Occult 4.0 安裝和使用
Occult 4.0 正式發佈，用戶可在這裏下載

要正常執行Occult 4.0

軟件要求

作業系統：視窗 XP (service pack 2) 或者 Vista
XP 須安裝微軟 .NET 2.0 或以上版本
XP 須用 I.E. 7.0 或以上版本

要預報至 20 等星須另裝 NOMAD 星表 (星表佔 96 GB 空間)

Occult 4.0.2.8 更新已經可以在這裏下載

請解壓更換同名檔案便可。

The TWO MOST IMPORTANT CHANGES FOR OCCULT 4.0

1. The decimal separator issue that depends on the Regional Setting - has been fixed. If
you are in a region that uses a comma as the decimal separator, you can run this version
without changing the decimal separator of your regional setting (Internally, Occult will
always use the period. To be precise - if Occult detects the decimal separator as a comma,
the program will internally use the 'culture' settings of the US, without affecting
anything else on the computer.)

2. For asteroid occultation predictions - map of the event. If the middle of the event
occurs on one day, but the event starts on the previous day, the heading _should_ give the
date as the 'previous' day, with the time range from 23 hrs to 24 hrs. A bug in 4.0.1.0
prevented the day being set as the 'previous' day - although the hours were adjusted to
the 23 to 24 hour range. As a result, the heading gave an event time 1 day after the
actual event. Unfortunately, as a result of this bug someone had the misfortune of going
out to observe such an event a day late. [Ooops.] This has been fixed!

Other main changes are:

1. For asteroid occultations, added an estimated Red magnitude, and light-drop in
Red (which is the colour most appropriate for CCD video cameras.)

2. For lunar graze predictions, added an extra output option of decimal degrees for
latitude/longitude.

3. Added the ability to save various animated outputs as animated-GIf files.

4. Revised the data used to calculate the orientation of a planetary disk; added
Carrington rotation number to the Solar Ephemeris output.

5. The HelpFile has been updated for the various changes. Additionally content description
for all the files in the Resource Files directory has been completed, and a list of key
constants/values used in the program has been added..

Various other changes have been made to address a number of minor bugs identified by
users.

Example of animated outputs

To ensure continued high accuracy of predictions into 2009 and the next few years,
the next leap second needs to be updated to the fact of it occurring at the
end of this year.  This requires a very simple edit - as follows:

********
Occult 4
********
1. Select the Maintenance tab, 'Edit deltaT' button.
2. On the LEFT-hand table for 'delta TA' select the year 2010. The details for that year
will be displayed in grey in relevant boxes
3. Now click the button 'Add a new year'. This will enable boxes with the data for 2010.
Change the year 2010 to 2009 (with no other changes), and click OK.
4. Repeat with the year 2014 - this time changing the year to 2012 (a guess on my
part....)
5. Now delete the entries for 2010 and 2014. The last three lines of the table should now
read:
2006.00: 33 0.33
2009.00: 34 0.50
2012.00: 35 0.50

Finally, click 'Save delta TA and deltaT tables'. You can now close the form. Predictions
will continue to be fully accurate after the leap second next year.

Important update to Occult

************ ********* ***
Main changes in Occult 4.0.5
************ ********* ***

The main changes in this version of Occult are associated with supporting the processing
and archiving of lunar occultation observations. The Japanese Hydrographic Department
(ILOC) has been the agency responsible for collecting lunar occultation observations since
19981. Unfortunately they are unable to continue with that role, and the International
Occultation Timing Association (IOTA) has agreed to take on the responsibility.

As part of this responsibility:
* the lunar occultation report format has been revised;

* Occult has been revised to support the new format, and to email observation reports to
regional coordinators;

* Occult has been revised to allow regional coordinators to reduce the observations, and
make them ready for archiving in the Astronomical Data Centres of VizieR.


Additionally there have been a range of updates and improvements, with the following being
the more noteworthy:

* Lunar occultation reports are emailed from within Occult

* A download form to make it easy to update a full range of data files.

* Update of the JPL planetary Ephemeris source, to DE414 and DE421. This is an optional
download, that improves the accuracy of both asteroid and lunar occultations

* Revision of the Tycho2 catalogue, to incorporate the star positions and proper motions
from the Hipparcos2 catalogue. This is an optional download that improves the accuracy of
asteroid predictions involving Hipparcos stars.

* Complete rework of the files of historical lunar occultation observations, including a
new reduction using the DE421 ephemeris. This is an optional download, but essential for
grazing occultation profiles. It completely supersedes the files of historical occultation
observations used in previous versions of Occult.

* For lunar occultations and grazes - if the star is likely to have a significant apparent
diameter, the possible duration of a fade, or diameter of the star at the distance of the
moon (for grazes) is indicated.

New Lunar Occultation reporting Process - some extra points

New process for reporting lunar occultations.

1. Grazing occultations. The members of a graze expedition should continue to report their
results to the person who organised the graze (as has been done for the last 40 years).
That person will then send the combined observations to Mitsuru Soma. Individual observers
should not send their observations direct to Mitsuru.

2. Reporting frequency. At this stage we are working on the basis of observers reporting
their observations on a monthly basis, and aim to have a monthly update to the publicly
available file of current observations. But if you make a lot of observations over a
couple of nights, you can send your report at that time. Graze reports should be sent to
Mitsuru as soon as all observations have been collected.

3. Please do not send your report to more than one person. The process for archiving the
observations involves merging the reports gathered by the different coordinators into a
single file. If you report your observations to different coordinators, they will create
duplicate observations in the merged file - and someone will have to go through and delete
the duplicates.

Occult 現時最新版本 4.0.5.19 (2009年1月23日發佈)
更新事項
1. For people that use Occult to demonstrate astronomical events. Later this year the Earth passes through the ring plane of Saturn (Sept 4). What may not be as well known is that for about a month prior to the ring-plane crossing, the sun will be illuminating the other side of the rings - such that the rings will be invisible from early August. The graphic display of Saturn has been amended to indicate this period when the rings will be 'open' but invisible.

2. For lunar occultation observations, you can now plot the lunar limb on the surface of the Earth (in GoogleEarth) at the time of each event in a report. While this has been added mainly to resolve site location problems, observers may find it interesting to plot their own observations.

3. The plot of world maps for all occultations of an object (eg Venus) has been improved to ensure all events are plotted (a small number were skipped previously).

更新版本可以在以下網址下載
http://www.lunar-occultations.com/occult4/occult405%20update.zip

將解壓檔案複蓋到原有路徑上，並取代同名檔案。

2008年第六期天文愛好者有介紹其使用

Occult 現時最新版本 4.0.5.20 (2009年2月23日發佈)
更新事項

1. Asteroid predictions. IMPORTANT CHANGE. The header for the graphic now includes an
extra line giving the star's RA and Declination on the mean equinox of date. This is the
position that is required for many GoTo scopes to slew correctly to the star. [Definitely
the Meade Autostar system]. This new feature, which is important for anyone using a GoTo
scope, will filter through to the various predictions over the next few weeks as new
predictions are generated.

2. Generating plots in GoogleEarth. Previously I used a single file name for all plots. I
have changed this so that plots generated from different parts of Occult have their own
file name. This allows plots of different data to be made at the same time.

3. For those conducting searches for asteroid occultations using NOMAD, there is now a
check option to exclude B1 and N1 stars from the search.

4. For lunar observations, download of Earth Orientation Parameters - you can now set the
reminder interval in the user settings form.

5. Star catalogue details for XZ stars. Enhanced the details for double stars - so that
the usual star number is given for each component, and a 5-year ephemeris is provided for
stars with orbits.

6. On the Downloads form, the flag to indicate that there is XZ catalogue data to be
downloaded will now operate correctly.

更新版本可以在以下網址下載
http://www.lunar-occultations.com/occult4/occult405%20update.zip

將解壓檔案複蓋到原有路徑上，並取代同名檔案。

Occult 現時最新版本 4.0.6 (2009年3月8日發佈)
更新事項

This version contains a significant update relevant to lunar occultations. As a result of some queries concerning a graze of ZC844 predicted to occur on March 5 (in the US), a significant issue came to attention. In brief:

* XZ80P was compiled by Mitsuru Soma many years ago. In that exercise he put much effort into incorporating data from Hipparcos.
* XZ80Q adopted XZ80P positions without change, where the position was derived from Hipparcos.
* The issue that escaped my attention (although Mitsuru alerted me to it at the time ... oops!) was that where Hipparcos included positions for the components of a double star, the position used in XZ80P was a mean position of the two stars. [The mean being derived on the basis of relative magnitudes.]

The consequence is that for all such stars, the XZ80Q position is not of either star, but of the mean position. And this creates a problem when the positions of the components of the double star are determined for accurate graze predictions, and accurate reductions - since double star offsets are traditionally referenced to the brighter star of a pair.

Initially I thought there would only be a few 10's of stars affected. In fact there are 693 stars affected by this issue. And
they are generally relatively bright stars.

The issue was further complicated by the fact that for a number of these stars there is a separate entry for one of the
components. The usual situation is for the A component to have an entry in XZ80Q, and occasionally for the B component to have a separate entry. However (and as a result of this 'mean' position issue) it turned out that there were two stars where the second entry was in fact for the A component, but was interpreted as being the B component. [ZC844 was one of those two stars...]

As a result of this:
* the file XZDoubles.dat has been revised to flag all those doubles where the XZ80Q position is a mean position; and
* the program has been changed to properly handle the situation where the XZ80Q position is a mean position. This includes an enhanced display of double star details in the 'View catalogue details of a star' form.

Finally, the measurement of double star details as a result of lunar occultation observations is an area where useful observations can be made. Small groups have formed in Australia/New Zealand, and North America, to coordinate observing activity to record lunar occultations of doubles at significantly different position angles - so that the PA and separation can be measured (as well as the relative magnitudes). To support this activity, Occult now includes a form to do a least-squares solution for the PA and separation of a double star using 2 or more observations of the pair. Those observations can be on the same night. But if the pair is not changing quickly, observations in the same year can be used. As an example, from 4 observations of the reappearance of Antares on 2006 May 14, the following solution is obtained:

Sep = 2.694 ±0.014" PA = 275.92 ±0.71° RMS fit: 0.00 ±0.03"

One of the interesting aspects of double stars is that for close doubles the magnitudes of the components is very poorly known. And there is an inherent 180 deg ambiguity in the measured position angle when observed with speckle interferometry. Last year 3 of us observed an occultation of chi Sagittarii (which has an orbit for the pair), and found the stars to have a mag difference of 1.54 (WDS has the components of the same magnitude), and that the A star of the orbit was the fainter star. To quote Brian Mason (of US Naval Observatory, responsible for the Washington Double Star catalogue)
*********
It is certainly possible that we've got the quadrant wrong on this one. It is an easy system for us to resolve with speckle, but delta-m isn't really possible to any degree of accuracy (at least for standard autocorrelation techniques). I think this is a unique niche that Lunar Occultation can make a significant contribution to double star analysis. The pairs of William Finsen are especially interesting as they are bright close pairs with, allegedly, small delta-mags.

更新版本可以在以下網址下載
http://www.lunar-occultations.com/occult4/occult405%20update.zip

將解壓檔案複蓋到原有路徑上，並取代同名檔案。

Occult 現時最新版本 4.0.6.7 (2009年4月25日發佈)
更新事項

The main change in this version concerns the probability estimates for occultations involving slow-moving asteroids. For all
occultation predictions, there is an along-track uncertainty that is indicated as an uncertainty in the time of the event. That
uncertainty necessarily involves a corresponding uncertainty in the rotational orientation of the Earth. Up until now, that
uncertainty in the orientation of the Earth has not been allowed for in the prediction uncertainty - mainly because the effect is
usually very small. However when the asteroid motion across the Earth is slow, the effect can be significant. This version adjusts
the 1-sigma uncertainty lines, and the predicted uncertainty at a location, for this effect.

This correction has immediate relevance for the occultation by Philosophia in Europe on May 2. The 1-sigma uncertainty lines are
several 10's of km further separated from the cental path. And the event probability within the path drops in value by about 3% -
from about 28% to 25%.

Other changes included are:
- on the main form, access to the 7-Timer weather prediction for your 'home' site (limited to cloud and temperature) . This
provides ready access to a 3-day cloud forecast.
- for lunar occultations, provided some base functionality for reporting double star observations - including the ability to copy
and paste a LiMovie light curve directly into an email message from the clipboard..

更新版本可以在以下網址下載
http://www.lunar-occultations.com/occult4/occult406%20update.zip

將解壓檔案複蓋到原有路徑上，並取代同名檔案。

Occult author reply about new UCAC3 catalog update


1. The biggest change is the inclusion of star data for the far northern declinations. However in practical terms this is of little effect for asteroidal occultations, as very few occur at such declinations. For lunar occultations there is no consequence.

2. Another significant change is the inclusion of stars which were excluded from UCAC2 because of complications (in particular, double stars). This affects the whole catalogue. It will introduce a small percentage of new stars, so not a major effect. However it may be assumed that the positional uncertainties in such extra stars is larger than usual - which means asteroidal occultation
predictions will be of lower reliability for these stars. That is, there is a risk that these extra stars _might_ turn out to be more of a nuisance that a help.

3. There is the re-processing of the image data to improve the accuracy of the position at the UCAC2 epoch. My understanding is that they have developed algorithms to deal with the effect of the inter-pixel space on the CCD. It remains to be seen what improvement arises from this.

4. There is the issue of proper motions - where they have expanded the catalogues used to determine it. It is important to appreciate that the UCAC images were taken between Feb 1998 and May 2004 - with the ecliptic region having been finished before 2002. Consequently current epoch positions involve at least 8 years of proper motion correction. That means the accuracy of current epoch positions is becoming increasingly dependant upon the accuracy of the old epoch catalogues used to
generate the proper motion values. For asteroidal occultations, it is this issue that is of the greatest potential impact. Have the proper motions been significantly improved in UCAC3? Only experience will tell

5. For asteroidal occultation predictions, it will be relatively straight-forward to implement a search based on the full UCAC3 catalogue. I intend doing that as soon as I get a copy of the catalogue. This will allow UCAC3-based predictions to be generated, and compared to UCAC2 predictions and to actual observations. This will allow us to get an appreciation of whether UCAC3 offers any significant improvement in accuracy.

6. Occult uses a catalogue called 'Tycho2' - although it is not strictly the Tycho2 catalogue. It is based on the Hipparcos and Tycho2 catalogues, but uses UCAC2 positions in preference to Tycho2 for mags fainter than about 9. This catalogue is in need of revision as it does not include error information. And there are questions about whether its coverage should be extended to fainter magnitudes. I have put that offreeforumtil the availability of UCAC3 - that is, now. But such a task is not a 5-minute exercise. It is not something to be rushed. I would be thinking of early 2010 as a time frame.

7. In a related vein, the XZ catalogue has used UCAC2 in preference to Tycho2. Assuming UCAC3 is more accurate that UCAC2, the XZ80Q catalogue should be updated. However (i) I expect the changes will be small, and (ii) it still needs to be established that UCAC3 is a real improvement over UCAC2. However provided USNO can provide a cross-reference between UCAC3 and UCAC2, such an update should be relatively easy.

8. Similarly with asteroid observations. There will be a need to look at how UCAC stars are referenced in the file of asteroid observations, as well as in the reporting of astrometric positions.

9. On the NOMAD catalogue. - in particular, Nomad_Short. UCAC3 includes a full gamut of magnitudes - although I would want to see the catalogue to assess who complete the magnitude coverage is. All being well, UCAC3 is likely to negate the need for Nomad_Short. But that will need to be a future assessment.

Recently I did several lunar occultation timings and would like to report using Occult 4.0 software. Would you please advise who should I report to as there is no reporting address for Asian observers except Japan in the software. Thanks.

引用:

原帖由 tequila 於 2009-9-14 11:10 發表
Recently I did several lunar occultation timings and would like to report using Occult 4.0 software. Would you please advise who should I report to as there is no reporting address for Asian observers ...

You can send it to Japan or keep it for a while, I'll send you the regional co-ordinator e-mail address for China, Hong Kong, Macau, Taiwan and Singapore / Malaysia later.

The report (6 events in total) was submitted to Mr. Miyashita. Thank you for the information.

Bug in Occult that has an extremely serious affect on lunar occultation predictions during a lunar eclipse.

In lunar occultation predictions, the user sets the date, and selects the relevant 'Starting at' hour - so that the generated predictions match a night's observing. Europe would typically select +12hrs, and North America would select -6 hrs.

The error involves the application of the time offset to the solar ephemeris. In short, because a certain division was processed as an integer division, the position of the Sun is not adjusted for the time offset. For normal occultation predictions the effect is almost invisible (and hence the error escaped detection). However it has a huge effect when there is a lunar eclipse. Effectively the location of the umbral shadow is displaced by about 15 arc mins [corrections of +/- 6 hrs] or 30 arcmins [correction of +12hrs] . This has a HUGE effect on the stars listed for occultation during the eclipse.

The next release of Occult will have this problem fixed.

In the mean time the simple 'work around' for anyone needing to generate occultations during next year's lunar eclipses (or the slight partial lunar eclipse on Dec 31 this year), is to set the time offset to 0.

Occult 現時最新版本 4.0.7. (2009年10月22日發佈)
更新事項

A number of significant changes. They relate to implementing UCAC3, ability to compare star positions from several catalogues in the context of asteroidal occultation predictions, a range of changes associated with double stars for both asteroidal and lunar occultations, revised XZ catalogue data for lunar occultations, and revised historical occultation observations.

UPDATING Occult to 4.0.7.0 *** Read carefully and fully! ****

For those who already have Occult4 installed, the update file can be downloaded directly from:

http://www.lunar-occultations.com/occult4/occult407%20update.zip

Merely unzip the contents into your existing Occult 4 directory.

The next step is to update the data files used in Occult. Run Occult, and go directly to the
Maintenance/ Downloads page. From there, download:

1. Latest Lunar observations (5th item in the download list)
2. Historical files of Lunar Occultations (1st item in the bottom group in the download list)
3. XZ catalogue. (2nd item in the bottom group in the download list) [This download is ESSENTIAL.
Without it, lunar predictions will crash.]
4. WDS Catalogue (3rd from bottom in the download list)
5. Interferometric catalog (2nd from bottom in the download list)
6. AAVSO Variables (last item in the download list)

UCAC3 'installation'

If you have a copy of the UCAC3 DVD, Occult can conduct searches for asteroidal occultations against
that catalogue, draw star charts using that catalogue, and reduce observations using that catalogue.
To use the UCAC3 catalogue:
a. copy the entire contents of the UCAC3 DVD (both sides) to a single directory- anywhere on your
system.
b. in the Maintenance/ User Settings form, set that directory location in the group 'Paths for
optional catalogues'. A tree-structure dialogue is now available to make this easy.
c. The UCAC3 catalogue as supplied has a very course index in RA. For efficient searching, Occult
creates a much finer index in RA. The button to create this index [Index UCAC3] is located just
below the location for specifying the directory location. IMPORTANT. The index will take some time
to complete. Most machines will take at least 20 minutes. Old or slow computers may take over an
hour.... Indexing progress is displayed.

Once the index is completed, UCAC3 is available for use in almost every area where the UCAC2
catalogue is available.