The way I see it, you only need an adapter plate on your pier if you have a wedge mounted Meade or Celestron alt/az mount.
Proper equatorial mounts such as the EQ5/EQ6 and all its rebranded siblings, Takahasi's, Paramounts etc all have the ability to have their bases adjusted in azimuth, and their altitude adjusted of course. With these two adjustments you can just mount the base directly on top of the pier and still achieve polar alignment. Yet everyone whacks on an adapter plate, perched on top of three or four flexy bolts.
Please, correct me if I'm wrong, but are people just putting adapter plates on just because everyone else is?
Wouldn't you want the top of the pier to be level first to let you get polar alignment?
No I don't believe so. Adjustment in the two planes allows you to point the R.A. axis at the pole.
Imagine even an extreme case where the top of the pier is angled at 45 degrees. Rotation of the mount's az mounting adjustment allows you to bring the R.A. axis in to the same plane as the pole, the mount's Az mounting adjustment then allows the R.A. axis to be wound up or down to become polar.
I think you're technically right, but I recall reading somewhere that if you have the base level, it isolates interactions between azimuth and altitude when doing polar alignment. Old fashion drift alignment is easier if you can correct for azimuth when pointing up and altitude when pointing to the horizon. My guess is that it is also easier for the "computer aided" polar alignment routines that many use with the mounts you mentioned above. These routines usually say to turn the azimuth & altitude knobs so far - I would expect that the software is assuming the pier top is level when making those calculation??? (Although, I also have vague recollections of a recent thread that may have mentioned the Paramount software being able to cope with it being out of square too?)
DT
Last edited by DavidTrap; 13-06-2011 at 09:03 PM.
Reason: added a bit
I also like the fact that with an adapter plate being above the pier, allows me to attach the center bolt to the EQ Head. Did this many a time with the EQ6. Without the adapter plate, I wouldn't be able to put the bolt in the hole...
I have another reason for using one: I have a small fanless ATOM dual-core computer (an Israeli-made fitPC2i)that actually sits between the 2 plates and feeds to a screen mounted on the pier itself so that all my computer connections are at the scope and not scattered across the floor.
Peter
Old fashion drift alignment is easier if you can correct for azimuth when pointing up and altitude when pointing to the horizon. My guess is that it is also easier for the "computer aided" polar alignment routines that many use with the mounts you mentioned above. These routines usually say to turn the azimuth & altitude knobs so far - I would expect that the software is assuming the pier top is level when making those calculation?
Fair enough, and if the top of the pier was grossly out of whack like in my extreme 45 degree scenario I can understand that. But, the top of your average pier is more than likely within one degree of being perfectly level anyway, so I don't think this will make a difference to drift or computer aided alignment.
I also like the fact that with an adapter plate being above the pier, allows me to attach the center bolt to the EQ Head. Did this many a time with the EQ6. Without the adapter plate, I wouldn't be able to put the bolt in the hole...
This is how I'm solving that on my pier. Nice and simple, and still no floppy bolt mounted plate swinging around up in the air!
I have another reason for using one: I have a small fanless ATOM dual-core computer (an Israeli-made fitPC2i)that actually sits between the 2 plates and feeds to a screen mounted on the pier itself so that all my computer connections are at the scope and not scattered across the floor.
Peter
Hmm, ok. Nice little PC Peter, I'd love one of those fitPC2's, but still not a valid reason for mounting your scope on a wobbleboard!
Hmm, ok. Nice little PC Peter, I'd love one of those fitPC2's, but still not a valid reason for mounting your scope on a wobbleboard!
Cheers,
Jason.
I wonder if there are many people who can remember what a 'wobble-board' is; or worse still, who would admit to having owned one. It brings back some very old memories of Rolf Harris, among others.
But even so, 4 1/2 inch bolts and 12 nuts holding 2 sheets of 16mm steel no more than 40mm apart hardly seems to qualify. I don't have any uncontrolable urge to sing oLD mAN eMU' when I go near it.
I used 4 x 3/4" bolts on mine and it is very solid. The gap provides a very handy space for keeping observing papers, reading glasses, etc. whilst observing. As it turned out, I actually cut my pier pipe a bit short, so by using the "adapterr plate", I was able to raise the scope to the preferred height.
Proper equatorial mounts such as the....Paramounts....have the ability to have their bases adjusted in azimuth, and their altitude adjusted of course.
The Paramount ME even has micro-levelers built-in so that getting the pier reasonably level is good enough. One just tweaks the micro-levelers for perfect level. Most people just put one level on their Paramount ME, but you can put two of them on the mount if you want to, one on each side. I've done that. Alas, the two levels give two different readings, so I average them.
But back to the original topic of adapter plates. In my mind an "Adapter Plate" isn't for leveling, it's for adapting incompatible mounting bolt patterns and sizes, which in an ideal world should only be the case when putting a new mount on an old pier that was originally made for a different mount.
I used 4 x 3/4" bolts on mine and it is very solid. .....
Chris
Same here in stainless.ZERO movement and necessary as the 1/2" steel plate welded onto the pier top has a buckle in it.
The powr supply fits nicely under there as well
