Pseudo wedge?

I have a silly question:

If I were to tilt my altaz mount to an angle of 30 degrees to match my
latitude, would that enable me to use my scope as if it were mounted on
a wedge? I know, I know, but let's just say hypothetically speaking....

-Al

"Al Arduengo" wrote in message
...
I have a silly question:

If I were to tilt my altaz mount to an angle of 30 degrees to match my
latitude, would that enable me to use my scope as if it were mounted on
a wedge? I know, I know, but let's just say hypothetically speaking....
The angle needed is 90-(your latitute). A scope would sit parallel to the
ground at the pole (90 lat), and perpendicular to the ground at the equator
(0 lat).
In your case then the angle would need to be 60 degrees.
The big caveat is balance. If you look at most wedges, the wedge assembly
sticks out quite a long way to one side of the tripod. Then the scope is
leaning from this towards the centre of the tripod, and passes over the
tripod middle with the tube a little way out the other side. In my case, the
centre of gravity of the wedge and scope, is within 1", of the centre of the
tripod when normally loaded. If you just tilt the head of the tripod, all
the weight is now on once side of the tripod, and overbalancing becomes more
and more likely...

Best Wishes

Al Arduengo wrote:
I have a silly question:

If I were to tilt my altaz mount to an angle of 30 degrees to match my
latitude, would that enable me to use my scope as if it were mounted on
a wedge? I know, I know, but let's just say hypothetically speaking....



If you arrange it so a line perpendicular to the base plate points to
North, it will become an EQ mount. That is what a wedge does.

But if a Dob, tilting it that much may make the AZ bearing behave very
strangely (have not tried it, myself). And most of the mass in the EL
bearing will be on the lower pad, so that may do odd things, too (though
likely the OTA will not fall out of the base at only 30 deg).

Phil

You can make a wedge with some scraps of plywood, a barn door hinge, a
jack screw and a couple of supports for the edges. It may not look
pretty, but it will serve until your wife is more agreeable.

Richard Kenney

Al Arduengo wrote:

"Roger Hamlett" writes:


"Al Arduengo" wrote in message
...

I have a silly question:

If I were to tilt my altaz mount to an angle of 30 degrees to match my
latitude, would that enable me to use my scope as if it were mounted on
a wedge? I know, I know, but let's just say hypothetically speaking....

The angle needed is 90-(your latitute). A scope would sit parallel to the
ground at the pole (90 lat), and perpendicular to the ground at the equator
(0 lat).
In your case then the angle would need to be 60 degrees.
The big caveat is balance. If you look at most wedges, the wedge assembly
sticks out quite a long way to one side of the tripod. Then the scope is
leaning from this towards the centre of the tripod, and passes over the
tripod middle with the tube a little way out the other side. In my case, the
centre of gravity of the wedge and scope, is within 1", of the centre of the
tripod when normally loaded. If you just tilt the head of the tripod, all
the weight is now on once side of the tripod, and overbalancing becomes more
and more likely...

Best Wishes


Hmm, so it would seem. Guess I'll have to quit being a cheap-a** and just
get a wedge. I wonder if there are widely available plans for an
inexpensive homemade wedge? My wife is getting a little irritated at my
expenditures so i have to keep it low/no cost.

Thanks for the input.
-Al

Hmm, so it would seem. Guess I'll have to quit being a cheap-a** and just
get a wedge. I wonder if there are widely available plans for an
inexpensive homemade wedge? My wife is getting a little irritated at my
expenditures so i have to keep it low/no cost.

Thanks for the input.
It is very possible to do.
The 'best' way, depends on your engineering skills/resources. The 'easiest',
is making it out of some nice marine ply. Tooling required, a jigsaw, drill,
some sandpaper, screws, screwdriver, and a method of providing the 'angle'
adjustment (a trip to the local hardware shop, will often find some
adjustment screws than can do this, and a nice solid 'hinge' for the other
end of the angled plate). It is well worth drawing the side plates out on a
nice full size piece of paper, so you can get an idea of where the centre of
gravity will sit.
I made my own wedge, but having a milling machine, made it out of 5/8"
2024T3 aviation grade aluminium plate. The material alone cost as much as
many wedges on the market, but it brings a new meaning to 'rigid'...
You should be able to make a perfectly 'competent' wedge, for a few hours
work, and perhaps 1/10th the typical cost of an 'off the shelf' unit.
Go to:
http://www.mapug.com/pages/memberprod.html
If you look at the bottom of the page, there are a number of 'wedge
designs'. The first, and fifth ones are wooden wedges, that might well give
you some ideas (remember to draw it for the angle you need...).

Best Wishes