropped to the central 40 by 40 pixels and arranges the result in a mosaic on a single frame of five rows and eight columns. The time each image is taken is saved in a text file for reference. In either Mosaic mode, unless you stop it, the STV will keep making mosaics until all the available memory slots are full. (See also Auto Grab Interval for setting the interval between exposures). Best Sharp: The video frame is bifurcated and begins with the same image displayed on both sides. The image on the left half of the video frame is updated continuously but the image on the right half of the video frame is updated only when subsequent images are sharper than the one stored in temporary memory. The central 100 x 100 pixels are used to determine the FOM. This mode works best on planets. In Best Sharp (and Best Peak ) mode you will see a display similar to this:

Optical Quality

If you select the Optical Quality mode from the Monitor Setup Menu you will see a display similar to the following:
MONITOR SETUP OPTICAL QLTY

Do It!

Press the Value button and the STV captures a star image, displays it in a small box on the video screen above a graph and begins measuring the optical quality of your system. Selection of the star and exposure times is automatically calculated by the STV. A graph of the results is displayed on the video screen similar to the sample below:
OPTICAL QUALITY MONITOR TIPS
Perform this measurement only on nights of exceptional seeing. Chose a relatively bright star high in the sky. The Optical Quality mode measures optical image quality independent of seeing and drive problems. The way it does this is by taking many very short exposures and reporting the best stellar widths it measures. The assumption is that drive errors are insignificant over short times, and seeing occasionally allows one to see the full performance of the optical system. This last assumption is only valid on a good night. See Appendix C, page 49, for details.
When the graphic information is on the video screen you can toggle on the 3 dimensional graph of the star profile by hitting the Value button again. Displaying the 3D graph will slow the update rate. As the graph is updating, the alphanumeric display provides the quantitative data:
OPTICAL QLTY. Exp=50ms FWHM= 2.6^s Strehl= 72%
In this example the STV is using an exposure time of 50 milliseconds, the FWHM (Full Width Half Maximum) of the star image is 2.6 arcseconds and the Strehl ratio of the optical system compared to a theoretically perfect system is 72% (Reminder: You must accurately set your telescope's focal length and aperture diameter in the Setup Menu before using this function). For an explanation of the theory and calculations behind the Optical Quality Monitor mode see Appendix C, page 49.
Drive (fast) and Drive (slow)
When you select the Drive Monitor mode, the display will appear similar to the following:
MONITOR SETUP DRIVE (fast)
Select Drive (fast) or Drive (slow) by toggling the Parameter button or turning the rotary knob directly under the Parameter button. When ready, press the Value button to start the Drive monitor function you have selected. The STV will automatically adjust the exposure time to capture star images by taking sample exposures and measuring the results. When the best exposure time is calculated, the STV will capture an image and select the brightest star in the frame. A shrinking box will briefly highlight the selected star. At the fast rate, the star's centroid is determined every 200 milliseconds. The fast rate is best for measuring high frequency drive or mount vibrations. At the slow rate the star's centroid is determined every 2 seconds. The slow rate is best for measuring the drive's periodic error. The video screen will show a graph similar to the screen shot below:

FILE OPS SETUP RECALL

Turn the rotary knobs to move the highlight box from slot to slot and then press the Value button again to recall an image in the selected slot. There may be more than one page of image thumbnails and if you continue to move the highlight box after it reaches the first or last image on the video screen, the next page available will be displayed.
As you turn either rotary knob the highlight box will scroll through all of the memory slots and you will see thumbnails of the saved images on the video screen. If a slot contains an image the date and time the image was taken will appear on the alphanumeric display. If a slot is empty the word "Empty" appears on the display.

RECALL Image 6

01/01/00 23:55 Do It!
When you have selected an image, press the Value button and the image will be recalled to the video screen and displayed full size.

Download

From the File Ops Setup menu, turn the rotary knobs or toggle the Parameter button until the Download command is displayed. The alphanumeric display will show:

FILE OPS SETUP DOWNLOAD

Hit the Value button to download the image currently displayed on the STV to your PC. Note: In order to download images to your PC you must be running STV REMOTE software on your PC. For complete instructions please refer to Chapter 6, page 37.

Download All

From the File Ops Setup menu, turn the rotary knobs or toggle the Parameter button until the Download All command is displayed. The alphanumeric display will show:
FILE OPS SETUP DOWNLOAD ALL
Select Download All by hitting the Value button. The STV will download all of the images in its internal memory to your PC. Note: In order to download images to your PC you must be running STV REMOTE software on your PC. For complete instructions please refer to Chapter 6, page 37.

Slide Show

From the File Ops Setup menu, turn the rotary knobs or toggle the Parameter button until the Slide Show command is displayed. Select Slide Show by hitting the Value button. The alphanumeric display will show the following:

SLIDE SHOW Auto

You may select Auto or Next. If you select Auto by pressing the Parameter button, the STV will automatically display each image in its memory with a short pause after each image is displayed. If you select Next by pressing the Value button, the STV will display each image in its memory, however it will pause after each image until you hit the Value button again.

Erase One

From the File Ops Setup menu, turn the rotary knobs or toggle the Parameter button until the Erase One command is displayed. Select Erase One by hitting the Value button. The STV will bring up a page of image thumbnails or empty slots on the video screen.

FILE OPS SETUP ERASE ONE

Turn the rotary knobs to move the highlight box from slot to slot and then press the Value button again to select an image to erase. There may be more than one page of image thumbnails and if you continue to move the highlight box after it reaches the first or last image on the video screen, the next page available will be displayed. As you turn either rotary knob the highlight box will scroll through all of the memory slots and you will see thumbnails of the saved images on the video screen. If a slot is empty the word "Empty" appears on the display. If a slot contains an image, the date and time the image was taken will appear on the alphanumeric display. When you have selected the image to erase, press the Value button and the STV will prompt you to press both the Parameter button and the Value button at the same time.
ERASE ONE 01/01/00 23:55 Press Both to Erase
This extra step helps prevent the accidental deletion of an image.

Erase All

From the File Ops Setup menu, turn the rotary knobs or toggle the Parameter button until the ERASE ALL command is displayed. Select ERASE ALL by hitting the Value button.

FILE OPS SETUP ERASE ALL

The STV will prompt you to press both the Parameter button and the Value button at the same time to erase all the images in the STV's internal memory.
ERASE ALL Press Both to Erase

Baud Rate

From the File Ops Setup menu, turn the rotary knobs or toggle the Parameter button until the BAUD RATE command is displayed. Toggle a baud rate by pressing the Value button or by turning the rotary knob under the Value button. The range is 115.2K to 9600.

FILE OPS SETUP Baud Rate

115.2K
This is the baud rate at which the STV will communicate with your remote computer over the serial link. It does not affect the STV's operations in stand alone mode. The STV will attempt to establish a link at the baud rate you have selected, so you should try it at the highest rate to begin with. However, if you experience difficulty maintaining a reliable link (particularly if you are using a long serial cable), then try adjusting the baud rate to a lower setting.

Exposure: Set an exposure time from 0.001 seconds to 600 seconds Cal. Time: Set a calibration time from 0.1 seconds to 60 seconds. This is the amount of time the STV will close each relay to move the telescope for the purpose of calibrating the drive speeds. This time
should be long enough to see a star move at least 10 to 20 pixels but not so long that the star moves off the CCD. Relays: Select 1234, 12 or 34. 1234 means that all four relays are exercised. 12 means that just relays 1 and 2 are exercised. 34 means that just relays 3 and 4 are exercised.
When you have set the items in the Full Menu, press the Calibrate button again to start the calibration process. The STV take an image and report the number of stars it is using for calibration and initial position of the brightest star:

CALIBRATE Initial: Star

Stars 8 219, 78
As the STV moves the telescope the alphanumeric display provides the following information:

CALIBRATE Relay 1: Star

Mv=10.0 150, 84
In this example, the calibrate move time is 10.0 seconds, relay 1 has completed its move and the new location for the brightest star is pixel x=150, y=84. If the STV does not detect motion in one direction (or too little motion) it will abort the calibration process and give message: "Error: No Move."
Use the Move function simply to test the relays and the relay cable connection to your telescope. When you select Move and tell the STV to "Do It!" the STV will present you with Relay 1: and prompt you to "Do It!" You can toggle through each of the four relays by pressing the Parameter button or by turning the up-down rotary knob. Press the Value button when ready to move a relay. The STV will close the relay for 5 seconds and indicate that it is MOVING. You should be able to see the motion of the telescope using a high power eyepiece.

View Results

After a successful calibration, the relative speed and direction of the motion detected for each relay is indicated in a graphic display on the video screen. The alphanumeric display will also report that the calibration passed. In the graphic display the orientation of the arrow indicates the direction of the move and the length of the arrow indicates the relative speed:
CALIBRATE Passed! Relay 1: 4.91, 279o Next
In this example the STV reports that when Relay 1 was activated the measured speed was 4.91 arcseconds per second in the compass direction of 279 degrees as seen on the video screen (straight up as seen on the video screen is 0 degrees, straight down is 180 degrees, etc.,). You can toggle through the factors for each relay by hitting the Value button. Note: the STV calculates the correction rate in arcseconds per second based on the focal length you have entered in the Setup menu. If you change the focal length of your system you must recalibrate. If, instead of "Passed!" the alphanumeric display contains the message "Angles?" or "Speeds?" then the calibration is suspect and you are prompted to check the angels of motion or the speeds of the drives to determine if there is a problem. Unlike earlier autoguiders, The STV will calibrate with the camera head in any orientation, even if the X and Y directions are oriented at a 45 degree angle to the mechanical axis of your telescope. However, it assumes that the angles it will see for RA and DEC motion will be approximately at 90 degrees relative to one another. It also assumes that the drive speeds in different directions do not differ by more than a factor of about 4X. You can override these assumptions by using the Full-Menu mode.

STV Remote Console Layout
When you run STV REMOTE software you will see a virtual copy of the STV control panel on your computer screen similar to the sample screen shot on the pervious page. Updates or modifications to the software will undoubtedly occur in the future so your screen may appear slightly different from the sample screen shot in the manual. For the most part, any function that you can perform by pressing buttons on the STV control panel can also be performed by clicking on the corresponding button on your computer screen. However, there are some differences: 1. The STV REMOTE console has two additional windows for display of data, one for display of image header information and one for display of PC messages and crosshair information. 2. The STV REMOTE console has a Turbo button that can be toggled to increase the rate at which the virtual rotary buttons make the crosshairs move on the video screen. 3. The STV REMOTE console has a menu bar across the top of the panel with pull down menus. These pull down menus and commands are described in detail in the next section of the manual. 4. The STV REMOTE console will display digital images downloaded from the STV as well as STV images previously saved to a disk on your computer. However, the STV REMOTE console does not display a live video image. In order to view the video image as you control the STV from a remote computer you must run a video cable from the STV control box to a video monitor near your computer.

STV Remote Console Menus

The STV REMOTE console contains several simple pull down menus for handling images from the STV and for remotely controlling the camera. This section describes each menu item:
File I/O Download Link Display Process Edit Data Units Upload Load STV Frame from Disk Save STV Frame to Disk in SBIG Format Save Displayed Image in Bitmap Format Receive and Automatically Save Images Exit
Load STV Frame from Disk: Use this command to view an STV image that has already been saved on your computer's hard drive or a floppy disk Save STV Frame to Disk in SBIG Format: Use this command to save the image that is currently displayed on the STV REMOTE console screen to your computer's hard drive or floppy disk. The image will be saved in SBIG compressed format. Saving all of your images in SBIG format is recommended because this will preserve the image bit depth (up to 16 bits) and will also preserve the header information. STV compressed image files are approximately 66 Kbytes. SBIG image compression utilizes a routine that does not degrade the image data but saves disk space. The latest versions of CCDOPS for DOS and CCDOPS for Windows 95/98/NT will also read

Battery Operation

The STV will run from any 12VDC source such as a car battery. The pin configuration for the STV power plug is shown in the diagram below.
+12VDC on Outside Ground in Center Mating plug is 5.5mm outside and 2.1mm inside
Caution: The STV will draw approximately 2 amps of current, which can drain a car batter to low levels over the course of an evening. It may be wise to use a separate battery to run the STV if you intend to image for any significant length of time, particularly if you are also running an external monitor and/or telescope mount from the same battery. Deep discharge marine batteries are recommended.

Telescope Port

The autoguider output from the STV is via the Telescope port on the back of the STV chassis. The pinouts for the Telescope port are shown below. Please note that you cannot use an off-the-shelf telephone cable to make the connection between this port and your telescope. The connectors on a telephone cable are reversed relative to the connectors on a relay cable.

123456

1 = +RA (Right) 2 = +DEC (Up) 3 = -DEC (Down) 4 = -RA (Left) 5 = Common 6 = No Connect
The relays in the STV are mechanical, however, they are normally open relays only. If you require a special interface that uses relays that are normally closed you must use a Relay Adapter Box available from SBIG. Use of the Relay adapter box requires setting two jumpers on the STV CPU board. The diagram below shows how the jumpers are set at the factory. The inset shows how they should be set for use with the Relay Adapter box. See also Appendix B, page 45, if you have any difficulty locating jumper block 4 on the CPU board (Note that the orientation of the diagram below is rotated 180 degrees relative to the larger diagram in Appendix B).

RS232 Connector / Cable

If you intend to remotely control the STV from a distance greater than a few feet, you will need to purchase or make a custom serial cable. The pin configuration for the RS232 port on the STV is as follows:
STV Pin 5 Function Transmit data from STV Receive data to STV Ground PC/XT (25 pin D) 7 AT (9 pin D) 5

Making the Measurement

To measure optical quality, use a focal length of at least 100 inches (2.5 meters), more if you have a large aperture and a very good night. A barlow lens works well for extending the focal length if your system is shorter than this. Be sure to set the proper focal length and aperture in the Setup menu. Focus the image on the CCD as best as you can, and then enter the optical quality monitor mode. Use the filter built into the STV if you are worried about chromatic aberration. Avoid trusting the numbers with short focal lengths since the sampling of the stellar image with the CCD pixels is too coarse.
The mathematics behind the displayed values
The calculation of optical quality uses the following procedure. The formulae assume an Airy disk (theoretical) shaped energy distribution, even if the star is bloated up several times this size.

1. 2. 3. 4.

Measure peak star brightness Measure total counts in star image relative to background ( box is 66 x 66 pixels) Find the ratio (peak/total counts) Using Table 1, determine the pixel width relative to the Airy Disk that matches the ratio calculated in step 3 5. Since the pixel width is 7.4 microns, calculate the effective Airy disk diameter in microns 6. The FWHM is 0.422 times the diameter of the Airy disk in arcseconds To calculate the Strehl ratio a similar procedure is used. 1. Based on system data in Setup menu, calculate theoretical unobscured Airy disk diameter ( = 2.44 * 0.6 microns * F number) 2. Calculate ratio of pixel width (7.4 microns) to Airy disk 3. Using Table 1, calculate how much energy should have been on one pixel 4. The Strehl ratio = 100* measured fraction/ calculated fraction that should have been on one pixel
Table 1: Fraction of counts on a single pixel
Airy Disk Calculation Alan Holmes 12/16/99 Size of Pixel Width (Relative to Airy disk) 0.05 0.15 0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95
Numerically Calculated Fraction of energy on one pixel 0.013 0.115 0.290 0.494 0.682 0.825 0.921 0.970 0.985 0.992

Adj Filter Shtr:0, 7.5%

3.15V Pass
In this example the following information is displayed:
Adj filter 3.15V Shtr:1, 7.5% You are in the Adjust Filter mode The sensor voltage is 3.15 volts (range is 0 to 5 volts) Shutter (Filter wheel) is moving, 1 and 0 are displayed alternately as the sensor sees the marks. The position is within 7.5% (acceptable range is 2.5% to 15% and 7.5% +/- 2.5% is nominal) The shutter wheel is working correctly and does not need adjustment (pass or fail)
If the alphanumeric display reads "Fail" instead of "Pass" then you should make the following adjustment: Turn the right hand rotary knob to adjust the voltage value up or down until the shutter position ("Shtr") falls within the acceptable range of 2.5% to 15%. Try to get it as close to 7.5% as you can.

Appendix F Menus

[Power On] |___ Set Date / Time [Set Up] |___ Date / Time |___ CCD Temp |___ Grid |___ Night Vision |___ Filter |___ Units |___ Focal Len. |___ Aperture Diam. |___ Telescope |___ Mag. Corr. |___ Site |___ Beep |___ Adj Filter |___ Video |___ Mode | |___ NTSC | |___ Int PAL | |___ Ext PAL | |___ Off | |___ Date / Time |___ TEST PTRN |___ GRAY SCALE [Focus] |___ Sensitivity |___ Zoom | |___ Zoom | |___ Normal | |___ Wide | |___ Subframe |___ Full |___ Partial [Image] |___ Image Setup |___ Exposure |___ Gain |___ Zoom |___ Dark Sub. |___ Mode | |___ Continuous | |___ Snap | |___ Track & Accumulate | |___ Mosaic (Sm) | |___ Mosaic (Lg) | |___ Best Sharp | |___ Best Peak | |___ Auto Grab | |___ Auto Grab Interval [Monitor] |___ eFinder | |___ Exposure | |___ Zoom | |___ Flip | |___ Optical Quality |___ Drive (fast) |___ Drive (slow) |___ Seeing (DIMM) [Display/ Crosshairs] |___ Auto contrast |___ Adjust Image |___ Select Back. |___ Select Pos. 1 |___ Select Pos. 2 [File Ops] |___ Save |___ Recall |___ Download |___ Download All |___ Slide Show |___ Erase One |___ Erase All |___ Baud Rate |___ Test Comm [Calibrate] |___ Mode | |___ Auto | |___ Full Menu | |___ Exposure | |___ Calibrate Time | |___ Relays | |___ Move |___ View Results [Track] |___ Mode |___ Auto |___ Full Menu | |___ Exposure | |___ Guide to | |___ Selected star | | |___ Last position | |___ Cursor | | | |___ Aggressiveness (X) | |___ Aggressiveness (Y) | |___ Relay Tone

Appendix G Glossary

Antiblooming Gate - When a CCD pixel has reached its full well capacity, electrons can effectively spill over into an adjoining pixel. This is referred to as blooming. The Antiblooming gate can be used to help stop or at least reduce blooming when the brighter parts of the image saturate. Astrometry - Astrometry is the study of stellar positions with respect to a given coordinate system. Autoguider - All SBIG CCD cameras have auto guiding or "Star Tracker" functions. This is accomplished by using the telescope drive motors to force a guide star to stay precisely centered on a single pixel of the CCD array. The camera has four relays to control the drive corrector system of the telescope. The CCD camera head is installed at the guide scope or off axis guider in place of a guiding eyepiece. CCD - The CCD (Charged Coupled Device) is a flat, two dimensional array of very small light detectors referred to as pixels. Each pixel acts like a bucket for electrons. The electrons are created by photons (light) absorbed in the pixel. During an exposure, each pixel fills up with electrons in proportion to the amount of light entering the pixel. After the exposure is complete, the electron charge buildup in each pixel is measured. When a pixel is displayed at the computer screen, its displayed brightness is proportional to the number of electrons that had accumulated in the pixel during the exposure. Dark Frame - The user will need to routinely create image files called Dark Frames. A Dark Frame is an image taken completely in the dark. Dark Frames are subtracted from normal exposures (light frames) to eliminate fixed pattern and dark current noise from the image. Dark Frames must be of the same integration time and temperature as the light frame being processed or numerous hot and cold occur. Dark Noise - Dark Noise or Dark Current is the result of thermally generated electrons building up in the CCD pixels during an exposure. The number of electrons due to Dark Noise is related to just two parameters; integration time and temperature of the CCD. The longer the integration time, the greater the dark current buildup. Conversely, the lower the operating temperature, the lower the dark current. This is why the CCD is cooled for long integration times. Dark noise is a mostly repeatable noise source, therefore it can be subtracted from the image by taking a "Dark Frame" exposure and subtracting it from the light image. This can usually be done with very little loss of dynamic range. Double Correlated Sampling - Double Correlated Sampling (DCS) is employed to lower the digitization errors due to residual charge in the readout capacitors. This feature results in lower readout noise. FITS Image File Format - The FITS image file format (which stands for Flexible Image Transport System) is a common format supported by professional astronomical image processing programs such as IRAF and PC Vista. CCDOPS can save image files in this format but can not read them. Flat Field - A Flat Field is a image with a uniform distribution of light entering the telescope. An image taken this way is called a flat field image and is used with CCDOPS to correct images for vignetting. Focal Reducer - A Focal Reducer reduces the effective focal length of an optical system. It consists of a lens mounted in a cell and is usually placed in front of an eyepiece or camera. With the relatively small size of CCDs compared to film, focal reducers are often used in CCD imaging.

4. If your mount is stable, try longer exposure times while tracking to average out the atmospheric effects. Q. What do I do if my CCD frosts? A. If your camera starts to frost after a year of use it's time to replace the desiccant as described in Appendix B, page 47. Q. The moon is too bright, what do I do? A. Try using the built-in lunar filter (Select Filter "On" in the Setup menu) and use a very short exposure. If the moon still saturates try using an aperture mask to cut down the light entering the telescope or or insert a neutral density (or any dark filter) in the STV's nose piece. Q. Why are my images grainy looking and not smooth? A. The grainy look is from low signal to noise. A longer integration time will increase signal and reduce graininess. A focal reducer will also help. Try doubling exposure times. This works up to a point where you begin picking up sky background (light pollution) which limits maximum practical integration times. Also make sure your cooler is running at 70% capacity or more. Q. What are the advantages of shorter focal lengths and faster F# telescopes? A. Shorter focal lengths increase the field of view, allowing you to image larger objects. Faster F# telescopes increase the field of view and shorten the exposure times. Do not underestimate the benefits of focal reducing your f/10 SCT systems!

12VDC, 3, 43

Dark Frame (def), 56 Dark Noise (def), 56 Dark Subtract, ii, 18, 19 Date / Time, i, 10, 15, 55 Date displayed, 10 Date/Time, i, 7, 13, 14, 15, 16 desiccant, 47 Display / Crosshairs button, 9 Double Correlated Sampling (def), 56 Download, ii, 1, 27, 29, 38, 39, 40, 41, 42, 55 Drive Accuracy, 50 Drive Monitor, ii, 21, 24
Aggress, 34, 35 aggressiveness, 34, 35, 36 Alphanumeric display, 9 antiblooming, 56 Antiblooming Gate (def), 56 Aperture Diameter, i, 14, 16, 41 Assembly, 3, 4, 5, 6 astrometric measurements, 56 Astrometry (def), 56 Auto Grab, ii, 1, 18, 19, 21, 55 Autoguider (def), 56 Autoguiding, 7 Average error, 35
Edit Data, ii, 38, 39, 40, 41, 42 eFinder, ii, 1, 5, 6, 7, 8, 10, 21, 22, 23, 48, 55 eFinder Assembly, 5, 6 Erase All, 27, 30, 55 Erase One, 27, 30, 55 Establish Link, ii, 40 Expansion slot is not used at this time., 3 Exposure, ii, 7, 9, 18, 19, 22, 32, 34, 43, 52, 55
Back Panel, 3 background, 10, 26, 40, 50, 53, 57, 60 Battery Operation, 43 Baud Rate, ii, 27, 31, 40, 55 Beep, i, 14, 16, 55 Best Peak, ii, 18, 19, 20, 21, 55 Best Sharp, ii, 18, 19, 20, 55 bit depth, 38, 43
Features, 1 File I/O, 38 File Ops, 27 File Ops button, 9 File Ops Menu, 27 Filter, 1, 7, 14, 16, 36, 54, 55, 60 FITS format (def), 56 Flat Field, ii, 41, 53, 56 Flat Field (def), 56 Focal Length, 14 focal reducer, 5, 48, 60 Focal Reducer (def), 56 Focal Reducer Assembly, 5 Focus, 17 Focus button, 7, 9, 17 focus display, 17 Frame Transfer CCDs (def), 57 Full Well Capacity (def), 57 Fuse, 45 FWHM, 23, 25, 49, 50, 51, 52

ASTRONOMICAL INSTRUMENTS

SANTA BARBARA INSTRUMENT GROUP P.O. Box East Valley Road, Suite #33 Santa Barbara, CA 93150 Phone (805) 969-1851 FAX (805) 969-4069 e-mail:sbig@sbig.com home page:www.sbig.com
Application Note Supporting SBIG Images from the STV
Introduction This Application Note describes how to support STV Images created by SBIG's STV Server and CCDOPS software. A future Application Note will describe the hardware and software interface to the camera. The STV is a new genre of CCD camera, offering video display with high-speed readout (10 frames per second), exposure times from 1 millisecond to 600 seconds, stand-alone autoguiding and imaging with built in Track and Accumulate1 and telescope diagnostic utilities. In a breath it's bitchn'. So much for the marketing. SBIG STV Images The first line in the header for SBIG format STV images shows "STV Image" or "STV Compressed Image" depending on whether the image is uncompressed or compressed, respectively. Additionally, since the image header uses integers for the Exposure and Each_exposure fields and these are in units of hundredths of a second (10 milliseconds), the image header for STV images will show exposures of less than 10 milliseconds as 10 milliseconds. To allow determination of the actual value for these fields, the User_2 field may have (not guaranteed to be there) the format:
User_2 = Exposure = XXX.XXX, Each_exposure = XXX.XXX
Where the exposures, in seconds, are show in floating point format. Also note that at this time, SBIG uses User_1 to indicate the Software and Version that captured the image and that User_4 is the format:

User_4 = Y2KYear = XXXX

To specify the full (4 digit) year the image was acquired. For compatibility with various SBIG readers, the year shown in the Date field only contains 2 digits.
Track and Accumulate covered by SBIG US Patent 5,365,269 October 6, 1999