California, NGC 1499

23дек
Despite its bright integrated magnitude the California nebula is one of the more illusive objects in the sky. Without the aid of a filter it is one of the most difficult objects to observe in any aperture. Burnham’s describes this nebula as “A difficult object visually.” But in his day they didn’t have the deep sky filters that are available to us. With an OIII, UHC, or H-Beta filter it is visible to the unaided eye!
That doesn’t make it easy, however. The basic problem with observing this nebula is that it is very large. Even though its total integrated magnitude is that of a 5th magnitude star, this light is spread over an area larger than 2.5o. The large aperture instruments that collect the most light also give smaller fields of view. The result is that the apparent surface brightness of the nebula is more or less constant with aperture. In fact, it is probably best detected with a small aperture that affords a field of view large enough to fit the entire nebula.

Imaging telescopes or lenses: AT65EDQ 65mm f/6.5 ED quadruplet astrograph AT65EDQ
Imaging cameras: QSI690
Mounts: Celestron Advanced VX
Guiding telescopes or lenses: AT65EDQ 65mm f/6.5 ED quadruplet astrograph AT65EDQ
Guiding cameras: QHY5L-II QHY5 L – II MONO
Software: PHD2 Guiding, PixInsight, Main Sequence Software Sequence Generator Pro, Photoshop CS5
Filters: Astrodon Blue Tru-Balance E-Series Gen 2, Astrodon Green Tru-Balance E-Series Gen 2, Astrodon Red Tru-Balance E-Series Gen 2, Astrodon L
Accessories: Feathertouch Motorised Focuser HSM30
Resolution: 3620×5093
Dates: Dec. 15, 2014
Frames:
Astrodon Blue Tru-Balance E-Series Gen 2: 11×300″ -20C bin 1×1
Astrodon Green Tru-Balance E-Series Gen 2: 11×300″ bin 1×1
Astrodon Red Tru-Balance E-Series Gen 2: 11×300″ bin 1×1
Integration: 2.8 hours
Avg. Moon age: 22.56 days
Avg. Moon phase: 45.62%
RA center: 60.127 degrees
DEC center: 36.538 degrees
Orientation: 97.280 degrees
Field radius: 1.566 degrees
Locations: Greenville, Home, Greenville, NC, United States

Authors:

Info: http://observing.skyhound.com/archives/dec/NGC_1499.html

Photo: Astrowood