About accuracy: I simply don't know if it will work out, but here are the numbers I'm building upon:
- It's actually not really an IMU, but a set of accelerometers and gyroscopes. - The accelerometers have 16-bit converters built in, the gyroscopes have 13 bits. This should give me a resolution (not accuracy or repeatability) of far less than 0.5°. That's the innermost circle's diameter in a telrad. - Aligning: The sensor data is converted to altitude and azimuth. The readout can be offset with known values of a known star at a certain time and should be more or less accurate in the region surrounding that star. Example: If I want to find M57 in Lyra, it's probably a good idea to align with Vega first, because that's easier to find. If the IMU idea fails, I can still use (relatively coarse) axis encoders, it's not aligning for fotos or GoTo, after all. The point is not having a lot of information in the display, but something like a "spoiler" that's doesn't interfere with the art of actually finding an object: It could just be "Yes, you found it" indicated by a change in the circles shown, or a marker when I'm closer than 1°. The easier variant is showing a directional marker that tells me where the desired object is or how far out. There are lots of possibilites. And to prevent misunderstandings: I dont want a separate display in addition to the telrad. The OLED display will be built into the real, see-through telrad instead. It will display the circles and everything else I program into it. Regards Christoph Am 28.08.2013 12:54, schrieb Georg Zotti: > Sounds like a nice project! But are the IMU sensors accurate enough to > allow see-through support where what you see on screen centermarks is what > you see in the main telescope? Such support until now requires aligned > mounts and axis encoders. Unquestionable, a small dim map screen next to a > (real, see-through) Telrad that shows the surroundings of where a big > Dobson is pointing sounds like an interesting project. > > There is definite Qt5 support for Raspberry Pi, and OpenGL1 hardware (Atom > netbooks and such) is supported via ANGLE. So these aspects are all > catered for. A second application based on Raspberry Pi could be a > dedicated telescope remote control unit (for GOTO scopes) running > Stellarium, which will hopefully be even more power-friendly than an Atom > netbook (but could maybe also be used as travel/email computer). > > Both devices don't need 3D foreground rendering, and the "telrad support > device" can be limited to perspective projection (OpenGL built-in). > > Good luck with that! > G. > > > On Mi, 28.08.2013, 09:53, Christoph wrote: >> Re VR: >> >> I'm currently building a telrad-like device with an OLED display and an >> IMU that can be attached to a telescope. I'm not sure what I want to >> display in it, but I'm planning to get the information from stellarium >> over bluetooth. For that, it would be nice to be able to strip it down >> in such a way that it can run (just a bare-metal core, no rendering) on >> a raspberry pi or even a cortex M3. Otherwise I could let it run on my >> atom laptop - so I'd appreciate a "runs-on-cheap-hardware-path", but not >> from a 3D point of view. >> >> Also, please keep writing plugins as simple as it is now. I'm not >> familiar with the new features of Qt5, but the current implementation of >> e.g. StelButton feels a bit clumsy. Qt4 does support widget layouts in a >> QGraphicsView if the widgets inherit from QGraphicsLayoutItem, but >> StelButton inherits from QPixmapItem which is a QGraphicsItem. I think >> much of the code of e.g. the Oculars plugin could be much simpler if the >> given Qt features were used. >> >> Regards >> >> Christoph >> >> Am 28.08.2013 01:32, schrieb Georg Zotti: >>> Dear Jörg and Fabien, >>> >>> if the old classes return, I hope scenery3D will finally be integrable. >>> I >>> did not like the Qt announcement to drop OpenGL1.4, but with ANGLE also >>> cheap hardware (Atom etc) should be kept alive, so there's a chance. >>> Unfortunately my students finished their respective tasks just before >>> that >>> big merge towards 0.12.0, and left for other business, and my project >>> time >>> is up as well. So, when porting to Qt5 is done, I will likely require >>> somebody to go through and reanimate the scenery3D code. It included >>> quite >>> a lot, including cascaded shadow mapping, and allows rendering of and >>> walking in OBJ models. Of course, Qt5 will require to adapt some OpenGL >>> hacks which were necessary in Qt4.6. >>> >>> How does one move/walk with these glasses, or what would be your aim to >>> display in eye-separated 3D? In the mid-late 1990s there were >>> experiments >>> with VR glasses (with thick cables dangling from the lab ceiling...) fed >>> by SGIs (remember those?), but the full-cutoff was seen problematic, >>> leading to AR ideas (with semitransparent glasses). I have since then >>> imagined semitransparent goggles with explanatory displays augmenting >>> the >>> live stars. I think Celestron built such a device some time ago, and now >>> there are cellphone apps using these sensors, augmenting camera views. >>> Time flies... >>> >>> So, if you wish, (I think we had contact before), feel free to reanimate >>> this plugin and enhance it with oculus rift, but it should please also >>> work without. >>> >>> G. >>> >>> On Di, 27.08.2013, 22:59, Fabien Chéreau wrote: >>>> Hi Jörg, >>>> to reply to your email about oculus rift: >>>> It sounds quite a nice project :) >>>> - For 3, you need first to use perspective projection, and I guess >>>> simply adjust screen size so that the ratio is correct, and FOV so >>>> that it matches the FOV of the glasses. >>>> - For 4, This is not so clear what you want to do here: most of the >>>> stuff displayed in Stellarium are infinitely far away, so it's >>>> difficult to add parallax effect. Maybe on the landscape, but we don't >>>> have 3D models, our landscapes are flat. Maybe you can try to use the >>>> 3D landscape code done by Georg's team? >>>> - For 5, I would suggest you rather implement a special proper >>>> projection doing just the inverted distortion than the one from the >>>> glasses. >>>> >>>> Fabien >>>> >>>> On Mon, Aug 26, 2013 at 5:53 PM, Jörg Müller <nex...@gmail.com> wrote: >>>>> Hi, >>>>> >>>>> and about the Oculus Rift part, which actually was the main part of my >>>>> mail? >>>>> >>>>> Regards, >>>>> Jörg >>>>> >>>>> Am 2013-08-26 17:42, schrieb Fabien Chéreau: >>>>>> Hi Jörg, >>>>>> well I had a lot of conflicts with this code indeed. We should try to >>>>>> re-integrate it properly on the branch, if we decide to go this way. >>>>>> Fabien >>>>>> >>>>>> On Mon, Aug 26, 2013 at 5:33 PM, Jörg Müller <nex...@gmail.com> >>>>>> wrote: >>>>>>> Hi Fabien, >>>>>>> >>>>>>> interesting news to read. Does this mean my shadow code gets removed >>>>>>> too? I don't know if GLES2 supports the required float textures. >>>>>>> >>>>>>> Apart from that I recently tried to integrate Oculus Rift [1] >>>>>>> support >>>>>>> in >>>>>>> stellarium. The steps needed to be done for integration are: >>>>>>> >>>>>>> 1. Headtracking (Moving the view based on the movement of the >>>>>>> headset) >>>>>>> 2. Rendering in two viewports each taking half of the screen space >>>>>>> for >>>>>>> the left and right eye >>>>>>> 3. Calculating and adjusting the projection matrix based on aspect >>>>>>> ratio,field of view and other settings of the hardware and using it >>>>>>> in >>>>>>> the rendering pipeline >>>>>>> 4. Adjusting the view matrix for each eye location >>>>>>> 5. Correcting the distortion of the hardware's lense using a pixel >>>>>>> shader >>>>>>> >>>>>>> I succeeded in the first two steps, but as for the next two >>>>>>> stellarium >>>>>>> is a very special case I failed to properly change the projection >>>>>>> matrix >>>>>>> of the rendering pipeline. What do you think about this project and >>>>>>> would you be willing to help me understand how the transformations >>>>>>> in >>>>>>> the rendering pipeline of stellarium work so that I can integrate >>>>>>> the >>>>>>> required calculations? >>>>>>> >>>>>>> Regards, >>>>>>> Jörg >>>>>>> >>>>>>> [1] https://oculusvr.com/ >>>>>>> >>>>>>> On 2013-08-26 15:51, Fabien Chéreau wrote: >>>>>>>> Hi Bogdan, >>>>>>>> >>>>>>>> I currently have a bit more free time, and I was actually >>>>>>>> investigating doing some major refactoring of the project (not a >>>>>>>> total >>>>>>>> rewrite but not very far from that :D ) >>>>>>>> Basically what I want is to produce a much lighter version of >>>>>>>> Stellarium based on Qt5 and OpenGL ES2 features only (it's a >>>>>>>> requirement of Qt5 itself). This involves: >>>>>>>> - revert all changes from GSOC 2012 on the renderer: after >>>>>>>> having >>>>>>>> a >>>>>>>> detailed look I am convinced that all this work is almost useless >>>>>>>> from >>>>>>>> the moment on we want to support only GLES2. It also introduced a >>>>>>>> number of rendering bugs, as well as a large performance penalty. >>>>>>>> I've >>>>>>>> done most of this revert in a branch called >>>>>>>> https://code.launchpad.net/~stellarium/stellarium/simplegles and >>>>>>>> went >>>>>>>> from 45 FPS to 62 FPS on my computer. >>>>>>>> - suppress completely GL1-related code and focus on >>>>>>>> shader-based >>>>>>>> rendering only. This is also almost done in the branch. >>>>>>>> - switch to the new Qt rendering system, i.e. abandon rendering >>>>>>>> based >>>>>>>> on QGraphicsView / QWidgets and use only classes from the new QtGUI >>>>>>>> module (the one from Qt5). I am not completely sure but this may >>>>>>>> involve a complete GUI re-write based on QML. This last task may >>>>>>>> sound >>>>>>>> quite ambitious. I'm quite confident that we can reproduce a GUI >>>>>>>> similar to the current one based on QML, but it may cause some >>>>>>>> troubles for interactions with plugin etc.. >>>>>>>> >>>>>>>> Fabien >>>>>>>> >>>>>>> >>>>>>> ------------------------------------------------------------------------------ >>>>>>> Introducing Performance Central, a new site from SourceForge and >>>>>>> AppDynamics. Performance Central is your source for news, insights, >>>>>>> analysis and resources for efficient Application Performance >>>>>>> Management. >>>>>>> Visit us today! >>>>>>> http://pubads.g.doubleclick.net/gampad/clk?id=48897511&iu=/4140/ostg.clktrk >>>>>>> _______________________________________________ >>>>>>> Stellarium-pubdevel mailing list >>>>>>> Stellarium-pubdevel@lists.sourceforge.net >>>>>>> https://lists.sourceforge.net/lists/listinfo/stellarium-pubdevel >>>>>> ------------------------------------------------------------------------------ >>>>>> Introducing Performance Central, a new site from SourceForge and >>>>>> AppDynamics. Performance Central is your source for news, insights, >>>>>> analysis and resources for efficient Application Performance >>>>>> Management. >>>>>> Visit us today! >>>>>> http://pubads.g.doubleclick.net/gampad/clk?id=48897511&iu=/4140/ostg.clktrk >>>>>> _______________________________________________ >>>>>> Stellarium-pubdevel mailing list >>>>>> Stellarium-pubdevel@lists.sourceforge.net >>>>>> https://lists.sourceforge.net/lists/listinfo/stellarium-pubdevel >>>>> >>>>> >>>>> ------------------------------------------------------------------------------ >>>>> Introducing Performance Central, a new site from SourceForge and >>>>> AppDynamics. Performance Central is your source for news, insights, >>>>> analysis and resources for efficient Application Performance >>>>> Management. >>>>> Visit us today! >>>>> http://pubads.g.doubleclick.net/gampad/clk?id=48897511&iu=/4140/ostg.clktrk >>>>> _______________________________________________ >>>>> Stellarium-pubdevel mailing list >>>>> Stellarium-pubdevel@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/stellarium-pubdevel >>>> >>>> ------------------------------------------------------------------------------ >>>> Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more! >>>> Discover the easy way to master current and previous Microsoft >>>> technologies >>>> and advance your career. Get an incredible 1,500+ hours of step-by-step >>>> tutorial videos with LearnDevNow. Subscribe today and save! >>>> http://pubads.g.doubleclick.net/gampad/clk?id=58040911&iu=/4140/ostg.clktrk >>>> _______________________________________________ >>>> Stellarium-pubdevel mailing list >>>> Stellarium-pubdevel@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/stellarium-pubdevel >>>> >>> >>> >> >> ------------------------------------------------------------------------------ >> Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more! >> Discover the easy way to master current and previous Microsoft >> technologies >> and advance your career. Get an incredible 1,500+ hours of step-by-step >> tutorial videos with LearnDevNow. 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