of the HNSKY planetarium program.
Please send you comments or bug
2017-4-16, very minor corrections in the help files.
2017-4-14, HNSKY version 3.3.3. Added access to wide field DSS images from NAO. This allows large fields up to 6° similar as Skyview. Example:
2017-4-12, HNSKY version 3.3.2d and Linux version 3.3.2d_FPC, several minor corrections.
version 3.3.2c and Linux version 3.3.2c_FPC. Some minor improvements.
The Linux version is no longer ß. Will be identified with same version
ending with FPC.
Two new features
for supplement manipulation and one could be be used to keep a logbook
of observations :
Edit menu for a single supplement entry:
1) For convenience HNSKY provides and
additional edit menu to access a single supplement entry. This
could be used to add a log or an observation in the "type" field.
You could either use an existing supplement or add a new label at
the mouse position (home key). Rename an existing supplement before
you use it otherwise a new HNSKY version could overwrite it if
See in the online help file:
Import tool in the editor:
2) New option for creating a supplement from a text list of objects.
I made this for personal use. If I copy my HTML based astro image
web page and then paste it inside the editor, the program will
process and create a list of labels with their corresponding
position. All recognizable deep sky names will be recorded once and
remainder will be ignored. This helps me personally to keep an
updated record of deep sky objects images taken. Any textual list of
deep sky object will be imported. Maybe useful for others.
2017-3-31, Introduced Spanish help file.
2017-3-7 and 8,
Excellent translation work by Roberto2017-3-8,
HNSKY Linux version 3.3ß42
. Fixed a problem with the map clock.
, Roberto made very nice new style. Thanks.
Hope you like it.
HNSKY version 3.3.1a/ 3.3ß41 Updated the help file
and non-English files.
HNSKY version 3.3.1
a modern date & time input and a monthly calender. The
doesn't allow dates beyond year 1752 and 9999 so there is
traditional input. The midnight button is now setting
hours. since 24:00 hours is not allowed in the current setup.
- Automatic daylight saving adjustment for time zones
in the setting menu
PST/PDT, MST/MDT, CST/CDT, EST/EDT
Europe: GMT/BST CET/CEST
The daylight saving is based on the current valid rules and
works from 1977 (arbitrary)
year 20.000+. No effort is made to follow historical
using a so called Time Zone Database. Using the function
F4, F5, F6 it is possible to step through the daylight saving
- Uses the decimal separator dot or comma as specified in your
(Windows) system settings . However the dot as separator is
the daylight saving and date & time menu took significant
implement. Please review and report any bug or problem.
Some work for the translation files is still required.
2017-2-25, HNSKY version 3.3.0f, added the ASCOM telescope
driver park,/unpark, setpark, home and tracking functions
2017-2-23, HNSKY version 3.3.0e/3.3ß40, included
comets in the min
mode of the OBJECT menu.
2017-2-22, HNSKY version 3.3.0d, added a help link for Jet
Laboratory Development Ephemeris
version 3.3.0c/3.3ß39, Changed open cluster contour to dotted
line to follow the convention.
HNSKY version 3.3.0b/3.3ß38, Added comet and minor planet
statusbar message. Unit is arcsec/hour sky motion. Could be
used in PHD2 for comet guiding.
Overhauled the deep sky database. Added some
the old SAC72. Replaced all published brightness values by
values. Now more consistent brightness values.
version 3.0.0/3.3ß37, added α, δ
symbols for RA
and DEC If you don;t like this select English languge in
menu. Updated non English ini files. Updated the help
version 3.3.0, (3.3ß37 Linux), Added support for Jet
Laboratory Development Ephemeris (like DE430, DE431).
Covering years –13,000 to +16,999 . The
Jet Propulsion Laboratory Development Ephemeris will
bring high accuracy for occultations. Overhauled
planet unit. Added
apparent position. Updated time menu and added
Julian day input.
version 3.2.7f/3.3ß36, fixed a problem in IAU designation.
initialization problems after closing polar view window.
Very minor update in the
Deepsky database 3.
version 3.2.7d/3.3ß34, improvement in star_index.
Removed some PGC and vdB
doubles in the deepsky database. The current deepsky
database is one of the finest error
free compilations available.
version 3.2.7c, fixed set time menu alignment for higher DPI
version 3.2.7b /3.3ß34 , added tool bar buttons to the
Fixed a small problem in the drawing mode. Updated Deepsky
level 3.hnd.. Added VDB supplement.
version 3.2.7a /3.3ß33 , changed the north/south line in
dotted line for meridian flip and other reasons.
version 3.2.7 /3.3ß32 , all numbers on the altitude grid and
have now orientation zenith. This to assist you with
and it looks nicer.
version 3.2.6.e, made all extensions in editor down case.
Kepler K2 campaign supplement as demonstrator of the
possibilities. Moon occultations in Kepler field:
version 3.2.6.d & Linux 3.3ß31d, overhauled the bright
star (text) find routine.
3.2.6b & Linux 3.3ß31b, introduced the 290-9 and 290-5
database format. Reduced file size again with 10% and
star in the Gaia or U16 databases takes around 5 bytes
space. These database versions are compacter but there is
gain in speed. You could keep the older databases for time
being. For technical
see the help file
. Made the star plotting routine a
little faster. Disabled the mouse find function for disabled
deep sky database.
version 3.2.5a & Linux 3.3ß30 and new
compacter format for the star databases without quality loss.
TYC and TUC record size goes from 11 to 10 byte saving
U16 and G17 go from 7 to 6 bytes saving 14% space. Works only
latest HNSKY versions 3.2.5a en
3.3ß30. These database versions are compacter but there
gain in speed. You could keep the old databases. For technical
see help file.
HNSKY database up to magnitude 17
Gaia stars. Note that Gaia DR1 is missing some stars so is
less suitable for star
maps. HNSKY version 3.2.4b or Linux 3.3ß28 required, just
released today. Unpack
in the program directory, typically c:\program files\hnsky
version 3.2.4b & Linux 3.3ß28. For above Gaia 290 star
issued a new version of the TUC star database up to magnitude
Contains 7 % more stars due to other magnitude selection.
version 3.2.4a & Linux 3.3ß26. Fixed a problem in
reading U16 star database type 290 with 7 byte record
HNSKY database up to magnitude 16
contains 113 million
stars. A compilation of UCAC4 and Tycho-2. (RAR file of 437
version 3.2.4.001 or Linux 3.3ß25 required. No Tycho-2
or UCAC4 indentifiers are available due to 7 byte record
size. Instead an IAU style designation based on the position
version 3.2.4 & Linux 3.3ß25. Introduced 7
size in 290 database.
version 3.2.3b, Gaia DR1 support using Vizier online database
up to magnitude 20. Gaia proper motion implemented.
version 3.2.3a, fixed an stream error if switching off
database. Adapted plotting range of the TUC database to
HNSKY database up to magnitude 15
containing 36 million
stars made form TYCHO-2 and UCAC4. Compressed in a RAR archive
the size is 192 mbytes. It will only work with the latest
version 3.2.3. of HNSKY since it is in the "290" format.
Abbreviation in the program as TUC
2016-08-06, HNSKY version 3.2.3
with new .290 star file format. Installer will
replace the d32 files with .290 files! This
star database format will be faster and allow larger
Update in deepsky databases. Improved several minor
things including Rosetta nebula.
Minor corrections in version HNSKY 3.2.2g. Added
new supplement with official IAU star names, version
Linux version, changed constellation Bayer letters to
Updated the program ORB_DEB, executables for win32 and
win64 and Linux!. Simple windows program which calculates the
orbital elements of a minor planet based on three
observations/positions using the Gauss method: Download ORB_DET.ZIP version 1.02.
database (type hnd)
2016-7-135 (26 MB) Unpacked is this file 103 mbytes, so
Place this huge deepsky database in the HNSKY PROGRAM
have to select either this one or one of the three deepsky
Very minor update in the MS-Windows version v3.2.2.f. Adaption
size handeling for Calibre, Night vision menu check mark was
2016-5-14 version 3.2.2.d Added an image on/off
button to the object menu. Fixed color change option of main
menu in menu color settings.
2016-4-27 version 3.2.2.c Fixed an exception error
only occuring under Wine (Linux). Better adaption of the stars density
to the window size.
The printing routine will rebuild and adapt the screen view
to the printer resolution. Laser printers will produce
sharp and good quality prints. The size of the window and
monitor resolution are irrelevant. From version 3.2.2b
the size of the printed stars is no longer adapted to the
DPI resolution of the printer. A low resolution
of of 72 or 144 DPI will give the correct star size (a
few pixels) for printing on paper. If you select 1200
DPI you will get much smaller stars (still a few pixels),
more intended for zoomable digital maps. You could use this
for printing to PDF
2016-4-19, Removed twelve Sharpless2
duplications in deep sky database.
2016-4-18, small update of the help file, added
describtion of the deep sky observations file.
version 3.2.2b, small update in printing routine.
2016-3-28, update for the Catalan and Esperanto
module added. Webpage cleanup. Release specialised
tool: SKY_TOASTER, program for conversion
to the TOAST projection,with Delphi source. v0.0
update for the Spanish module added.
3.2.2a. Added missing Milky Way toast projection to the
2016-3-11,version 3.2.2a. Improved azimuth in degrees
- Milky way panorama based on an
ESO full sky panorama.It is slow, so use it optionally.
- Introduced galactic coordinates.
- Added 150 Sharpless-2 objects to deepsky database 3
- Auto size filter in object menu.
- Filter function now also works for supplements
- Added the unicode planet symbols "☿♀♁♂♃♄♅♆♇", sun "☉",
moon "☾", comets "☄" to new language files
english_symbolic_win7.ini. Win10 allows some more unicode
symbol like the floppy symbol "💾"
- Better protection against bad FITS files.
- Many small improvements.
1) All non-english.ini language files are now converted to
unicode encoding (UTF-8) rather then ANSI encoding. If your
native speaker of one of the languages, please check if they
2) The Milky Way in a "TOAST" projection is stored in a single
PNG image and kept in memory for speed. It is made from the
ESO0932a full sky panorama in equirectangular projection. This
panorama had some distortion up to one degree, but I managed
to warp it such that it match pretty well. The specialist tool
(sky_toaster) for making a TOAST projection including code
will be released to public domain the next days.
Version 3.2.1a, improved protection against bad FITS
2016-2-4, Version 3.2.1 Allowing
access to Axel Mellinger low resolution sky survey. From the
pop-up menu select "Get DSS image from internet",
"Skyview" for downloading wide field FITS files. If
you select a field larger the 3.5 degrees height it will
select the Mellinger survey. Default is the MELL-R (red) of
2016-1-31, Version 3.2.1ß4. More
improvements. Yo can also try halpha survey by
modifying download link. Maximum field is limited at
around 140 degrees by Skyview. Minimum pixel
size is 350x350 unless you pull a box large then 350x350
pixels. For better quality add &sampler=Lanczos to the
Skyview instruction in settings.
2016-1-30, Version 3.2.1ß3. Allowing access
to Axel Mellinger low resolution sky survey. From the pop-up
menu select "Get DSS image from internet", "Skyview"
for downloading wide field FITS files. If you select a
field larger the 3.5 degrees height it will select the
Mellinger survey. Default is the MELL-R (red) of the survey.
Version 3.2.0b Dropdown of comboboxes has now
variable width. Fixed statusbar message flickering during
animation. Fixed minor problem with trying to pull a mouse
rectangle during animation. Added a half second in the
routine for UTC hint to fix a rare problem in julian date to
2016-1-24, version 3.2.0a with
new powerful animation menu. if you have v3.2.0 with a
date 2016-1-23, then download an update.
Version 3.2.0ß13/14 Minor adjustments
Version 3.2.0ß12 Fixed an animation problem for
units larger then 1, e.g. step size of 10 days.
Version 3.2.0ß11a Improved control of animation.
Stop/pause/continue all possible. Progress bar added.
Version 3.2.0ß10a Fixed asteroid/magnitude filter
problem of version ß10
Version 3.2.0ß10 Major modifications.
Animation window will allow you to follow Hale Bopp comet and
it's return in 2500 years. (search for bopp*). All
planetary objects can now be followed rigidly. Furthermore
have a look to proper motion of stars of M4 using UCAC4 (zoom
in) with an interval of 10 years over the next 5000 years or
so. Allowing now running with secondary stardatabase
only. Make primary in object menu blank.
Version 3.2.0ß9b Minor improvements. Active window
Version 3.2.0ß8b Minor improvements.
2016-1-12 Version 3.2.0ß8
Minor improvements. Smoother moon orbit lines.
Version 3.2.0ß7c Mouse button routines updated.
Added dates&time to tracks, Fixed reset for Wine under
Linux, some internal cleanup
3.2.0ß5 Beta version, executable only. Minor
3.2.0ß4 Beta version, executable only. Improved
locking of Mercury, Venus, Mars, Jupiter, Saturn. NEO's
distance to 0.05 a.u. including comets. Improved displaying
distance of NEO's at very short distances.
3.1.2f Fixed a small problem for supplement
3,4,5 when loading events. Added two new supplement for
meteors and constellations
3.2.0ß3 Beta version, executable only. Fixed a
major problem in cycling animation causing the application
3.2.0ß2 Preliminary version, several small
3.2.0ß1 Preliminary version with new
animation menu. Simple NEO filter checkbox. Copy/paste import
of JPL orbital elements comets. Send your remarks and
Version 3.1.2e Modified abbreviations
conversion to unicode.
Version 3.1.2c, d More updates in deep sky
database. Fixed saving menu font size.
3.1.2b Significant update deep sky database. In program
improvement abbreviation translation, fixed problem brightness
Version 3.1.2a Internal code optimisation, updated
the deepsky.chm file.
Version 3.1.2, Replaced deepsky observations file format from
HTML to HTMLHELP (CHM) format.
Version 3.1.1a, Fixed initial directory of save as
Version 3.1.1, Introduced the new deepsky observations
file in HTML. This replaces the old HNS_DEEP.HLP file Fixed
the HTML help for Firefox. Fixed wildcard search.
Version 3.1.0h Fixed asteroid positions. Where wrong due
to unicode support.
Version 3.1.0g Fixed save command supplement 3 and
Version 3.1.0f Fixed ASCOM sync command.
Version 3.1.0e Fixed comet update from settings menu.
Version 3.1.0d, Fixed a small problem with rise and set times.
Fixed a freeze of the program if Skyview reports with an error
file rather then a FITS file. Delete all downloaded FITS files
if you phase this problem..
Version 3.1.0c Minor corrections and fixed the updating
of the asteroid and comet database from the settings menu.
Version 3.1.0b, setup or version 3.1.0b executables
only Minor tweaks for rise/set times. If the set time is
before the rise time then is reported as Set:... Rise:....
else Rise:... Set:.... to prevent confusion.
release of version 3.1.0a setup or version 3.1.0a
executables only Allows now 5 supplements. Introduced a new
entry line for goto menu. Works with unicode and will display
the greek alphabet correctly and many other alphabets
contained in unicode.. Improved processing speed of deep sky
and supplement routine again and reached same speed as the
classic version. Streamlined string operations.
2015-11-16 Added supplements: Constellations
IAU & named stars.sup, Asterisms.sup
2015-11-15 Added new
supplements for double/multiply stars fully based on "SAGUARO
ASTRONOMY CLUB DOUBLE STAR DATABASE VERSION 4.0", called
"SAC_double_star_v4.sup" to version
package Version 3.0.3b executable
2015-11-12 Release of version 3.0.3b Fixed a problem with statusbar indication.
2015-11-5 Release of version 3.0.3
basic earth view or horizon. In the settings menu you
can select transparent or not.
- Internal simple Milky Way boundaries.
- Adjustable magnitude setpoint for the three
deep sky colors.
- More powerful editing mode for the line
drawing mode. Modify or add any line.
- Added JPL Horizons
orbital elements import via clipboard. For this select in
the JPL webpage "orbital elements", generate ephemeris and
select all and then copy it to the clipboard. Then use the
special paste shift-V function in the HNSKY editor to paste
the converted elements into the asteroid editor. Please
select in JPL Horizons the orbital element output, not
- Split the save menu in the editor
to "save" and "save to".
2015-10-7 Release of version 3.0.2f4
2015-10-3 Release of version 3.0.2f
Minor changes. Updated deepsky database 3, North_arrow is
clickable, Skyview FITS images with higher background level
such as in Cygnus are better displayed.. Added
constellations supplement files. Added simplified chinese
2015-9-23 Release of version 3.0.2e
Fixed statusbar position.
2015-9-20 Release of version 3.0.2d
Added options to hide icons or text of the mainmenu. Fixed
naming of deepsky object in "draw solar tracks." Fixed
font width problem for unsual wide fonts.
2015-9-19 Release of version 3.0.2
Fixed path problems after saving and correction in
supplement handling. Editor search menu extend.
2015-9-18 Release of version 3.0.2ß12
Fixed path problems after saving and correction in
supplement handling. Editor search menu extend.
2015-9-17 Release of version 3.0.2ß11
Move hide menu to popupmenu mainmenu, hide mainmenu text
2015-9-16 Release of version 3.0.2ß10b
2015-8-31 Release of version 3.0.2ß10a
Fixed sluggish behaviour. Introduced internal database
search for an area.
2015-8-23 Release of version 3.0.2ß8
Hide main menu introduced.
2015-8-23 Release of version 3.0.1e
Fixed label indication supplements.
2015-8-21 Release of version 3.0.2ß7
Cylindrical projection introduced:
2015-8-18 Release of version 3.0.2ß6
2015-8-17 Release of version 3.0.2ß5 Menu
buttons can be removed with pop-up menu. In later version,
default will off.
2015-8-16 Release of version 3.0.2ß2 Aero
implemented and adjustable menu top color.
2015-8-15 Release of version 3.0.2ß Significant menu
2015-8-11 DSS viewer HNS_REAL
2.0.0c. Updated getdss.dll for win64 load problem.
2015-8-6 Release of version 3.0.1d Fixed star names for
local copy of UCAC4 and GSC.
2015-8-6 Release of version 3.0.1c Fixed ASCOM for 64 bit
windows and some path issue with saving settings.
2015-8-6 Release of version 3.0.1b Minor corrections in
saving/loading protocols. Added in "About" 32 or 64 bit
appliation version indication.
2015-8-4 Release of version 3.0.1a Important file
location change. Editable files are now in documents folder.
Please copy your settings file Default.hns file to the new
Located in: C:\Program
database,SAO stars to magnitude
PPM star database
to magnitude 10.0 (468861 stars)
||Tycho-2 star database
containing 2.5 million stars. D32 file format. (32
Small deep sky databases with 267 selected objects.
Good start for beginners.
deep sky database with 2600 objects. Up to magnitude
12. GX>=1 arcmin.
- Very large deep
sky database with 26000 objects. Up to magnitude 15.5.
help file containing about 1000 A4 pages of deep sky
Tom Lorenzin and Steve Coe and other authors.
english translation files
Located in: Documents\hnsky
|The comet database.
||The asteroid database.
deep sky and star supplements files, in ASCII
format. (Milky Way, Yale catalog,
binary and variable stars, messier objects,
|Setting and event files in ASCII
format.you can load/save. During
startup 'default.hns is loaded'
Located in: Documents\hnsky\fits
sky and planetary images in FITS format.
Located in: Documents\hnsky\cache
||Cache of online
downloaded star catalogues UCAC4, NOMAD.
The above files locations are for v3.0.1 and higher
The Windows hidden "Application Data" directory is
not used by purpose.
2015-8-3 Release of version 3.0.0n2 Small fix in 64 bit
version for application error message.and small initialisation
problem when starting
2015-8-2 Updated the installer to set
file/directory permssions correct.
2015-8-1 Release of version 3.0.0n release of
both 32 and 64 bit versions in one installation package
2015-7-31 Release of version 3.0.0m1 and
experimental 64 bit version
(executable only). Tiny update in deepsky database..
2015-7-18 Release of version 3.0.0m Added width and
height indication for mouse pulled square. Added redo view
menu option (shift-ctrl-z) to existing undoview option
(ctrl-z). Very minor update deepsky databases.
2015-6-22 Release of version 3.0.0L Switches
automatically between native star databases and external star
catalogue depending on zoom factor. See http://hnsky.org/help/uk/hnsky.htm#object_menu
2015-6-17 Release of version 3.0.0k Move SIDEREAL
popup option to main menu SCREEN.
2015-6-14 Release of version 3.0.0j2 Adapted the
help links for the Chrome browser. Context sensitive help
(HTML with anchors) works now for both Firefox and Chrome and
newest versions of Internet Explorer.
2015-6-7 Release of version 3.0.0j Added online
URAT1 catalogue. New epoch 2016 version of SAO and PPM
star database. So star positions are for 2016-1-1
calculated using proper motions. Tycho-2++ updated, total
4.504.823 stars up to magnitude 12.5 from wich 2.050.961 UCAC2
2015-6-2 Release of version 3.0.0i2 Fixed a problem
with online star catalogs resulting in streaks and faulty
magnitudes. ADDED SOME MISSING STARS IN TYCHO-2
2015-5-31 Release of version 3.0.0i Overhault
completely the function behind de star density and star
boldness sliders. Some background info to get a unoform
2015-5-29 Release of version 3.0.0h Tycho-2+
database has been replaced by Tycho-2++. About 2 million UCAC4
stars where added to tycho-2 and it is complete up to
magnitude 12.5 containing 4.4 million stars. Epoch is set to
2015-5-17 Release of version 3.0.0g Communication to
telescope selects now equinox for communication automatically
from ASCOM. Settings menu updated accordingly.
2015-5-13 Release of version 3.0.0f Changed menu
"dark nights next days" back to orginal setup. Moon did
not display correctly for higher altitudes >50degrees
2015-5-9 Release of version 3.0.0e2 Modified completely
the line drawing menu in popup menu. Drawing deep sky outlines
is now much easier using the mouse. See first demo
included, Deepsky outline.SUP
2015-5-3 Release of version 3.0.0d
Automatic update download link asteroids. Was
still downloading the 2013 file rather then the 2015 file.
Fixe the plot solar object message.
2015-5-2 Release of version 3.0.0c
Fixed a problem plottings the planets at wide
field with FITS images on. Map_mercury .fit
updated with new Mercury overview of Messenger
2015-4-11 Release of version 3.0.0a
Added moon shadow on planets. Have a look to
Jupiter at 2015-1-24, 6:30 UTC.
2015-4-5 Release of version 3.0.0
- Replaced WINHLP file
with HTML files. Installed under
.\help\uk\hnsky.htm. Help files of version
31-3-2015 in .\help\*.* can be removed.
- v3.0.0ß8a, modified the cache
file format of the online UCAC4, NOMAD to reduce file
size. If you have used v3.0.0ß8, remove all *.TXT
files (cache) from the FITS directory.
- Added online UCAC4 and
NOMAD star catalog.
- Added a wildcards option in
the search menu. E.g. type PAN* and press comet
button. See the help file.
Object filtering in OBJECT
MENU changed into a combobox.
Fixed long abbreviation
Fixed telescope-sync wrong equinox problem
Help file updated to version 3.0.0
Map can be displayed in terrestrial,
sidereal and solar view.
UCAC4 conversion program included for wide
field views. UCAC4 magnitude selection adapted to
min(u4Fmag, APASS_V, U4Amag)
Add new menu "polar aligment scope view"
under help menu. This shows polaris or equivalent southern
area to polar align your telescope.
Grid line resolution set higher for
Removed USNO B and UCAC3 support.
Fixed search function UCAC4 stars.
Animation solar object introduced. See
settings menu option ANIMATE and hit "INS" key to animate.
Moon covers stars, optional in settings
Persistent feature of the window's canvas.
So if a program is in the front of HNSKY window and moved
away again, repainting will be almost instantly.
Database complete updated using Wolfgang
Steinicke 2014 NGC/IC database and SAC81, revision
Deepsky database reading works now
correctly for 3 names. (supplements only 2)
Search shortcuts are now CTRL-F and ALT-S
Dark night forecast display for Moon
Night vision improved.
Supplement plotting speed improved
Added brightness estimate for deep sky
Ascom telescope interface moved to popup
menu, azimuth indication in altitude grid changed in N,
NE, E, SE, S, SW, W, NW . Outstanding language modules and
interfacing to be updated.
Ascom connection can be saved in settings.
Program can guide the telescope to follow
Measuring frame erase
Telescope cursor improved.
supplement Dated 2015-1-5 (10 Mbytes) Slow but
nice to identify al those small fuzzy objects on your CCD
images. Here a demo image using a 65 mm
telescope CCD image.
Made HNSKY compatible with Maxim DL images
2014-7-14 Release of version 2.4.1 No changes
compared with version ß3
2014-6-29 Release of version 2.4.1ß3 Total overhaul of the
bold and density function of star plotting. Start with
the bold/density gliders in the middle. Note that faint
stars are displayed as a single pixel with grey level so they
are not so explicit vissible. Secondly improved simulation of
conjuction of jovian moons. e.g. In case of conjuction of
Callisto with Ganymede, Callisto can be both in the front or
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