IC 1805 the Heart open cluster and emission nebula in Cassiopeia

IC 1805 refers to the bright open cluster in the centre (also known as Melotte 15). Some of the stars are massive at >50 solar masses and excite the clouds of dust and gas to emit in hydrogen alpha via a fierce stellar wind.

 

W3 is the bright H2 region just below the Heart (also cataloged as NGC 896 or the "fish head" nebula.

W4 are the H2 regions forming the Heart

W5 is the neighbouring Soul nebula

 

W stands for Westerhout catalog - a catalog of radio sources

 

Tombaugh 4 is a small dense open cluster at the apex of the Heart

 

480/80mm f/6 Altair Starwave refractor

Astro-modified Canon 80D at ISO800, 28 x 5 minute subs

Backyard EOS acquisition control

IDAS LPS D1 filter.

Ioptron ZEQ25GT mount with StarFi/Sky Safari Pro 6 remote control.

 

33 dark frames

30 flat frames (electroluminescent panel @ 1/80s)

Master bias frame from library

 

Post processed in PixInsight 1.8 and Photoshop

 

Local parameters:

Temp: 5.7 - 7.0c

Humidity: 73.4 - 77.5%

Camera Sensor Temp: 12-16c

Estimated seeing (BYEOS FWHM/pixel scale) 4.6 arcseconds.

 

Light Pollution:

SQM (L) at start of session (2129 hrs UT) =19.8 mag/arcsec2.

SQM (L) at end of session (0017 hrs UT) =20.1 mag/arcsec2 .

 

Polar Alignment:

QHY Polemaster alignment -

Error measured by PHD2=2.4 arc minute.

RA drift +0.37 arcsec/min

Dec drift -0.64 arcsec/min

 

Guiding:

PHD2 guiding with ZWO ASI290mm/Altair Starwave 206/50mm guider. Dithered.

RA RMS error 0.85 arcsec, peak error -3.64 arcsec

Dec RMS error 0.78 arcsec, peak error -3.75 arcsec

 

Astrometry:

Center (RA):02h 32m 14.638s

Center (Dec):+61° 29' 05.035"

Size:2.67 x 1.78 deg

Pixel scale: 1.59 arcsec/pixel

Done