[Lvas] Observing Friday Jan 30

[David Blanchette]

At 07:22 PM 1/31/2009, you wrote:
>David Blanchette wrote:
>>I went out to my spot on Lee Canyon last night, despite the moon.
>>Seeing was average, but the overall sky was very good.  I wasn't 
>>sure whether it was Vegas or the moon that lit the sky  The main 
>>light dome of Vegas did not rise above Sirius.
>>Forecast for tonight looks better than Friday (hint, hint)
>>
>>I'll try posting a couple of images here...
>Dave,
>
>Both images were excellent.  Do you know what caused the circular 
>artifact on the Orion Nebula?
>NGC 891 is one of my favorite galaxies.
>I would be interested in knowing what your exposure and settings were.

The artifact is a reflection of a bright star out of field.  It 
appears when I use my focal reducer, but I'm not sure the reflection 
is in the focal reducer.

The exposure was at least 30 seconds for Orion at ISO 1600.  I did 
some 3 minute exposures at ISO 400 tonight.  NGC 891 was 2 minutes at ISO 1600.

Tonight (Saturday) had more moon, and a touch less transparency 
(Vegas light dome just above Sirius instead of just below, as it was 
Friday.)  Actually less breeze tonight...

-- David