"Report on HNSKY accuracy." by  Giuseppe Matarazzo:

(Email:  joematara X XX @ XXX  (remove XXX))

Dated: 25 Nov 2000

The QUALITY CONTROL of any product is basically the CORE of our highly developed industrial society. Software must ETHICALLY follow the same rules, independently of the matter that its COST is nul (freeware) or not. HNSKY has been submitted to the following STRONG TESTS through comparisons with professional astronomers' documents:

1) SOLAR ECLIPSE of 11 August 1999, at the site Stuttgart (Germany):

lat.=48.766 deg.N; lon=9.183 deg.E, location covered by TOTALITY.

Reference source: Schedule issued on paper "l'astronomia", the most important italian revue on astronomics

HNSKY: Settings at UT 9:17 of the date and geographic coordinates of location as above; Search the Sun, Field inflated up to 110x65'.This is the moment of starting eclipse; increasing time with F4, time of total eclipse understandable between 10:37 and 10:38 UT; end of eclipse at 11:58 UT

PAPER: Start eclipse at 9:13.9, start totality 10:33.7, end totality 10:36.0, end eclipse 11:57.7

2) URANUS planet OCCULTS star PPM 237981 alongside a "shadow" crossing South Africa, Atlantic Ocean, South America on 27 August 1998, max. phase at 01:15.6 UT. Location choice: lat.=50 deg.S, lon.=70 deg.W, sited in south of Chile.

Reference source: Italian almanac 1998, edited by "Astronomia-UAI", data and graphics coming from E.Goffin software.

HNSKY: Settings at UT 23:45 of 26 Aug, the above coordinates, Star PPM button, Max.Field 1x1', Occultation starts at this time and ends at 00:27 of 27 Aug; elapsed time 42m.

PAPER: Phenomenon Duration: 2508.8s = 41m 48.8s

3) Jupiter satellites INVISIBLES - It sometimes happens that the 4 satellites are SIMULTANEOUSLY invisible, as shown in this

Example: Date: 27 August 1997 - 22:00:00 UT

Reference source: J.Hedley Robinson: Astronomy Data Book, 1972 John Wiley & Sons, New York:

" #1 will be occulted, #2 in transit, #3 occulted and eclipsed with #4 eclipsed".

HNSKY: Field enlarged up to 2x1', #2 visible on Jupiter Disk (transit), #1 and #3 occulted and properly not intercepted by the program at Search request (occulted), #4 outside the Jupi ter disk, but not shown on the screen because it is ECLIPSED by Jupiter. To see its re-appearence, Search it at the time 22:17 and a yellow spot appears in video. Switching F3 and F4 between 22:16 and 22:17 the IV spot "flicks" in the screen.

4) MUTUAL OCCULTATIONS of Jupiter satellites; such circumstances happen every 6 years and are visible from any location.

Example: Date: 2 August 1997 - 02:53:07 UT max.phase 3O2T -> it means sat #3 (Ganymede) OCCULTS sat #2 (Europa) Totally

Reference source: J.-E. Arlot from Bureau des Longitudes (Paris) "Prediction of mutual events of the Galilean satellites of Jupiter occurring in 1997" - edited by "Astronomy & Astrophysics", 15 May 1996

HNSKY: Time at UT 2:54, Search Planetary Europa, Max.Field 1x1', First Contact at the time, F4 increasing 1 minute, 2:59 max. coverage (few pixels not in totality), 3:05 last contact; elapsed time 11 minutes.

PAPER: Event Duration: 763s = 12m 43s

5) MUTUAL OCCULTATIONS of Saturn satellites (1995)

Example: Date: 18 May 1995 - 02:17:01 UT max.phase 5O2T -> it means sat #5 (Rhea) OCCULTS sat #2 (Encedalus) Totally Reference source: Viriol D'Ambrosio (Bureau des Longitudes, Paris) - Schedule of Saturn mutual events issued on the italian revue of astronomics "l'astronomia" - April 1995

HNSKY: Time at UT 2:49, Search Planetary Encedalus, Max.Field 1x1', 2 spots OVERLAPPING each other; reducted dimensions of spots cannot permit to see contacts and time of occultation

PAPER: Event Duration: 109s = 1m 49s


C O N C L U S I O N: HNSKY software is HIGHLY ACCURED on applied

algorithms alongwith good video definition.


Subject: Again on HNSKY performances

Date: Tue, 21 Aug 2001 22:22:22 +0000

From: "Giuseppe Matarazzo" <joematara  XXX @> (remove XXX)

To: h a n _ k l e i j n

Hallo Han,

I have recently downloaded from an astronomical and professional website (see the compressed file transits.tar.gz) all TRANSITS of Mercury and Venus over the Sun from -1000 up to +4000 years.

Due to the short limits of HNSKY [1750-2250], I have chosen the transit of Mercury at the earliest date, say May 6, 1753. Results are as shown underneath:

Entrance on the disk Exit from the disk

HNSKY 02:17 UT 10:10 UT

Almanac 02:14 UT 10:11 UT

In PERFECT harmony! My HNSKY version is 2.08c, dated 2001-4-26.

Probably HNSKY limits could be enlarged!

With my compliments, Han

bye, Joe