Astro Appendix

Appendix                                                                         11/07/15

Before light pollution got worse, I was able to view and admire most of the items listed below from my backyard. No more, civilization in the form of development has fogged out most of these objects.


Backyard equipment includes an Orion 8 inch reflector telescope with a Pro EQ tripod, a Canon S2IS camera, a Philips SPC900 webcam and various viewing accessories and a laptop computer. An Orion 90EQ telescope is used for viewing, but not for photography. Large (landscape) astrophotos with the Canon S2IS are sometimes made with a hinge tracker to reduce star drift in longer exposures.


Contains various locations and system modifications.

Focuser bridge extended with eyepiece
Focuser bridge extended with eyepiece
Focuser bridge and eyepiece collapsed
Focuser bridge and eyepiece collapsed
Parts for the focuser bridge
Parts for the focuser bridge
Rational for focuser bridge
Rational for focuser bridge
Drawing of bridge slider plate
Drawing of bridge slider plate

Space distances

Space distances are given in three different units, light years (ly), parsecs (pc) and astronomical unit (AU). A light year is the distance that light would travel in one year. The speed of light is 186,000 miles per sec or 300,000 km/sec, so one light year would represent 836 Giga miles (836 thousand million miles). An astronomical unit is the average distance from the Earth to the Sun (1 AU = 1.5 x(10)^8 km or 93x(10)^6 mi). 1 parsec = 206,265 AU or 3.26 ly.

Nominal Distances for Selected Items (will vary at times).

***Our Solar System***

Earth diameter 12,700 km (7,926 miles)

Earth’s orbit 150 million km (94 million miles)

Moon orbit 384,400 km (238,855 miles)

Mercury Orbit   58 million km (36 million miles)

Venus Orbit 108 million km (67 million miles)

Mars Orbit 228 million km (142 million miles)

Jupiter Orbit 778 million km (484 million miles)

Saturn Orbit         1429 million km (888 million miles)

Uranus Orbit         2875 million km (1786 million miles)

Pluto Orbit         5916 million km (3700 million miles)

***Milky Way***

Diameter 100,000 light-years

+++Open Star Cluster Distances from Earth+++

Pleiades 400 light-years

M36         4,100 light-years

M37         4,400 light-years

Double cluster         7,000 light-years

+++Globular Star Cluster Distance from Earth+++

M13   25,000 light years RA 16 41.7  Dec +36 28

M15     31,000-40,000 light-years RA  21 30.0  Dec +12 10

***Nebula ***

IC 434 (Horsehead Nebula)  in Orion 1,500 light-years from Sun RA 05h 40m 59.0s Dec -02 deg 27 min 30 sec

M8 (Lagoon Nebula)  in Sagittarius  2,500 light-years from Sun         RA 18 03.8 Dec -24.23

M20 (Trifid Nebula) in Sagittarius  2,500 light-years form Sun         RA18 02.6  Dec -23.02

M42 (Orion Nebula)  in Orion      1,350 light-years from Sun         RA 05 35.4 Dec -05 27

M57 (Ring Nebula) in Lyra      2,300 light years from Sun             RA 18.54   Dec +33.02

*** Galaxies***

M31 (Andromeda Galaxy) 2.2 Million light-years from Earth  RA 00 42.7 Dec +41 16

M32 (Galaxy) 2.9 Million light-years from Earth              RA 00 42.7 Dec +40 52

Table of Properties of the Planets and Moons

Distance         Radius    Mass

Name       Orbits (000 km)    (km)     (kg)

———  ——- ——–  ——-  ——-

Sun               697000  1.99e30

Mercury    Sun        57910     2439  3.30e23 +

Venus      Sun       108200     6052  4.87e24

Earth      Sun       149600     6378  5.98e24

Moon       Earth        384     1738  7.35e22

Mars       Sun       227940     3398  6.42e23

Jupiter    Sun       778000    71492  1.90e27

Ganymede  Jupiter     1070     2631  1.48e23 +

Callisto   Jupiter     1883     2400  1.08e23

Io         Jupiter      422     1815  8.93e22

Europa     Jupiter      671     1569  4.80e22

Saturn     Sun      1429000    60268  5.69e26

Titan      Saturn      1222     2575  1.35e23 +

Uranus     Sun     2870990    25559  8.69e25 *

Neptune    Sun      4504300    24764  1.02e26 *

Triton     Neptune      355     1353  2.14e22

Pluto      Sun      5913520     1160  1.32e22

*Note: Neptune is slightly denser than Uranus.

+Note: Mercury is much denser than Ganymede and Titan.

Table of Properties of Significant Stars 

Magnitude is a measure go star brightness and is measured on a scale is based on very early observations, and as a result, is not entirely straightforward. The reference zero (0) was the minimum brightness perceived by observers at an earlier date, It was discovered, however, that stars existed dimmer than the selected zero value. Thus, 0 is only a  reference visibility and numbers with  + sign are dimmer and those with a negative sign are brighter. The values reported here are visual based (V). The relative brightnesses within this scale are correct.


Name      Location     Magnitude (V)      Spectral Type          (LY)

———   ————   ————–            ————-      ———–

Sun +4.82 G2 V 8 light minutes

Alnitak zeta Orion -5.5 O9.5 I

Alnilam  eta Orion -6.6 Bo I

Mintaka delta Orion -5.4 O9.5 II

Aldebaran Taurus -0.8 K5 III 65

Polaris Ursa Minor -4.1 F5 8I 431

Rigel Orion  -6-6 B8 I 773

Betelgeuse Orion  -5.0 M2 I 522

Sirius Canis Major 1.5 AI V 9

Procyon Canis Minor 2.8 F5 IV-V 11

Pollux Gemini 1.1 K0 III 34

Regulus Leo -0.6 B7 V 77

Spica Virgo -3.6 B1 V 262

Arcturus Bootes -0.6 K1.5 III 37

Antares Sco -5.8 M1.5 I 604

Vega Lyra 0.6 A0 V 25

Altair Aquarius 2.1 A7 V 17

Deneb Cyngus -7.5 A2 I 1467

Formalhaut PsA 1.6 A3 V 25