A method of immediate detection of objects with a near-zero apparent motion in series of CCD-frames

The paper deals with a computational method for detection of the solar system minor bodies (SSOs), whose inter-frame shifts in series of CCD-frames during the observation are commensurate with the errors in measuring their positions. These objects have velocities of apparent motion between CCD-frames not exceeding three rms errors (3σ) of measurements of their positions. About 15% of objects have a near-zero apparent motion in CCD-frames, including the objects beyond the Jupiter’s orbit as well as the asteroids heading straight to the Earth. The proposed method for detection of the object’s near-zero apparent motion in series of CCD-frames is based on the Fisher f-criterion instead of using the traditional decision rules that are based on the maximum likelihood criterion. We analyzed the quality indicators of detection of the object’s near-zero apparent motion applying statistical and in situ modeling techniques in terms of the conditional probability of the true detection of objects with a near-zero apparent motion. The efficiency of method being implemented as a plugin for the Collection Light Technology (CoLiTec) software for automated asteroids and comets detection has been demonstrated. Among the objects discovered with this plugin, there was the sungrazing comet C/2012 S1 (ISON). Within 26 min of the observation, the comet’s image has been moved by three pixels in a series of four CCD-frames (the velocity of its apparent motion at the moment of discovery was equal to 0.8 pixels per CCD-frame; the image size on the frame was about five pixels). Next verification in observations of asteroids with a near-zero apparent motion conducted with small telescopes has confirmed an efficiency of the method even in bad conditions (strong backlight from the full Moon). So, we recommend applying the proposed method for series of observations with four or more frames

Розробка обчислювального методу виявлення близьконульового видимого руху об'єктів на серії ccd-кадрів

A computational method for detecting near-zero apparent motion of objects on the series of CCD-frames using the XY-wise and coordinate-wise decision rules is developed. The method is based on checking the statistical significance of the factor of speed of the object apparent motion on the studied series of measurements using the Student's t-test for coordinate-wise decision rules and F-test for XY-wise decision rules. This is the main feature of the developed computational method compared with the conventional decision rules based on the maximum likelihood criterion.The developed computational method for detecting near-zero apparent motion of the objects was tried and tested, and embedded in the block of inter-frame processing of the CoLiTec software package for the operational automated detection of new and tracking of the known asteroids, comets and faint celestial bodies.Using the CoLiTec software package and the proposed embedded computational method, the comet C/2012 S1 (ISON) — long-period sungrazing comet was discovered, which at the time of discovery was the object with near zero apparent motion.Разработан вычислительный метод обнаружения околонулевого видимого движения объектов на серии CCD-кадров с использованием двухкоординатного и покоординатных решающих правил. Метод основан на проверке статистической значимости фактора скорости видимого движения объекта c использованием t-критерия Стьюдента для покоординатных решающих правил и f-критерия Фишера для двухкоординатного решающего правила.Розроблено обчислювальний метод виявлення близьконульового видимого руху об'єктів на серії ПЗЗ-кадрів з використанням двокоординатного та покоординатних вирішальних правил. Метод заснований на перевірці статистичної значимості фактору швидкості видимого руху об'єкта на досліджуваній серії вимірювань з використанням t-критерія Стьюдента для покоординатних вирішальних правил і f-критерія Фішера для двокоординатного вирішального правила

Improving the accuracy of identifying objects in digital frames of one series through the procedure of preliminary identification of measurements

The object of this study is images of various objects of the Solar System on a series of digital frames. The variety and quality of shooting conditions make it difficult to identify a frame with the corresponding part of the sky. This fact significantly reduces the quality indicators of detection and estimation of the position of objects of the Solar System using already known computational methods and international astronomical astrometric and photometric catalogs. To solve this problem, a procedure for preliminary identification of measurements of digital frames of one series was devised. This procedure is based on the determination of the shift parameters between the dimensions of a frame and the forms of a catalog or another frame. Also, taking into account the possibility of forming false measurements has made it possible to increase the accuracy of identification and resistance to various kinds of destabilizing factors. Based on this, the final estimation of the shift parameters between frames was performed. Due to these features, the use of the devised preliminary identification procedure makes it possible to improve identification with reference astronomical objects and reduce the number of false detections. The study showed that when identifying frames, the fitting gives the best accuracy of binding to the starry sky. Also, the standard deviation of frame identification errors in this case is 7–10 times less than without using the devised procedure. The procedure developed for preliminary identification of measurements of digital frames of one series was tested in practice within the framework of the CoLiTec project. It has been incorporated into the Lemur software for automated detection of new and tracking of known objects. Owing to the use of the Lemur software and the proposed procedure implemented in it, more than 700,000 measurements of various astronomical objects under study were successfully identifie

A method of immediate detection of objects with a near-zero apparent motion in series of CCD-frames

The paper deals with a computational method for detection of the solar system minor bodies (SSOs), whose inter-frame shifts in series of CCD-frames during the observation are commensurate with the errors in measuring their positions. These objects have velocities of apparent motion between CCD-frames not exceeding three rms errors (3σ) of measurements of their positions. About 15% of objects have a near-zero apparent motion in CCD-frames, including the objects beyond the Jupiter’s orbit as well as the asteroids heading straight to the Earth. The proposed method for detection of the object’s near-zero apparent motion in series of CCD-frames is based on the Fisher f-criterion instead of using the traditional decision rules that are based on the maximum likelihood criterion. We analyzed the quality indicators of detection of the object’s near-zero apparent motion applying statistical and in situ modeling techniques in terms of the conditional probability of the true detection of objects with a near-zero apparent motion. The efficiency of method being implemented as a plugin for the Collection Light Technology (CoLiTec) software for automated asteroids and comets detection has been demonstrated. Among the objects discovered with this plugin, there was the sungrazing comet C/2012 S1 (ISON). Within 26 min of the observation, the comet’s image has been moved by three pixels in a series of four CCD-frames (the velocity of its apparent motion at the moment of discovery was equal to 0.8 pixels per CCD-frame; the image size on the frame was about five pixels). Next verification in observations of asteroids with a near-zero apparent motion conducted with small telescopes has confirmed an efficiency of the method even in bad conditions (strong backlight from the full Moon). So, we recommend applying the proposed method for series of observations with four or more frames