microMAX does not have the EP or GP settings). These represent the following:

AV

Alt/az

Vertical. For use with altitude/azimuth mounts

 

initialized to a vertical* position.

AZ

Alt/az

Zero.

For use with altitude/azimuth mounts

 

initialized to a level* (or 0°) position.

EQ

EQuatorial.

For equatorial mounts using a two-star

 

alignment. This must be used if you have a non-polar

 

aligned, non-German, equatorial mount.

correct values to use for your telescope mount. If you purchased your encoders with the MAX computer, the resolutions are already defined for your mount.

Under this setup, the first value is that of the Right Ascension, or Azimuth encoder. The second value is that of the Declination, or Altitude encoder. The correct resolution is that of the encoder multiplied by the number of turns it makes each time the telescope axis is rotated. For example, an encoder with a resolution of 5000 tics, when geared 2:1, yields an effective resolution of 10000.

EP

Equatorial Perfect.

Only for use with a non-German,

 

equatorial mount which will be used in a perfectly

 

polar aligned configuration.

 

 

ET

Equatorial

Table.

For

use

with a

mount whose

 

tracking motion is not apparent to the encoders (such

 

as an altitude/azimuth mount utilizing a tracking

 

platform). In this mode, the MAX computer assumes

 

that the telescope is being driven at exactly sidereal

 

rate, however it does not require that the mount be

 

polar aligned.

 

 

 

 

GQ

German

EQuatorial.

Used

with

non-fork type

equatorial mounts. If the telescope can be pointed in the same direction from two unique positions (as with German mounts), the computer assumes one of these positions.

Refer to the addendum "Star Alignments with a German Equatorial Mount" for further information.

GP German Perfect. Used with non-fork type equatorial mounts which will be used in a perfectly polar aligned configuration.

Refer to the addendum Star Alignments with a German Equatorial Mount for further information.

*See the separate addendum The Importance of the Initial NGC Alignment for details.

Scroll Rate. This determines how fast the information on objects is scrolled across the MAX computer display. The default value (that set prior to shipment) is 5, with the range being 0 (slowest) to 9 (fastest).

Chart Reference. Whenever information on an object is scrolled across the display, the last item shown is the chart number on which that object can be found. With the NGC-MAXyou may select between two popular star atlases: Sky Atlas 2000 or Uranometria. The appropriate chart number will appear after "SA=" or "UA=" respectively.

Encoder Resolution. These values tell the MAX computer what the final output resolutions of the encoders are. A separate sheet, JMI Encoder Setup Specifications, which was included with your encoders, specifies the

SET DEC=0, LEVEL ME, and VERTICAL

For non-polar aligned telescopes, or polar aligned telescopes using the two-star alignment method, the only case in which you can ignore the initial pointing instruction is when the MAX computer will not be used for actual viewing (such as when conducting the Encoder Test). At all other times, this step is vital to proper performance, and can greatly affect the accuracy of the unit (either beneficially or detrimentally). None of the above messages will appear if the MAX computer is set for use with a polar aligned telescope.

When the initial pointing instruction is displayed (immediately after the power-up version message), no button on the MAX computer should be pressed until that positional requirement has been met. This initial position tells the computer where your two encoder axes are perpendicular (or parallel) to each other. This point is not affected by polar aligning or leveling, so it does not matter how your mount is oriented relative to the Earth or sky.

The meaning of each of the three possible messages is outlined here:

SET DEC=0 or LEVEL ME

The telescope should be pointed with the tube perpendicular to the polar/azimuth axis. A Declination setting circle, if set properly, may be used to find this point.

VERTICAL

The telescope should be pointed with the tube parallel to the polar/azimuth axis. A Declination setting circle, if set properly, may be used to find this point.

It should be noted that improving this initial alignment can greatly increase the guiding accuracy without showing an improvement in the warp factor (which only measures the accuracy of the distance between the two alignment stars). Since factory marks are often off by a significant amount, you may wish to do the following test. First, adjust the initial position in one direction a few thousandths of an inch, finish the alignment, then test the guiding accuracy. If it is worse, try adjusting the initial alignment in the other direction. Do several more adjustments in the direction that showed improvement until you see the most accurate guiding. This process is time consuming but well worth the effort.

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