Lunar Module IMU Realign (P52) Procedure

Wedge313

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Trying to do a P52 in the LM, pretty sure I've made the marks correctly but not getting any indication on the DSKY that the marks are being accepted. I'm obviously doing something wrong, could someone point out a good source for me to study? (There's Orbiter wiki articles and tutorials for a P52 in the CSM but I can't find any comparable info for the LM). Thanks
 

indy91

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The G&N Dictionary is a good reference: https://utmb-ir.tdl.org/handle/2152.3/9629
The AGC User's Guide is a very comprehensive document about all AGC programs in CMC and LGC: https://www.ibiblio.org/apollo/Documents/j2-80-E-2448-REV1_text.pdf P52 in the LM begins on PDF page 697.

I guess for you specific case you should look at verb and noun. If you are still on the 01 71 display then you aren't at the point yet where you should take the marks, so you have to do another PRO. If you have the 54 71 up then you are ready to mark. Verb 54 means "mark X or Y-reticle", 52 for X-reticle, 53 for Y-reticle. Basically you have to do alternating marks with x and y (buttons on your keyboard Q and Y). 4 or 5 in total. So those 52-54 numbers are only relevant when you get confused what mark you did last. I'm not usually going back to the DSKY in this process. Once I see the verb 54 I'm just going to the AOT and do my 5 marks, always starting with the X-Reticle.
 

Wedge313

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Thanks. A little light reading and I'll be a LM Magellan in no time.
 

MrFickles

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Also, don't worry too much if you see a PROG error when you're done with the marks. It's most probably because you did 2 X or Y marks consecutively by accident. As long as you've done more than 3 of each, the marking process should be well within the 0.1 degree error.
 
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