Numerous minor releases of SIMS were released from the v1.0 version. These releases brought many enhancements and we will not cover them all in this document. Description of these upgrades can be found in the Products/Software/Articles section of this web site. We only summarize major enhancements and bug fixes between last SIMS v1.1.7 and SIPS v2.0.

Background processing

Major changes are related to SIPS internal workings. Basically, SIPS v2 become heavily multi-threaded, almost every time-consuming operation was moved to background. This means the user can interact with the software during image processing, image download from the camera etc. Not only the SIPS GUI is much more responsive, but numerous operations (e.g. attempt to load multiple images at once) can be simply canceled.

The following operations were moved to background threads:

• Image calibration and creation of calibration images.

• Image mathematical operations (filters, processing of image sets etc.).

• Transformations of image sets.

• Automatic image matching in Blink and Combine Image tools.

• Multiple image load and save.

• Image astrometry solution.

• Communication with connected camera, including filter settings, chip clearing, image download etc.

Moving of these operations to background threads not only made SIPS more responsive, but also opened the possibility to use modern multi-core CPUs (even the cheapest netbook computer are capable to process two or four threads in parallel these days). Not all operations are completely parallelized yet, but doing so is now relatively easy and more and more time-consuming operations will utilize the SMP (Symmetric Multi Processing) of modern PCs in the subsequent minor releases of SIPS.

User interface

Also user interface underwent some updates. New mode of displaying of images in tabbed panes, filling the whole SIPS workspace, was introduced:

Compared to traditional windowed documents interface:

Switching between these two modes can be performed using “Show images in tabs” menu item or directly by clicking of the corresponding tool . If images are displayed in individual windows, any attempt to maximize any window (be it from window menu or by clicking the maximize button or double-clicking the window title) switches SIPS workspace to tabbed mode. However, switching back from tabbed mode to window mode is possible only by clicking of the tool.

SIPS v2 also added the possibility to arrange multiple image windows:

Another small, but quite useful enhancement is the ability to show cross over every displayed image center. The cross is displayed when the tool is checked. The cross does not alter image data, it is only displayed.

Marking of the image center can be useful feature for various observing tasks:

• While performing equatorial mount polar adjustment using drift method. Placing observed star in the field center allows the user to precisely determine the star drift.

• While aligning the mount to sky, displayed cross enables precise centering of the star in the field of view.

New features

Various other enhancements were introduced in SIPS v2.

SIPS can export images not only to common 8-bit file formats, where original dynamic range of FITS images is lost (the same image transformations, used to display images on computer screen, are used to transform 16 or 32 bit image to 8 bits dynamic range), but also to 16-bit PNG and TIFF formats. Only 16-bit images can be exported to 16-bit PNG or TIFF, because no dynamic range transformation is applied in this case.

There is a possibility to define binning independently for each captured image in the Series tab of the CCD Camera control tool.

SIPS includes sophisticated algorithm for searching stars in images. The algorithm uses several parameters to identify stars properly. Optimal values of these parameters depend on image S/N ratio, on star FWHM etc. These parameters were common for the whole SIMS and used for star matching in Astrometry, Combine Images or Blink tools. These parameters were also used for searching of a star on images used for automatic guiding.

But typically guiding telscope/camera has very different properties compared to main imaging telescope and camera. Stars has different FWHM caused by different telescope focal length and different pixel size of guiding camera. This is why SIPS started to use independent set of star search parameters for main camera/telescope related tasks (astrometry, image matching, ...) and another set of these parameters for guiding.

Support for new hardware

SIPS v2 supports new hardware devices as well as enhances existing drivers.

All communication with devices utilizing serial line (RS-232C interface) was also moved to background threads. This affects mainly drivers for telescope mounts (LX200, NexStar) and eliminated possible problems with missing of telescope commands, causing unreliable communication.

New drivers for NMEA-compatible GPS receivers was added to SIPS. This is widely adopted standard and almost every GPS receiver is able to communicate with a host PC using NMEA protocol. NMEA driver also utilizes serial line interface, similarly to the telescope mount drivers.

Support for newly introduced G0 series of autoguiding and planetary CCD cameras was added to the G1 camera driver. G0 cameras are basically the same like G1 ones, but camera housing is smaller and of round shape (similar to an ordinary 1.25" eyepiece). However, G0 physical shape changes leaded to slightly different electronic and resulted to driver updates.

It is now possible to create multiple configuration files for multiple G2, G3 and G4 cooled CCD cameras. For instance if the user uses G2-3200 camera equipped with photometric BVRI filters for scientific and research tasks and G3-11000 camera with RGB or narrow-band filters for “aesthetics” atrophotography, it was necessary to use two 'g3ccd.ini' configuration files, each containing different filter description. One of these files should be copied to SIMS directory, so the 'g3ccd.dll' driver, used for all G2, G3 and G4 cameras, can use appropriate .ini file. SIPS includes enhanced 'g3ccd.dll' driver, which looks for an .ini file containing camera identifier (ID number) in its name first and general 'g3ccd.ini' file only if the camera-specific .ini configuration file is not found.

If the user has G2-3200 camera if ID 3200 and G3-11000 camera with ID 11000, if is possible to create two .ini files:

• 'g3ccd.3200.ini' file for the G2-3200 camera, containing BVRI filters description

• 'g3ccd.11000.ini' file for the G3-11000 camera, containing LRGB filters description

G2, G3 and G4 camera drivers are able to crop the image matrix even before the image is passed to SIPS. Although it is possible to define sub-frames directly in SIPS camera control tool, limiting camera resolution this way is not very convenient when multiple frames of different types (light, dark, flat) are acquired. If for instance the user wants to use only center area of a large CCD because the optics used cannot utilize such large CCD detector, it is possible to read only a sub-frame (sub-frame 512, 512, 3072, 3072 converts 16Mpx G1-16000 camera into 9MPx camera). But different sub-frame is used e.g. when focusing the camera and it is necessary to properly restore above mentioned subframe before each dark, light of flat field is acquired. And 1 pixel difference between light and dark frame harms the possibility to properly calibrate images.

This is why the 'g3ccd.dll' driver allows definition of sub frame in the appropriate .ini file in the [crop] section:

[crop]
x = 512
y = 512
w = 3072
h = 3072

Such camera will report resolution 3072 × 3072 pixels to SIPS and all other sub-frames, defined in the SIPS camera control tools, will be related to the above defined subframe.

Bug fixes

SIPS v2 fixes problems, found in the previous versions of the software.

• Switching of imaging camera in the CCD Camera tool did not update limits for frame binning. So if e.g. G1 camera was selected as imaging one, hardware binning limit is 1 pixel (G1 cameras do not support hardware binning). After selecting of G2 camera as imaging camera, binning limit was kept on 1 pixels instead on 4 pixels (Gx cameras support up to 4 × 4 hardware binning).

• Zooming images in various tools (e.g. Blink tool) did not reflect actual zoom ration in image status bar.

• 32-bit image, whose dynamic range was stretched to 16 bits using histogram transform could not be saved due to omitted update of bit depth information in FITS header.

• Image rotated by 90 could not be saved, because rotation did not update image width and depth in FITS header.

• Image crop failed when image was scrolled so the image upper-left corner was not visible.

• Calibrate Immediately option th the Calibration tool did not work properly when the Calibration tool remained open.

SIPS v2 is a freeware and can be downloaded from the download section of this WWW site.