CN101017240A

CN101017240A - Astronomical telescope video CCD automatic guiding method

Info

Publication number: CN101017240A
Application number: CN 200710020041
Authority: CN
Inventors: 朱庆生; 陈伟民; 周小军
Original assignee: Nanjing Astronomical Instruments Co Ltd
Current assignee: Nanjing Astronomical Instruments Co Ltd
Priority date: 2007-02-09
Filing date: 2007-02-09
Publication date: 2007-08-15
Anticipated expiration: 2027-02-09
Also published as: CN100454079C

Abstract

This invention relates to one space telescope visual frequency CCD automatic guide method, which comprises the following steps: fixing visual frequency CCD in guide lens cylinder and main lens cylinder; through CCD image process getting space object image; rotating CCD to make the space image parallel along X direction and rectascension or declination for space object imaging by CCD; computer uses visual frequency to catch image for guide according to visual image and its changes.

Description

Astronomical telescope video CCD automatic guiding method

Technical field

The invention belongs to astronomical telescope research and manufacturing field, be specifically related to a kind of astronomical telescope video CCD automatic guiding method that is used for celestial body is carried out automatic guiding.

Background technology

Astronomical telescope needs for a long time, stably to observe a celestial body, reach high precision, and the automatic guiding method and apparatus must be arranged.To the automatic guiding of celestial body, three kinds of methods are arranged at present.

1, photoelectric tube automatic guiding.Its deficiency is, can't use substantially because of energy is too low faint objects such as fixed stars, and is very unstable again to the bright celestial body that the sun is such, and very responsive to the brightness of the sun, cloud amount, the daylight etc., precision is very low, so be eliminated substantially;

2, line array CCD or bar shaped CCD automatic guiding.Its deficiency is: the celestial body information of reception very little, precision is low, poor anti jamming capability;

3, big target surface area array CCD automatic guiding: performance is good, the precision height, but price is high, and guiding speed is also not ideal enough, even the professional astronomical observatory that has sufficient funds also is difficult to a large amount of outfits, is difficult to promote the use of.

Summary of the invention

Above-mentioned deficiency at prior art, the present invention will provide a kind of new video CCD automatic guiding method, this method can obtain high-precision celestial body mobile message with cheap general little target surface (1/3 ", 1/2 ") video CCD or camera, comprise guiding to all kinds of celestial bodies (for example fixed star, planet, the sun, the moon, artificial object etc.), guiding speed greatly improves, and cost can decline to a great extent.

The scheme of finishing the foregoing invention task is:

Video CCD automatic guiding method, step is as follows:

At a lens barrel that is used for guiding, video CCD or camera that guiding is used are installed, this CCD can both be used for observation as being contained on the body tube, was used for guiding again;

Handle by ccd image, obtain the image of celestial body;

Rotation CCD makes moving at directions X of celestial body parallel with right ascension or declination;

Computing machine obtains video image by capure card, carries out guiding according to this video image and variation thereof.

More particularly, after computing machine obtained video image by capure card, the treatment scheme of carrying out guiding was as follows:

1., obtain a two field picture, all processed for guaranteeing every two field picture, should dash in the full message (interruption) in district at the frame silk ribbon attached to an official seal or a medal of video card, obtain the view data of this frame;

2., to N two field picture stack, to eliminate the star picture shake that atmospheric disturbance causes, it is fixed with actual measurement guiding effect that N looks the guiding rate request, generally can choose at 20～50.General per second is caught 30 two field pictures, can provide one time the guiding signal in 2～5 seconds;

3., the image after the stack is done simple conventional denoising;

4., calculate the brightness center (x of stack back image _i, y _i), the skew at relative first width of cloth figure brightness center

(Δx _i，Δy _i)＝(x _i-x1，y _i-y1)；

5., the spatial movement amount of day body image is:

(Δx _i*P _x，Δy _i*P _Y)

P _xBe the picture rate resolution of CCD at directions X, P _YBe picture rate resolution in the Y direction;

6., according to the spatial movement amount situation of star picture, revise the speed of telescope right ascension, declination, the mobile of star picture narrowed down in the required scope.If amount of movement surpasses the threshold values of setting (can be made as 10～20 pixels, so big deviation just often can not appear in guiding) too greatly, then suspend guiding, continue guiding when treating less than threshold values, can effectively solve and meet spissatus grade for abnormal problem;

7., circulation execution said process finishes until guiding.

The present invention has overcome the deficiencies in the prior art, the general little target surface video CCD that available rates is cheap obtains high-precision celestial body mobile message, effect stability, not being subjected to day luminance brightness to change and approach cloud influences, though run into spissatus for a long time, also can the automatic pause guiding, automatically continue guiding after waiting to disperse like the clouds, therefore even at cloudy weather, still can the whole day auto-guide, guarantee to greatest extent uninterruptedly observation.Guiding speed greatly improves simultaneously, and cost declines to a great extent.

Description of drawings

Fig. 1 is the single-frame images of celestial body;

Fig. 2 is through the celestial image after 50 stacks.

Embodiment

Embodiment 1, and video CCD automatic guiding method is handled by ccd image, obtains celestial image; Rotation CCD makes moving at directions X of celestial body parallel with right ascension or declination.To the sky volume imaging, computing machine obtains video image by capure card with video CCD, and treatment scheme is as follows:

3., the image after the stack is done simple conventional denoising, gone processing such as background;

4., calculate the brightness center (x of every width of cloth stack back image _i, y _i), the skew at relative first width of cloth figure brightness center

(Δx _i，Δy _i)＝(x _i-x1，y _i-y1)；

5., the spatial movement amount of star picture is:

(Δx _i*P _x，Δy _i*P _Y)

6., according to the spatial movement amount situation of star picture, revise the speed of telescope right ascension, declination, the mobile of star picture narrowed down in the required scope.If amount of movement surpasses the threshold values of setting (can be made as 10-20 pixel), then suspend guiding, continue guiding when treating less than threshold values, can effectively solve the spissatus problem of meeting.

7., circulation execution said process finishes until guiding.

Application example 1:

In April, 2006, on the 65cm of astronomical observatory of Nanjing University optical telescope, realized the video CCD automatic guiding, use commercial MTV-1881EX video CCD, pixel resolution is 0.22 rad, 240 rads of 320 rads of * in visual field, 1 hour leading precision is 0.85 rad of right ascension 0.80 rad (RMS) and a declination; Leading precision right ascension was 0.96 rad in 4 hours, 0.9 rad of declination.

Application example 2:

In May, 2006, on full-time the video magnetoheliograph that is Beijing Observatory, with the automatic guiding (guiding to the sun be also referred to as leading) of video CCD realization to the sun, use commercial MTV-1881EX video CCD, pixel resolution is 1 rad, 240 rads of 320 rads of * in visual field, 1 hour leading precision is 0.50 rad of 1 hour right ascension 0.50 rad (RMS) and a declination; 4.5 0.90 rad of hour leading precision right ascension, 0.5 rad of declination.

Claims

1, a kind of astronomical telescope video CCD automatic guiding method, step is as follows:

On guiding lens barrel or body tube, video CCD is installed;

Handle by ccd image, obtain the image of celestial body;

The rotation CCD, make moving of day body image parallel with right ascension or declination at directions X, with video CCD to the sky volume imaging;

Computing machine obtains video image with capure card, carries out guiding according to this video image and variation thereof.

According to the described astronomical telescope video CCD automatic guiding method of claim 1, it is characterized in that 2, after computing machine obtained video image by capure card, the treatment scheme of carrying out guiding was as follows:

1., obtain a two field picture, the described image of obtaining is to dash in the full message in district at the frame silk ribbon attached to an official seal or a medal of video card, obtains the view data of this frame;

2., to N two field picture stack, N looks the guiding rate request, chooses at 20～50; Per second is caught 30 two field pictures, provides the guiding signal in 2～5 seconds one time;

3., the image after the stack is done conventional denoising, gone background process;

4., calculate the brightness center (x of stack back image _i, y _i), skew (the Δ x at relative first width of cloth figure brightness center _i, Δ y _i)=(x _i-x1, y _i-y1);

5., the spatial movement amount of sun picture is:

(Δx _i*P _x，Δy _i*P _Y)，

Wherein, P _xBe the picture rate resolution of CCDX direction, P _YPicture rate resolution in the Y direction;

6., according to the spatial movement amount situation of sky body image, revise the speed of telescope right ascension, declination, the mobile of sun picture narrowed down in the required scope;

If amount of movement surpasses the threshold values of setting, then suspend guiding, continue guiding when treating less than threshold values;

7., circulation execution said process finishes until guiding.