Diffraction SBIG STC-428-OEM, User Manual

Page: 19 / 44

SBIG STC-428-OEM CAMERA
USER’S MANUAL
19
For this introductory imaging procedure, set the following:
•
Autosave Filename : Enter the base filename (e.g. “ Area A ”) you want to
use for the sequence of images. Each image file taken will use this
name, appended with an individual frame number, for example,
"Area A-001.fit".
•
Dither : Off
•
Delay First : Specify a delay time (in seconds) prior to taking the first
exposure, if desired.
•
Delay Between : Specify a delay time (in seconds) between exposures, if
desired.
•
Click the Slot 1 button and configure each of the parameters on the line
as you require. The Repeat parameter allows you specify how many of
these particular exposures will be taken. An optional Suffix can also be
automatically applied to the end of the filename to aid you in
identifying subgroups of images later on. For example, if you add a
suffix of "a", this will produce a filename such as "Area A-001a.fit". If
you use only one imaging slot for your custom sequence then you
don’t
really need a suffix. However, if you set up multiple slots then you
must add a suffix, and each suffix must be unique. You can configure
up to 32 slots when setting up an Autosave sequence.
•
Click OK when you are finished configuring the sequence.
8. To begin the custom sequence, ensure that the Autosave radio button is
selected and click Start . You can end the Autosave sequence at any time
prior to its completion by pressing Stop .
2.3 StackPro
TM
Subexposure Function
The subexposure function allows you to increase the effective dynamic range of
the camera. It works by taking a series of shorter exposures, and then
numerically summing them internally to the camera. Since the STC-428-OEM
has very low read noise, this greatly increases the camera's dynamic range
while only modestly increases the total read noise in your image. Due to the
very fast readout speed of the CMOS sensor, the extra time required is
negligible.
As an example, when using the
Medium Gain mode the camera can record
about 10,000 photoelectrons before saturating, corresponding to a readout
value of 4095 (12 bits). The read noise is approximately 2.5 electrons.
If you mathematically stack 16 individual
Medium Gain exposures the total
number of photoelectrons that can be recorded increases 16X, but the readout
noise only increases 4X. The read noise is now 10 electrons, and the stacked
exposure can record 160,000 electrons, corresponding to a readout value of
65,535 (16 bits).