The following paragraphs are some techniques I've learned using Astroart 3.0 to enhance my images.

1.  I use Astroart for image acquisition and a good majority of my processing.  The documentation presented with the program seems to be adequate for the camera controlling portion of the software but lacking in the image processing section.  The following are some of my techniques or habit patterns I've gotten comfortable with while using Astroart.

2.  I currently use GUI 2.41 for  controlling my MX7C.  This version includes the drizzle guiding feature which I have tried with some success.  The program seems to work as advertised, at least with my MX7C.  I normally use Star 2000 while guiding with my LX200 and always use Hires-self guide mode.  When going unguided while imaging through my Stellarvue I normally use Hires Progressive mode to take full advantage of the chip sensitivity.    I've found that I can guide on stars at dim as mag 11 when using at least 1 sec guide frames.  This is fine when imaging at short focal lengths but the drive system in my LX200 has several "fast" errors in the worm which require me to use .5 sec guide frames when imaging at f6.3 or above.  This allows me to keep my guide errors under 1 pixel for the majority of the time.  I always use 2X2 binning for the guide frames although a very bright star in the field would allow use of non binned modes.
 
    Drizzle guiding is a feature of the new GUI that show some promise, at least with one shot color camera's.  The idea is to move the guide star a pixel in each direction in between exposures.  The guide star is recentered before each exposure starts.  The idea behind this is to decrease the intensity of the stacked hot and cold pixels in the processed stack.  Any hot or cold pixels get averaged in with normal pixels.  The benefit to using this with a one shot color camera is this.  The color filter matrix or CMYG covers a square of 4 pixels.  If a star you are imaging only covers a pixel or two then you will not adequately sample the star color, hence the funky colored stars at times.  This feature would move the star through several pixels during a series of exposures.  This in theory  would allow the star to be sampled by each color filter in the matrix.  I have used the drizzle guide feature a few time with good results.  The only problem I have seen is that the declination backlash on my LX200 needs to be set more closely.  When the drizzle feature moves the star in dec, the LX200 is slow to recenter the star so the exposure stars prior to the star really being centered which causes some trailing at times.    I have had good color results using this feature so I need to evaluate it more thoroughly.   

    Speaking of adequate sampling of the MX7C color matrix in order to produce accurate star color, here is a description of what has to be done.  This was written by Al Kelly.  

3.  The following is a step by step process that I use when processing images from the MX7C.

        a.  Aquire your light frames, your darks ( there are several ways to do this but I prefer the Vanderbei method, see the  dark frame                          page for the ways I've done this, and your flats (see the Flats page).  For the best color balance always use an IR filter.

        b.  Calibrate your raw images.  This can be done with any of the Astronomical software programs out there. 

        c.  Open a calibrated image in Astroart.  Run Mikes Color Plugin.  ( http://www.sigma-tech.co.uk ) or another plugin of your choice.               I use the following settings with Mikes plugin
                
                1.  An initial color image will appear when you initially start the plugin.

                2.  Go to the "Color Adjust" tab and set the avg. altitude of the object during your exposures.  (This corrects for atmospheric                          extinction)  Press the "White Balance" button.  Note: If you have a G2V star in your field, you can select the star by  drawing a box around it when you first bring up your image.  This will white balance against just the star.  The resulting color adjusted image should be fairly good assuming you used a IR blocking filter of some sort.  I normally go with what it gives me at  this point.  I  normally do not adjust the saturation and luminance.

                3.  Select the "Synthesis" tab.  If you are going to do your normal processing in Astroart, i.e.. decon, filtering, etc.,  leave the Lum                  Stretch set on Linear, turn the Luminance HPF to off and set the Lum Histogram to 0.0.  These settings will leave your image as it was exposed at the camera.  Select the Batch FITS tab and select your raw images.  Select open and the program will batch convert your raw images to synthesized RGB and L.

                4.  At this point you have your R,G,B and L frames.  I open a L frame and select a star for stacking alignment (if your images were               rotated during the exposures or you took exposures over more than one night select two stars for alignment), close the frame, go to the tools/Preprocessing menu, select the L frames to stack and drag them to the "images window".  Go to the "Options" tab and select  "add or average", deselect the "confirm image" box, select the "Auto Alignment" box and either one star or  two star. Select "Okay"and you will see your images being stacked at the bottom of the screen.  When its done a minimized "noname" image will be left.  This is your stacked image.  The same process is used for your R,G,B frames.

                5.  Open you raw stacked image.  Set the visualization to your liking.  I normally bring up the background so I can easily see any                     gradients. If you have uneven gradients you can use the "gradient plugin" to fix them.  The gradient plugin for AA3 is a little different than AA2.  Actually I think its easier to use.  You select evenly space points along the edges of the image and throughout the image.  I make a grid type pattern. Below are the results you should expect. 

                     
                                                           Uncorrected                                                                                      Corrected

So now I have my lum frame which has been corrected.  At this point I decide whether or not I'm going to use deconvolution. I  normally use AIP4WIN to do deconvolution, but since this is a Astroart tutorial this is the way I do it in AA3.  I use the Maximum Entropy decon routine.  Select a box around a star which is not saturated.  Zoom in to make the selection easier and keep the box  small.  Select the "Filters" tab, "deconvolution" and "maximum entropy".  Select "get psf",  and "gauss".  If working on a  normal size image, 779x580, I only use .7 for the sigma setting because anything more usually causes artifacts.  I also only do 4-6 iterations to reduce background noise.  This should result in a noticeably sharpened image. This technique is also used to correct for focusing errors.  More information can be found under the Astroart deconvolution help page.

Next I sometimes use a DDP filter.  If I used deconvolution, I set the high pass to the minimum.  I also leave the "threshold" setting  to its default.  The resulting image looks washed out so readjust the black point slider to a visualization that pleasing to you.  DDP is good to use to show faint background details.  It works especially good on globulars.  Below is an image of M83 before and after DDP.

                                                                   Before DDP                                                                                   After DDP

At this point I normally stop as more filtering usually add objectionable noise.  Any other filtering like unsharp masking is done in                                   Photoshop.

                7.  Processing of color frames.  Stack each color frame the same way you did the lum frame to create master R, G, B frames.  I use the gradient plugin on the color frames as well since they will show the same gradient as the lum frame.  Resize the color frame to square the pixels  and select the"gauss" function to blur the color frames a little.  Then set the "view range" to min/max.  I normally save the master color frames at this point.   You want to equalize the background values.  I use the "arithmetic", "add offset" function to do this.  Subtract from each frame a value that will leave the background  at 100adu.  If the background is 2500, subtract 2400, etc.   Next, increase the white point using linear scaling to a value that begins to show the object fairly well.  Set the background visualization at 50.  Now, set the same white point and black point on the other two color frames using the "view range" "user defined" function.  I usually just right click on the frame to bring up the menu.   Now you have three color frames each with a background of 100 and the visualization is the same with each frame.    If you do not set each frame to the same white and blackpoint, the color balance will be affected.  Select the "color" button on Astroart menu and select "trichromy". Use the defaults and select "Okay". The resulting image is a synthesized RGB image. Check the background color, it should be grayish.  If not adjust the bottom sliders on the color balance menu until it background meets your satisfaction.  The image will look dim  but should not affect the LRGB.  To make the LRGB, again select to "Color" tab on the Astroart menu and select LRGB synthesis.  This will ask you to select you Lum image.  Once you do so and select "Okay" your  LRGB image will be created.  If the colors look muted at this point, select to "Color" then "Saturation" tab and increase the saturation to your liking.

At this point your done.  Hopefully you have a colorful deep sky image in front of you.  If your colors look funky or too red you                                 probably did not use a IR blocking filter shooting your images.   Further touch ups can be done in Photoshop or other image                                     editing software of your choice to tweak the brightness/contrast or color balance.

I hope this tutorial helped you produce a pleasing color image from your MX7C.  Please email me if you have any other                                       suggestions or comments.