California Nebula (Emission nebula NGC 1499)

Grateful for an opportunity to get a scope out into the back garden after so many cloudy nights in Northern Ireland!

 

This is an emission nebula of fluorescing hydrogen gas glowing under the immense bombardment of hard UV light from the bright star to the right in this image (Xi Persei).

 

 

Technical card

480/80mm f/6 Altair Starwave triplet refractor.

Altair Planostar 1.0 x FF with 2 inch L-eNhance filter

ZWO ASI2600MC; 32 x 360 second subs, Gain 100, Offset 25, Temp = -15c.

 

EQ6 R mount with EQMOD control.

Primalucelab Sesto Senso electronic focuser.

 

Session control;

SharpCap 4.1 on miniPC on scope with WiFi link to IPad indoors .

Automated plate solving GOTO.

Automated FWHM multistar focusing +/- 500 steps at 4s and 578 gain.

 

Calibration:

20 dark frames

61 flat frames (EL panel, 6500ms exposure @ 0 gain).

No bias frames

 

Post processed in PixInsight 1.9.3.

 

Light Pollution and Weather:

SQM (L) not recorded - 60% Moon

Session ended by wind causing scope to judder

 

Polar Alignment:

Error measured by PHD2= 0.2 arc minute.

RA drift + 0.08 arcsec/min

Dec drift - 0.03 arcsec/min

 

Guiding:

PHD2 guiding with ZWO ASI290mm/Altair Starwave 206/50mm guider. Every 8th sub dithered.

RA RMS error 0.64 arcsec

Dec RMS error 0.49 arcsec

Mean RMS error 0.81 arcsec

 

Astrometry:

Resolution ............... 1.612 arcsec/px

Rotation ................. -103.578 deg

Focal distance ........... 481.06 mm

Pixel size ............... 3.76 um

Field of view ............ 2d 47' 48.1" x 1d 51' 46.7"

Image center ............. RA: 3 58 57.002 Dec: +36 49 22.41

Done