Částečné zatmění slunce 2015

Je to hodně z ruky, selhala dálková programovatelná spoušť a na focení po přesných intervalech jsem byl prostě líný :) Aligning není úplně přesný, ale mě se to líbí i tak.

Stativ, Canon EOS 60D, Canon EF 200/2.8 L II, ND8 + Baader Astrosolar.  Každý snímek animace cca 6 – 10 RAW obrazů @ ISO 100, 1/125s, F/4, bez flatfield.  Registax 6.


Firefox HTTP cache v1 API disabled

Recently we landed the new HTTP cache for Firefox (“cache2”) on mozilla-central.  It has been in nightly builds for a while now and seems very likely to stick on the tree and ship in Firefox 32.

Given the positive data we have so far, we’re taking another step today to making the new cache official: we have disabled the old APIs for accessing the HTTP cache, so addons will now need to use the cache2 APIs. One important benefit of this is that the cache2 APIs are more efficient and never block on the main thread.  The other benefit is that the old cache APIs were no longer pointing at actual data any more (it’s in cache2) :)

This means that the following interfaces are now no longer supported:

  •   nsICache
  •   nsICacheService
  •   nsICacheSession
  •   nsICacheEntryDescriptor
  •   nsICacheListener
  •   nsICacheVisitor

(Note: for now nsICacheService can still be obtained: however, calling any of its methods will throw NS_ERROR_NOT_IMPLEMENTED.)

Access to previously stored cache sessions is no longer possible, and the update also causes a one-time deletion of old cache data from users’ disks.

Going forward addons must instead use the cache2 equivalents:

  •   nsICacheStorageService
  •   nsICacheStorage
  •   nsICacheEntry
  •   nsICacheStorageVisitor
  •   nsICacheEntryDoomCallback
  •   nsICacheEntryOpenCallback

Below are some examples of how to migrate code from the old to the new cache API.  See the new HTTP cache v2 documentation for more details.

The new cache2 implementation gets rid of some of terrible features of the old cache (frequent total data loss, main thread jank during I/O), and significantly improves page load performance.  We apologize for the developer inconvenience of needing to upgrade to a new API, but we hope the performance benefits outweight it in the long run.

Example of the cache v1 code (now obsolete) for opening a cache entry:

var cacheService = Components.classes["@mozilla.org/network/cache-service;1"]

var session = cacheService.createSession(

    onCacheEntryAvailable: function (entry, access, status) {
      // And here is the cache v1 entry

Example of the cache v2 code doing the same thing:

let {LoadContextInfo} = Components.utils.import(
  "resource://gre/modules/LoadContextInfo.jsm", {}
let {PrivateBrowsingUtils} = Components.utils.import(
  "resource://gre/modules/PrivateBrowsingUtils.jsm", {}

var cacheService = Components.classes["@mozilla.org/netwerk/cache-storage-service;1"]

var storage = cacheService.diskCacheStorage(
  // Note: make sure |window| is the window you want
    PrivateBrowsingUtils.privacyContextFromWindow(window, false)),

    onCacheEntryCheck: function (entry, appcache) {
      return Ci.nsICacheEntryOpenCallback.ENTRY_WANTED;
    onCacheEntryAvailable: function (entry, isnew, appcache, status) {
      // And here is the cache v2 entry


There is a lot of similarities, instead of a cache session we now have a cache storage having a similar meaning – to represent a distinctive space in the whole cache storage – it’s just less generic as it was before so that it cannot be misused now.  There is now a mandatory argument when getting a storage – nsILoadContextInfo object that distinguishes whether the cache entry belongs to a Private Browsing context, to an Anonymous load or has an App ID.

(Credits to Jason Duell for help with this blog post)

NGC 7000, NGC 6974, IC 1318 a okolí + IR

NGC 7000, NGC 6974, IC 1318

NGC 7000, NGC 6974, IC 1318 + Infrared


Dvě téměř zapomenuté fotky z lokace jižně od Prahy, focené loni v létě v noci z 16. na 17. června. Velmi krátká noc, slunce definitivně zapadlo snad až před jedenáctou a po druhé už zase začalo svítat. Zato divokých psů a prasat v okolní vysoké trávě bylo požehnaně :)


Horní fotografie je jen viditelné světlo, dolní má modrý overlay v IR pásmu nad 742nm. Kvalita je sice mizerná, základ je vždy jen jedna fotografie, ale mě se to líbí.


Canon 30D, MC mod
Canon EF 35mm/F2
HEQ5, ustavena tentokrát driftovou metodou
Astronomik CLS-CCD: 1x600s @ F4.0, ISO 1000
Astronomik ProPlanet IR 742: 1x300s @ F4.0, ISO 1000
0x Flat/Dark/Bias
Zpracování v CR a PS

Headless Fedora 20 and VNC with autologin

“Oh no! Something has gone wrong” message is all what you get when you VNC to Gnome 3 in Fedora 20 on a box without any physical monitor attached to any of the video outputs with enabled autologin and screen sharing (vino).  There is an error in /var/log/messages ‘TypeError: this.primaryMonitor is undefined’ at /usr/share/gnome-shell/js/ui/layout.js:410.  I haven’t found a Fedora bug open for this.

You cannot also simply configure e.g. tiger-vnc because of other two bugs, one closed and one open preventing login screen from entering the password – as somebody would be pressing the entry key on and on.

I was not able to find a straight and simple fix unless I’ve hit this solution for Ubuntu, and ported it to Fedora 20:

  • #yum install xorg-x11-drv-dummy
  • put this content to /etc/X11/xorg.conf (you will probably need to create the file):

Section “Monitor”
Identifier “Monitor0”
HorizSync 28.0-80.0
VertRefresh 48.0-75.0
Modeline “1280×800”  83.46  1280 1344 1480 1680  800 801 804 828 -HSync +Vsync

Section “Device”
Identifier “Card0”
Option “NoDDC” “true”
Option “IgnoreEDID” “true”
Driver “dummy”

Section “Screen”
DefaultDepth 24
Identifier “Screen0”
Device “Card0”
Monitor “Monitor0”
SubSection “Display”
Depth 24
Modes “1280×800”

You can then VNC to port :0 and you will be logged in directly without a need to enter the user password.  I suggest SSH tunneling.