Santa Barbara Instrument Group ST-8300M User manual

Model ST-8300M/C
CCD Camera
Operating Manual
Santa Barbara Instrument Group
147A Castilian Drive
Santa Barbara, CA 93117
Phone [phone] •Fax [phone]
Email sbig @ sbig . com •Web www . sbig . com

ST-8300 Operating Manual v. 1.2
December 2009
Very Important:
Before you attach the ST-8300 to your computer for the first
time you MUST install the software as described Section 2.
Note: This equipment has been tested and found to comply with the limits
for a Class B digital device pursuant to Part 15 of the FCC Rules. These
limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates,
uses, and can radiate radio frequency energy and if not installed and used in
accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not
occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by
turning the equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the receiver and the equipment.
• Connect the equipment into an outlet on a circuit different from
that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.
• Shielded I/O cables must be used when operating this equipment.
• You are also warned, that any changes to this certified device will
void your legal right to operate it.

Page i
Table of Contents
1. Introduction .....................................................................................................1
Getting Started.............................................................................................. 1
Overview and Connections...........................................................................3
2. Installing the Software.....................................................................................4
Installing the Software on 32-bit Windows Systems....................................4
Installing the Software on 64-bit Windows Systems....................................7
Migrating Old Drivers from 32-bit to newer 64-bit Systems...................... 10
3. Using the Camera Inside...............................................................................13
Running CCDOps....................................................................................... 13
Getting Help............................................................................................... 13
Brightness and Contrast.............................................................................. 16
Establishing a Link..................................................................................... 17
Camera Info................................................................................................ 18
Camera Setup ............................................................................................. 19
Grab Command .......................................................................................... 20
Focus Command......................................................................................... 21
4. At the Telescope............................................................................................. 24
Finding and Centering the Object............................................................... 25
Taking an Image......................................................................................... 26
Further Adventures..................................................................................... 26
5. Accessories for your CCD Camera............................................................... 27
Color Filter Wheel...................................................................................... 27
Battery Adapter .......................................................................................... 27
Camera Lens Adapters................................................................................ 27
Electromechanical Relay Adapter Box....................................................... 27
6. Glossary..........................................................................................................29
Appendix A – Connector and Cables................................................................... 33
Power Jack.................................................................................................. 33
Telescope Jack............................................................................................ 33
Appendix B – Maintenance................................................................................... 34
Cleaning the Window and Filters............................................................... 34
Replacing the Desiccant ............................................................................. 34
Appendix C – Camera Specifications...................................................................36
Appendix D – ST-8300CM Color Camera Supplement...................................... 37

SBIG ST-8300 Manual
1
1. Introduction
Congratulations and thank you for buying one of our ST-8300 cooled CCD
cameras. The ST-8300 has the following features:
• Uses Kodak’s microlensed, blue enhanced KAF-8300 CCD with
3326 x 2504 pixels, 5.4 micron square pixels.
• 16-bit A/D converter with correlated double sampling running at
1.7 megahertz.
• Temperature regulated Thermo-Electric (TE) cooling with 35C
delta for reduction in CCD dark current.
• Single board, small, compact design with internal shutter allowing
exposures down to 0.1 seconds that makes taking dark frames a
trivial task.
• USB 2 interface yielding up to 1.7 megapixels per second
digitization rates but full backward compatibility with USB 1.1
computers at 400 kilopixels per second.
• Input power requirements of 10.0 – 14.5 Volts DC at 3 Amps
through the new locking style center-positive power jack.
• Telescope interface with four optically isolated normally open
signals on the industry standard RJ-11 jack.
• T-Thread based mechanical interface that supports a variety of
nosepieces and adapters.
• Optional external filter wheels with choice of filters.
• Powerful yet intuitive CCDOps software for image acquisition and
processing.
Getting Started
In addition to this truly fine Operating Manual, the ST-8300 package
includes the following items:
ST-8300 Camera – The camera body is approximately 4 x 5 x 2 inches
with a T-Thread adapter on the front cover.
2 Inch T-Thread Nosepiece – This screws into the front of the camera for
telescope work and includes a soft rubber cap for keeping out the
dust when not in use. Optional Visual Back adapters are available
from SBIG. In addition a screw-in T-to-C adapter is available for
use with C-Mount camera lenses or C-Mount adapters.
Power Supply – The camera come with a 12V/3 Amp DC power supply
Outside the US the camera may be supplied with a Battery Clip
adapter.

SBIG ST-8300 Manual
Extremely Important! In the past SBIG has shipped products like
the STV, ST-5C and ST-237/A that used a 12-Volt, Center-
Negative power supply. Starting with the ST-402 series of
cameras we switched to Center-Positive 12-Volt power supplies.
How do you know the difference?
All 12-Volt, Center-Positive power jacks and receptacles are
locking with a threaded collar. Don’t ever try to mate an
unthreaded power supply to a threaded camera or vice-versa.
USB Cable – Included is a 15-foot, USB 2 certified, A-to-B type, USB
cable. USB has a limit of 15-feet but the range can be extended
with active boosters. Relatively low-cost (~$30) 15-foot boosters
that can be strung together are available from such sources such as
<www.usbgear.com>. Long haul boosters (more expensive) are
available from <www.icron.com>. Also note that putting a hub at
15 feet will allow you to go another 15 feet.
Tracking Cable – This cable looks like a simple “RJ-11 telephone cable”
but in fact is a “6-pin reversed RJ-11 telephone cable”. Telescopes
require 6-pin autoguider cables and reversed means that unlike
ordinary phone cables, this one flips the order of the wires. You
can tell a tracking cable from an ordinary cable by noting that with
tracking cables the tines that lock the RJ-11 jack into the receptacle
are both on the same flat side of the cable or when the ends are put
side by side the colored wires inside are in opposite order on the
two connectors.
Rack Handles and Attachment Screws – Rack handles are provided to
give a more steady grip when wearing gloves or for attaching a
safety strap to prevent damage to the camera if it should fall from
the scope. Not everyone wants or needs these handles, however,
so installation is left to the owner's discretion. To install the
handles, remove the back cover and pass the 4 socket-head screws
through the cover into the base of the handles and tighten with the
9/16 in hex wrench provided.
Software – We include several CD-ROMs with the ST-8300 but the most
important one is labeled “SBIG Software and Catalog”. This
disc contains the drivers and CCDOps software you’ll need to use
the camera.
Very Important:
Before you attach the ST-8300 to your computer for the first
time you MUST install the software as described below
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SBIG ST-8300 Manual
Overview and Connections
GUIDE PORT: This is where you connect the supplied 6 conductor
modular phone style cable to the Autoguider (sometimes labeled "CCD")
input port on your mount when using the ST-8300 as an autoguider, or
when using Track & Accumulate with mount corrections (see the CCDOPS
Manual for details of this mode
POWER: Plug in the power supply here, or attach any 12VDC power
source (10 - 14V) that provides 3 amps minimum. The power supply that
comes with the camera will operate from 100 - 240VAC and provides 3.5A
at 12VDC. (Note that while an ST-402 power supply will fit, it does not
provide the current required by the ST-8300 to operate properly)
USB: Attach the 15 foot USB cable to any USB port on your computer
AFTER you have installed the drivers and software for the ST-8300.
I2C: This special port is for connection of an SBIG filter wheel. The filter
wheel will get its power and commands through this port. No other cables
are needed for the filter wheel to function. (Note: This is NOT an RS-232
port. Connecting serial devices or your PC to this port may damage them or
the camera.)
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SBIG ST-8300 Manual
4
Installing the Software o 32-bit Windows Systems
This secti stem.
2. Installing the Software n
on describes how to install drivers on a 32-bit Windows sy
Note: If you are installing the camera drivers on a 64-bit Windows
System, skip this section and follow the instructions in the next section.
Don’t plug the camera into the computer until instructed to do so below and
please follow the instructions carefully.
1. Disable Driver Signing – Windows XP adds an extra level of security
to installing drivers that will complicate our installation. To disable it
open the Control Panel in the Start Menu, select System and then select
the Hardware tab. Click the Driver Signing button and in the dialog
that appears select Ignore then click OK. Click OK one more time to
close the Control Panel.
2. Insert the SBIG Catalog and Software CD-ROM in your com uter
and on most systems the installer program will automatically start. If it
doesn’t, explore the CD-ROM drive and double-click on the
autorun.exe icon. Then click on the Setup a New Camera button.
Install CCDOps – Click on the Install CCDOps button to install it
p
3. on
your computer, and then follow the on-screen instructions. CCDOps is
our powerful yet simple-to-use image acquisition and image processing
software and we’ll use it extensively throughout this manual.
Install the Driver Checker – Click on the Install Driver Che4. cker
button to install it on your computer and then follow the on-screen
instructions. The Driver Checker is a utility program that installs and
maintains the drivers that are required for operating the ST-8300 under
the Windows Operating System. At the end of the install when you are
given the option to launch the Driver Checker. Check that option.
When the Driver Checker starts it will ask you if you have an Intern5. et
Connection on this machine. If you do then answer Yes otherwise
answer No. The Driver Checker will install the camera drivers and at
this point all your drivers should all be current:

SBIG ST-8300 Manual
6. We’ve finished installing the drivers but now we need to bind them to
the ST-8300. Quit the Driver Checker by clicking the X in the
upper-right hand corner. If you’re running Windows XP then continue
with step 7 below. Users of older versions of Windows should now
look for instructions particular to their version of Windows in the
“Installing USB Drivers” Application Note that can be found on the
CD-ROM or our web site.
7. Now’s the moment you’ve been waiting for. We’re going to plug the
camera into the computer, but not so fast!
First plug the camera into the power source and note that the Fan
comes on but the Red LED does not. The ST-8300 actually has its
internal firmware downloaded to it by the PC at startup. If the LED is
off the camera has not been booted. Please remember that.
Now plug the camera into the USB port on the computer with the
supplied USB cable. Remember which port you’re using because
you’ll want to use the same port again next time or you’ll have to go
through this process of binding the drivers all over again. Windows
will crunch for a while and then present you with the Found New
Hardware Wizard (Wizard) dialog.
8. If you’re asked if it should connect to Windows Update to search for
software click “No, not this time”, then click Next.
9. Now the Wizard will ask you if you want to install the software
automatically. Select to do so then click Next.
10. Windows will grind for a while copying the SBIG ST-402 Loader
driver then show you the Completing the Found New Hardware
Wizard page (The ST-8300 and ST-
402 use the same drivers, so this
message is OK). Click Finish. At
this point the Red LED on the back of the camera should be on, and if
you had been watching it you would have seen it blink several times
while the PC was booting the camera.
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SBIG ST-8300 Manual
11. After booting the camera Windows will bring up another copy of the
Wizard. The ST-8300 actually uses two drivers. One to boot the
camera and one to talk to it after it’s booted. We now need to walk
Windows through installing the second driver.
12. Repeat steps 8 and 9, again telling the FNHW to not check for updates
and to install automatically. At this point windows will show you the
Select the best match page:
13. Select the oem file not the sbig file (the second item above) by clicking
on it then click the Next button.
14. Windows will grind one last time copying the SBIG USB Camera
driver then show you the Completing the Found New Hardware
Wizard page.
Click the Finish button and pat your
self on the back. You’re done!
If you ever doubt that the camera is actually connected you can open the
Device Manager from the Hardware tab of the System control panel and
expand the Universal Serial Bus controllers section. You should see a
SBIG USB Camera listed there:
While you’ve got the System Control Panel open, if you want to restore the
Windows Driver Signing security check, click the Hardware tab, click the
Driver Signing button and select:
If Windows can not automatically find the drivers , tell it to Install from a
Specific Location and then browse to the folder:
C:\Program Files\SBIG\Driver Checker\SBIG Drivers
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SBIG ST-8300 Manual
Installing the Software on 64-bit Windows Systems
This section tells you how to do a fresh install of 64-bit drivers for SBIG
Cameras on your 64-bit Versions of Windows XP or Windows Vista.
1. Make sure no SBIG cameras are attached to your system.
2. Make sure your account has Administrator privileges then run the
SetupBitDriverChecker64.exe program to install the 64 Bit compatible
SBIG Driver Checker application on your system.
3. On Vista based systems, find the icon for the SBIG Driver Checker by
opening the Start menu and typing SBIGDriver in the search box. The
icon should appear above the search box. Right click the icon and
select Properties then click the Compatibility tab. Click the “Run this
program as an administrator” as shown below and then hit the OK
button.
Note: Under Vista there are 2 levels of administrator privileges: one at
the account level and one at the program level. To properly install the
drivers the Driver Checker application requires both.
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SBIG ST-8300 Manual
4. Run the Driver Checker application and it will ask you about any ST
Series Cameras (ST-7/8/9/10/2K) you may plan on using. Prior to
2006 the ST Series cameras had only an internal Tracking CCD. We
call this the Classic Model. In 2006 we added the Remote Guide Head
capability to the ST Series and we call it the Pro Model. The Driver
Checker needs to know whether your ST Series camera is a Classic
Model or a Pro model.
5. After answering the Classic/Pro question above you'll see the following
dialog. The list of drivers shown may be different on your system but
it will generally indicate that no Installed Drivers were found and that
they all need to be updated.
6. Click the Update button and the Driver Checker will start to install the
SBIG drivers into your system.
7. Once the drivers have finished installing, the Driver Checker will show
the following. At this point you can quit the Driver Checker.
8

SBIG ST-8300 Manual
8. Now it's time to try out the new drivers. With your camera
disconnected from the PC, power it up and then plug it into the PC with
the USB Cable. In the lower-right hand corner of the screen you see
something like:
Followed by:
9

SBIG ST-8300 Manual
9. If for some reason the Add New Hardware Wizard asks you to
manually locate the drivers then navigate to the proper directory under
the Driver Checker directory in the Program Files or Program Files
(X86) directory. There are 4 possibilities and you must choose the
correct set of drivers. There are directories for 32 Bit and 64 Bit
drivers, based upon you version of Windows and under them
directories for Classic and Pro model cameras.
10. At this point the fan in the camera should come on and the camera
should show up in the Device Manager as shown below:
11. Run CCDOps and verify that you can establish a link to the camera.
Note: If you previously installed SBIG 32-bit drivers using the old 32-
bit Driver Checker program and now want to install 64-bit drivers
over the old installation, follow the procedure outlined below:
Migrating Old Drivers from 32-bit to newer 64-bit Systems
This section describes how to migrate drivers from the old 32-bit only
DriverChecker to the new 32/64-Bit Compatible DriverChecker64.
1. Uninstall the old DriverChecker software.
a. Run the Add or Remove Programs Control Panel in the
Start menu.
b. Click on the SBIG Driver Checker entry and then click
on the Change/Remove button.
2. Manually delete the old drivers files from the disk.
a. Delete the following files from the
C:\Windows\System32\Drivers directory:
sbigfldr.sys, sbiguldr.sys, sbiglldr.sys, sbigusbe.sys,
sbigusbi.sys
Some of these may not exist on your system but delete the
ones that do.
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SBIG ST-8300 Manual
3. Manually delete the old drivers files from the Device Manager.
a. In the Start menu, point to All Programs, point to
Accessories, and then click Command Prompt.
b. At the command prompt, type the following command ,
and then press ENTER:
set devmgr_show_nonpresent_devices=1
c. Type the following command a command prompt, and
then press ENTER:
start devmgmt.msc
d. In the View menu select the Show hidden devices
command.
e. Expand the Universal Serial Bus controllers section by
click on the adjacent “+”
f. For each of the items listed below, right click on the item
then select Uninstall:
”SBIG USB Camera", ”SBIG ST-402 Camera", “SBIG
USB Loader", “SBIG ST-L Loader", “SBIG ST-402
Loader"
g. Quit the Device Manager.
4. Install the new DriverChecker64 software.
a. Use the installer that came with your camera or download
it from our web site:
<www.sbig com>
5. Run the DriverChecker64 software.
a. From the Start menu select the DriverChecker64 item in
the SBIG folder.
b. Answer the question about your ST cameras.
6. Click the Update button to copy the new drivers to your system.
Link your old cameras to the new drivers.
a. For each type of SBIG Camera you own (ST, STL, ST-
402), power up the camera one at a time and then attach it
to the PC with the USB cable.
b. When the Add New Hardware Wizard comes up select
“No, not this time” when it asks if it can connect to
Windows Update then click Next.
c. Select “Install the software automatically” and click
Next.
d. If Windows asks you for the best match select any of the
entries with Version 2.41.0.0 then click Next.
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SBIG ST-8300 Manual
e. Click Finish and then you’ll have to go through steps b
through done more time for this camera.
f. Repeats steps athrough ffor each SBIG camera.
When you’re all done your camera should show up in the Device Manager
in the SBIG USB Devices section as shown below:
Updating CCDOps and Drivers
We are constantly adding new features and fixing software bugs in our
software, which is available for free download from our web site. You
should periodically visit our website to check for updated versions of the
CCDOps software and you should also periodically run the Driver Checker
to download and update your drivers. To find the latest software and
drivers, go to:
http://www.sbig.com -> Software Downloads
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SBIG ST-8300 Manual
3. Using the Camera Inside
When you first receive the ST-8300 it’s wise to get acquainted with its
operation inside the house where it’s warm and not to try to fight the
telescope operation in the dark. We’ve included a brief tutorial below to get
you acquainted with the ST-8300 and the CCDOps software.
Running CCDOps
Once installed, it’s easy to run CCDOps from the Windows Start menu.
Click the Start Menu, then find the SBIG Folder, which under Windows
XP is under the All Programs section. Finally click the CCDOps Icon to
start the program. You’ll be presented with the startup About Dialog that
shows the SBIG logo and the version of CCDOps. To dispense with it click
anywhere in the dialog other than the two blue fields or simply wait and the
dialog will close itself.
Getting Help
CCDOps includes an extensive help file that can be accessed through the
Help Topics item in the Help menu. In addition many of the
dialogs have an embedded Help button that will take you to the
Help Topic for that specific command. Just remember, help is
always just a click away.
Opening and Inspecting Dark Frames
We’ve included some sample images on the SBIG Software and Catalog
CD-ROM to get you acquainted with what you should expect from your
camera.
First, let’s look at what is called a dark frame. In the File menu use
the Open command and then navigate to the CD-ROM’s Images directory.
Double-click on the ST-8300 Tutorial folder to show its contents. Finally
double-click on the Image 1 – Sample Dark Frame icon to open the image.
CCDOps will present you with a dialog listing all the parameters
associated with the image such as the Exposure Time, the Date and Time
the image was acquired, etc. Note that the Exposure Time was 1.0 second.
Spend some time inspecting the data then click in the dialog to close it.
Data like this is always attached to saved images and you can show it
using the Parameters command in the Display menu. After the Image
Parameters dialog has gone you’ll see the image displayed in its own
window and the Contrast dialog will appear. The image is shown below:
13

SBIG ST-8300 Manual
This is what’s referred to as a dark frame and it’s what you get when you
take a picture with the nosepiece covered and the shutter closed. It’s a
picture in the dark. Although there’s not much interesting to look at in this
image there are some very important features that you need to understand.
The first thing you’ll see is that while the image looks mostly like salt
and pepper there are hundreds of bright specks. These are called hot pixels.
They are present in every CCD image to one extent or another, even in
images from our most expensive cameras. If your digital snappy camera
didn’t automatically remove them for you, they would be seen in those
images too.
What causes hot pixels? It’s an attribute of CCD sensors called dark
current. A pixel in an ideal CCD, in the absence of light, would maintain a
steady value. When exposed to light the pixel’s value would increase in
response to the light but then as soon as the light went away the pixel would
maintain its value again.
In the real world CCD pixels suffer from the affects of dark current
whereby the pixel’s value slowly increases (brightens) over time. All the
pixels in the image shown above have some component of their signal due
to the build up of dark current.
Dark current builds up over time in a linear fashion but cooling the
CCD can reduced the rate at which it accumulates. For example, cooling
the CCD by 25°C reduces the dark current 16-fold. That’s why
Astronomical CCD cameras are cooled – to reduce the dark current when
imaging very faint objects.
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SBIG ST-8300 Manual
15
Hot pixels are simply the pixels where the dark current is higher than
the average and thus they show up as white specs against the salt and
pepper background. Again, this is completely normal for CCD images.
The second effect you’ll notice is a brightening on the left of the image,
as if something bright was just outside the field of view. This is called the
readout glow and is caused by the electronics in the CCD, in particular by a
very small but ever present glow emanating from in the on-chip amplifier
that conditions the weak signals in the CCD so that they may be digitized.
The readout (or digitization) of images from CCDs is a sequential
process whereby every pixel is digitized one-after-another until the whole
image has been digitized. The readout starts at pixel (1,1) in the top-left
corner and proceeds to pixel (3326, 2504) in the lower-right hand corner.
As each pixel in a row is readout the pixels to the right of it within the same
row are shifted to the left one position in preparation for the next pixel
readout. The next pixel is then readout and the process repeated until every
pixel in the first row has been digitized.
At this point the whole CCD is shifted up one row and digitization
starts with the left-most pixel of the second row. The readout glow on the
left of the images is a buildup of light from a glow from the preamplifier
structures in the upper-left hand corner of the CCD while rows are queuing
up for readout.
The final effect you’ll notice is the salt-and-pepper look of the
background. What you’re seeing here is the ultimate noise floor of the
CCD whereby adjacent pixels have slightly different values due to noise in
the CCD and readout electronics. The noise in dark frames that have a zero
exposure time is referred to as the read noise of the camera.
Fortunately for us there are very simple image processing techniques
we can use to eliminate the effects of dark current and readout glow.
Let’s open another image. Close the first image by clicking the X in
the upper-right corner then use the Open command in the File menu again
but, this time double-click on Image 2. Note in the Image Parameters
dialog that this image had an Exposure Time of 10 seconds. Click in the
dialog to close it.
Now this image has a whole lot more hot pixels! That’s because this
exposure was 10 times as long and the pixels built up 10 times the dark
current. It’s hard to even see the background through all the hot pixels.
About this time you’re probably asking yourself “How can I ever take
deep sky images with all these hot pixels?” The answer is simple. Because
the build up of dark current at a given CCD temperature is a repeatable
effect you can remove the effects of dark current by taking two images, one
with the shutter open (light frame) and another of equal exposure with the
shutter closed (dark frame). You then subtract the dark frame from the
light frame, and because the hot pixels and the readout glow repeat from
one image to another they are removed by the subtraction.
Let’s see how this works. Close Image 2 and Open Image 3, which is
a 10-second light frame where you can get a hint of the object but the hot

SBIG ST-8300 Manual
pixels are definitely obscuring it. Now use the Dark Subtract command in
the Utility menu. This brings up the Open File dialog where CCDOps
wants you to select which image to subtract. Double-click on Image 2, the
10-second dark frame. The displayed image turns completely black! What
did we do? Did we destroy the image by dark subtracting? No we didn’t
but it’s time to learn something else regarding CCD images.
Brightness and Contrast
Images from the ST-8300 are 16-bit images meaning any pixel can have
values from 0 to 65,535 ADU where ADU is short for A/D Converter Units.
Said another way this means there are 65,536 possible brightness or gray
scale values that each pixel can have. In CCD lingo this is referred to as the
dynamic range. But computer monitors and our eyes can typically only
distinguish a hundred or so different gray scale values. How do we
accommodate the large dynamic range of CCD images with our computer?
The answer is through Brightness and Contrast adjustments of the
displayed image.
Getting back to our dark subtracted image and why it’s completely
black. Find the Contrast dialog shown
to the right and then click the Auto
checkbox. Magically our object
appears, and as promised, the hot pixels
and the readout glow are gone, replaced
by the object and the salt-and-pepper
noise. What did we do?
16
Click the small up and down buttons adjacent to the Back
several times and you’ll see the overall image brightness increase
By clicking the Auto checkbox we
told CCDOps to adjust the image
display to match the actual image’s
pixel values. Auto Contrast is a very
handy tool to have in your bag of tricks.
Just for fun click the Smooth checkbox in the Contrast dialog. The
noise in the image is greatly reduced. The Smooth option is handy when
for reducing the noise in underexposed images like Image 3.
Let’s explore the Contrast dialog further. Close the dark subtracted
Image 3 and when CCDOps asks you if you want to save the changes
you’ve made click No. Use the Open command again to open Image 4,
which is just like Image 3, but with a proper exposure.
The first thing to notice is that in the Contrast dialog the Back is set to
8,000 and the Range is set to 20,000. What does that mean? In short it
means that pixel values from 8,000 (Back) to 8,000+20,000 (Back +
Range) have been displayed using the monitor’s available gray scale.
Pixels with values 8,000 ADU or below are completely black. Pixels with
values 8,000+20,000=28,000 ADU or above are completely white. Finally,
pixels with values between 8,000 and 28,000 are shades of gray.
setting

SBIG ST-8300 Manual
17
and decrease. Click the ones adjacent to the Range setting and you’ll see
the image contrast increase and decrease. Here’s a summary of how this
works:
Increasing the Back decreases the image brightness and vice-versa.
Increasing the Range decreases the image contrast and vice-versa.
Set the Back to 8,000 and the Range to 20,000 by typing in the fields
(without the comma) and then hit the Apply button to get us back to where
we started. When you manually enter values in the Back and Range you
must hit Apply to see the effect.
Let’s learn a little more about the controls in the Contrast dialog. Click
the Invert checkbox and notice that the image now looks like a negative.
For images of faint objects, viewing the image as a negative by clicking
Invert can reveal faint structure.
Unclick Invert and then click Sharpen on and off several times while
looking at the fine detail in the image. With the Sharpen checked it’s
almost as if the focus improves. That’s the effect of Sharpen. It works
great on well-exposed images but tends to increase the noise in faint areas.
The last thing to try in the Contrast dialog is the Mag popup. It’s set to
1:1 but selecting 2:1 or 4:1 zooms in on the image, enlarging the image
display. Selecting 1:2 or 1:4 zooms out on the image. Try the 1:2 and 2:1
settings. You may wonder if all these changes to the Contrast dialog are
destructive to the image data. They are not.
Changes to the settings in the Contrast dialog only affect the way the image
is displayed. They do not modify the actual pixel values.
In Summary
• Clicking Auto is a good place to start with most images.
• Back controls image brightness and Range controls contrast.
• Clicking Invert can help reveal faint detail in images.
• Clicking Smooth can reduce the noise in underexposed images.
• Clicking Sharpen reveals additional detail in well-exposed images.
Establishing a Link
It’s time to actually connect up to your camera and take some images. If
you haven’t installed the drivers already go back to Section 2 and do so
now.
If you’ve taken a break from the tutorial and the camera isn’t powered
up and attached to the computer do so now by plugging in the power source
and then connecting the camera to the computer. At this point the Fan and
LED on the back of the camera should be on.