A Sagittarius triplet – M8, M20, and NGC 6559

Edit 9/10/2021: This image was featured by APOD GrAG: apod.grag.org/2021/09/10/a-sagittarius-triplet-m8-m20-and...

 

This so far is my favorite image! Nearly 21 hours of data (taken across 4! nights) and 3 hours of processing went into this huge project. I love the color range so much - golden milky way stars, pink lagoon nebula, and light blue trifid reflection.

 

Equipment:

- Nikon D90

- Sigma 300mm prime lens

- Sky-Watcher Star Adventurer

- Star Adventurer Tripod

- Bahintov Mask

- Intervalometer

- DIY diffraction spikes using a violin strings

- Stellarium

- All Sky Plate Solver

- Sharpcap

- Laptop

 

Acquisition:

- Taken from Sharon, CT

- Bortle 2-4

- ISO 800

- F/4.0

8/7/2021

- 112 x 3′ lights

- 200 bias

- 50 flats

- 32 darks

8/8/2021

- 92 x 3′ lights

- 50 flats

- 12 darks

8/11/2021

- 102 x 3′ lights

- 50 flats

- 16 darks

8/14/2021

- 108 x 3′ lights

- 100 bias

- 50 flats

- 27 darks

Total:

- 414 x 3′ lights (20.7 hours)

- 300 bias

- 200 flats

- 87 darks

 

Processing:

- Calibrate using WBPP

- Assign weights with subframe selector

- Star align

- Integrate 10 best images for a local norm reference

- ABE degree 1 on the image

- Local norm scale 256

- Image integration

- CFA drizzle

- DBE

- Background neutralization

- PCC

- Extract L

- Histogram transformation and ArcsinH stretch on RGB

- Masked stretch and Histogram stretch on Luminance data

- LRGB combine

- create starless image

- Exponential transformation on starless image

- Blend back to LRGB with pixel math to avoid blowing out stars

- Slight curves

- Adam block style star reduction

- blend back using straight average with normal image

- Annotate image with watermark

 

Instagram: www.instagram.com/

Website: theastroenthusiast.com/

 

Done