Automatically connect to selected driver
When SIPS is used to control a fixed observing setup, it is
convenient if it loads all drivers automatically upon startup and
the user needs not to take care about selection of appropriate
drivers. This functionality was added for all connected cameras
earlier, version 3.9 introduces this feature also for other
Calibrate in situ option
SIPS uses image sets each time it has to process multiple
images at once. Handling all images in RAM leads to much faster
processing compared to disk-oriented operations. On the other
side, a lot of memory is needed to keeping many multi-megapixel
The 64 bit version of SIPS
comes handy here, as it is not limited to 2 GB of memory accessible to 32 bit applications. All modern PCs are equipped
with 8 or 16 GB RAM and 64 bit SIPS can use it all.
The most memory intensive operation is calibration, which
creates set of calibrated images in memory in addition to already
loaded raw images. Raw images can be removed from memory
immediately after calibration finishes, but memory consumption
doubles during calibration itself.
New in situ option of the Calibration tool allows it
just to replace original raw image with calibrated one. The memory
footprint remains exactly the same. So, new SIPS version can
handle almost twice as big image sets on the same computer
compared to previous versions.
Because original raw images are modified (replaced
with calibrated versions), any Save operation on individual image
or on the whole set replaces the original raw image file(s) with
calibrated one and original data are lost.
Repeated exposures with main imaging camera
While both Guider and Context camera tools offered the
possibility to perform exposures with defined parameters until
user stops it, the main imaging camera control tool relied on
defined number of exposures to be performed. If the user needed to
performing of repeated exposures, it was necessary to enter some
big number into cont box labeled Repeat, which was not so
Adding a function to repeat indefinitely is not
difficult to program, but it was difficult to find some place for
a GUI control, allowing this functionality, within already stuffed
Exposure tab of the Imager control window. Hopefully SIPS
v3.9 solved this problem by intuitive and elegant way.
The Repeat label was replaced with a check-box
control. If the check-box is unchecked, the tool works exactly
like in previous versions — Start
Exp button performs exposure and if the Repeat control
contains number > 1, it is
decreased and new exposure begins. This repeats until the Repeat
number reaches 1.
Now if the Repeat check-box is checked, number of exposures
control is disabled and exposures are repeated indefinitely (the
Repeat control number is not decreased). Un-checking the check-box
resumes decreasing of the number of exposures until number reaches
Photometry tool updates
Photometry tool underwent numerous bug fixes between version
3.8 and 3.9. These bugs occurred in very specific situations only,
which is why such long time was necessary to fix them. Majority of
users never met a problem, which makes locating of the bug causes
particularly difficult (if the developer cannot reproduce the
error, it is virtually impossible to fix it). Either way, we have
no knowledge about any stability issues in the current
Matching images from arbitrary reference image
New function introduced in Photometry tool is the ability
to choose any image within the processed image set to be a
reference image to which other images are aligned. Prior
versions always used the first image of the set.
The image set alignment code is used also in other
tools, e.g. Image Add or Image Blink. Changes described here
apply also to these tools.
Using of the first image as reference worked well when the
observing session started well after twilight, when sky was
dark and the first image quality was generally the same like
quality of the following images. But in situations when
observing started at twilight (or was affected by clouds,
thick air-mass close to horizon, light pollution etc.) and
first image was of poor quality, matching of later images to
such low-quality first image could cause problems.
SIPS v3.9 starts matching of image set from the image
actually selected in the image set (such image is usually
displayed in the panel and its name is highlighted in the list
box with image names). Only if no image is selected
(highlighted), the first image is taken as reference.
Other Photometry enhancements
When the Field description is sorted according to
variable name, the simple string comparison was replaced
with intelligent comparison, which users know e.g.
from Windows Explorer. In standard string comparison the
name var2 is located after the name var10
because character on the same position 2 is after
the character 1. The new algorithm recognizes when
the name ends with number and if the name prefix text
equals, number values are used for sorting, so var2
is located before the var10, because 2 is less than
Automatically calculated apertures now cannot be
arbitrary small. If the calculated automatic aperture is
less than smallest defined fixed aperture, the smallest
defined aperture is used instead.
When the alignment was invoked on set with one image
only, the OK button remained disabled and the operation has
to be canceled even after the single image was processed.
Despite aligning single image has no sense (only stars are
found within the single image, there is nothing to align),
the operation now performs correctly.
The option Calculate next image stretch using
histogram auto type sometimes worked
When anther image is selected, the field description
table is updated to show whether stars in the field
description were found on newly selected image (stars not
found on active image are listed in red instead of black
General updates and bug fixes
Small updates include:
Numerous parameters of every new image (image opened from
file or read from camera) are calculated prior to its display
(e.g. mean value, standard deviation, extreme pixel values, low
and high stretch limits according to selected Auto type and
image histogram is also calculated). When exposures are take
with exposure time counted in seconds or minutes, time needed to
handle every image is negligible. But if fast camera is used for
video-like observing, time needed to handle every frame limits
While SIPS is not designed to achieve high
frame rates, at last some overhead reduction was introduced when
the Histogram and Stretch tool Auto type is se to
Keep current. No image statistics is calculated in such
case and frame rate is somewhat higher. Still, some
time-demanding operation must be performed either way (e.g.
calculation of histogram).
The Save As option of image set allowed storing
all images under different name as FITS files or exporting them
into common format (PNG, JPG, TIFF, ...). SIPS v3.9 added a
possibility to export whole set also to 16 bit PNG and TIFF formats (only 8 bit PNG and TIFF were supported by previous
The reworked Context camera handling, which kept
capturing parameters like binning and sub-frame between
sessions, sometimes lead incorrect image width and depth of 1
pixel only. Version 3.9 fixes this problem.
ASCOM telescope driver was updated to better cooperate
with common drivers (for instance EQMOD). ASCOM standard
sometimes allows usage of different functions for the same task
(e.g. stop movement in particular axis), but not all drivers
allow usage of all specified functions. This is why the
direction buttons in the Telescope control tool could not work
properly in previous versions.
SIPS is a freeware and can be downloaded from the Download section of this web site.
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