tequila

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 selectsthe relevant 'Starting at' hour - so that the generated predictionsmatch a night's observing. Europe would typically select +12hrs, andNorth America would select -6 hrs.

The error involves the application of the time offset to the solarephemeris. In short, because a certain division was processed as aninteger division, the position of the Sun is not adjusted for the timeoffset. For normal occultation predictions the effect is almostinvisible (and hence the error escaped detection). However it has ahuge effect when there is a lunar eclipse. Effectively the location ofthe umbral shadow is displaced by about 15 arc mins [corrections of +/-6 hrs] or 30 arcmins [correction of +12hrs] . This has a HUGE effect onthe 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 togenerate occultations during next year's lunar eclipses (or the slightpartial lunar eclipse on Dec 31 this year), is to set the time offsetto 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 thecontext of asteroidal occultation predictions, a range of changesassociated with double stars for both asteroidal and lunaroccultations, revised XZ catalogue data for lunar occultations, andrevised 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.

Occult 現時最新版本 4.0.7.2
更新事項

* Fixed bug in Archive graze editor - for tagging components of doubles

* Lunar observations - double star solution. The plot of the lunar limbs was not always
   correct. Plus issues when the PA of teh star was close to zero. Bugs fixed.

* Archive editor - grazes - site coords. When site coords pasted, also paste telescope details.

Occult 現時最新版本 4.0.8.2 (2009年11月11日發佈)
更新事項

* Provided a Lunar Limb file based on the Kaguya data.
* Changed code to use the Kaguya data if available
* Added indication on Lunar observations editor of profile source, and ensured correct source
   was written to reduction outputs
* Removed code for converting old graze reports
* Removed the files
     NCassini.dat
     SCassini.dat
     Watts.bin
     Watts corrections.bin
     WATTS.LIM
     WattsPhotos.dat
   from the Resource files in the complete installer package. That is, new installations will
   not have access to the Watts data. (Updated installations will still be able to access
   existing versions of the Watts data.)
* Removed a plotting glitch with the profile line that could occur at the center of the pr

Occult 現時最新版本 4.0.8.6 (2009年11月22日發佈)
更新事項
Kaguya data available in its full resolution,which has now been achieved in v4.0.8.6 .

The update files for this version can be downloaded from the IOTA web site at:
http://www.lunar-occultations.com/iota/occult4.htm
or the direct download address of:
http://www.lunar-occultations.com/occult4/occult408update.zip

Occult 現時最新版本 4.0.8.13 (2010年2月13日發佈)
更新事項

* improved the allocation of colours to the various catalogues - so that they are more easily distinguished in the plot.
* add an option to replot the data for a different epoch, without having to re-download the data from Vizier.
* add an option to created an animated GIF file that shows the motion of the stars over a 15 year period - from 10 years before the specified date, to 5 years after. I'm not sure how useful people will find this - but it was easy to add.

A separate change relevant to lunar occultation observers - the moon map that shows where the event will occur can now be plotted with South at the top (as well as being mirror-reversed) .

Occult 現時最新版本 4.0.8.16 (2010年3月8日發佈)
更新事項

***********
V4.0.8.16
***********
* Refined outputs of the star catalogue comparison, including a set of flags to indicate
   issues noted ifreeforumh catlogues
* Lunar predictions. Added option to generate multi-column predictions for publications
   like the BAA and RASC Handbooks.

***********
V4.0.8.15
***********
* Expanded weather map functionality to provide animation, and to save the animation
   as an animated GIF
* Asteroid Observations. Added ability to copy a selected line from an Occult path
   coordinates listing - so that it can be pasted in the Observations Editor as
   a prediction line.
* Download of Astorb. Improved the code to avoid an error that has occassionally
   appeared when unzipping the downloaded file.
* Star catalogue comparison. Brought over the magnitudes when selecting from an asteroid
   prediction. Display Blue, Visual and Red magnitudes. Display Epoch for the 2MASS catalog
   Included full error data. Restructured the display

***********
V4.0.8.14
***********
* Added new weather functionality - to access the 7Timer Weachart functionality. This
   displays regional maps showing cloud and other paramters for up to 16 days in advance.

A new JPL ephemeris recently became available - DE423.  It is now available for download.

What are the differences from the current DE414/421 ephemeris used in Occult?
The primary purpose of the DE423 revision was to improve the orbit of Mercury for the Messenger mission. However it clearly has incorporated recent data for the other planets and the moon.

What is the year coverage of the new ephemeris?
DE423 covers twice the year range as did DE421. The new Occult ephemeris uses DE414 for 1600 to 1900, DE423 for the _300_ year period 1900 to 2200, and DE405 for 2200 to 2201. [The previous version uses DE414 for 1600 to 1900, DE423 for the _150_ year period 1900 to 2050, DE414 for 2050 to 2200, and DE405 for 2200 to 2201]

Do I need to update to DE423?
In short, most people will not _need_ to update to DE423. The differences from DE421 are generally very small. However in the case of Pluto the differences are of the order of 0.04" to 0.05", which is significant. Other 'significant' differences are 0.02" for Neptune, and 0.01" for Jupiter.

How do I update?
Go to the downloads page of Occult. The 6th item in the bottom group is 'JPL Planetary ephemeris'. Click this, and the download will occur. Once it has downloaded, another click will be required to unzip the file. The download size is about 50MB.

How do I know what version of the DE ephemeris I am using?
The planetary ephemeris basis is indicated at the bottom left of the main Occult form. For users with the recent JPL ephemeris, this will show:
DE414/LE414 with DE421
The next time Occult is started after this latest JPL ephemeris has been downloaded, it will display
DE414/LE414 with DE423/LE423
(although the first few characters may be cut off...)

1. Currently the WDS catalog cannot be downloaded. It looks like the file maintained at Vizier has been changed from a simple ASCII file to a Gzipped file. While this will make downloads much faster, Will need to make some code changes so that the Gzipped version can be accessed.

2. Current revision of Occult has been undertaken pending the availability of the new PPMXL catalogue at Vizier. That catalogue is now available. As a result to do a release of Occult 4.0.9.0 sometime in the next week. Will provide details of the changes in several emails at that time. But the good news for many is that once you have updated to this new version, the update process for future versions will be MUCH simpler - with all updates being handled through Occult.

Occult 4.0.9.0 is now available as an update to existing installations of Occult4.

This update incorporates a number of significant changes and improvements, many of which have come about as a result of suggestions from users. These will be summarised in two further emails, as well as a further email indicating future changes.

The most important change with this update is the ability to update the program from within Occult.

**IMPORTANT**
This present update is the last update requiring users to _manually_ download an update file from the IOTA web site. All future updates will occur through the Occult program.

*** REALLY REALLY IMPORTANT ***
ALL USERS ARE STRONGLY ENCOURAGED TO UPDATE THEIR VERSION OF OCCULT TO THIS NEW VERSION. This will avoid difficulties with updating Occult in the future.

To update to this new version of Occult:
A. Download the program update file from
http://www.lunar-occultations.com/occult4/occultupdate.zip
and unzip it into the Occult 4 directory

B. Run Occult. At the bottom left you should see a notification that data updates are available. Click that notification - and you will be taken to the downloads page. At the top left there is advice of the number of items that are tagged for download. Download all the tagged items.

To learn more about the new Updating process, read the Help topic that is available under the new Menu item on the Main form:
Program updates.... Help with updates

***************
IMPORTANT - Frequency of update checking
***************

Several data updates per month can be expected - especially for asteroidal occultation observations, and lunar occultation observations. [This is mainly because people are reporting observations, which is what we do!] Some users will want to update files whenever updates are available. Other users will only want to update the program and data files on an infrequent basis. You can set how often the program will automatically check for updates, under
Maintenance, User Settings
at the 2nd item (Check for availability for updates to the Occult program and data files).

The available options are:
- every start up
- daily
- weekly
- monthly
- yearly
- never
with the default setting being monthly.

Note that you can manually check for updates at any time, using the items under the new Menu item
Program updates...

**************
IMPORTANT - VISTA and Windows7 users
**************
If you have problems with the new update process, it will be caused by the User Account setting. There are two ways to avoid this (if it is a problem). The first way is to ensure the User Account setting is set to Off whenever you do an update. The second way is to move the entire Occult 4 directory to a location outside of the Program Files directory structure. Indeed, for this reason the default location for new installations of Occult is the C: root directory.

The following is a list of the more notable changes implemented in Occult 4.0.9

Summary of some general changes
1. Incorporated a file of stellar diameters.
2. Enabled retrieval of variable star light curves from the AAVSO
3. Improved process for updating Occult program and data
4. Added capability to generate/display an ephemeris of an asteroid

Summary of changes relating to asteroidal occultations.
1. Catalogue comparison - expanded to include the new PPMXL catalogue, and the 'long-term prediction' position from FK6.
2. Search for occultations. Provided an option to create a file of occultation elements sorted by event date
3. Moved the selection criteria for displaying occultations to a new form. Allowed the site location used in the selection criteria to be elected from a Site File.
4. Display of expected fade durations from Fresnel diffraction and stellar diameter. [This was triggered by the recent Roma occultation observed in Europe.]
5. For reductions, enabled incorporation of Shape Models from DAMIT, and Miriade. Enabled display of data from the asteroid 'Light Curve DataBase'.
6. Check that the file of asteroid orbital elements is of the correct length (to avoid a problem experienced by some users.)
7. Changed the format of the file of occultation elements, so that the full precision coordinates of the star as used in the prediction are available, as well as the stellar diameter.

Summary of changes relating to lunar occultations
1. Extra information included with the double star report form, to assist with data evaluation
2. Added the capacity to filter a prediction output on the basis of a range of criteria (such as
observing hours) and to exclude various messages.
3. Graze reduction profiles - added ability to draw the path of the star on the profile, for any observer.

Summary of data file changes/improvements
1. The DE ephemeris file has been revised to expand the coverage of DE423 back from 1900 to 1800.
2. New file added - Stellar diameters
3. New file added - asteroid Light Curve Database
4. Updated the addresses for the downloads of Comet.dat, and the WDS catalog.

A full list of all the changes is available under the new menu item
Program updates.... List version changes.

As part of the revision process leading to Occult 4.0.9.0, I asked users for suggestions for
improvements they would like to see. The following is a list of those suggestions, and
whether they have been implemented.

***************************
* CHANGES IMPLEMENTED
***************************

* Change download address for MPCORB and Comet - as a result of the
MPC hacking incident and consequential changes
[DONE]

* I'd like to be able to sort large occultation files into chronological order.
[DONE]

* Could you add a digit or two in the Ephemerides part on 'De', the planetocentric
declination of the Earth for Saturn?
[DONE]

* Software download of Occult updates
[DONE - major revision in the way updates are handled.]

* Star comparison. Increase search radius to allow for high proper motion stars. Ensure comparison epoch is event epoch
[DONE. Distance changed to 4". A change in OccultWatcher was also required]

* One feature that I have desired is the ability to quickly and easily produce predictions visible
from other observing sites. My suggestion would be to add a second button next to the Home button
on the Asteroid Predictions page. The second button would be linked to the 'Sites' files so that
you can load the coordinates of any site in any of the Site files. Preferably, when you click the
button, the site file menu pops up, you select the site file you want, open that file, click on a
name or site, and then the site coordinates are automatically loaded on the Asteroid Predictions page.
[DONE. 'Home' button changed to 'Select'. Form appears with full choice of Site files, plus the
option to use 'Home' (not enough room on the main form for both a Home and Select button)]

* Asteroid - Plot Event Observations - with plot ... Save ... to remember the
last drive:\folder it had used. You did this at some point BUT when you added the Save Entire Form as Image
.... it always goes back to C:\Program Files\Occult 4\Asteroid\Observations folder.
[DONE]

* In the star catalog comparison list, could you add for each catalog the cross-track and along-track
(in time as well as arc seconds) distances?
[DONE. Also ensured full-precision star coords were available in the Occelmnt file for the comparison.]

* On the Convert AstOrb and MPCOrb files dialog box (attached), can the asteroid diameter that is set
be retained for the next time? I routinely use the 4km setting and it's just one less step if it's retained.
[DONE]

* Also, when the program gets done converting the files to the Occult format, can that dialog box
just close? There's a message saying the conversion is done, but then the box remains open.
[DONE]

* Graze reduction - include a curved line to indicate star path. [Comment: there are issues associated
with combining grazes from several locations - as the line will have a different curvature.)
[DONE. Check box added in form that displays list of current observers in the graze profile. Check the box
and double-click on an observer - the observer's events are highlighted in Yellow. The star path for
that observer is drawn as a dashed Cyan line.]

* Parallax. I just noticed that you are not adding the parallax offset for the HIP & FK6 positions.
I do include those in my positions and the difference can be significant in some cases. So you
should probably add parallax to make the new "offsets" accurate.
[DONE. + the parallax shift is shown, so that the effect on other catalogue positions can be seen.]

* I'm still using Occult 3.6 thanks to a feature I like: you could compute the ephemerides of asteroids.
It was 'Ephemerides of the planets => ephemeris of an object. Positions => positions from orbital
elements and Elements => asteroid elements. You can pick up an asteroid, get it's elements and
compute it's ephemeris.
[DONE]

* I find when using Occult to do lunar occultation predictions I need to 'manually' filter out the
results afterwards to reflect the way I pick events. In my case;
1) I'm only interested in disappearances or (to a lesser degree) reappearances
against the dark limb (NOT the lit limb).
2) I'm only interested in events before 10pm (local time) on Sunday to Thursday
(as I have to work the next day) while I'll do any time if on a Friday or Saturday.
Could you add some options to the predictions to allow this type of filtering to be done?
[DONE. Implemented in a way where it is difficult to inadvertently filter the results. The
filtering relates to the various messages and types of events, but no filtering based
on day-of-week has been added.]