Image stacking

Hi all,

I'm *extremely* new to astrophotography, and appologies for what may be
an off-topic question.

For my studies I am required to take a series of photographs of flames
and get an average. A bit of hunting around on the net lead me to
discover astrophotography. Very different subject matter, but similar
process. The photos I saw blew me away, so I started taking some shots.

I tried to use "Registax" to stack my images (both of flames and the
sky), but am having troubles with the "align" process. If I'm taking
shots of flames, or the sky at night (eg just the clouds) without a
telescope then there aren't any particular features I want to align to.
I want to be able to stack the images, but without aligning them to a
particular feature. Sure, if I had a really high powered scope, or I
wanted to track something moving then I understand why it would be
necessary, but otherwise, could someone please explain to me why I have
to align the images, and why can't I just overlap the images directly on
top of one-another?

Is there other software out there that would do what I want? I've tried
downloading Astrostack, but kept getting Java errors, although this
doesn't seem to do what I want anyway.

Cheers,
Steve

Because Registax in particular, and astronomy imaging in general, does an
alignment procedure because telescopes do not exactly and perfectly track an
object, due to several factors. So unless the individual frames are aligned
before stacking, you wind up with a blurred planet.

For what you want to do, just use the arithmetic feature on Photoshop or Paint
Shop Pro and add the images one at a time, or in batch mode (although I've not
tried the latter). Registax was designed for a specific case, astronomical
imaging. For that, Photoshop or Paint Shop Pro would be the hard way to do it,
when you're stacking hundreds or thousands of images.

--- Dave
--
----------------------------------------------------------------------
Pinprick holes in a colorless sky
Let inspired figures of light pass by
The Mighty Light of ten thousand suns
Challenges infinity, and is soon gone




"Steve Irwin" wrote in message
...
Hi all,

I'm *extremely* new to astrophotography, and appologies for what may be an
off-topic question.

For my studies I am required to take a series of photographs of flames and get
an average. A bit of hunting around on the net lead me to discover
astrophotography. Very different subject matter, but similar process. The
photos I saw blew me away, so I started taking some shots.

I tried to use "Registax" to stack my images (both of flames and the sky), but
am having troubles with the "align" process. If I'm taking shots of flames, or
the sky at night (eg just the clouds) without a telescope then there aren't
any particular features I want to align to. I want to be able to stack the
images, but without aligning them to a particular feature. Sure, if I had a
really high powered scope, or I wanted to track something moving then I
understand why it would be necessary, but otherwise, could someone please
explain to me why I have to align the images, and why can't I just overlap the
images directly on top of one-another?

Is there other software out there that would do what I want? I've tried
downloading Astrostack, but kept getting Java errors, although this doesn't
seem to do what I want anyway.

Cheers,
Steve

Download Iris (http://www.astrosurf.org/buil/us/iris/iris.htm)
Install Iris
Open Iris
Set the various defaults (read the manual first)
Go to the file menu and select the AVI conversion option
A pop-up menu will appear
Fill in the required field for the location of the avi file you want to
take the average of
If a color avi fill in the 3 fields with generic file names like: r_,
g_, b_
Click on the "Convert" button
At the end of the conversion process Iris will create 3 x n (with n =
to the number of unique frames in your original avi file) indexed files
in your default home directory named like r_1, r_2, r_3... and so forth
for the g and b channels frames
Open the command line menu (click on the fourth button from right on
the toolbar)
Iris will show you the last green channel frame in its window
After the "" type: add_norm r_ n (where n shall be replaced by the
number of frames Iris tells you he has created for each RGB channel)
The window may become white but don't worry
Go on the Processing menu and click on Divide
Type in the n value and click ok
Voila': you have you average R (or G or B) channel image
Save with an unique file name and repeat the process for the remaining
channels.
Once finished go on View menu and select the (L)RGB option
Fill in with the file names of your averaged R, G and B channel files
Click ok
Click on auto and adjust the visualization threshold band to suit your
taste. You can also modify the relative intensities of the RGB channels
by going to the View menu and selecting the White balance option
Save the resulting image in any file type supported by Iris
Have fun

Andrea T.

David Nakamoto wrote:
Because Registax in particular, and astronomy imaging in general, does an
alignment procedure because telescopes do not exactly and perfectly track an
object, due to several factors. So unless the individual frames are aligned
before stacking, you wind up with a blurred planet.

For what you want to do, just use the arithmetic feature on Photoshop or Paint
Shop Pro and add the images one at a time, or in batch mode (although I've not
tried the latter). Registax was designed for a specific case, astronomical
imaging. For that, Photoshop or Paint Shop Pro would be the hard way to do it,
when you're stacking hundreds or thousands of images.


Thanks for the explanation David.

Many thanks,
Steve

wrote:
Download Iris (http://www.astrosurf.org/buil/us/iris/iris.htm)
Install Iris
Open Iris
Set the various defaults (read the manual first)
Go to the file menu and select the AVI conversion option
A pop-up menu will appear
Fill in the required field for the location of the avi file you want to
take the average of
If a color avi fill in the 3 fields with generic file names like: r_,
g_, b_
Click on the "Convert" button
At the end of the conversion process Iris will create 3 x n (with n =
to the number of unique frames in your original avi file) indexed files
in your default home directory named like r_1, r_2, r_3... and so forth
for the g and b channels frames
Open the command line menu (click on the fourth button from right on
the toolbar)
Iris will show you the last green channel frame in its window
After the "" type: add_norm r_ n (where n shall be replaced by the
number of frames Iris tells you he has created for each RGB channel)
The window may become white but don't worry
Go on the Processing menu and click on Divide
Type in the n value and click ok
Voila': you have you average R (or G or B) channel image
Save with an unique file name and repeat the process for the remaining
channels.
Once finished go on View menu and select the (L)RGB option
Fill in with the file names of your averaged R, G and B channel files
Click ok
Click on auto and adjust the visualization threshold band to suit your
taste. You can also modify the relative intensities of the RGB channels
by going to the View menu and selecting the White balance option
Save the resulting image in any file type supported by Iris
Have fun

Andrea T.


Thanks Andrea, I'll give it a try when I get the chance.

Lata,
Steve