Re: Rookie Question

If useful to the below, here are some photos after the AP1100 did a hard night’s work.


Top view showing screw placement and saddle placement on the DEC plate.  The two bottom screws old the PPBAdv (and notice they are not quite straight across so there is a slight twist, not terribly noticeable, but not worth me drilling new holes although there is plenty of room to do so.



One of these screws needs to be short to avoid the bracket screws, also no room for a normal castle nut (I said earlier it was avoid a cable, sorry, bad memory, it was the bracket itself).



Here’s the real issue to be aware of: there is plenty of room to clear the motor housing on rotation, and by “plenty” I mean “not much at all”.  The bracket is holding the PPBAdv off the saddle maybe 1/8” or so (and is stiff enough it stays there despite only one bracket).  But you cannot do anything that increases that spacing much or it’s going to hit on RA rotation, same with any bracket that goes over top of the PPBAdv (or under-top in this orientation).


But despite being a bit of a hack, this works exceptionally well, all the wiring I need for the back of the OTA – camera, FW, focuser, guide, etc. is right there at the back, cables can be really short.  Only wire running to the OTA front is the dew heater.   And while there’s room for a dozen cables thru-mount, this keeps it down to only two, 12V and USB3.


The covered holes is because this is a PPBAdv first generation, and that top right USB (in this orientation) will not work with USB3 ZWO devices, or any USB2 device, so … basically nothing. The other is a variable 12V hole that exactly aligns with the 12V input power supply on the other side – I got inverted and plugged in the wrong one and smoke came out once.  Don’t do that.  (Pegasus repaired it quickly and relatively inexpensively though).  So the tape is to prevent a sleep deprived human working in the dark from doing it again.



From: ap@...
Sent: Friday, October 1, 2021 10:08 PM
Subject: RE: [ap-gto] Rookie Question


Derek S wrote:


  • How did you attach the powerbox?  I was thinking 1 screw and velcro?

It’s the pocket powerbox, I’m not sure if the larger ones would fit as the RA axis rotates.


I used two 1/4x20 screws, and one of the two brackets it came with (or maybe it was extra I do not know, but from Pegasus).  The bracket does not quite fit a 1/4x20 screw, so I reamed it out (it only takes a very little bit and plenty of metal).


I found two 1/4x20 holes, one was for a socket head, one for the countersunk angled head, and these happen to line up (I think there’s only two that do on one end only of the 16” saddle).  It is not quite straight but pretty close.  You have to slide the saddle back a step also.


With nuts on the bottom tight it holds the PPBadv straight enough I did not need anything else; I had planned thick double sided tape near the end, but didn’t use it.  If I recall you need a specific length for one bolt or it sticks up and blocks the temp probe connector.


It’s outside working for a living right now (and not doing well, it’s attracting clouds!) or I’d send a photo, but can tomorrow if that doesn’t make sense.


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