Monday, February 05, 2018

captured HR 890 (Halifax)

The Burke-Gaffney Observatory imaged HR 890 (aiming at GSC 03322-1203). A double-star in Perseus also known as STF 331. It is on an Astronomical League list as well as the Coldfield beautiful doubles. Sissy Haas calls it a showcase pair.

double-star HR 890 in luminance

Luminance only, 2 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

Tight pair oriented east-west with the primary to the west. I estimated the separation at about 10 arc-seconds (SkyTools says 11.9"). I estimated the Δm to be about 1 or 1½ (ST3P said the mags were 5.2 and 6.7).

The Clear Sky Chart showed curious conditions. The cloud indicator was 10, clear. The transparency was 5, transparent! I had never seen that before. However, the seeing was rated 1/5 or bad. Ugh. The Moon was 8 degrees below the horizon. Good time for galaxies...


Quickly processed in Photoshop in full colour. Discovered stacking errors in the green data unfortunately. The HR 890 stars are intense white-blue. They appear the same in Aladin with the DSS Colour data. Lovely. The dim star to the far east is pale orange; the brighter star far to the north-west is also white.

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