Share:
Notifications
Clear all

Panels with OSC and narrowband?


(@syberand)
White Dwarf Customer
Joined: 1 year ago
Posts: 15
Topic starter  

What is the correct way to do panels when you extract Ha and Oiii?

My current process is to stack the individual panels and integrate them. Then take those and do a Mosaic of them. Is there a better way to do that?

And what is the correct process when you want to extract the Ha and Oiii? How do those fit into everything?

 

I'm using a asi533 and L-eXtreme.


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 

@syberand Hi Andres, I recently explained this to another user. See

https://www.astropixelprocessor.com/community/postid/18040/

 


ReplyQuote
(@syberand)
White Dwarf Customer
Joined: 1 year ago
Posts: 15
Topic starter  
  • In tab 1, load the three integration results (meaning Ha and OIII ones for the IDAS and one for the L-Pro filter)
  • Go to tab 2 and click "create Masters & assign to lights". Yes you didn't load calibration frames but do this anyway.
  • Then still in tab 2 enable "split channels" and then click "SAVE (calibrated) Light frames". In the save popup make sure to select 32 bit floats for bit depth.This will produce 5 images: 2 for the IDAS filter (Ha and OIII) and 3 for L-Pro (R, G and B)
  • Go to tab Tools and open "combine RGB"

I assume you just load them in "light"?

What actually happens in tab 2? Why not just use them as they are?

If you are doing a mosaic, at which point do you put the panels together when you are working with all these channels?


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 
Posted by: @syberand

I assume you just load them in "light"?

Correct!

Posted by: @syberand

What actually happens in tab 2? Why not just use them as they are?

Since you are not loading any calibration files, nothing will happen in tab 2.

Posted by: @syberand

If you are doing a mosaic, at which point do you put the panels together when you are working with all these channels?

Sorry, I missed the fact that you are creating mosaics. I would first create the mosaics per separate channel and then load those as lights.

Also, my apologies for my first reply. I assumed that you were loading RGB images as well and I think this is actually not the case! So the workflow would be

  • In tab 0 select Ha - OIII extract Ha
  • In tab 1 load the lights and calibration files.
  • In tab 3 increase the number of stars to 2500 or more.
  • In tab 4 set scale stop to at least 10, enable dynamic distortion correction, disable same camera and optics and set registration mode to mosaic.
  • In tab 5 set mode to advanced
  • In tab 6 enable MBB and you may need to set it to 10 or 15%
  • Click Integrate
  • Go back to tab 0 and select Ha - OIII extract OIII
  • Go back to tab 6 and click integrate

ReplyQuote
(@syberand)
White Dwarf Customer
Joined: 1 year ago
Posts: 15
Topic starter  

@wvreeven
So you would add all the frames before anything is stacked and do the stacking and mosaic'ing at the same time?


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 

@syberand I usually do, yes. However, if your subs contain obvious gradients (for instance because of light pollution) then you may want to first integrate all subs separately and remove the light pollution in them. Then you can take all Ha images and create a mosaic and do the same with the OIII images. It depends.


ReplyQuote
(@syberand)
White Dwarf Customer
Joined: 1 year ago
Posts: 15
Topic starter  

@wvreeven
When I intergrate a panel and go back and extract the Ha and Oiii, those two channels seem to come out with a fair bit vignette that is not in the Ha-Oiii Color. What am I doing wrong there?


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 

@syberand That is hard to say without having a look at the data. Can you upload 5 lights, darks, flats and either bias or darkflats or both to

https://upload.astropixelprocessor.com/

using upload for both username and password? Please create a directory called syberand_ha_oiii and put the data in there. Let me know when the upload is done and I'll have a look. Thanks!


ReplyQuote
(@syberand)
White Dwarf Customer
Joined: 1 year ago
Posts: 15
Topic starter  

I cannot seem to log in, but i have sent you a pm over the forum with a dropbox link if that is ok.

The easiest place to see the gradiant is in the lower left corner, it doesnt seem to be there when I do a normal color-stack but when I extract the channels and combine them, that is when it is visible.


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 

@syberand Please read my comment again. You need to use upload as both username and password and not your forum name. 


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 

@syberand I downloaded your data, thanks! You don't use darkflats or bias? With only darks of 3 minutes the flats (0.2 sec) cannot be calibrated properly.

Also, for an ASI533MC flats of 0.2 seconds are too short. You should aim at at least 1 sec because of the rolling shutter of the camera that can introduce a gradient in the flats which could lead to unwanted gradients in the lights.


ReplyQuote
(@syberand)
White Dwarf Customer
Joined: 1 year ago
Posts: 15
Topic starter  

Bias with a 533 doesn't make sense since the camera can not expose fast enough to get the "native noise", dark flats i should look in to, but it seems to go fine without.

The thing with flats I have heard before and I need to change my setup to match it.

 

Can you tell me why it calibrated fine with the color and not the extract?


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 
Posted by: @syberand

dark flats i should look in to, but it seems to go fine without

It doesn't go fine. I get popups indicating that flat correction cannot be done properly. What version of APP are you using?


ReplyQuote
(@syberand)
White Dwarf Customer
Joined: 1 year ago
Posts: 15
Topic starter  

1.082


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 

@syberand And with that version you do not get a popup informing you that you need to use either bias or darkflats?


ReplyQuote
(@syberand)
White Dwarf Customer
Joined: 1 year ago
Posts: 15
Topic starter  

It does, but do they make a difference when it comes to vignetting? Doesn't that only affect noise?


ReplyQuote
(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1651
 
Posted by: @syberand

It does, but do they make a difference when it comes to vignetting? Doesn't that only affect noise?

It makes all the difference. If the flats cannot be corrected properly then the flat correction cannot be done properly either. Please take dark flats with the same exposure time, temperature, gain and offset as the flats and process your lights again in APP.

 


ReplyQuote
Share: