Registar for Registering Images

[ashobservatory]

I have been asked to explain how I use (combine) images taken with my different telescopes. Being of different focal lenghts and field of views.  Meade LX200GPS 14", Orion XT-10, Orion ED 80 and 102. Hope this helps !
 
Registar is by far and away the easiest and most accurate method to register and align images because it was designed to work with astronomical images. Using a sophisticated algorithm for registering images, it automatically corrects for distortions and mis-alignments from a variety of causes.
Using Registar:
Open the two images to be registered, one taken with my Orion ED102 and one with my Meade LX200GPS 14"




 
 
 
Both images opened within Registar:


 
 
Click the Register Images Button and the Registration Control Panel will open:


 
 
Click the register button in the Registration Control panel....No other parameters need to be changed.
The screen will now show the process of the registration process. As the stars are counted in the first step a black overlay will scroll down the image as a progress indicator. The same thing will happen as the stars are counted in the second image are scanned.
A black and white image will appear in the third step of the automatic registration process.


 
 
Stars that are in the first image but not in the second image are shown red. Stars that are in the second image but not the first are shown cyan. Stars that are in both images appear white.
At the end of the registration process, the image that has been registered needs to be cropped, and the extra pixels padded onto the edges for where there was no overlap between the two images. This ensures that the two images are exactly the same size and have exactly the same resolution.
Click on the Crop/Pad button on the menu bar and OK in the Crop/Pad control panel. No changes need to be made in the control panel.


 
 
Finally a color image will appear. This image has been registered and cropped. This allows me to open both images later in PhotoShop and composite (layer) them together.


 
 
Open both images in PhotoShop:


 
 
Click on the widefield image to select it. From the tool bar go to select and then click select all.
From the edit button on the toolbar click copy. 
Click back on the registered image and click edit from the toolbar and then click paste. This will paste the widefield image as a layer on top of the registered image.
From within the layers panel in PhotoShop adjust the opacity and fill levels as desired.


 
 
Next adjust the brightness and contrast in PhotoShop to blend . Color may need to be adjusted at this stage also.


 
 
Once you are happy with the blending, click layers on the toolbar, then click flatten image. This will combine the two images as one. From this image further adjustment ( color, brightness, hue, curves or whatever you feel needs to be done) can be done.


 
 Here is the before and after:
 
Before


 
 
After


 
 
Example:Images taken with Orion ED102, Orion XT10 and Meade LX200GPS 14. Registered with Registar and combined in PhotoShop.


 
 
 

[ashobservatory]

Yes, Registar is commerical software.  REGISTAR

Some facts on how it works from the site:

RegiStar is an image alignment, or registration, program that was designed to work specifically with astronomical images. RegiStar finds the stars in an image, and uses their positions to align this image to another image or group of images. RegiStar uses a sophisticated matching algorithm that allows images at different scales and orientations to be registered. RegiStar automatically corrects for geometric distortions, so it works on images taken with different optical systems. Also, it works on image pairs that have only a small overlap. RegiStar registers most images that have at least a 1% overlap and at least 10 stars in common.

RegiStar requires no user input to complete a registration, other than the specification of the images. The matching and alignment are performed automatically without the input of any matching points or parameters.

RegiStar includes the capability of processing several images at once, in a batch. An entire directory of images can be registered using a single command, and several other commands can also handle multiple images.

RegiStar also includes some tools to assemble and manipulate images after they have been registered. These tools were designed specifically to automate tasks commonly done by digital astrophotographers, such as forming mosaics, forming tricolor images, and stacking exposures.

TIFF, JPEG, and FITS images are supported. RegiStar supports 8- and 16-bit depth internally, but will read higher depth FITS images.

RegiStar is not an image-editing program. It is designed to register and assemble images, and, except for the ability to calibrate one image to another, does not have any commands for adjusting brightness or contrast, removing flaws, or otherwise editing images. It is assumed that RegiStar will be used in conjunction with another program that has these capabilities. RegiStar is designed so that other programs can easily be used together with it.

[MidnightSun]

Nice little tutorial...Worth looking into.....

[seeker372011]

Thanks for writing this, Tom

I have downloaded Registar and am having a play..so you don't use the combine feature in Registar but prefer to do this part of processing in PS?

Narayan

[ashobservatory]

YEs, I prefer combining in PS. Total control on the blending, fading, contrast and color adjusts before actually flattening ( combining ) images.

• Kokatha man
• MidnightSun
• Grendel

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