by Richard Crisp
The weather was much cooler than the hot valley had been during the day, but the temperature remained warm and was dry all night long. The lowest temp I saw was 19 C.
I was doing some imaging of southern end of NGC6992 in the Veil Nebula, using some emission line filters. The Red was Ha, the Green was OIII and the Blue was SII. Note the hydrogen cloud to the left ot the object.
http://www.rdcrisp.darkhorizons.org/ngc6992_network_nebula_in_ha_page.htm
On Friday night I went up again with Rob Griffin to do imaging and several others were up there too at the observatory and pads area. I counted at least 6 scopes at one time. Again it was warm and dry up there all night long. Neither night had any marine layer below, so the skies were not as dark as they often are. The wind picked up last night about 2:30am and I would estimate it was gusting to 15-20 mph by dawn.
Again doing emission line imaging like the previous night I moved to NGC6888, the Crescent Nebula. I again assigned Red to Ha, Green to OIII and Blue to SII.
http://www.rdcrisp.darkhorizons.org/ngc6888_crescent_nebula_emission_line_page.htm
This odd color rendering may look really weird to you, but notice how the object is floating in a sea of red hydrogen nebulosity.
I really get a kick out of how the detail becomes more apparent when using these filters in this way to create false color images.
Comments welcome.