EQUIPMENT

 

My Refractor Setup as of October 5, 2017

  • William Optics GT-81 (81mm, 487mm focal length)
  • William Optics 50mm (200mm FL) guide scope
  • ZWO ASI120MM-S (mono) guide camera
  • Orion Atlas EQ-G or iOptron CEM25P equatorial mount
  • Atik 414EX Monochrome CCD camera
  • Atik EFW2 Filter Wheel (filters: L R G B Ha OIII SII Clear DarkFrame)
    • Raspberry Pi 3 64-bit computer Ubuntu Mate distro with INDI, Ekos, KStars remote observatory control software for all the hardware
    • Shoestring Astronomy FCUSB Focuser Controller
    • USB 3 hub (powered)
    • GL-AR150 Wifi Router
  • Thousand Oaks Optical dew heater controller
  • Dew control heater strips




Best combinations for resolution:
Astro-Tech AT6RC + Atik414EX w/0.8x Reducer = 1.23"/pixel
William Optics GT-81 + QHY5III178 = 1.03"/pixel
William Optics GT-81 + ZWO ASI120MM = 1.62"/pixel


Atik EFW2 Filter Wheel config


Filter Wheel (5 filter Solomark manual)
I mainly use this for moon shots, with the #58 Green and #80a Blue filters, but I also have the UHC and OIII filters in this wheel
5 Green - #58 Green (24% Transmission)
4 Blue - #80A Medium Blue (28% Transmission)
3 UHC
2 OIII
1 EMPTY

NOTES on blue and green filters:
#58 Green (24% Transmission)
Lunar surface detail
Contrast of blue and red structures on Jupiter, including The Great Red Spot
Melt lines around Martian polar ice caps
Contrast of Saturn's subtle cloud belts

#80A Medium Blue (28% Transmission)
Details of Jupiters cloud belts and Great Red Spot
High clouds and polar caps of Mars
Lunar surface details
Contrast of some comet tails


Field Flattener / Reducer Notes:

I have two reducers:

William Optics APO 0.8x Flattener for GT81 (F6-A)
Lens-to-chip suggested distance: 64.38 mm
Reduces f/6 to f/4.7; f/9 to f/7



2" 0.5x Reducer sold by several companies, GSO/Highpoint
Recommended working distance is 53mm

Camera info:
Atik 414EX Backfocus: 13.5mm



ZWO ASI 120MM Backfocus: 12.5mm



Nikon D750 Backfocus: 46.5mm (Lens flange to sensor, lens flange to film)



QHY5III178 Backfocus: 10mm - 12mm



Nikon Backfocus: 46.5mm





Spacing from the center of the pickoff mirror
to the base of threads for the guide cam: 31mm





Filter Wheel Info:
Atik EFW2 width: 22mm




Spacing notes:
Nikon D750 + T-Adapter + spacer + WO 0.8x reducer...Scope
Nikon D750 + T-Adapter + M42/M48 Adapter + 0.5x Reducer...Scope

           13.5mm +  22mm +                       10mm +    20mm
Atik 414EX + Atik EFW2 Filter Wheel + spacer + M48-to-M42 Adapter + WO 0.8x reducer...





Links:
Edmund Optics spacers
Astrophotography Tutorials on Reducers and spacing: Astrophotography Field Flattener & Focal Reducer Spacing https://www.youtube.com/watch?v=CZ-ipPmR9ec


ATIK 414EX Monochrome CCD Camera Notes: Atik Cameras, in their selecting a camera video, suggests that I should be aiming between 1 and 2 for the following image scale formula. (The Atik 414EX CCD sensor has a pixel size of 6.45µm). Calculating this out with the focal length of my two scopes will give me the number of arc-seconds / pixel. Under 1.0 means I'm over-sampling the image, and I will get large and bloated stars. Undersampling will give me blocky stars. The first time I tried out the 414EX I connected it and the Atik filter wheel right up to the AstroTech, and sure enough, I was looking at frames that looked exactly like the oversampled example below.



    Pixel size (µm)
--------------------------- x 206 = arc-seconds/pixel
Focal Length (mm)

Astro-Tech AT6RC Ritchey-Chrétien Reflector Specifications
Aperture 152mm (6”)
Focal Length 1370mm
Focal Ratio f/9

Atik 414Ex - Monochrome Camera
Pixel Size 6.45 µm
Pixel Array 1392 x 1040


Deep Space Astro camera scope combinations

WO GT81 + Atik414EX (2.78"x2.78" per pixel)
WO GT81 + Atik414EX + 2xBarlow (1.39"x1.39" per pixel)
WO GT81 + Atik414EX + 0.8x Reducer (3.47"x3.47" per pixel) Plate Solving: Focal Length: 382.00 - Aperture 64.83
WO GT81 + Nikon D750 + 0.8x Reducer (2.57"x2.58" per pixel)
WO GT81 + QHY5III178 (1.03"x1.03" per pixel)
WO GT81 + QHY5III178 + 0.8x Reducer (1.29"x1.29" per pixel)

AT6RC + Atik414EX (0.98"x0.98" per pixel)
AT6RC + Atik414EX + 0.8x Reducer (1.23"x1.23" per pixel)
AT6RC + Nikon D750 + 0.8x Reducer (1.14"x1.14" per pixel)

Nikon NIKKOR 180mm f/2.8 + QHY5III178 (2.75"x2.75" per pixel)
Nikon NIKKOR 180mm f/2.8 + Atik414EX (7.38"x7.38" per pixel)
Nikon NIKKOR 180mm f/2.8 + Nikon D750 (6.83"x6.84" per pixel)



Daytime shots of my two setups Left: William Optics GT-81 (81mm, 478mm FL) with Atik 414EX monochrome CCD, Atik Filter Wheel (EFW2 with LRGB Ha O3 S2 Clear DarkFrame filters), William Optics 50mm guide scope with ZWO AS120 guide camera, all on an Orion Atlas EQ-G mount. Right: Astro-Tech AT6RC Ritchey-Chrétien telescope, Nikon D750 fullframe DSLR, on an iOptron CEM25P mount.



AstroTech RC6 with Atik 414EX
6.45 / 1370 x 206 = .9698  (Oversampled image)

AstroTech RC6 + WO 0.8 Field Flattener/Reducer with Atik 414EX
6.45 / 1096 x 206 = 1.2123  (Correctly sampled image)

AstroTech RC6 + WO 0.5 Field Flattener/Reducer with Atik 414EX
6.45 / 685 x 206 = 2.448  (Slightly undersampled image)

William Optics GT-81 (with the 2" extension to handle backfocus")
6.45 / 478mm x 206 = 2.7797  (Slightly undersampled image)


William Optics GT-81 + WO 0.8 Field Flattener/Reducer with Atik 414EX
6.45 / 382.4 x 206 = 3.474  (Undersampled image)

William Optics GT-81 + WO 0.5 Field Flattener/Reducer with Atik 414EX
6.45 / 239 x 206 = 5.559  (Undersampled image)

William Optics GT-81 + 2x Barlow with Atik 414EX
6.45 / 956 x 206 = 1.3898  (Correctly sampled image)

Nikon D750
AstroTech RC6 + 0.5x Field Flattener/Reducer with Nikon D750
5.9 / EFL 685 x 206 = 1.7743  (Correctly sampled image)

AstroTech RC6 + 0.8x Field Flattener/Reducer with Nikon D750
5.9 / EFL 1096 x 206 = 1.108  (Correctly sampled image)

Nikon 300mm Lens with Nikon D750
5.9 / 300 x 206 = 4.051  (Undersampled image)

ZWO ASI120-MM - Monochrome Camera
Pixel Size 3.75 µm
Pixel Array 1280 x 960
Minimum Exposure Time 64µs (0.000064s)
Maximum Exposure Time 1000s

AstroTech RC6 with ZWO ASI120-MM
3.75 / 1370 x 206 = .5238  (Oversampled image)

AstroTech RC6 + WO 0.8 Field Flattener/Reducer with ZWO ASI120-MM
3.75 / 1096 x 206 = .7048  (Oversampled image)

AstroTech RC6 + WO 0.5 Field Flattener/Reducer with ZWO ASI120-MM
3.75 / 685 x 206 = 1.127  (Correctly sampled image)

William Optics GT-81 with ZWO ASI120-MM
3.75 / 478mm x 206 = 1.616  (Correctly sampled image)

William Optics GT-81 + WO 0.8 Field Flattener/Reducer with ZWO ASI120MM
3.75 / 382.4 x 206 = 2.02  (Correctly sampled image)


QHYCCD - QHY5III CMOS USB 3.0 Color Camera
Pixel Size 2.4 µm
Pixel Array 3072 x 2048
50FPS, Planetary/Lunar Camera

AstroTech RC6 with QHY5III-178
2.4 / 1370 x 206 = .3607  (Oversampled for stars and DSOs)

AstroTech RC6 + WO 0.8 Field Flattener/Reducer with QHY5III
2.4 / 1096 x 206 = .4510  (Oversampled for stars and DSOs)

AstroTech RC6 + WO 0.5 Field Flattener/Reducer with QHY5III
2.4 / 685 x 206 = .7217  (Oversampled image)

William Optics GT-81 with QHY5III
2.4 / 478mm x 206 = 1.034  (Correctly sampled image)

William Optics GT-81 + WO 0.8 Field Flattener/Reducer with QHY5III
2.4 / 382.4 x 206 = 1.292  (Correctly sampled image)



Nikon 70-300mm f/4.5-5.6G ED IF AF-S VR Nikkor
Nikon AF-S FX NIKKOR 24-85mm f/3.5-4.5G ED

24 / 3.5 = 6.85mm aperture
85 / 4.5 = 18.8mm aperture
300 / 5.6 = 53.57mm aperture
70 / 4.5 = 15.5mm aperture


Imaging train:
With the Barlow I need the extension in almost every case--the barlow increases focal length, and so the camera sensor needs to be moved back in the train.
2x Barlow --> 2" Extension --> Filter Wheel --> Camera
2x Barlow --> 2" Extension --> WO 0.8 Field Flattener/Reducer --> Filter Wheel --> Camera


Setup Weight

William Optics GT81 - 81 mm f/5.9 FPL53 Apo Refractor, Gold Edition
tube weight 8 lbs. (3.7 kg), tube length 440 mm

Atik 414EX
Weight approx. 400 gr (0.4 kg)

Atik EFW2
Weight: approx. 500 gr (.5 kg, ~.85kg with filters)

William Optics 50mm CCD Guide Scope # M-G50
Tube weight (without eyepiece) = 15.0oz (0.425 kg)

ZWO ASI120MM Monochrome
Camera Weight (lb.)‎: ‎0.22, 100gr

Spacers, Extension tubes
Weight: approx. 1 kg

Total 6.475 kg, 14.27 lbs.


...

Follow, friend, communicate


Saltwater Witch copyright © 2017 Chris Howard