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Last Updated:   02/04/17

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Overview:

Setting up the telescope for a night of imaging is only half of the equation. Capturing the images and post-processing them can be time consuming but the end result can also be quite rewarding. Depending on the equipment and software used there are many methods to capture and process the image data.  The following steps are simply the way I capture and process my images using a Meade LX90 and DSI Pro II imaging camera.

 

My Equipment Setup:

The following is an example of my equipment setup when preparing for a night of  imaging:

  1. Position and level tripod.
  2. Attach LX90 OTA (Optical Tube Assembly) to the tripod and fasten securely.
  3. Attach Dew Shield to Optical Tube as needed.
  4. Re-level scope.
  5. Run Power. This can be either 110v current, or 12V DC power depending on the location.
  6. Setup folding work table.
  7. Setup Laptop computer.
  8. Attach the appropriate focal reducer and spacer to the DSI depending on which objects I am planning to image.
  9. Attach the DSI imager to the telescope and connect it to the laptop using a USB cable.
  10. Position counterweights to achieve balance at approximately 30 degrees.
  11. Turn on the telescope and ensure that the Autostar hand controller has current information such as Location, Date, Time, etc.
  12. Prior to darkness, Calibrate the Sensors, and Train motors on the telescope for more accurate tracking (if necessary).
  13. Once dark, turn on the telescope and perform an automatic (2-star) alignment. I use a 9mm Illuminated Reticular eyepiece for this although I can also use the DSI and laptop to align as well.
  14. Boot up the laptop and start the Meade Autostar Envisage program.

Once the telescope has been powered on and aligned it can then locate objects in the sky. The Autostar controller contains a database of over 12,000 astronomical objects. An object is selected, and the go-to button is pressed. The telescope will now locate that object and center it in the field of view then track the object. Once this is performed the object can then be imaged.

 

 

Why I prefer a Monochrome camera over a Color CCD camera:

 A mono CCD has every single pixel sensitive to shades of black/white.
  A color CCD has a series of RGB (red/green/blue) pixels across its surface. So when a photon hits a mono CCD, it will "excite" all of the pixels in the area it hits. The same pixel hitting a color CCD will only  excite the RGB pixel that responds to color of the photon.
  The mono CCD is more sensitive to light since all of its pixels are identical and respond to all photons. The color CCD will have pixels that only respond to the color hitting them.
 
While a mono chip can create a better image, if you want to get a color image out of a mono CCD, you will need to use filters and take a series of 3 or 4 images (RGB/LRGB) then stack them. So, while the color CCD certainly is more convenient, the mono CCD puts out the better image.

 

 

Image Capturing with Autostar Envisage:

There are a number of  various programs that can be used to capture images.
          For Lunar, Solar, and Planetary imaging I prefer to use the Meade Autostar Envisage and K3CCDTOOLS programs.
          For Deep Space imaging with the Meade DSI Pro II I use the Meade Autostar Envisage and Stark Labs Nebulosity  programs.

Here's an example of the Meade Envisage program:
 

(Click on the image to enlarge)

Using Envisage to capture images can be somewhat complex but the more it is used, the more familiar the user will become with the program. Images can be captured in a number of file formats but I have found that the best format to capture with is FITS. More on this later.

My Save options are to 'Save All Uncombined Images'. Once the image has been located, centered, focused, and adjusted, clicking the Start button will begin the process of capturing images. By selecting the 'Save All Uncombined Images' option, each image will be captured separately and a combined image will be produced as well. Separate images can then later be combined using various programs like Registax,  Astrostack Meade Autostar Suite's Envisage,  or  DeepSkyStacker  (which is my personal choice). 

 

 

Image Capturing with Nebulosity:

Here's an example of the Stark Labs Nebulosity program:


(Click on the image to enlarge)

Nebulosity is designed to be a powerful, but simple to use capture and processing application for a wide range of astronomy CCD cameras. Many cameras are supported for capture and images from just about anything can be processed (support for many FITS formats, PNG, TIFF, JPEG, CR2/CRW, etc). Its goal is to suit people ranging from the novice imager who wants to create his or her first images to the advanced imager who wants a convenient, flexible capture application for use in the field.  In it, you get a host of purpose-built, powerful tools to make the most out of your images (e.g., Digital Development Processing, traditional alignment/stacking (equatorial and alt-az), Drizzle alignment/stacking, Bad Pixel Mapping, LRGB tools, real-time tricolor histograms for color balancing, star tightening via edge detection, adaptive scaling of stacks, Canon CR2/CRW RAW Bayer matrix loading, 32/96-bit accuracy, etc.)

 

DSI Pro II with attached filter bar:

If I am creating a color image, I capture 4 sets of individual images. They are Luminance, Red, Green, and Blue using the provided filters that come with the camera.  See the following image which shows the camera, filter bar,  and focal reducer:


(Click on the image to enlarge)

 

 

Image Stacking:

My  image processing program of choice is DeepSkyStacker. This freeware program is an improvement over the Meade Image Processing program and provides additional features which makes my image processing quicker and with better results. DeepSkyStacker can be downloaded from  http://deepskystacker.free.fr/english/index.html.

(Click on the image to enlarge)

The screenshot above shows a number of raw images that have been added to the DeepSkyStacker program.  The individual images are of M1, The Crab Nebula. In the example above, this group of Luminance (mono) images will be stacked together in DeepSkyStacker to create one composite image. The procedure will then be repeated for my individual Red, Green and Blue images. Once completed, I will have four composite images that will then be aligned with each other in Autostar Image Processing then post-processed in Photoshop to create the final image. Note how faint the Crab Nebula looks. That is because the image above is only one single raw image. Stacking many frames on top of each other, will bring out more detail. Combining all four sets of stacked images together in Photoshop and post-processing will bring out even more detail.

The individual settings of each person using DeepSkyStacker varies. The following are the settings I use when stacking individual images. The version I use is 3.2.2 so other versions may differ slightly.

(Click on the images to enlarge)
 

  Register Settings - Actions                            Register Settings - Star Detection                           Stacking Parameters - Result                              Stacking Parameters - Light Frames
                    
   

Stacking Parameters - Alignment                     Stacking Parameters - Intermediate Files                      Stacking Parameters - Cosmetic                                 Stacking Parameters - Output
                      

 

Once I have stacked my four sets of individual images into 4 combined images, I need to align them with each other for final post-processing in Photoshop. I can do this using DeepSkyStacker, or I can stack them using Meade's Image Processing program which is part of the Meade Autostar Suite software package.

The following are the settings I use when stacking the 4 combined images. These vary slightly from the DSS windows above:

(Click on the images to enlarge)
 

                                           Register Settings - Actions                                   Stacking Parameters - Result                             Stacking Parameters - Intermediate Files                    Output files to be combined in Photoshop
                                                     

 

 

Autostar Image Processing:

With Meade Autostar IP astronomical image processing software one can perform many of the same image processing tasks that a professional astronomer would do on a large institutional computer. With Meade Autostar IP you can:

                Enhance high resolution images using advanced image processing techniques.

                Determine stellar magnitudes directly from electronic images, and a number of other powerful features.

 

One can also use Meade's Autostar Image Processing program to stack the 4 combined images. Image Processing will align all four combined images with each other and create four aligned images so that each combined image will line up with the next. The way to do this is:

  From the main Processing window, select Group/New and select your 4 combined images (L,G,R, and B).

  Select Group/Align/Two Star. You are looking for a star pattern from all 4 images. These patterns are usually somewhat consistent across the entire image. In the example below similar patterns of four stars exist throughout the image.

  Using your mouse draw a box around a 4-star pattern. Go to the opposite side of the image and draw a second box around another 4-star pattern. The four unaligned images will now automatically process.
 

Example of 4 separate combined images before aligning.


(Click on each image to enlarge)

 

Once the 4 unaligned images have processed with each other Image Processing will automatically create four aligned images into the same directory as the four unaligned images. If the first alignment is not successful, or additional aligning is needed, process the four aligned images and create a new set of four images using the same process as above.  Once the images are aligned, the result will look something like the following example:

The four aligned images are now ready to be post-processed in Photoshop.

 

 

Photoshop Processing:

FITS Liberator:
L
ike all of the above steps, there are a number of different tools available to process one's images. With post-processing, Photoshop is used by many because of the quality of the software, and the ability to bring out the rich detail of an image. The following will not be attempt to guide one through each and every step within Photoshop. Rather the following steps will serve as a guide for processing an image. More detailed links to step-by-step processing will be included below.

I post-process my images using Photoshop CS2. My images are captured in FITS format.

What are FITS images?
FITS stands for `Flexible Image Transport System' and is the standard astronomical data format endorsed by both NASA and the IAU (International Astronomical Union).  FITS is a file format used for many years in astronomy to store and move images from telescope-based instruments. It has been designed to provide capabilities needed by astronomers but is not a generally known format such as JPEG or TIFF.

In order to process FITS images, either download  a free FITS Liberator plug-for Photoshop (v2.2), from  spacetelescope.org, or download a standalone version (v3) that does not require Photoshop from  The European Homepage For The NASA/ESA Hubble Space Telescope.  Since I post-process in Photoshop I prefer the v2.2 plug-in.  The system requirements are as follows:

bulletWindows PCs
bulletMacs (v2: OS X 10.3+, v1: OS X 10.2+)
bulletScreen resolution of 1024 x 768 pixels or better
bulletPhotoshop CS2 (best), or
bulletPhotoshop CS (16 bit color)
bulletPhotoshop Elements 3.0 (partly 16 bit color), or
bulletPhotoshop 7.0 (only 15 bit color, and only partial functionality for more than 8 bit color)
bulletPhotoshop Elements 2 (only 8 bit color) (Elements 1.0 NOT supported)

Once downloaded and installed, the FITS Liberator plug-in will open automatically in Photoshop after a FITS file is selected and opened. The FITS Liberator screen will look something like this:

 

It is at this point that the FITS image will be initially adjusted before it is further processed using the Photoshop tools. I use the White Level and Black Lever sliders in the Histogram to make my initial adjustment before selecting OK. Picker Tools (eyedropper icons to the left of the image) can also be used to automatically adjust the White and Black levels. Once adjusted, the image looks like this:

While the black level has now been adjusted, the object data is not as apparent. Don't worry. It is still there, and further processing in Photoshop will bring it out.

 

As I mentioned earlier, I use the Meade DSI Pro II imager. If I am capturing a mono image (Luminance) this is the only image I have to process. However when processing a color image, I will be manipulating 4 separate images - Luminance, Red, Green, and Blue (LRGB).

There are a number of methods used for post-processing the image in Photoshop. I recommend that the new user join the Yahoo DSI group. Once you become a member, you will find many helpful hints in the 'Files' section of this group that will walk you through the post-processing steps. I am also including the following  Adobe PDF documents that will walk you through the steps necessary to process and post-process your images. These documents are:
 

bullet DSI Astrophoto Processing Steps - Part 1
Created by Brian Atteridge of the Texas Astronomical Society, this PDF file offers one example of how to capture DSI images using the Meade Envisage software.
 
bullet DSI Astrophoto Processing Steps - Part 2
Created by Brian Atteridge of the Texas Astronomical Society, this PDF file offers one example of how to post-process DSI images using Photoshop CS or CS2 and FITS Liberator v2.1.
 
bullet Photoshop CS2 Post-Processing
Composed by Dean Caddaye, this PDF file offers one example of how to post-process FITS images.

 

 

Photoshop Actions:
Photoshop is a very powerful graphics tool that can take hours and hours to master. As I began post-processing in Photoshop, I followed the guidelines in the documents mentioned above and had good success though time consuming.  I then became aware of a couple of software products called Astronomy Tools v1.6 by Noel Carboni and Annie's Astro Actions v6.0 by Anna Morris.  Both contain a set of Actions - or Macro Operation Sequences - that you load into Photoshop, producing top-quality results. These Actions were designed by Noel and Anna specifically for Astro-Imaging. Instead of manually processing individual steps in Photoshop, these actions can do this automatically for you. Some Actions encompass literally dozens of individual steps. This saves a lot of time in the post-processing experience. Both programs will install directly into Photoshop and each Action will be listed in the Actions tab. See the following example:

Astronomy Tools Listing

(Click on image to enlarge)

 

Annie's Astro Actions Listing

(Click on image to enlarge)

 

I now use both of these action programs on every image that I post-process as well as a certain amount of manual processing. While these actions are not a replacement for manual processing, it saves a considerable amount of  time. Both action programs are very affordable and the diversity between both programs complements each other well.

 

 

Before and After Images:

As I mentioned at the beginning of this section, I am not going to go through the post-processing of an image step-by-step. Using the guide documents I have provided, and a bit of time spent experimenting, one will quickly grasp the process of creating a final image. But for those interested, the following images of M101 - The Pinwheel Galaxy  will show what unprocessed images look like followed by the final image.

M101 Luminance (Mono) Image                                                                                 M101 Luminance (Mono) Image
Before FITS Liberator                                                                                                      After FITS Liberator

                                                     

 

M101 Red Image                                                                                                              M101 Red Image
Before FITS Liberator                                                                                                      After FITS Liberator

                                                    

 

 M101 Green Image                                                                                                          M101 Green Image
Before FITS Liberator                                                                                                      After FITS Liberator

                                                   

 

M101 Blue Image                                                                                                            M101 Blue Image
Before FITS Liberator                                                                                                      After FITS Liberator

                                                   

 

After combining the Luminance, Red, Green, and Blue images in Photoshop, and adjusting the combined image. this is the end result:

 

 

A Review:

The following flowchart summarizes the steps taken from once the telescope has been setup until the final image is processed in Photoshop:

 

 

FITS Practice Files:

Care to practice?  Below are combined FITS files from one of my M42 images as well as my M31 image. Each file is around 6.58MB in size. Each of these files is a result of combining all individual exposures using DeepSkyStacker then aligning each of the combined images with each other. They are ready to be opened in Photoshop, combined, and processed.
 
M42 - Orion Nebula:
Mono
Red
Green
Blue
 

M31 - Andromeda Galaxy:
Mono
Red
Green
Blue


 

Light Pollution:

I recently read an article from a gentleman who stated that one can do CCD imaging as well in the city as in rural conditions. I don't know what equipment he is using, but I have found that dark site conditions produce the best images with the Meade DSI. His belief might be closer for objects such as M42, or star clusters, but when it comes down to those fuzzies, get out of the city and into a dark rural area whenever possible.

The following is a pretty accurate representation of the varying levels of light pollution. The images below this comparison are an example of the differences in quality between my suburban backyard and our clubs dark sky site. It is apparent that getting to a dark environment will greatly improve the quality of your images.

 

The M81 images below reflect the difference in image quality between my backyard, in the Suburban/Urban Transition, compared to Rural/Dark Sky Site. Each image was captured using the same equipment and exposure times.

                               

 

     

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