IC4756 "Graff's Cluster" and NGC6633 "Captian Hook Cluster"

Posted: May 23rd, 2021

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Technical Info

Telescope/Lens: Jupiter-37A 135mm

Camera: Canon EOS 550D

Mount: EQ5 with DIY Arduino controller and guiding

Guide Scope: Jupiter-37A 135mm

Guide Camera: Datyson T7C

Software: APT + PHD2, DeepSkyStacker 4.2.2, FITSWork 4

Exposure:

56 x 60" ISO/Gain: 800

Orange zoneLight Pollution:

Odesa, Ukraine

May 21st, 2021

IC4756 "GRAFF'S CLUSTER" AND NGC6633 "CAPTIAN HOOK CLUSTER"

Telescope/Lens: Jupiter-37A 135mm
Camera: Canon EOS 550D
Mount: EQ5 with DIY Arduino controller and guiding
Guide Scope: Jupiter-37A 135mm
Guide Camera: Datyson T7C
Software: APT + PHD2, DeepSkyStacker 4.2.2, FITSWork 4

Odesa, Ukraine
Light Pollution: Orange zone

Exposure:
56 x 60" ISO/Gain: 800

Lens aperture: f/4 Darks: 60s x 40 @ ISO 800 Offsets/Bias: 1/4000s x 20 @ ISO 800 Guide scope lens aperture: f/3.5 IC4756 "Graff's Cluster" NGC6633 "Captain Hook Cluster" ------------------------------------------------------ Two bright and beautiful open star clusters. IC4756 belongs to the Serpens constellation, while NGC6633 belongs to Ophiuchus. These two clusters are located close to each other in the sky and also have other names. IC4756, named after the Polish-German astronomer Kasimir Romuald Graff, is also called the "Secret Garden Cluster." NGC6633 is also known as the "Wasp-Waist Cluster." Additionally, these two clusters, NGC6633 and IC4756, are together referred to as "Tweedledum and Tweedledee," respectively. Tweedledum and Tweedledee are characters from an English nursery rhyme and also appear in Lewis Carroll's book "Through the Looking-Glass, and What Alice Found There." Both star clusters are quite bright (magnitude 4.6) and may be visible to the naked eye under very dark skies. They are wonderful objects for a small telescope or binoculars. For example, NGC6633, when observed through binoculars, has a distinct triangular outline. ------------------------------------------------------ Used materials: @ https://en.wikipedia.org/wiki/IC_4756 @ https://en.wikipedia.org/wiki/Kasimir_Graff @ https://en.wikipedia.org/wiki/Tweedledum_and_Tweedledee @ https://en.wikipedia.org/wiki/Through_the_Looking-Glass

Original size: https://deepskyhosting.com/xIKCOnn
Author: Serhii Solohub

56 m

3364

Lens aperture: f/4
Darks: 60s x 40 @ ISO 800
Offsets/Bias: 1/4000s x 20 @ ISO 800
Guide scope lens aperture: f/3.5

IC4756
"Graff's Cluster"

NGC6633
"Captain Hook Cluster"

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Two bright and beautiful open star clusters. IC4756 belongs to the Serpens constellation, while NGC6633 belongs to Ophiuchus.
These two clusters are located close to each other in the sky and also have other names.

IC4756, named after the Polish-German astronomer Kasimir Romuald Graff, is also called the "Secret Garden Cluster."
NGC6633 is also known as the "Wasp-Waist Cluster."

Additionally, these two clusters, NGC6633 and IC4756, are together referred to as "Tweedledum and Tweedledee," respectively. Tweedledum and Tweedledee are characters from an English nursery rhyme and also appear in Lewis Carroll's book "Through the Looking-Glass, and What Alice Found There."

Both star clusters are quite bright (magnitude 4.6) and may be visible to the naked eye under very dark skies. They are wonderful objects for a small telescope or binoculars. For example, NGC6633, when observed through binoculars, has a distinct triangular outline.

------------------------------------------------------

Used materials:

@ https://en.wikipedia.org/wiki/IC_4756
@ https://en.wikipedia.org/wiki/Kasimir_Graff
@ https://en.wikipedia.org/wiki/Tweedledum_and_Tweedledee
@ https://en.wikipedia.org/wiki/Through_the_Looking-Glass

Resolution: 4925x3157 px

Scale: 22843 KB