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Telescopes · Binoculars · Microscopes


 
Magellan Telescope Computer System Instruction Manual
 IV. Operations
IMPORTANT NOTICE! Never use a telescope or spotting scope to look at the Sun! Observing the Sun, even for the shortest fraction of a second, will cause irreversible damage to your eye as well as physical damage to the telescope or spotting scope itself.
Magellan operates under one of four modes that are cycled by pressing the MODE key. The four modes are,
  • Telescope Mode
  • Coordinate Mode
  • Timer Mode
  • Blank Mode
Some modes have sub-menus accessed by moving the LCD arrow (positioned to the left of the menu item) up or down using the PREV or NEXT key, and then pressing ENTER.

[ toc ] A. Telescope Mode

The default start-up mode for Magellan is Telescope Mode. This mode has telescope related functions. The sub-menus for this mode are: Object Library, Align, Date, Encoders and Help. These functions allow the telescope to be aligned and the object libraries to be accessed for pointing at these objects.

[ toc ] 1. Object Library

This menu item defaults to the top of the menu listing for quick access. All library data and object search filters are accessed from this menu. When selected, by pressing the ENTER key, a scrolling menu appears listing the object library functions. These functions include: Select Object, Object Information, Start Find, Field, Parameters and User Library.

[ toc ] a) Select Object

When the Select Object menu is activated by pressing the ENTER key, the display will offer various object catalogs to be selected. Scroll through these libraries using the PREV or NEXT keys and select a library by pressing the ENTER key. When selected, a blinking cursor is displayed, prompting you to input the catalog number of the desired object. Use the PREV/NEXT keys to change the digit value and ENTER to fix the value and advance to the next digit.

Pressing ENTER after the last digit displays the object's description (i.e. the name, type, magnitude and size or separation). If the object is known by a common or popular name, this will be displayed first, otherwise the size and magnitude will be displayed. If the popular name is displayed, an additional press of ENTER will display the size and magnitude information. Pressing ENTER again displays the object's coordinates in Right Ascension and Declination. A third press of ENTER displays the distance to the object from the telescope's current position. This distance is continually updated as the telescope is moved, allowing you to steer the telescope to the object.

The MODE key aborts the selected menu item and returns to the previous menu list.

[ toc ] b) Object Information

The display shows information about the selected library object. Pressing ENTER displays the object's description (i.e. the name, type, magnitude and size or separation). Pressing ENTER again displays the object's coordinates in Right Ascension and Declination. A third press of ENTER displays the distance to the object from the telescope's current position. This distance is continually updated as the telescope is moved allowing you to steer the telescope to the object.

As you move to various parts of the sky, you may find that object positions differ slightly from the position indicated by Magellan. These differences arise from inaccuracies in leveling (squaring) or centering stars during the initial alignment. You can make minor corrections to the alignment by "synchronizing" Magellan on any object within the Magellan catalogs. This is done by centering the known object in the field of view while the object information for that object is displayed. Press and hold the ENTER key for one or two seconds and the display will show the message, "Center object, then press ENTER." Pressing ENTER will now synchronize the Magellan to the coordinates of the centered object. This will improve the accuracy of Magellan for objects in the immediate vicinity. While any object from the object catalogs may be used to "sync" the Magellan, you may wish to select a bright neighbor of a fainter object to provide the final pointing accuracy to find that faint object. Appendix A lists the bright stars from the STAR catalog which may be used for this purpose.

The MODE key aborts the selected menu item and returns to the previous menu list.

[ toc ] c) Start Find

Selecting this option filters the library database for objects that match the specifications listed under the Parameters menu (see below) and displays the closest object's description (i.e. the name, type, magnitude and size). Pressing ENTER again displays the object's coordinates in Right Ascension and Declination. A third press of ENTER displays the distance to the object from the telescope's current position.

Press NEXT to display the information for the next closest object. PREV will display the information for the farthest object (or the previous closest object).

The MODE key aborts the selected menu item and returns to the previous menu list.

[ toc ] d) Field

This command identifies objects in the field of view of the telescope. By pressing ENTER Magellan displays the central object's description (i.e. the name, type, magnitude and size). Pressing ENTER again displays its coordinates in Right Ascension and Declination. A third press of ENTER displays the distance to the object from the telescope's current position.

The MODE key aborts the selected menu item and returns to the previous menu list.

[ toc ] e) Parameters

Start Find uses the specifications listed below to filter the database for matching objects. Scroll through these 6 specifications using the PREV/NEXT keys and select the ones to change by pressing ENTER.

[ toc ] 1) Type

This menu file option allows you to select the type of CNGC objects you wish to locate. The symbols GPDCO represent:

G Galaxies

P Planetary Nebulae

D Diffuse Nebulae

C Globular Star Clusters

O Open Star Clusters
Initially, the blinking cursor appears over the G symbol. If you decide not to look for galaxies, press the PREV/NEXT key and the letter will disappear, deselecting the GALAXIES category. If you wish to leave GALAXIES selected, then move the blinking cursor over to one of the other category symbols by pressing ENTER. You can then deselect the undesired categories. If you wish to recall a category symbol, move the blinking cursor over the symbol location and press the PREV/NEXT key. After your selections are made, press ENTER.

[ toc ] 2) Better

The BETTER menu file option allows you to define the visual object quality range. At power up, the range is set at the bottom of the scale on VP. When using the START FIND menu selection, it will select all objects that are very poor through super or what could be considered an "ALL" setting. The object quality symbols are:

SU Super

EX Excellent

VG Very Good

G Good

FR Fair

PR Poor

VP Very Poor
If you wish to define the visual object quality range to very good and better, press ENTER and the blinking cursor will appear on the quality value. From the quality setting press PREV/NEXT to move to higher or lower quality settings. Once you have selected the quality value required, press ENTER to complete the selection process.

[ toc ] 3) Larger

The LARGER menu file option allows settings of the lower apparent size limit of the objects you wish to see. At power up, it is set to 000' (arc minutes). In order to make a decision as to the size limits that you may impose, it helps to have a clear understanding of exactly what an arc minute of sky is. A good example is the apparent size of the Moon, which could be expressed as 1/2 degree, 30 arc minutes, or 1800 arc seconds. Each arc minute is 60 arc seconds, and there are 60 arc minutes for each degree of sky.

Some beginning observers have a tough time discerning objects less than about 1 arc minute in size unless it is a double star or a planet. Astrophotographers and those involved with CCD imaging may want to set a higher value based on a desired image scale coverage that would be most impressive with different films or types of CCD cameras. Enter the new value in arc minutes by pressing ENTER to place the cursor on the desired digit and then press PREV/NEXT to increase or decrease the value of the digit. Pressing ENTER will fix the value of a digit and move to the next digit until the last digit is completed, when pressing ENTER will complete the option field.

[ toc ] 4) Smaller

The SMALLER menu file option is the upper size object limit. At power up, the setting is for 200' arc minutes or 3.33°. This setting is high enough to cover the largest objects in the OBJECT LIBRARY. You may want to lower the value because of field-of-view limitations of a particular eyepiece.

Other reasons for limiting the value in SMALLER is for astrophotographic or CCD imaging requirements where you don't want the object to exceed the imaging area of the film or the CCD chip. Setting values by using PREV, NEXT and ENTER are the same as previously described.

[ toc ] 5) Brighter

The lower brightness limits based on stellar magnitude can be limited in the BRIGHTER menu file option. At power up, the magnitude value is set to a very faint level of +20.0. You may want to adjust the magnitude level to a brighter value starting at perhaps the limiting visual magnitude of your telescope. Sky conditions also greatly affect the limiting magnitude due to atmospheric haze, high clouds, light pollution, or combinations thereof. Setting values by using PREV, NEXT and ENTER are the same as previously described.

[ toc ] 6) Fainter

The upper level of brightness may also be adjusted with the FAINTER menu file option, although you may find few applications for limiting it to a lower value. Setting values by using PREV, NEXT and ENTER are the same as previously described.

[ toc ] f) User Library

This option allows the user to create a user library of 125 objects selected from the existing libraries. Pressing ENTER will display the first of these 125 possible selections. Pressing PREV/NEXT will scroll through these items with ENTER selecting a particular item. Using PREV/NEXT and ENTER as with other options, allows new objects to be selected from existing libraries and added to the User Library.

[ toc ] 2. Align

Alignment of your telescope is the most critical procedure for the successful use of Magellan. The alignment procedure allows Magellan to determine the orientation and position of the telescope, and to thereafter guide you accurately to objects in the sky. Two types of alignment are possible, namely, Polar and Altazimuth (Altaz). If your telescope is equatorially mounted a polar alignment is possible, otherwise you will need to use one of the two Altaz alignment options provided.

The Align function is selected from the menu by pressing the ENTER key when Align is indicated by the display arrow. Magellan now offers three methods of alignment (1 Polar and 2 Altaz). If you are equatorially mounted select the Polar align method, all others must select one of the Altaz methods.

Next to the word "Align" on the Magellan display there is a number ("0" after power is applied). This number represents the quality of the alignment procedure performed. It is derived from taking the measured alignment values and comparing them with what should be expected based on the distances between the alignment objects. A value of 100 (as in 100%) means that your actual alignment measurements matched those expected based on calculations. Values between 90 and 110 are accepted but may affect pointing accuracy when moving to other objects. Values out of this range are not acceptable and will require that you make another attempt to align your telescope. The initial value of "0" indicates that Magellan is not aligned.

[ toc ] a) Polar Alignment

Polar alignment may be used if your telescope is mounted equatorially. Press the ENTER key to initiate this function while "Polar" is selected. Position the telescope/mount system such that it is aligned with the pole (the pole is in the center of the field of view and the telescope is at 90° Declination. Your telescope instruction manual will provide information on this initial telescope positioning. Once in position, press ENTER as requested by the display.

At this point the first alignment star needs to be selected. Press ENTER and the alignment star catalog will appear. Scrolling with PREV/NEXT, select a star familiar to you which is near the meridian and press ENTER. Move the telescope to the selected star and center it in the eyepiece and press ENTER. At this point polar alignment is complete and you may exit by pushing the MODE key. Magellan also offers the option of selecting a second alignment star to further correct alignment inaccuracies in the original polar positioning of the telescope. The procedure for using the second alignment star is the same as for the first and Magellan will prompt the user with display messages.

If errors occur during the alignment procedure Magellan can detect these based on calculations of expected values. For example, if the wrong star is centered during alignment, Magellan will detect that the distance between stars is not what should be expected. If this variation exceeds preset limits, Magellan will display the message "Alignment Error Check Stars." If this occurs, press ENTER and begin the alignment procedure again. If the alignment is successful a number will be displayed next to the "Align" display which gives a relative value of merit for alignment quality (100 is perfect as in 100%).

[ toc ] b) Altaz Alignment

There are two choices for the Altaz alignment method. The preferred method (Altaz Horizontal) requires that you initially start with a bubble level and the telescope tube in the horizontal position. This is the preferred method simply because of the reduced physical contortions required by the user.

[ toc ] 1) Altaz Horizontal

The purpose of this alignment is to find the telescope elevation that is perpendicular to the azimuth axis of rotation and to instruct the Magellan. To do this, place a bubble level on the rocker box base of the telescope under one of the two elevation bearings. The telescope does not need to be on level ground!! Rotate the telescope base until the bubble level reads level (this will occur in at least two locations, 180° (apart). Without moving the telescope from this level position, tilt the telescope tube horizontal and place the bubble level along the top side of the tube. Adjust the tilt of the tube until the bubble level again reads level, and press the ENTER key. Once this horizontal position has been located, you may wish to scribe lines on the telescope bearing and the side panel to locate the true horizontal for future alignments. This would be done by simply lining up the scribe marks and pressing the ENTER key without the need for the bubble level or the preceding procedure.

You are again instructed to press ENTER and to select an alignment star from the catalog. By scrolling with PREV/NEXT, select a star familiar to you and press ENTER. Move the telescope to the selected star, center it in the eyepiece and press ENTER again. Magellan then offers the selection of a second alignment star which should be selected and aligned as was the first star.

If errors occur during the alignment procedure Magellan can detect these based on calculations of expected values. For example, if the wrong star is centered during alignment, Magellan will detect that the distance between stars is not what is expected. If this variation exceeds preset limits, Magellan will display the message "Alignment Error Check Stars." If this occurs, press ENTER and begin the alignment procedure again. If the alignment is successful a number will be displayed next to the "Align" display which gives a relative value of merit for alignment quality (100 is perfect as in 100%).

[ toc ] 2) Altaz Vertical

This method of alignment requires that the telescope be perpendicular to the base (parallel to the axis of rotation). This is achieved by placing the telescope in a vertical position and rotating the base while observing the star field in the eyepiece. If the telescope is perpendicular to the base the stars will appear to rotate around the center of the field of view. Adjust the telescope as required. When you have determined the vertical position, scribe marks on the base and telescope that will allow this position to be found in future sessions.

Once the telescope is vertical, press ENTER. You are now instructed to press ENTER and to select an alignment star from the catalog. By scrolling with PREV/NEXT, select a star familiar to you and press ENTER. Move the telescope to the selected star, center it in the eyepiece and press ENTER again. Magellan then offers the selection of a second alignment star which should be selected and aligned as was the first star.

If errors occur during the alignment procedure Magellan can detect these based on calculations of expected values. For example, if the wrong star is centered during alignment, Magellan will detect that the distance between stars is not what should be expected. If this variation exceeds preset limits, Magellan will display the message "Alignment Error Check Stars." If this occurs, press ENTER and begin the alignment procedure again. If the alignment is successful a number will be displayed next to the "Align" display which gives a relative value of merit for alignment quality (100 is perfect as in 100%).

[ toc ] 3. Date

The date is required to locate planets and is in Month/Day/Year format. The date can be altered by pressing ENTER to select the date function. This causes the cursor to blink on the first date digit. The value of each digit is changed and selected by using the PREV/NEXT and ENTER keys. After the last digit of the year is selected pressing ENTER will complete the date function.

[ toc ] 4. Encoders...

This function is used to select the encoder specifications used on the telescope. The default values are correct for high resolution encoders shipped with your telescope. If the standard value of the encoder is different due to a change in gear ratios, a note will appear in the installation instructions which will direct you to change this ratio setting. ENTER, PREV and NEXT are used to select and modify these numbers as in previous functions.

Caution Dobsonian Owners!! It is possible to install the elevation encoder on either side of the rocker base. These two locations cause the encoder to rotate in opposite directions giving different readings to the Magellan. The Magellan is initialized to expect the elevation encoder bracket to be installed on the side panel with the clamp attaching near the back plate of the rocker base. If the encoder is installed properly the reading will decrease as the telescope is moved from the vertical to the horizontal position. If this is not the case, move the encoder to the other side of the rocker box, otherwise, alignment will not be possible.

[ toc ] 5. Help...

A very brief description of Magellan functions is given by this option. Pressing ENTER will display the help messages and the PREV/NEXT keys move the user through this text. Pressing the MODE key will end the help session.

[ toc ] B. Coordinate Mode

This mode displays the direction coordinates of the telescope (where it is pointing). If the telescope has been aligned the display will show RA and DEC values. If alignment has not been accomplished the display will show the raw encoder counts.

[ toc ] 1. Encoder Display

This display shows raw encoder counts. As the telescope is moved these values will increase or decrease depending on the direction of movement and axis involved. This display will quickly show any malfunctions in the encoder system or cables.

[ toc ] 2. Coordinate Display

If the telescope has been aligned, the display will be in RA and DEC values. You will see the RA = and DEC = coordinates of where the telescope is pointing. If you move the telescope, the coordinates display will immediately update the new position in Right Ascension (RA) and Declination (DEC).

[ toc ] C. Timer Mode

The timer mode displays the stop watch timer and the current time.

[ toc ] 1. Timer

This function allows the user to measure precise time periods for such activities as photographic time exposures. The timer display shows time remaining in Hours:Minutes:Seconds. The timed duration is set by holding the ENTER key for more than one second while the timer display is present and selected. The cursor will appear in the hours position of the display and will respond to the PREV/NEXT and ENTER keys to set the values of each digit. After the last digit of the seconds position is completed, pressing ENTER will return the display to the original condition. A short duration press of ENTER will start the timer counting down. Pressing ENTER quickly will toggle the timer from running to stopped and stopped to running. When running the timer will continue to count down even if the display is not visible. Upon returning to the timer display the time remaining will be accurate and available to the user.

[ toc ] 2. Local Time

The local time display shows local time as entered by the user. It will start at 00:00:00 when power is turned on. Local time is set by holding the ENTER key for more than one second while the Local display is present and selected. The cursor will appear in the hours position of the display and will respond to the PREV/NEXT and ENTER keys to set the values of each digit. After the last digit of the seconds position is completed, pressing ENTER will return the display to the original condition with Local time now displaying the entered value.

[ toc ] D. Blank Mode

This mode is used to set the brightness of the LCD backlighting.

[ toc ] 1. Adjust Brightness

Pressing ENTER in the blank mode will cause the "Set Brightness" message to appear. Pressing the PREV key will make the display backlight brighter, while pressing the NEXT key will make the backlight dimmer. There are 16 levels of brightness available. After the lighting has been adjusted for the best viewing, press MODE to exit this function.

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