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Disclaimer: All the how-to directions below are for information only. They are not intended to be sold or used for unlawful purposes. The author takes no responsibility if they cause the reader bodily harm, loss of life, or cause the damage of any property, person, dog, cat, or any other animal. They are presented for information only and all liability is on the part of the reader.
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First Timer's guide to using Registax 4.0
Preface: Registax helps reduce the noise and other artifacts of astro images by selecting the best images from a set or from a video. It takes those images, aligns them (or performs registration on them), and then stacks them in a way that averages out the noise. It is a very popular program that works very well for all sorts of astro images including Planetary, Solar, and Lunar imaging.
I have run the program in Windows XP with no issues but found that it is mostly CPU intensive. It is best that no other programs be running at the same time it is running. It has loads of options in it that may be discussed further in an advanced user’s how-to later on but for the purposes of this simple how-to we will be sticking to a basic operation of the program for some solar work.
Step 1: Capture Optimization
The first step will be to capture the images or video to use with Registax. I have found that it works best when Raw images or video is used. BMP images are best but JPG images will also work. Keep in mind the GIGO rule (garbage in garbage out). Your images should consist of images that were taken over a short period of time using equatorial tracking. For our purposes we will use the Sun as an example. To get the best image you will need to equatorially track the sun as it moves to keep the image centered in the field of view. Registax can align images or ‘register’ images in an x or y direction but cannot de-rotate them. Our example will consist of a solar video taken over a 10 second interval. The subject was a sunspot and the tracking system used was an equatorial tripod. If your capture duration is too long the image will suffer from natural blur because the subjects in the sky not only orbits but they also have surface movement. Don't expect miracles if you start cutting corners. Every little detail and every small adjustment counts. If you can't capture semi decent images to begin with the rest of the instructions will not matter because of the GIGO rule. Seeing conditions also play a major part in the final result so imaging on mushy days when the wind is whipping the scope around will make it very hard to process the images. Choose a good day with wind speeds from 5 to 10 mph. Choose a good location to setup your tripod and if possible set it up at night and align it to the stars to ensure accuracy. These little things will pay off in the images you capture.
Step 2: Open up the program
The program face is pretty intimidating. Lots of confusing buttons and check boxes but rest assured that it is much easier than it looks. The top most left button is the first we will use. Click on it and you will have a browser open up. Navigate to your set of images or video (avi format) and select the images or video file.
Step 3: Choosing the alignment box
In this step we will choose the best alignment point and alignment box size. At the top of the window around the center you will see a selection area for "Alignment Box Size". The numbers next to them relate to the pixel size of the length and width of the box. Clicking the circle next to 128 will allow you to set an alignment area that is 128 pixels x 128 pixels. The larger the image the larger the box you should use. There are some other options in this area but for general purposes that's all you need to know right now. It should be noted that the larger the alignment box the longer it will take to process your video or set of images. Choose wisely. Once you have chosen an alignment box your happy with put the mouse over an area on the image and click on a contrasting area such as the spot below. The box selected will appear around it and a couple other windows will pop up. These windows are for information only and for our purposes will not be used at this time.
Step 4: Choosing the quality and other items
Under the "Quality Estimator" choose Gradient. There are other selections but for our purposes we will only use the one named. The lowest quality is in reference to how much distortion you are willing to live with. 85% is pretty reasonable quality 75% would start to compromise the image quality and 50% would be pretty rough unless the images captured were all excellent. Typically with video 85% is good for a good day of 5 to 10 mph seeing. On rough windy days you may want to drop down to 75%. After that's set, put a check mark in the area on the left that says "Automatic Processing" and a check in the "View Full Image". The View full images is mainly for those that use bigger ccd's or DSLR's. It helps to choose a good alignment point. From the image below you can see that I changed my alignment point after having clicked on the "View Full Image". If your shooting at 640x480 there is really no need to check this as you are probably already viewing the full image.
Step 5: General Options
We are almost ready to start it up. The last thing to
set is under the "General Options" tab. In the image below the boxes next
to "Ignore Misaligned Frames" should be checked along with "Track Object".
Now you can click on the box to the left that says
"Align". This will start the program running through the frames. The
Initial alignment window will show how well the image is aligned to the
reference. Because we chose the "Automatic Processing" box the program
will run through the tabs "Optimize" and "Stack" and will stop at the "Wavelet"
tab.
Step 6: Wavelet Magic
This next step is where the details in the image are brought out. The program did alot of work to get to this point and the results are seen in the image below. It is a composite of all the frames that were within the 85% range we specified and they are all averaged together. The image looks good but sometimes is a little blurred. This is normal we will brighten it up as well as sharpen it up too. In the window below I clicked on "View Full Image" so I could see the whole picture.
Step 7: Brightening the image
To brighten the image click on the Histogram button on the right side. It will pull up a small window as seen below. The histogram can be altered by either putting a number in the slots or by manually moving one of the two sliders on either side of the window. Clicking on stretch will apply the new histogram to the image care area. Get the brightness to your liking. If you make it too bright you can reset it by clicking on the "Reset" button.
Step 8: Working the wavelets
The wavelet adjustments depend alot on your tastes and how sharp you want the image. I typically start from one end and work up using the "Default" and "Linear" settings which you can specify under the "Wavelet filter" box and the "Wavelet scheme" box. After selecting "Default" and "Linear" adjust the sliders starting from the bottom. Not all the sliders need adjusting. As you go up they get much stronger. As you move the slider the image in the care area will get more sharp. Stop when the image in the care area looks good to you.
Step 9: Do all
Click on the button "Do All" and the program will apply the histogram and wavelet settings to the whole image. Afterwards click on "Save Image" and store the image on your harddrive.
