Williams FLT A7Ra
Observatory Oberallgäu - First visual light and alignment of the Williams refractor on the mount (by Peter Oertel).


w1800 20161030 M45 A7Ra ISO3200 14x30s
First photographic light of the Williams refractor, no flattener!
Full moon was two hands width aside and produced bright background 17.0mag/sqrsec.
Nevertheless we did a quick shot of 80 seconds.

ObjectM42 - Orion Nebula - First Light
Constellation: Orion
Position: RA 5h 35,3m DEC −5° 23,5′
Apparent Size: 60 arcmin
Apparent Magnitude: +4.0
Distance (average) 1350 ± 23 ly
Photo Datas 
Date 12.12.2016, 20:06 UTC
Location Knottenried/Oberallgäu, 1002m ASL
GPS: 47°36’13“ N, 10°11’24“ E
Sky darkness SQM-L Object 17.0mag/sqrsec (full moon)
Ground Temp./Air Pressure -2.0°C / mbar
Thermal sky temp./weather  -62.1°C Zenit
Seeing (Bortle)  
Telescope Williams FLT 110/770mm f/7.0
Camera Sony A7Ra mod @ T sensor=2.5°C
Expose frames ISO 3200, RAW 8x10s, 4 darks
Total expose
1 min 20s
Filter no
Mount HPS 10Micron GM 3000
Guiding Cam no
Software DSS 3.3.4, Photoshop CC
Remarks Full moon two hand width aside
First light of the Williams refractor, no flattener!

C 2016 Peter Cerveny