Jonathan's Astronomy Page

After the 2017 Solar Eclipse my astronomy juices started flowing again.
I had stopped using my Quantum 4 telescope because I had so much difficulty finding anything
(I now know that a red dot finder would have made finding objects much easier than the right angle finder scope)
I decided to try a computer controlled "GOTO" scope and purchased a Celestron NexStar 8 Evolution and I've been very very happy with it.

My Telescope

Star Parties I have attended

Eyepiece Magnifications

Seeing - is a meaure of sky stability. Ratings: SS( SkySafari number), AL (Astronomical League's wordings)

Transparency - for the faintest star you can see, truncate the magnitude to get the rating.

From home I can usually on see a couple of stars in the little dipper. I usually try for Megrez in the big dipper.

Normally from home I cannot see Meissa

Twilight

Compass deviation from home (-11 degrees)

Saturn's rings and Jupiter's belts

The Trapezium (Theta 1 Orionis)

Deep sky observation tips

Things to note when observing deep sky objects

General - Descriptions at various magnifications, direct and averted vision comments, and filter comments and any friends who I looked at it with or anything else interesting that is happening at same time.

Nebulas - Stellar, Disk, Ring, Bi-Polar, Shells, Shapes, Orientation, Color, Brighter areas, Central star visible, Blink

Globular Clusters • Shape, Core location (e.g. Core is centered to NW of cluster), bright areas • Unresolved - looks like a nebula with no stars. • Partially Resolved - most of the outer stars are seen and averted vision shows some brighter members of the core. Record the number of stars that can be counted. • Moderately Resolved - stars seen across the core of the cluster (perhaps noting percentage that stars can be seen across the core e.g. stars resolve to outer 50% of core) and unresolved dead center. Don't expect any cluster to be able to be fully resolved. Record the number of stars that can be counted

Galaxies • The shape (round, oblong, edge on), Envelope orientation (e.g. NW ot SE), Structure (is a bar visible, are arms visible) • Mottling - the brightness of the envelope is not uniform (like rippling). • The brightness of the envelope fades off at the edges can be described as "poorly defined" or "indistinct". • A common description for many galaxies I've seen might be, the distinct core is surrounded by a large, bright and soft glow that fades smoothly into the sky background. • A dark line might be an absorption feature, such as a dust lane or gas cloud in the plane of the galaxy - the Sombrero Galaxy (M104) is an excellent example of this. • A brighter line might be the central bar if the galaxy is a barred spiral. • Any notable field stars or other objects in the field (other galaxies, globular clusters, PNs, etc) • Great page of sketches of Messier Galaxies

Open Clusters - Number of stars, density of star field, any nebulosity, colors

Galaxy Type Descriptions

Barred spiral galaxies in Messier's catalogue are Messier 58 (SAB(rs)b), Messier 91 (SBr), Messier 95 (SB(r)b) and Messier 109 (SB(rs)bc),

Nebula Types

Filters

How to check battery status in SkySafari

How to do a star sense alignment

My Celestron Evolution 8" Schmidt-Cassegrain Telescope

The Schmidt-Cassegrain (SCT) optical system uses a combination of mirrors and lenses and is referred to as a compound or catadioptric telescope. This unique design offers large-diameter optics while maintaining very short tube lengths, making them extremely portable. The Schmidt-Cassegrain system consists of a zero power corrector plate (usually the mounting point for the secondary lens - to correct for spherical aberration), a spherical primary mirror, and a secondary mirror. Typical focal ratio is f/10.

Dobsonian Light Path

Some Fun Facts

The Universe - The universe is all of space and time and their contents. It is estimated to be about 13.8 billion years old and contains approximately 200 billion trillion stars.

Sun - Its diameter is 109 times larger than the earth (diameter 7,915 miles) and over a million earths could fit inside the sun. It takes sunlight 8.4 minutes to reach earth. The sun's surface temperature is 10,000F

Moon - Has a diameter of 2,159 miles. Approximately 50 moons could fit inside the earth. It goes around the Earth at a distance of about 239,000 miles. Mare Crisium is 345 miles in diameter

Planetary Nebulas - Are formed when the central star, during the last stages of its evolution before becoming a white dwarf, expels a vast luminous envelope of ionized gas into the surrounding interstellar space.

M27 The Dumbbell or Applecore Nebula - It is ~1300 light-years away and is ~14,600 years old. It was the first planetary discovered in 1764 by Charle Messier.

M57 The Ring Nebula - It is ~2500 light years away and is ~7000 years old.

Galaxies - There are typically 100 billion stars in a galaxy, there are about 2 trillion galaxies in the universe. There are approximately 200 billion trillion stars in the universe.

The Milky Way - Our galaxy contains about 100 to 400 billion stars and is ~87,000 light years in diameter.

M31 The Andromeda Galaxy - It is ~2.5 million light years away and approximately 1 trillion stars and is ~152,000 light years in diameter. The Milky Way and Andromeda galaxies are expected to merge in around 4-5 billion years.

Globular Clusters - A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of member stars, all orbiting in a stable, compact formation. Some are among the oldest objects in their galaxies and even the universe, constraining estimates of the universe's age.

M13 The great globular cluster in Hercules - It is ~25,000 light-years away estimated to be 11.65 billion years old, it is estimate to have 300,000 to 500,000 stars and is about 145 light-years in diameter.