Optical Equipment

• 10.1" f/4.5 homebuilt Dobsonian reflector with Crossbow equatorial platform
  • Celestron 8x50mm finder (~4 degree FOV)
  • 1.25" eyepieces
    • 5mm to 8mm Speers-Waler Zoom
    • 6mm Kellner
    • 10mm Plossl
    • 12mm Kellner
    • 12mm Speers-Waler
    • 18mm Meade Ultra Wide Angle
    • 27mm Orthoscopic
    • 32mm TeleVue Plossl
  • Filters
    • Meade Series 4000 Nebular Filter, ~ 440 to 535 nanometer wavelength
    • Lumicon OIII filter  ~ 484 to 506 nanometers
  • 2.5x Televue barlow

• 80mm f/5 Orion Short tube refractor on German equatorial mount

• 2.4" (60mm) f/11 altitude-azimuth refractor with 6x15mm finder
  • 0.965" eyepieces -- 6mm, 12.5mm, and 25mm Huygens

• 10x30 binoculars

• Mallincam SkyRaider DS432CTEC camera
  • An essential part of Electronically Assisted Astronomy (EAA), video astronomy equipment has resusitated my deep sky observing in Bortle 7 skies!
  • Unless otherwise specifed, camera settings used for most photos include
    • Live Stack: Mode = Average, Type = Planet
    • Conversion Gain = HCG
    • Digital Binning = 1x1
    • Dark field and Flat field corrections applied (in most cases)

Fields of view and magnification

The edge of the field of view (white circle) in each drawing covers an area of sky that is dependent on the telescope and magnification.

For the 10.1" reflector the fields of view (FOV) and magnifications are roughly as follows:

• 6mm Kellner: 15' (fifteen minutes of arc), 192x (192 times magnification)
• 5-8mm S-W:
  • 5mm: 19', 231x
  • 6mm: 24', 193x
  • 7mm: 28', 165x
  • 8mm: 34', 145x
• 10mm Plossl: 25', 115x
• 12mm Kellner: 30', 96x
• 12mm S-W: 55', 96x
• 18mm UWA: 1 degree 17', 64x
• 27mm Ortho: 1 degree, 43x
• 32mm Plossl: 1 degree 23', 36x
• 8x50mm finder: 4 degrees, 8x

For the 2.4" refractor, FOV and mags are:

• 6mm: 15', 117x
• 12mm: 30', 56x
• 25mm: 1 degree, 28x

For the 10x30 binoculars, FOV is approximately 4.5 degrees.

For the Mallincam DS432CTEC camera, FOV is approximately 42' x 29' and about 83x on the 10.1" Dob. With the 0.5 Mallincam Universe focal reducer it's about 65' x 45' and 54x.
FOV with the 80mm refractor is 124' x 85', and with the 0.5 focal reducer 190' x 130'.

All the sketches indicate the magnification, so the information above tells you how much area of the sky your looking at (eg. a sketch saying 115x would suggest the 10mm eyepiece on the 10.1" was used, and it has a 25' FOV). 

Observing Conditions

Unless otherwise noted, all deep-sky sketches were done with the Moon somewhere between last quarter and first quarter and below the horizon. Sky conditions were generally good to excellent both for seeing and sky contrast. The limiting visual magnitude for most sketches was usually between 5.8 to 6.2 (NOTE: I moved to a suburban location years ago so some of the more recent sketches were done with poorer sky conditions - my current location has a limiting visual magnitude of about 5.0 under Bortle 7 skies). Observing site lattitude and longitude is 45 degrees N, 75 degrees W.

8^)