To summarize: 

Choose 3 alignment stars that differ in RA by at least one or two hours 

Select   Align Telescope

GoTo Bright Star   

Select your first alignment star from the submenu 

Mount will slew close to that star 

Use Hand Controller buttons to center the star in the eyepiece 

Select   Align Telescope

Synchronize   

Display will confirm the object to which you are pointing  

Press RA+ to complete the alignment 

2.4.3.3  Additional Alignments 

If you are satisfied with the rough accuracy of a one star alignment, you may skip this 

section.  Otherwise, you should now repeat a similar process with at least 2 more stars on 

the same side of the meridian.  Select   Align Telescope

GoTo Bright Star   from the 

menu and select your next alignment star from the list of Bright Stars.  Press RA+ to 

GoTo that star, and again use the Hand Controller buttons to center the star in your 

eyepiece.  Now select   Align Telescope

Additional Align.    As before, Gemini will 

confirm the object to which you are pointing by displaying its name.  Press RA+ to 

complete this alignment.  Repeat the process for the third alignment star on the same side 

of the meridian.  This will establish a basic pointing model.   

Next, pick one more alignment star on the side opposite the meridian from the first 3, and 

repeat the Additional Align process just described.  The reason for doing this is that after 

a meridian flip, you 

ll experience an offset in RA caused by play in the RA gear (Now the 

opposite side of the worm and teeth are in contact). Additionally, some parts of the 

system (such as the main mirror of an SCT) will have flopped to the other side.  Adding 

one more alignment after a meridian flip allows Gemini to know how big the play in the 

RA gear and the flop are, and take them into account.  For best results, choose a star in 

the middle of the hemisphere, ensuring that the RA gear is in good contact.  Refocusing 

also helps to move the mirror into a stable position after the meridian flip. 

To summarize: 

For each of your other 2 alignment stars: 

o 

Select   Align Telescope

GoTo Bright Star   

o 

Select an alignment star from the  "Bright Stars" catalog 

o 

Mount will slew to that star 

o 

Use Hand Controller buttons to center the star in the eyepiece 

o 

Select   Align Telescope

Additional Align   

o 

Display will confirm the object to which you are pointing  

o 

Press RA+ to complete the alignment 

Choose a star on the opposite side of the meridian 

Perform the above steps for an Additional Align on that star 

Gemini Users Manual 

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