Thursday, March 23, 2017

KStars 2.7.6 for Windows & OSX released

I am glad to announce the release of KStars 2.7.6 release for Windows & OSX. Linux users using the official PPA can install the latest release as well.

In this release, we introduce the Ekos Mount Modelling tool developed by Robert Lancaster. It's currently in Beta now and we would appreciate any feedback. The tool enables you to build a comprehensive mount model if supported by your mount. Any mount that improves its internal pointing model after a SYNC command is applicable. Furthermore, INDI mounts that supports INDI Alignment Subsystem (EQMod, Nexstarevo, Synscan..etc) are also applicable.

Along with the advanced mount modelling tool comes the new Solution Results plot in the Align Module. It displays the quality of your GOTO after each solve and it can help you to identify if there are issues with your mount or the quality of the image..etc.

You can zoom, pan, and drag to explore the plot in details. Annotation for the quality of each GOTO is available on mouse over.

Ekos Polar Alignment Assistant tool also received a few bug fixes from the community feedback. Most users were able to achieve impressive results using the this easy to use Polar Alignment tool.

While Ekos is designed for ease of use, it can be intimidating for new users unfamiliar with the architecture of Ekos/INDI on several operation systems. Therefore, a new Ekos Profile Wizard is now available to guide the users to setting up their equipment for the first time in Ekos across several operating systems and connection topologies.

With INDI v1.4.1+, figuring out which port to use for your mount & focuser is now trivial across Linux & OSX. INDI automatically scans ports on your system and can even automatically connect to all potential available ports as well until a successful connection is established.

Last, but not least, KStars' NEO (Near-Earth-Object) data query from NASA's JPL is now properly working again thanks to our newest KStars developer Valentin Boettcher. Valentin (aka Hiro) is only 18 years old but is quite brilliant and experienced with KDE/Qt development environment. Welcome abroad!

Sunday, March 19, 2017

How to get 100 million stars in KStars

USNO NOMAD star catalog which contains ~100 million stars has been available in KStars for many years, but it appears many KStars users do not know how to get the catalog up and running.

The primary problem is its sheer size (1.4 GB) which tends to fail when being downloaded via KStars Download New Data tool. So here is a quick guide on how to obtain this catalog.

USNO NOMAD requires Tycho-2 catalog to be installed first. It is a relatively smaller download at only 32MB and can be safely installed using the Download New Data tool. Using the keyboard, click Ctrl + N to bring up the dialog, or go to Data → Download.

Navigate to Tycho-2 and click Install.

Wait until Tycho-2 is downloaded and installed. Now download the USNO NOMAD Catalog. Please either use a download manager to download the file, or use wget from the console. To use wget, open a console and type:


Alternatively, you might want to checkout the mirror list first to download the files from a mirror close to you. After downloading the file, extract it and copy USNO-NOMAD-1e8.dat to ~/.local/share/kstars

If you are using console:

tar -xzf USNO-NOMAD-1e8-1.0.tar.gz
cp USNO-NOMAD-1e8.dat ~/.local/share/kstars

Now restart KStars, and go to Settings → Configure KStars. You'll see the Star Catalogs density slider, move it up and click Apply. You can control how many stars KStars draw on the screen, the more stars, the more resources it would take to render them, so adjust the slider carefully.

And if all goes well, you should have millions of stars on in your KStars Sky Map, enjoy!

Tuesday, February 28, 2017

KStars 2.7.5 is released for MacOS and Windows

I'm very excited to announce the release of KStars 2.7.5 for MacOS and Windows!

This is the first official KStars release for MacOS 10.11+, and while we made sure to test it thoroughly, please treat it as a beta release and report any bugs to the KDE bug tracking website.

KStars for MacOS supports all the features of the Linux KStars release, including Ekos and INDI. It comes ready with support, xplanet, and ability to download and install General Star Catalog (GSC) data used for CCD Simulator stars.

Most INDI drivers are imported with the exception of few Linux-specific drivers; we are investigating different approaches to improve INDI 3rd party drivers support under OSX. This release would not have been possible if not for the tireless efforts of KStars developers and INDI forums members.

Specifically, I'd like to thank the following volunteers for their significant contribution to the MacOS release:

  • Robert Lancaster: KStars latest developer and chief driver of the MacOS release. Robert greatly improved the usability and cross-platform capabilities of KStars while adding several very exciting and useful features to both KStars and Ekos.
  • Stephane Lucas: Initiated the longest (110+ pages) INDI thread Ekos for OS X that resulted in this release. Stephane carried out extensive testing and suggestions for Ekos Scheduler and aided in the KStars OSX Port.
  • Jamie Smith: Developed script to automate building of KStars using Craft, CMake, and XCode methods in addition to automating DMG builds.
Many INDI forums users also helped in testing this release, so I'd like to extend my thanks to all our users.

Along with the Mac OS release, a new KStars for Windows 64bit release is also available for download. You can download both release from KStars website.

Friday, February 17, 2017

KStars 2.7.4 for Windows is released!

Glad to announce the release of KStars v2.7.4 for Windows 64bit. This version is built a more recent Qt (5.8) and the latest KF5 frameworks for Windows bringing more features and stability.

This release brings in many bugs fixes, enhancements for limited-resources devices, and improvements, especially to KStars premier astrophotography tool: Ekos. Windows users would be glad to learn that they can now use offline astrometry solver in Windows, thanks to the efforts of the ANSVR Local solver. The ANSVR mimics the online server on your local computer; thus the internet not required for any astrometry queries.

After installing the ANSVR server and downloading the appropriate index files for your setup, you can simply change the API URL to use the ANSVR server as illustrated below:

In Ekos align module, keep the solver type to Online so it would use the local ANSVR server for all astrometry queries. Then you can use the align module as you would normally do. This release also features the Ekos Polar Alignment Assistant tool, a very easy to use spot-on tool to polar align your mount.

Clear skies!

Thursday, February 16, 2017

Ekos Polar Alignment Assistant Tool

When setting up a German Equatorial Mount (GEM) for imaging, a critical aspect of capturing long-exposure images is to ensure a proper polar alignment. A GEM mount has two axis: Right Ascension (RA) axis and Declination (DE) axis. Ideally, the RA axis should be aligned with the celestial sphere polar axis. A mount's job is to track the stars motion around the sky, from the moment they rise at the eastern horizon, all the way up across the median, and westward until they set.

In long exposure imaging, a camera is attached to the telescope where the image sensor captures incoming photons from a particular area in the sky. The incident photons have to strike the same photo-site over and over again if we are to gather clear and crisp image. Of course, actual photons do not behave in this way: optics, atmosphere, seeing quality all scatter and refract photons in one way or another. Furthermore, photons do not arrive uniformly but follow a Poisson distribution. For point-like sources like stars, a point spread function describes how photons are spatially distributed across the pixels. Nevertheless, the overall idea we want to keep the source photons hitting the same pixels. Otherwise, we might end up with an image plagued with various trail artifacts.

Since mounts are not perfect, they cannot perfectly keep track of object as it transits across the sky. This can stem from many factors, one of which is the mis-alignment of the mount's Right Ascension axis with respect to the celestial pole axis. Polar alignment removes one of the biggest sources of tracking errors in the mount, but other sources of error still play a factor. If properly aligned, some mounts can track an object for a few minutes with only deviation of 1-2 arcsec RMS.

However, unless you have a fancy top of the line mount, then you'd probably want to use an autoguider to keep the same star locked in the same position over time. Despite all of this, if the axis of the mount is not properly aligned with the celestial pole, then even a mechanically-perfect mount would lose tracking with time. Tracking errors are proportional to the magnitude of the misalignment. It is therefore very important for long exposure imaging to get the mount polar aligned to reduce any residual errors as it spans across the sky.

Several polar-alignment aids exist today, including, but not limited to:

1. Polar scope built-in your mount.
2. Using drift alignment from applications like PHD2.
3. Dedicated hardware like QHY's PoleMaster.
4. Ekos Legacy Polar Alignment tool: You need to take exposure of two different points in the sky to measure the drift and find out polar error in each axis (Altitude & Azimuth)
5. SharpCap Polar Alignment tool.

Out of the above, the easiest to use are probably QHY's PoleMaster and SharpCap's Polar alignment tool. However both software are exclusive to Windows OS only. KStars users have long requested support for an easy to use Polar Alignment helper in Ekos leveraging its backend.

During the last couple of weeks, I worked on developing Ekos Polar Alignment Assistant Tool (PAA). I started with a simple mathematical model consisting of two images rotated by a an arbitrary degree. A sample illustration of this is below:

Given two points, we can calculate the arc length from the rotation angle, and hence the radius. Therefore, it is possible to find two circle solutions that would match this, one of which would be the mount's actual RA axis within the image. Finding out which solution is the correct one turned out to be challenging, and even the mount's own rotation angle cannot be fully trusted. To be able to uniquely draw a circle, you need 3 points. So it was suggested by Gerry Rozema, one of INDI venerable developers, to capture 3 images to uniquely identify the circle without involving a lot of fancy math.

Since it relies on, PAA has more relaxed requirements than other tools making it accessible to more users. You can use your own primary or guide camera, given they have wide-enough FOV for the astrometry solver.

Moreover, the assistant can automatically capture, solve, and even rotate the mount for you. All you have to do is to make the necessary adjustments to your mount.

The new PAA works by capturing and solving three images. It is technically possible to rely on two images only as described above, but three images improves the accuracy of the solution. After capturing each, the mount rotates by a fixed amount and another image is captured and solved.

Since the mount's true RA/DE are resolved by astrometry, we can construct a unique circle from the three centers found in the astrometry solutions. The circle's center is where the mount rotates about (RA Axis) and ideally this point should coincide with the celestial pole. However, if there is a mis-alignment, then Ekos draws a correction vector. This correction vector can be placed anywhere in the image. Next the user refreshes the camera feed and applies correction to the mount's Altitude and Azimuth knobs until the star is located in the designated cross-hair. It's that easy!

Ekos PAA is now in Beta and tests/feedback are highly appreciated.

Wednesday, November 23, 2016

New Supernovae Data Source in KStars!

The initial support for Supernovae in KStars was added back in 2011, but it relied on parsing an HTML page using a Python script to extract the necessary information on the latest discovered supernovae. It was obviously a very crude and hackish way to get the data, and I longed to rely on a better source for our data.

The Harvard page we were relying on for supernovae updates suddenly stopped posting any further updates, its last update was made in 2015. Thankfully, we discovered a new gold trove of information: The Open Supernovae Catalog project!

Every small orange dot is a supernova!

Before this project was created, the state of open and accessible data for supernovae was severely lacking in the astronomical community. Thanks to the Open Supernova Catalog, KStars is now again properly displaying old and newly discovered supernovae across the cosmos! The data is available by a JSON file that includes the supernova metadata required in KStars. It can be updated by the user from the data menu.

I'd like to especially thank Dr. James Guillochon, an an ITC Fellow at the Harvard-Smithsonian Center for Astrophysics, for his excellent support to make Supernovae in KStars possible!

Sunday, November 20, 2016

KStars 2.7.2 for Windows is released

Less than a month from the release 2.7.0, KStars v2.7.2 for Windows 64bit is now available for download on KStars website! Get it now and give it a go.

The new release features many minor improvements and bug fixes including very fast startup time (about 300% faster) in addition to more streamlined Ekos GUI for capture and schedule modules. Images captured with Ekos on Windows would now conform to legal filenames in Windows when using ISO 8061 time stamped files.

Unfortunately, a few problems remain in this release most importantly is that KStars does not gracefully closes, it always remains in the background and must be terminated explicitly by the Windows task manager. This bug was supposed to be fixed by Qt 5.8 but alas it is still affecting Qt 5.8 in emerge. Once fixed by Qt/KDE, we shall make another release addressing this issue.