JUXT Astronomy Guild Evening
2022-11-04

rig

My Telescope

STellamira 90mm APO

Basics

  • f-ratio = focal length / aperture

ME and mY f-ratio

  • My telescope ( the SM90 ): 540mm / 90mm = f/6
     
  • But, I use a Focal Reducer..
     
  • Increases FoV (field of view), and brings the focal length down to 0.8x, which is f/4.8.

THE JUXT scope

  • Celestron 8se
  • Aperture 200mm (8 inches)
  • Focal Length 2032mm
  • Focal Ratio f/10

BIG lesson #1

  • High f-ratios = very hard.
     

  • Each step up, requires 2x the amount of time to gather photons.
     
  • Images will take 2x the time to make for each step up!

F-ratio guide

  • f/2 - insanely quick

  • f/3 - quick

  • f/4 - f/6 normal (ME NOW & SWEET SPOT FOR BEGINNERS)

  • f/7 - getting serious

  • f/8 - getting very serious

  • f/9 - scary

  • f/10 - JUXTScope & the limit of what I will eventually try

 JU​XT

Short vs long focal lengths

Short focal lengths, let's call wide-field instead. Use for wider, bigger objects in the sky: Nebulae & near by galaxies

Longer focal lengths, use for smaller objects in the sky: Galaxies

Lets go to astronomy.tools.com

BIG LESSON #2

  • Bigger isn't always better
  • Start Astrophotography with a wide-field refractor
  • Loads of beautiful targets = AWE
  • Less imaging acquisition time needed = FUN
  • Guiding - MUCH - easier at lower f-ratios = EASE
  • Quality imaging scopes cheaper = EXPENSE

Telescope types

Reflectors

Sky-Watcher Explorer 130P-DS

Reflectors

Dobsonian

RASA

Trevor @ astrobackyard youtube

Big lesson #3:

prioritise the MOUNT

  • Mine: CGEM2
  • Equitorial vs AZ
  • Mount is where the $$$ goes
  • More $$$ = better guiding,
    more weight capacity

Hardware:

harmonic drive MOUNT

  • Rainbow Astro rst-300
  • ZWO AM5

Hardware:

premium mounts

  • 1100GTO German Equatorial Mount
  • Why?

Hardware:

mount showdown

Big lesson #4:

choose osc

  • Mine: zwoAsi2600MC
  • OSC = one shot colour
  • NOT MONO!

OSC bayer matrix

Mono filter wheel

  • Expensive (filters, EFW,
  • More work! Calibration steps for each filter
  • OSC produces amazing images, and processing capability to make better

big learning #5 - asiair is a gamechanger

Asiair awesomeness

  • With a dash of evil

Big learning #6

  • YouTube is addictive

youtubers:

lazy geek

youtubers:

Trevor - astro backyard

youtubers:

dylan o donnell - star stuff

Big learning #

  • Keep a journal, for me Asciidoc

Over to Asciidoctor...

Resources

  • Adam Block PixInsight Tutorial
  • astrobin.com
  • clearoutside.com
  • astronomy.tools

Thank you and ask me anything