service not visible when launched inside class.

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I'm attempting to implement a service in which the callback is a member function of a class (with reference to the tutorial)

My code, as below, builds and runs without error, outputting the expected "service launched!". Without using static in the callback signature I get error: invalid use of non-static member function pointsCallback);

But when I run rosservice list "test_service" or "X/test_service" isn't present. Why isn't my service visible?

#include <stdio.h>
#include <string>
#include <ros/ros.h>

#include "image_transform/TransformPoints.h"

class ImageTransform {
 public:
    ImageTransform() {
        ros::NodeHandle private_nh("~");
        ros::ServiceServer service = private_nh.advertiseService("test_service",
                                                                 pointsCallback);
        std::cout << "service launched!" << std::endl;
    }

    static bool pointsCallback(image_transform::TransformPoints::Request &req,
                               image_transform::TransformPoints::Response &res) {
        std::cout << "service called" << std::endl;
        return true;
    }
};

int main(int argc, char **argv) {
    // ROS NODE INIT
    ros::init(argc, argv, "image_tranform");
    ImageTransform image_transform;
    ros::spin();
    return 0;
}