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* GUIDE TO RECOVERY AND DISCOVERY WORK IN THE NEAT ARCHIVES (SKYMORPH) USING *
* ASTROMETRICA and FINDORB *

指南:利用ASTROMETRICA及FINDORB软件在NEAT档案图片中搜索小行星

by Marco Langbroek
作者:Marco Langbroek

http://home.wanadoo.nl/marco.langbroek/asteroid.html

09/08/2005
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* This guide was written after questions on how I work with NEAT data. It is the way
I work (other ways are possible) and can be a guide to novice users of Skymorph.
Much of the technique described in this guide, I learned from Rob Matson, whom I
heartfuly thank for his teaching!

不久前,有人问我是如何利用NEAT图片搜索天体的,本文就是关于我如何搜索的介绍,当然也可作为一个使用Skymorph新手的指南。本指南中的很多内容是Rob Matson传授于我的,在此我对他表示诚挚的感谢!

* The guide focusses on the discovery of new objects in the NEAT archives, but also
serves as a guide to doing precovery work on known objects.

本指南所针对的主要是如何利用NEAT档案图片搜索新目标,但也同样可通过NEAT图片来对一直天体进行重新发现。

* It is assumed that the astrometric program used is Herbert Raab's very fine shareware
"Astrometrica", see http://www.astrometrica.at

Herbert Raab所编的共享软件Astrometrica是用于天文测量的很好的程序,可访问http://www.astrometrica.at

* Also needed is Bill Gray's freeware "FindOrb", http://www.projectpluto.com

Bill Gray的免费软件FindOrb对于搜索NEAT图片小行星也是必须的,请访问http://www.projectpluto.com

* If you want to do this kind of work, you should get yourself acquainted with the meaning
of orbital elements.

如果你打算进行搜索,你必须知道有关轨道根素的基本知识。

Note: Astrometrica has very good step-by-step tutorials in the "help" section. Do these
tutorials to learn to work with the software.

注释:Astrometrica软件有一个很好的帮助文件和指南,你最好先学习一下。


**************************************************************************************


Okay, here it goes step by step:现在开始:

Step Action(s)步骤:

0. Go to Skymorph, http://skys.gsfc.nasa.gov/skymorph/skymorph.html and select "look
for images by time and position". Fill in a position (both RA and declination should
be input in degrees) and time search definition. Tip: mid-August 2002 has a number of
good quality nights close together.

0、访问Skymorph网站:http://skys.gsfc.nasa.gov/skymorph/skymorph.html并选择“look
for images by time and position(通过时间和位置搜索)”。添入所要搜索的时间和位置(赤经和赤纬都应该用度表示)。技巧:2002年8月中旬有很多质量较好,时间接近的图片。

*For precovery work, omit this first "step zero", go to step 8 immediately and omit
step 5. At step 8b, fill in the object designation at the top of the page or its
orbital elements below if it is a very recent discovery not yet in the HORIZONS
database*

*对于重新发现工作,忽略本步骤,请跳转到第8步并忽略第5步,在第8步b,在页面顶部填入目标的名称或者是在下部填入目标的轨道根素(如果这是个非常近的发现且尚未在HORIZONS的数据库中)。

1. Download triplet of 3 FITS files with about 20-30 minute time spacing from Skymorph;
FITS from station 644 have an a, b or c behind the image number, the other are images
from station 608. The 608 images have so many false artifacts (and worse limiting
magnitude) that I never use them for searching, only for additional positions after
a find. I usually download images of 1100 x 1100 pixels (you can set this before
downloading under "request parameters: NEAT pixels". Also un-tag "DSS-image" and
"NEAT/DSS SkyView overlay" as you won't need these)

1、从Skymorph中下载拍摄间隔大约为20-30分钟的一组(三张)FITS格式图片;如果图片名称后有a,b或c标识表示是644号站拍摄的图片,其他的则是608号站拍摄的图片。608号站拍摄的图片有很多人为的错误(而且极限星等也比较低),所以我从来都不用它们来搜索,除非用来补充一个已有的新发现数据。我通常下载的图片大小是1100*1100大小(你可以在你下载前合适填写"request parameters: NEAT pixels"中的内容来设置需要图片的大小。其他的两个选项——"DSS-image"和"NEAT/DSS SkyView overlay"请不要勾选。

2. Open them in Astrometrica (and type in image dates and time in the entry boxes
that appear); Make sure your configuration file used is the 644.cfg (you can
alter this through "settings"), an example of which can be found at
http://home.wanadoo.nl/marco.langbroek/644.cfg

2、用Astrometrica软件打开刚才下载的图片(在弹出的拍摄时间、日期对话框中输入相应的内容);请确认你使用的设置文件是644.cfg(你可以通过选择“settings”改变设置文件),你可以在http://home.wanadoo.nl/marco.langbroek/644.cfg得到这个设置文件。

3. Make a blink of these 3 images (tools ---> blink image, or click the appropriate
button);

3、将三幅图片组成动画(tools ---> blink image或点击适当的工具按钮)

4. Look by eye for moving objects (Rob and I never use the auto-detect function);
when you have one, check whether the movement is consistent with the image sequence;

4、用肉眼观察,搜索时候有移动目标(Rob和我从不使用软件提供的自动检测功能);如果你确实发现了一个移动目标,请再仔细检查动画图片的顺序是否与移动天体的特点符合。

5. If you have a moving object, check whether its a known asteroid or not using ASTPLOT:
http://asteroid.lowell.edu/cgi-bin/koehn/astplot

5、如果你确认是一个移动的目标,请先检查该目标是否是颗已知的小行星,可到ASTPLOT验证:http://asteroid.lowell.edu/cgi-bin/koehn/astplot

*note*: the reason for using ASTPLOT and not the "known image overlay" option of
Astrometrca itself, is that the MPCORB file Astrometrica uses will be for the current
epoch and not the epoch of these "old" images, which will introduce discrepancies.

*注释*:之所以没有使用Astrometrca自带的“known image overlay”功能,是因为该软件所依据的MPCORB文件只能用来验证最近的目标而不适用于NEAT的档案图片。

5a. Select the correct station code from the list in Astplot, fill in date, time and
image center of the middle image of the triplet, change limiting magnitude to
+21.5 and image vector to "1 hour" and then click "obtain plot".

5a、在ASTPLOT的列表中选择拍摄地点的编号并填入三张图片中中间那张图片的拍摄日期、时间和图片中心的坐标,将极限星等处改为+21.5等并把图片向量改为“1小时”,然后点击“获得区域示意图”。

5b. It takes a while, but after some 2 minutes or so it will generate a map.
Compare this map to your images.

5b、过一会,大概过了2分钟,会出现一个图,比较这个图和你下载的图。

6. If the object on your images is an unknown: measure 3 positions (3 images);

6、如果你发现的目标并不是已知目标,那么请你在三张图片上测量好相应的位置

6a: click "astrometry ---> data reduction";
6b: enter coordinates of image center (leave "object" field blank);
6c: Astrometrica will now download the appropriate set of
reference stars from USNO-B1.0 catalogue over the internet;
6d: after downloading it will proceed to auto-match this set
to the stars in the images *This can take several minutes!*;
6e: After the fit to the stars has been achieved, click on the
object you want to measure in the (first of 3) image;
6f: Astrometrica will auto-match to the center of the object. If
you are satisfied with this fit (99 out of 100 times), enter
a preliminary designation of 6 characters (e.g. "YOU111") in
the most lower-right box (the right-most box under "object
designation": leave the left box blank) and then click "accept";
if you are not satisfied with the fit click "reject", zoom in on
the image and mmanually put your cursor where you want it, then click
while holding the "ctrl"-key;

6a、点击“天文测量--->天文数据分类;
6b、填写好图片中心坐标(在 object 区域那里留空)
6c、Astrometrica软件将通过互联网,从USNO-B1.0星表目录下载对应的参考星
6d、下载完之后,软件会自动匹配参考星(大概要花费几分钟的时间)
6e、等自动匹配完成后,点击你想测量的目标(三张中的第一张)
6f、Astrometrica软件将自动定位到目标的中心,如果你认为满意(99%都会满意的),就在弹出窗口的下边偏右的输入框中填写一个临时的6个字符的名字(比如:"YOU111")("object designation"之下的那个输入框请空白),然后点击“接受”;如果你对软件自动找到的目标中心不满意,请点击“拒绝”,然后放大图片,手动用鼠标十字对准目标,按住Ctrl键并点击。

*Note*: if the object you measure is not a new discovery but a precovery,
enter it's "packed" MPC designation in the lower right box;

*注释*:如果你测量的目标不是个新发现而仅仅是某小行星的前期发现,请在右下的输入框中填写好该目标的MPC临时编号。

6g: Repeat steps 6e and 6f for the other two images.
6h: Astrometrica will auto-write each measurement to the file MPCReport.txt
in the correct MPC report format;
6i: *Note*: when starting up Astrometrica, it may say "MPCReport already
exists" and asks whether you want to overwrite it. DON'T DO THIS! You
will loose all previous measurements in the file... Periodically
archive MPCReport.txt by renaming it and then let Astrometrica create
a new, blank one. Note that new measurements on new objects are appended to
the existing MPCReport file, it will not overwrite older data in the file.

6g、对另两张图片重复第6e和6f步骤
6h、Astrometrica软件会自动将以上的测量结果以正确的MPC要求格式写入MPCReport.txt文件
6i、*注释*:当你每次启动Astrometrica软件的时候,软件会自动跳出窗口说"MPCReport文件已经存在,是否重新写该文件",不要选“是”!如此你将丢失以前所有的测量数据……定期的重命名该文件并归档,让软件自动建立新的空白的该文件是个好习惯。这样文件就可以纪录新的目标的测量数据。

Your first set of measurements is now ready! This was the easy part. Now comes the
hard part.....

你的第一步测量已经完成了,这仅仅是比较容易的部分,困难的马上就要开始了……

You now have to find the object back on images of at least two other nights, one of
which must be close to the first night (e.g. no more than a week later, preferrably
less...). For this, you have to "predict" where to look...

你现在必须在最少另两个夜晚拍摄的图片中重新找到这个目标,其中一个必须比较接近第一个拍摄夜晚(比如在一个星期之内,最好是更接近些……)为了这些,你必须会预测到哪里去寻找……

7. Switch to FindOrb software (www.projectpluto.com), which is an orbital propagator.
FindOrb will try to calculate a very preliminary orbit from a set of measurements.
It reads files in MPC format so it can directly read the file MPCReport.txt made by
Astrometrica;

7、转换到FindOrb软件(www.projectpluto.com),这是个轨道计算软件。它可以计算根据测量得到的目标的初步轨道。该软件可以直接读取由Astrometrica软件生成的MPCReport.txt文件。

7a: start-up FindOrb and open the file "MPCReport.txt" (which you can
find in C:/Program Files/Astrometrica);
7b: you will see a list of all objects in the file. Click on the name of the
object you want to process;
7c: you will now see a preliminary set of orbital element;
7d: fill in a value for the perihelion distance which is sensible for a
main belter in box "R1";
7e: click "Vaisala";
7f: You will now get a set of estimated orbital elements, and an
indication of the fit of the observations to this estimate.
*note 1* a Vaisala orbit is an orbit based on the assumption that
the object is in perihelion.
*note 2* you need to have some knowledge of orbital elements to
judge whether the FindOrb results make sense (they don't always do).

7a、运行FindOrb软件并打开MPCReport.txt文件(你可以在C:/Program Files/Astrometrica处找到改文件)
7b、你将看到你所确定的所有目标的一个列表。点击你想要处理的目标名
7c、你将看到一个初步的轨道根素
7d、在R1处填入一个对于主带小行星合适的近日距
7e、点击"Vaisala"
7f、你将得到一个初步的估计的轨道根素以及一个适合你的观测地点的初步预报。
*注释1*这个初步的轨道是假设目标现在正好在近日点。
*注释2*你需要有一些轨道根素的基本知识,从而可以判断FindOrb计算的结果是否有意义(计算结果并不总是正确的)

8. Now go back to the Skymorph website and:

8a: Choose "moving targets".
8b: scroll down and enter the orbital elements obtained by FindOrb into
the data input boxes, then click "send"

8、返回到Skymorph网站
8a、选择“移动目标检测“
8b、进入网页向下滚动鼠标,并在数据输入区输入由FindOrb计算出的初步轨道根素,然后点击“发送”

9. Skymorph will now return a list of images which *might* contain the object,
based on the preliminary orbit you submitted. This list should include the original
triplet of images which you measured, otherwise there is a mistake in the data input.

9、Skymorph将基于你所给的初步轨道根素给出一个图片列表,里面或许会包含你的目标。在这个列表中应该包括你所使用的最初的三张图片,否则可能是你输入的数据有问题。

10. Go back to step 1, and this time use a second night as close to your first one as
possible: repeat the whole sequence up to step 4;

10、返回到第一步,使用尽量靠近你用的第一组(3张)图片拍摄夜晚的图片,完成到步骤4。

11. Now you will either find an object of correct magnitude *and moving in the correct
direction* in the set of images, or you won't. This is the hard part. Sometimes you
simply do not find the object. Bad luck then. Note that the object need not be in the
image center, it only will be if the preliminary orbit obtained by FindOrb is a quite
good estimate.

11、现在,你要么是已经找到了该目标的运动方向和亮度,要么是一无所获。这是非常辛苦的工作。有时你根本无法发现目标,这只能是运气问题。需要注意的是,你要核对的目标并不一定在图片的中心,因为FindOrb计算的初步轨道仅仅是个估计值。

12. If you are lucky and do recover the object: repeat the whole sequence up to step 7c;

12、如果你运气好,发现了目标,那么请重复做所有的步骤到7c

13. After step 7c, this time check all planets for nclusion of their disturbing factors,and then click "Autosolve" instead of "Vaisala". You will get a new set of improved orbital elements.

13、在进行完7c之后,就需要处理那些复杂的分离的轨道根素了,点击"Autosolve",软件将给出一个新的更好的轨道根素

Take a carefull look now at your residuals. These should be below 1.0 arcseconds
for each data line. When they are (much) bigger, this is an indication that something
is wrong: for example that the object of the second night is *not the same* as that of
the first night (this is very well possible!)! Or maybe something went wrong when measuring an image. In this case, do *not* proceed to step 14!

请仔细注意你的误差,它应该在每个数据行中都要小于1.0个角秒。如果它们太大了,说明某些地方一定是出了问题:比如你所找到的第二个拍摄夜晚的目标和你所确定的第一晚的目标并不是同一个目标(这很有可能)!或者是在测量的时候有错误。如果是这样,请不要进行第14步!

14. You will now have a new set of improved orbital elements. Go back to step 8 and repeat. Try to do this again and again untill you have data from as many nights as possible. You'll also notice that the orbital solution will get better and better, and after 3-4 nights of data you'll start to recover your object in the center of the images.

14、你现在有了新的经过改进的轨道参数。回到步骤8并重复此工作,使你尽量获得更多的夜晚的数据。你将发现你所得到的结果将越来越准确,在经过3、4个拍摄夜晚的数据处理后,你将会发现你发现的小行星准确地出现在图片的中心。

At some point now, you'll not be able to get more nights. If you have at least 3 nights
including two that are close together (within a week), you can submit your data to the MPC now (in the case of recovery of a known object instead of discovery, you can report single night data).

需要说明的是,你没必要搜索更多的拍摄夜晚。如果你有至少三个夜晚的数据并且其中有一对是比较接近的拍摄夜晚(在一周内),你就可以将你的数据上报给MPC(如果你仅仅是重复发现已知的小行星,你只需要一个拍摄夜晚的数据)。

15. *BEFORE* you start to submit data to the MPC, carefully read their instructions at
http://cfa-www.harvard.edu/iau/info/ObsFormat.html ! I also advise to read
http://cfa-www.harvard.edu/iau/info/Astrometry.html

在你开始给MPC上报之前,请仔细阅读MPC的上报规则
http://cfa-www.harvard.edu/iau/info/ObsFormat.html
我建议你也看看http://cfa-www.harvard.edu/iau/info/Astrometry.html

16. Astrometrica already formats the data in the correct MPC format. Copy and paste the
data you want to sent from MPCReport.txt (which is in C:/program files/Astrometrica)
into a blank e-mail making sure you maintain the correct format (i.e., don't change
spaces, indentation etc.) and *include the correct header details*. Send the e-mail
to mpc@cfa.harvard.edu

16、Astrometrica软件已经提供了正确的MPC要求格式,从MPCReport.txt文件(在C:/program files/Astrometrica目录下)复制并粘贴这些数据到一个空白的Email中,并确认你的格式是正确的(比如不要随意增减空格已经缩进行首),包含正确的文件头信息。把它发送到mpc@cfa.harvard.edu

*Note* sent the e-mail as plain txt, *not* HTML, and remove any signatures from the mail.

*注释*用纯文本格式发送这个Email,不要使用HTML格式,不要移动任何信息。

A typical, correctly formatted e-mail with data and correct header will look like
this example:

下面是一个典型的、正确的、包括所有数据和正确的文件头说明的Email格式样本

COD 644
CON *your name and address*你的姓名和地址
CON *your e-mail in square brackets [] *用方括号括起来的你的Email地址
OBS R. Bambery, E. Helin, S. Pravdo, M. Hicks, K. Lawrence, R. Thicksten
MEA *your name*你的名字
TEL 1.2-m Schmidt + CCD
ACK *fill in a code or whatever that identifies this set for you*你的代号或你认可的身份标识
NET USNO-B1.0
LAMA90 C2002 08 08.44720 22 18 41.93 -13 37 36.8 20.7 R 644
LAMA90 C2002 08 08.45810 22 18 41.35 -13 37 37.6 20.8 R 644
LAMA90 C2002 08 08.46909 22 18 40.75 -13 37 40.0 20.6 R 644
LAMA90 C2002 08 18.42448 22 09 15.73 -14 02 21.6 20.7 R 644
LAMA90 C2002 08 18.43537 22 09 15.09 -14 02 22.8 19.4 R 644
LAMA90 C2002 08 18.44572 22 09 14.47 -14 02 24.7 20.1 R 644
LAMA90 C2002 08 26.17449 22 01 26.68 -14 20 27.2 20.7 R 644
LAMA90 C2002 08 26.24252 22 01 22.42 -14 20 36.8 19.9 R 644
LAMA90 C2002 08 26.31396 22 01 17.94 -14 20 45.6 20.2 R 644
LAMA90* C2002 08 29.36705 21 58 14.54 -14 26 57.7 19.8 R 644
LAMA90 C2002 08 29.38826 21 58 13.20 -14 27 00.2 20.1 R 644
LAMA90 C2002 08 29.41086 21 58 11.81 -14 27 02.7 20.6 R 644

In the above example (which is data I submitted for a new object that based on this
dataset got the official MPC designation K02Q66R), "LAMA90" is a preliminary personal
designation for the object. Use your own 6-digit personal designation here.

在上面的例子中(是我曾上报给MPC的数据,并得到临时编号的小行星K02Q66R),"LAMA90"是本文作者给它起的个人名称。使用6个字符的名称就可以了。

*Do not call your designations "LAMAxx" but design your own ID code!*.
"LAMAxx" is my personal system of temporary designations for my objects.

你自己不要使用"LAMAxx"的名称就可以了,用你自己的代号!
"LAMAxx"是我私人的编号,使用在我发现的目标上。

Under "ACK", fill in for example your personal object(s) designation(s) in this
dataset (see point 17).

在"ACK"之下,填写上你的私人的目标名称(见17步)

17. After receipt of your e-mail, MPC will within a few minutes automatically send back
an acknowledgement, which will have as subject line the line you specified under "ACK".

17、在收到你的信件之后几分钟内,MPC会回复一封感谢信,信的标题会使用你在"ACK"之下填写的内容

18. After some time (a few hours or up to a few days, this depends) someone at the MPC
will sent you a mail called "designations". You will see a line with your temporary
designation, followed by the official designation assigned by the MPC. This of course,
assuming the MPC accepts your report. To understand the meaning of the coded content
of this message, read http://cfa-www.harvard.edu/iau/info/Astrometry.html#des

18、过段时间(几个小时或几天,不确定),MPC的某位专家将会回信告诉你“编号”。你将会在编号后看到你给它定义的临时名称。这表示MPC接受了你的报告。想了解更多的信息请访问http://cfa-www.harvard.edu/iau/info/Astrometry.html#des

19. The next day after MPC mailed you the designation, you'll probably find it listed in
the Daily Orbit Update (DOU). You can find these at
http://cfa-www.harvard.edu/mpec/RecentMPECs.html

19、在你接到MPC信件的第二天,你发现的小行星将可能在MPEC的Daily Orbit Update(DOU)中列出。见http://cfa-www.harvard.edu/mpec/RecentMPECs.html

20. You can check whether the object has additional single night observations by other
stations linked to it at http://cfa-www.harvard.edu/iau/MPEph/MPEph.html ;
fill in the packed designation, check "MPC 8 line" format and check the "show
residuals" block and then click "get ephemerides"

20、你可以察看一下是否有其他的观测站对该目标有一个晚上的观测数据,请访问http://cfa-www.harvard.edu/iau/MPEph/MPEph.html;填写好MPC所给的编号,选择"MPC 8 line"和"showresiduals",然后点击"get ephemerides"

* NOTE * After recent MPC policy changes, you will no longer get official credit for new
objects for which a previous single night report exists. Credit instead will go formally
to NEAT or the other station that sent in the single night detection.
This is a bit of a disappointent after your hard work in prying out all these
undiscovered detections from the archive but then, that's the way it is. NEAT archive
hunters now count their finds unofficially as 'discoveries' just as SOHO comet hunters do.

*注释*由于最近MPC政策改革,如果你上报的新目标在以前曾有一个单个晚上的观测报告纪录,MPC将不授予你官方的认证,而把认证编号归给NEAT或其他观测站。这对你的来说似乎有些遗憾,虽然你艰难地在历史档案中发现了很多未被发现的小行星,但是,事实就是如此。像SOHO猎手们一样,NEAT档案搜索者们自己纪录他们的这些未被认可的“发现”。

Okay, hope this helps!!!! Happy hunting!

希望以上这些对你能有帮助。祝你成功。

- Marco Langbroek
Leiden, 09/08/2005


Note 1: My sincere thanks to Rob Matson, who introduced me to the wonderful world
of SKYMORPH precovery and discovery. Almost all of the things this guide
contains, I learned from him.

说明1、我真诚地感谢Rob Matson,是他给我介绍了如何利用SKYMORPH进行发现和前期发现,本指南中几乎所有的内容我都是跟他学习的。

Note 2: if you mirror this guide, please acknowledge the source

说明2、如果你要引用本指南,请注明出处。

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Dr Marco Langbroek
Leiden, The Netherlands

Volunteer image reviewer FMO Spacewatch Project
NEAT archive hunter
Admin FMO Mailing List

e-mail: meteorites@dmsweb.org
private website http://home.wanadoo.nl/marco.langbroek/asteroid.html
FMO Mailing List website: http://home.wanadoo.nl/marco.langbroek/fmo.html
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