AP#77 : M20
Name: The "Triffid" Nebula.
Constellation:Sagittarius
Instrument:
Image 1: 8-inch F5 reflector with Sky Watcher coma corrector and ASI 2600 MC (gain 100 -20C).
Image 2: 8-inch F5 reflector with Sky Watcher coma corrector and ASI 585 MC (gain 200 -20C).
Exposure time:
Image 1: A stack of 16 five-minute and 9 three-minute exposures.
Image 2: A stack of 30 three-minute exposures.
Star Chart from Michael Vlasov's Deep sky hunter star atlas available on line https://www.deepskywatch.com/deep-sky-hunter-atlas.html
Magnitude: 6.3
Angular size: 28'
This object is a large emission nebula that is split into three sections by a dark lane (with the designation B85). This results in the name, which means it has three lobes. The open cluster, M21, is above and to the east of the nebula.
This image used the same telescope but used the ASI 585 astro camera.
