Do it like this:
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
NSLog(@"This is an iPad - Creating popover!");
UIStoryboard *storyboard = [UIStoryboard storyboardWithName: @"MainStoryboard_iPad" bundle:[NSBundle mainBundle]];
EphemerisDataView *ephemView = [storyboard instantiateViewControllerWithIdentifier:@"EphemerisDataView"];
UIPopoverController *popOver = [[UIPopoverController alloc] initWithContentViewController:ephemView];
self.customPopoverController = popOver;
[popOver setPopoverBackgroundViewClass:[DDPopoverBackgroundView class]];
[popOver.popoverBackgroundViewClass setTintColor:[UIColor blackColor]];
popOver.delegate = self;
CGSize size = CGSizeMake(320, 480); // size of view
popOver.popoverContentSize = size;
[popOver presentPopoverFromRect:self.popOverAnchor.bounds inView:self.popOverAnchor
permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
}
else {
NSLog(@"This is not an iPad - Performing segue...");
// Show the next view
[self performSegueWithIdentifier:@"Ephemeris" sender:self];
}