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In this lesson it is discussed how different sorts of exposures can be taken for different reasons and how to make an imaging run 'preset'.
The process for exposing the camera is the same regardless of the length of the exposure; whether it is guided or unguided or which filter is being used. This lesson, therefore, assumes the images are unguided or that the imager has already set up the auto-guider. Auto-guiding is covered in [[Lesson 5]].
Assuming the object is now centred in the field, exposures may now be taken of the object. The simplest exposure is a single exposure. Select ''Single'' on the right of the ''Camera Control Window''. Adjust the exposure time, filter and binning as desired. Images should be taken with ''Camera 1'' as this is the imaging camera. The type of frame is 'light'.
When all the settings have been adjusted appropriately, the imager may then click ''Start''. The camera information window will display the current state of the camera. It may move through each of the following stages before an image is produced:
''Filter wheel moving'' -> ''Exposing'' -> ''Downloading''
When the image has been downloaded, it will be displayed on the computer screen. Images displayed this way have their contrast stretched automatically. Currently, this cannot be switched off. At this stage the imager can inspect the image to see if it is suitable for his purposes. It can be removed by closing it or it can be saved. '''Remember to save all images which are deemed successes. Images are sot saved automatically by the single exposure method!'''
At times it may be beneficial to read out only a fraction of the total area of the CCD. This will make it clear what the target of the image is and will speed up the download time. This is called 'windowing' in astronomy but MaxIm calls this process taking a 'subframe'.
To take a subframe an observer must first take a full sized image of his target. Then, in the ''Camera Control Window'', he must check the ''Subframe On'' box. This will activate some more options in the window. To create a subframe, check the ''Mouse'' box. A rectangle shape can now be highlighted on the full frame image by dragging across it. The boundaries of the rectangle show the subframe which will be taken. The subframe can be manipulated with the mouse or redrawn. When the imager is happy he may begin his exposures and the computer will only read out that subframe of the CCD.
This method of exposure was discussed in the [[Lesson 3 | previous lesson]]. It allows the CCD to be constantly read-out. It is not useful for imaging; it is only for centring the target in the CCD.
This method of exposure allows the imager to take a sequence of images with customisable settings. Each observation can have its own exposure time, number of repeats, binning, filter and frame type.
It is suggested that before beginning an autosave run that the user should take some test images in ''single'' mode to determine was settings to use.
To configure an autosave run select ''Autosave'' at the right of the ''Camera Control Window''. The ''Autosave'' button can now be pressed, which is immediately to the right of the autosave marker. The ''Autosave'' window will appear which allows the imagers to change the number and types of exposures to be made. The imager also has control over how each file in the sequence will be named and where it will be saved. The default file path is -> ''My Documents'' -> ''MaxIm Dl 5'' -> ''yyymmdd''. Other settings such as the idle delay between each exposure can be set. This allows the camera a period of rest between each image. This can be useful because the temperature of the camera may increase during readout. Delaying between exposures may also prevent the readout procedure from tainting the images.
Once an autosaving run has been set up the ''O.K.'' button may be clicked. When the imager is satisfied that everything is ready the ''Start'' button may be clicked. The computer will then run the sequence and automatically save the images with the desired filename structure to the desired folder.
MaxIm has a feature where particular exposure settings can be saved and recalled. This is helpful for processes which are always performed, regardless of the observation being made. Presets can be accessed on the ''Expose'' tab. When selected they change all settings to the preset's values.
''LRGB 60s 2x2 (all)'' is a simple colour image run. It takes three images in each colour filter with 2x2 binning for 60s each.
''Dark Run'' takes a series of dark frames with different exposure times. Before running this sequence the dome should be darkened and the telescope primary mirror should be covered.
''Bias Run'' takes a series of bias frames. Before running this sequence the dome should be darkened and the telescope primary mirror should be covered. The main imaging camera does not have a shutter so the blue filter is used as a 'shutter' since it admits the least light.
''Glance'' is used to see if a bright stellar target is on the field.
''Locate'' is used to find where a target is on the field and then can be used to centre the target.
''BG_Photometry'' was used to collect images for photometry. It produces images in blue and green filters.
If none of the above presets is close to what an observer requires he may make his own preset. When the settings for the preset have been configured in ''Camera Control'' go to the ''Exposure Preset'' field. Click the arrow to the right to open the preset options menu. Click ''Save as New Preset''. This preset can now be recalled at any time the observer wishes to take these particular images.
If observers can improve existing presets in any way they are welcome to do so. To change an existing preset make the relevant alterations, go to the ''Exposure Preset'' field, click the options arrow and select ''Update Current Preset''.
Presets do not consume a great deal of memory but if there is any reason to delete a preset it can be removed by going to the options arrow and selecting ''Delete Preset''.
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