Hemisphere:  Northern  ·  Constellation: Monoceros (Mon)  ·  Contains:  12 Mon  ·  NGC 2237  ·  NGC 2238  ·  NGC 2239  ·  NGC 2244  ·  NGC 2246  ·  Rosette A  ·  Rosette B  ·  Rosette Nebula  ·  Sh2-275  ·  The star 12Mon
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The Rosette (C49) – First Light for William Optics FLT 91, 



    
        

            Gary Lopez
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The Rosette (C49) – First Light for William Optics FLT 91

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The Rosette (C49) – First Light for William Optics FLT 91, 



    
        

            Gary Lopez
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The Rosette (C49) – First Light for William Optics FLT 91

Imaging telescopes or lenses: William Optics FLT 91 Triplet APO f/5.9

Imaging cameras: ZWO ASI1600MM Cooled PRO

Mounts: Orion Atlas EQ-G

Guiding telescopes or lenses: Orion 50mm Guide Scope with helical focusing

Guiding cameras: Lacerta M-Gen II Autoguider

Focal reducers: William Optics FLAT 6A III x0.8

Software: Adobe Lightroom CC  ·  Main Sequence Software Sequence Generator Pro, v3.0  ·  Pleaides PixInsight Core 1.8

Filters: Astrodon OIII 3nm-31mm  ·  Astrodon SII 3nm-31mm  ·  Astrodon Ha 3nm-31mm


Dates:March 26, 2021March 27, 2021March 28, 2021March 29, 2021March 30, 2021March 31, 2021April 1, 2021

Frames:
Astrodon Ha 3nm-31mm: 190x180" (9h 30') (gain: 139.00) -15C bin 1x1
Astrodon OIII 3nm-31mm: 80x180" (4h) (gain: 139.00) -15C bin 1x1
Astrodon SII 3nm-31mm: 73x180" (3h 39') (gain: 139.00) -15C bin 1x1

Integration: 17h 9'

Darks: 30

Bias: 50

Avg. Moon age: 15.59 days

Avg. Moon phase: 93.69%

Bortle Dark-Sky Scale: 4.00


Astrometry.net job: 4385367

RA center: 6h 32' 2"

DEC center: +4° 53' 26"

Pixel scale: 1.808 arcsec/pixel

Orientation: -116.121 degrees

Field radius: 1.324 degrees


Resolution: 4209x3182

Locations: Monterey Pines Observatory, Monterey, California, United States

Data source: Backyard

Description

A few months ago I was honored to be named an Ambassador for William Optics, and three weeks ago I received the new WO Fluorostar 91 to test (https://williamoptics.com/fluorostar-91). The FLT 91 is an Apochromatic refractor with a focal length of 540 mm and an aperture of f/5.9. I also received the WO FLAT 6A III x0.8 focal reducer, which brings the FLT 91 to a focal length of 432 mm at f/4.72. Coupled with my ZWO ASI1600 MM Pro, the field of view is 2.34 degrees X 1.77 degrees (see scope mounted, Version B). With is FOV I needed an object that was pretty wide to fill the frame, but since it was early March, there were only a few emission nebula candidates that were the right size and would be above the horizon for a few hours each night. The best choice was Rosette Nebula, the classic. At nightfall, the Rosette was at about 60 degrees above the horizon on its downward path, and about 2.5 hours later it cross about 30 degrees above the horizon, my usual stopping declination for collecting data. The other challenge was the Moon which was 80-100% during the week of data collection. I used Astrodon 3 nm narrowband filters to combat the lunar light pollution.

A few days after the scope arrived, I got lucky with a week of clear nights. All in all, the data were very good, especially the Ha of which I collected 9 hours with an HFR range of 1.6-2.2. Here is the SHO image from these data with standard Hubble color assignments. I am very happy with the detail and resolution of the image and attribute that to the excellent quality of the data. The FLT 91 is a superb instrument and I will be using it regularly when the nebula season returns this summer. If you have any questions about my experience with the William Optics FLT 91 please PM me.

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    The Rosette (C49) – First Light for William Optics FLT 91, 



    
        

            Gary Lopez
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Description: William Optics FLT 91 Triplet APO f/5.9

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The Rosette (C49) – First Light for William Optics FLT 91, 



    
        

            Gary Lopez