Best CHDK tips for the Orionid meteor shower this Sunday ?

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Best CHDK tips for the Orionid meteor shower this Sunday ?
« on: 16 / October / 2012, 23:12:41 »
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Either very late Saturday night or very early Sunday morning we are in for the second big meteor shower of the year :

http://www.space.com/18078-orionid-meteor-shower-halleys-comet.html

I'm trying to recall the best way to use CHDK to capture this.  I believe the consensus for the last meteor shower was to point your camera to the north star using a tripod and use an intervalometer to shoot continuous 20 second exposures in RAW mode with dark frame subtraction turned off.  You need to take reference dark frame photos at the beginning and end of the shoot by covering the lens for one shot.

Any other advice or suggestions ?   Any special settings recommended setting for ISO ?

Update :   looks like you want to be pointed south (at least in the northern hemisphere).  Here's some more details : http://earthsky.org/tonight/radiant-point-for-orionid-meteor-shower
« Last Edit: 16 / October / 2012, 23:27:11 by waterwingz »

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Offline blackhole

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Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #1 on: 17 / October / 2012, 03:00:07 »
Quote
looks like you want to be pointed south (at least in the northern hemisphere)

You do not have to be turn south. To the south is the only radiant from where the meteors are coming, but the emergence of a meteor on the sky is a local phenomenon on our blue ball, depending on where the meteor enters the atmosphere what is happening all over sky. If you point your camera to the zenith vertically above or just a few degrees to the south from the zenith surely you will not go wrong.

Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #2 on: 18 / October / 2012, 10:13:22 »
I just saw an article about this and I am SUPER excited to try and capture some meteors!   :D

I plan to use the same techniques that I used for my star trails photo.  I am still try to decide where I want to point my camera.  The articles I read indicate that the meteors originate from the direction of Orion (hence the name) but I don't think I want to point right at Orion.

I didn't do any dark frame subtraction on my last set of star trail photos but I want to try it this time.  If nothing else, it will give an idea on the difference between my images.

What is the best way to capture a dark frame?  My camera (G12) doesn't  have a lense cap... ::)

« Last Edit: 18 / October / 2012, 10:15:01 by whatalesyou1 »
G12

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Offline blackhole

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Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #3 on: 18 / October / 2012, 12:58:55 »
Quote
What is the best way to capture a dark frame?  My camera (G12) doesn't  have a lense cap...

You can use any box to cover the lens or you can use Fudgey Dark frame script but you must have native calls enabled.
http://forum.chdk-treff.de/viewtopic.php?f=7&t=2157
The ideal script for astrophotography would be one that would contain Intervalometer and dark frame function from Fudgey script. Dark frame should be done after every 10 frames but lua programming is not my strong side  :(

Code: [Select]
--[[
@title Shoot photo + dark frame pair
by fudgey 2010/11/16

Shoots a RAW photo and a RAW dark frame.

The dark frame will be shot using the same exposure parameters as the actual
photo, but it is not shot using Canon's automatic dark frame feature (instead,
a second photo is taken -- therefore you also get a useless(?) JPEG of the
dark frame).

The photo will use whatever exposure parameters the camera would normally
use without the script,  i.e. Canon's manual exposure or autoexposure and CHDK
exposure overrides should work as expected if they are active. Focus shouldn't
make a difference if the mehcanical shutter is between lens and sensor. Similarly
ND filter state shouldn't affect results.

The script requires native calls to be enabled in your CHDK build. They are not
enabled in CHDK autobuilds by default. Set OPT_LUA_CALL_NATIVE=1 in builconf.inc
and rebuild to enable them.

The script assumes all vxworks cameras to have InitializeAdjustmentFunction
eventproc, and it to register CloseMShutter eventproc. For dryos, it assumes
Mecha.Create eventproc to register CloseMechaShutter eventproc. If neither is not
true for your camera, the script will fail to work. It will most likely either
exit due to an error before shooting, or warn about the shutter close command
and shoot two normal RAW+JPG photos instead of a photo + dark frame pair.

--]]

propcase=require("propcase")

-- Register shutter control event procs depending on os and define functions
-- openshutter() and closeshutter() to control mechanical shutter.
function init()
  -- check for native call interface:
  if (type(call_event_proc) ~= "function" ) then
    error("your CHDK does not support native calls")
  end   
 
  local bi=get_buildinfo()
 
  if bi.os=="vxworks" then
    closeproc="CloseMShutter"
    openproc="OpenMShutter"
    if (call_event_proc("InitializeAdjustmentFunction") == -1) then
      error("InitAdjFunc failed")
    end
  elseif bi.os=="dryos" then
    closeproc="CloseMechaShutter"
    openproc="OpenMechaShutter"
    if (call_event_proc("Mecha.Create") == -1) then
      error("Mecha.Create failed")
    end     
  else
    error("Unknown OS:" .. bi.os)
  end

  -- close mechanical shutter
  function closeshutter()
    if (call_event_proc(closeproc) == -1) then
      print("closeshutter failed")
    end
  end

  -- open mechanical shutter
  function openshutter()
    if (call_event_proc(openproc) == -1) then
      print("openshutter failed")
    end
  end

  -- test for still photo rec mode:
  rec,vid=get_mode()
  if rec ~= true then
    error("Not in REC mode")
  elseif vid == true then
    error("Video not supported")
  end
end -- init()

-- store current exposure params (to be called during half shoot, after autoexposure has finished)
function get_exposure_params()
  print("remembering exposure")
  --tv96=get_tv96() -- exposure time
  --sv96=get_sv96() -- ISO
  tv96=get_prop(propcase.TV) -- exposure time
  sv96=get_prop(propcase.SV) -- ISO
  if get_nd_present() ~= 1 then -- aperture if camera has iris
    --av96=get_av96()
    av96=get_prop(propcase.AV)
  end
end

-- set previously saved exposure params (to be called during half shoot, after autoexposure has finished)
function set_exposure_params()
  print("overriding exposure")
  --set_tv96_direct(tv96) -- exposure time
  --set_sv96(sv96) -- ISO
  set_prop(propcase.TV,tv96) -- exposure time
  set_prop(propcase.SV,sv96) -- ISO
  if get_nd_present() ~= 1 then -- aperture if camera has iris
    --set_av96_direct(av96)
    set_prop(propcase.AV,av96)
  end
end

--[[
     Exposure parameter controlled shoot: if argument dark==false, function stores
     Tv, Av, Sv from this shot and shoots a real photo. If dark==true, function
     overrides camera exposure parameters to match previously stored ones and shoots a
     dark frame. Obviously one must always call this function with false before it can be
     called with true.
--]]
function expcontrol_shoot(dark)
  -- half shoot and wait for autoexposure (if disabled, it'll finish real fast)
  press("shoot_half")
  repeat
    sleep(1)
  until get_shooting() == true
 
  if dark == true then -- if dark frame   
    set_exposure_params() -- set overrides
    closeshutter() -- close shutter
    sleep(1) -- wait for shutter to close (don't know if this is required)
  end
 
  -- take the photo
  press("shoot_full")
  sleep(1)

  if dark ~= true then -- normal photo, store exposure params
    get_exposure_params()
  end

  release("shoot_full")
  sleep(1)
  release("shoot_half")
  repeat
    sleep(1)
  until get_shooting() ~= true
end

-- script starts here
init()

-- store user raw mode and dark frame reduction settings
rawmode=get_raw()
dfrmode=get_raw_nr()

set_raw(1) -- enable RAW or DNG
set_raw_nr(1) -- disable Canon's dark frame reduction

print("Shooting RAW+JPG")
expcontrol_shoot(false) -- shoot a photo, store its exposure params
print("Shooting dark frame")
expcontrol_shoot(true) -- shoot dark frame using stored exposure parameters

-- restore user raw mode and dark frame reduction settings:
set_raw(rawmode)
set_raw_nr(dfrmode)
« Last Edit: 18 / October / 2012, 13:04:05 by blackhole »


Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #4 on: 18 / October / 2012, 20:17:14 »
Dark frame should be done after every 10 frames but lua programming is not my strong side  :(
I'll give it a shot - but its looking to be cloudy here this weekend.  Grrrr....

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Offline blackhole

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Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #5 on: 19 / October / 2012, 02:52:42 »
Quote
I'll give it a shot - but its looking to be cloudy here this weekend.  Grrrr....

Do not worry, Leonids are coming soon - night of November 17  :)

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Offline lapser

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Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #6 on: 19 / October / 2012, 04:00:57 »
You can use any box to cover the lens or you can use Fudgey Dark frame script but you must have native calls enabled.
http://forum.chdk-treff.de/viewtopic.php?
I think I read somewhere that the German CHDK experimental versions have native calls enabled? Do you know if the download from this link would work?
http://forum.chdk-treff.de/download_modul.php

Any chance of someone adding a Lua dark frame function?

My experience with the Perseid Meteor Shower was that I saw the most meteors starting about 1-2 hours after sunset with the camera pointed just above the horizon towards toward Perseus as it rose. Ideally, Perseus would be in the center of the photos so you can see meteors in all directions.
Perseid Meteor Shower - August 10-11, 2012

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Offline blackhole

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Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #7 on: 19 / October / 2012, 05:40:38 »
Quote
I think I read somewhere that the German CHDK experimental versions have native calls enabled? Do you know if the download from this link would work?

It should be fine.
Attached is CHDK with native calls enabled for G1X_100g, if you use this camera.


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Offline msl

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Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #8 on: 19 / October / 2012, 06:42:18 »
I think I read somewhere that the German CHDK experimental versions have native calls enabled?
Both German versions have native calls enable.

stable version (1.1)
trunk (or experimental) version (1.2)

Read more about download from German CHDK forum: http://chdk.wikia.com/wiki/Downloads#Installing_CHDK-DE

Default CHDK language is German. If the camera language is English or Russian you can use the default CHDK script to change the CHDK language.

msl
German CHDK pages:  CHDK forum | CHDK inside | CHDK Twitter News by msl | Download CHDK-DE (Autobuild)
Note: SDM violates the GPL rules!

Re: Best CHDK tips for the Orionid meteor shower this Sunday ?
« Reply #9 on: 19 / October / 2012, 23:52:54 »
Dark frame should be done after every 10 frames but lua programming is not my strong side  :(
I'll give it a shot - but its looking to be cloudy here this weekend.  Grrrr....

Okay .. played with the fudgey script a bit and turned it into meteor.lua - a dark frame intervalometer script for capturing meteor showers.  Seems to run fine sitting there beside my computer but I'm going to test outside over this weekend so there may be updates.

Run it in "P" mode with the flash disabled. If you have manual focus,  you probably want to set that at infinity.  Not sure the best ISO value to use - I'm going to try 80.


Code: [Select]
--[[
@title Dark Frame Shooter for Meteors
2010/11/16 original script by fudgey
2012/10/18 modified by waterwingz to shoot continuously and record dark frame periocally

@param n Number of Shots
@default n 1000
@param r Raw On/Off (1=On/0=Off)
@default r 1
@param s Shots per Dark Frame
@default s 50
@param t exposure in seconds (0=auto)
@default t 25
--]]

propcase=require("propcase")

-- Register shutter control event procs depending on os and define functions
-- openshutter() and closeshutter() to control mechanical shutter.
function init()

   set_console_layout(5, 0, 40, 14)

  -- check for native call interface:
  if (type(call_event_proc) ~= "function" ) then
    error("your CHDK does not support native calls")
  end   
 
  local bi=get_buildinfo()
 
  if bi.os=="vxworks" then
    closeproc="CloseMShutter"
    openproc="OpenMShutter"
    if (call_event_proc("InitializeAdjustmentFunction") == -1) then
      error("InitAdjFunc failed")
    end
  elseif bi.os=="dryos" then
    closeproc="CloseMechaShutter"
    openproc="OpenMechaShutter"
    if (call_event_proc("Mecha.Create") == -1) then
      error("Mecha.Create failed")
    end     
  else
    error("Unknown OS:" .. bi.os)
  end

  -- close mechanical shutter
  function closeshutter()
    if (call_event_proc(closeproc) == -1) then
      print("closeshutter failed")
    end
  end

  -- open mechanical shutter
  function openshutter()
    if (call_event_proc(openproc) == -1) then
      print("openshutter failed")
    end
  end

  -- switch to record mode if necessary
  if ( get_mode() == false ) then
    print("switching to record mode")
    sleep(1000)
    set_record(1)
    while ( get_mode() == false) do
      sleep(100)
    end
  end

  -- test for still photo rec mode:
  rec,vid=get_mode()
  if rec ~= true then
    error("Not in REC mode")
  elseif vid == true then
    error("Video not supported")
  end

  -- make sure we are in P mode
  capmode=require("capmode")
  if ( capmode.get_name() ~= "P") then
    error("Not in Program mode!")
  end

  -- check that flash is disabled
  if ( get_flash_mode() ~= 2) then
      error("Flash not disabled!")
  end

 -- nasty hack to turn seconds into tv96 values
  tv96set=0
  if (t>=10) then tv96set=-320 end
  if (t>=15) then tv96set=-384 end
  if (t>=20) then tv96set=-416 end
  if (t>=25) then tv96set=-448 end
  if (t>=30) then tv96set=-480 end

end -- init()

-- store current exposure params (to be called during half shoot, after autoexposure has finished)
function get_exposure_params()
  if( t>=10 ) then
      set_prop(propcase.TV,tv96set) -- exposure time
  end
  tv96=get_prop(propcase.TV) -- exposure time
  sv96=get_prop(propcase.SV) -- ISO
  if get_nd_present() ~= 1 then -- aperture if camera has iris
    --av96=get_av96()
    av96=get_prop(propcase.AV)
    print("remembering tv=",tv96,"sv=",sv96,"av=",av96)
  else
    print("remembering tv=",tv96,"sv=",sv96)
  end
end

-- set previously saved exposure params (to be called during half shoot, after autoexposure has finished)
function set_exposure_params()
  --set_tv96_direct(tv96) -- exposure time
  --set_sv96(sv96) -- ISO
  set_prop(propcase.TV,tv96) -- exposure time
  set_prop(propcase.SV,sv96) -- ISO
  if get_nd_present() ~= 1 then -- aperture if camera has iris
    --set_av96_direct(av96)
    set_prop(propcase.AV,av96)
    print("overriding tv=",tv96,"sv=",sv96,"av=",av96)
  else
    print("overriding tv=",tv96,"sv=",sv96)
  end
end

--[[
     Exposure parameter controlled shoot: if argument dark==false, function stores
     Tv, Av, Sv from this shot and shoots a real photo. If dark==true, function
     overrides camera exposure parameters to match previously stored ones and shoots a
     dark frame. Obviously one must always call this function with false before it can be
     called with true.
--]]
function expcontrol_shoot(dark)
 
-- half shoot and wait for autoexposure (if disabled, it'll finish real fast)
  press("shoot_half")
  repeat
    sleep(10)
  until get_shooting() == true
 
  if dark == true then -- if dark frame   
    set_exposure_params() -- set overrides
    closeshutter() -- close shutter
    sleep(10) -- wait for shutter to close (don't know if this is required)
  end
 
  -- take the photo
  press("shoot_full")
  sleep(10)

  if dark ~= true then -- normal photo, store exposure params
    get_exposure_params()
  end

  release("shoot_full")
  sleep(10)
  release("shoot_half")
  repeat
    sleep(10)
  until get_shooting() ~= true
end

-- restore user raw mode and dark frame reduction settings:
function restore()
   set_raw(rawmode)
   set_raw_nr(dfrmode)
end


-- store user raw mode and dark frame reduction settings
rawmode=get_raw()
dfrmode=get_raw_nr()

-- script starts here
init()

set_raw(r) -- enable RAW or DNG
set_raw_nr(1) -- disable Canon's dark frame reduction

j=s
for i=1,n do
    print("shooting RAW+JPG", i, "of",n)
    expcontrol_shoot(false) -- shoot a photo, store its exposure params
    if j >= s then
        j=0
        print("shooting a dark frame")
        expcontrol_shoot(true) -- shoot dark frame using stored exposure parameters
    else
        j=j+1
   end
end

print("shooting final dark frame")
expcontrol_shoot(true)

restore()
print("done")

Update 1 :  added option to deselect saving RAW using patch posted below by  blackhole
Update 2 :  changed sleep(1) commands to sleep(10) as sleep(1) doesn't actually sleep at all
« Last Edit: 29 / June / 2013, 09:56:24 by waterwingz »

 

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