M13 - Great Globular Cluster in Hercules (Andrew Klinger)

Celestial hemisphere: Northern · Constellation: Hercules (Her) · Contains: Great Cluster in Hercules · M 13 · NGC 6205 · NGC 6207

M13 - Great Globular Cluster in Hercules, Andrew Klinger

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M13 - Great Globular Cluster in Hercules

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M13 - Great Globular Cluster in Hercules

One of the larger globular star clusters in the sky, M13 is home to over 100,000 stars.

This is a fairly large crop with my system. I shot this target a partial night to test a stop-down ring for my scope. The ring slightly improves some optical issues I've been dealing with on my stars.

Equipment:

OTA: William Optics GT81 w/Flat6A (382mm fl at f/4.7)

74mm aperture stop-down ring (brings scope to f/5.2)

Mount: Orion Sirius EQ-G (HEQ-5)

Guidescope: Orion 50mm guidescope

Guiding camera: Orion StarShoot Autoguider

Imaging camera: ZWO ASI1600MM-Cool

Software:

SGP

PHD2

CdC

PixInsight

Acquisition:

Location: Ft Griffin State Historic Park, TX (Bortle 3)

Dates: 4/1/19

Gain: 76 Offset: 15

Camera temp: -20C

R: 24x180"

G: 23x180"

B: 23x180"

Total integration time: 3hr 30min

64x darks per calibration (master from library)

30x flats per calibration

200x bias per calibration (master from library)

Preprocessing:

Batch PreProcessing script to generate calibrated images

StarAlignment to register all frames to the reference

LocalNormalization of all registered frames

ImageIntegration

DrizzleIntegration

DynamicCrop each master

DBE each master

RGB Processing:

TGV and MMT noise reduction (via Jon Rista's method)

LinearFit to Blue

ChannelCombination

PhotometricColorCalibration

Extracted Luminance channel and set aside for processing

ArcsinhStretch x2

MaskedStretch

SCNR green

CurvesTransformation for saturation

ColorSaturation to target blues

L Processing:

Deconvolution

Arcsinhstretch x2

MaskedStretch

Combined L and RGB with LRGBCombination tool

HistogramTransformation

CurvesTransformation to balance background

SCNR green

Resampled to 75% for web posting

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This table shows the distribution of awards per subject type, compared to the popularity of images of that subject type.
	Image of the day	Top pick	Top pick nominations	Total submitted
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	Image of the day	Top pick	Top pick nominations	Total submitted
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Amateur hosting facility
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Professional, scientific grade data
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Other
Unknown

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Status	Basic success
Started	...
Astrometry.net job	2665206
PixInsight job	n/a
PixInsight queue size	n/a
PixInsight stage	n/a

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M13 - Great Globular Cluster in Hercules

M13 - Great Globular Cluster in Hercules

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M13 - Great Globular Cluster in Hercules

M13 - Great Globular Cluster in Hercules

Equipment

Acquisition details

Description

Comments

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