imaged STF 594 (Halifax)

BGO captured Σ594, a neglected double-star in the constellation Perseus. Also known as HD 276956 and SAO 57445. Near the centre of the image. In a neat inverted T-pattern of stars.

Luminance only, 2 seconds subexposures, 12 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

SkyTools shows this as a double with a PA of 333° and a separation of 9.1 seconds of arc. Magnitudes 9.0 and 10.7. I.e. a slightly dimmer close companion to the north-west. I dunno about you but I don't see anything at this location...

Curiously, I see a double to the north-west, in the same orientation as what ST3P says should at target location... ST3P calls this star HD 276957.

Also, I see a faint companion to the north-west of that! ST3P refers to this star at TYC 02893-0092 1.

I pulled the entry from the WDS:

04495+3914STF 594      1832 2018   22 311 332   8.0   8.8 10.23 12.0  F0        +002-010 -006+001               044919.40+391554.6

Huh. There's 2018 data. PA 332 and sep 8.8. With mags 10.2 and 12.0. Huh.

But on examining the "Precise Coordinate" data, it gets interesting. The location of Struve 594 is noted as RA 04 49 19.4 and Dec +39 15 54.6.

And that's the location of obvious double that ST3P calls HD 276957. Mystery solved. The original entry recorded in 1832 by Struve was in error.

Stella Doppie shows a number of entries since 1998. The PA ranges between 331 and 332. The Sep. was noted as 9.1 or 9.2 until 2018 where 8.8 appears. There's a jump in the mags too.

I plate solved my image.

Size: 23.9 x 23.9 arcmin

Pixel scale: 3.59 arcsec/pixel

Orientation: Up is 0.026 degrees E of N

Using Visio, I made a scaled ruler and measured the PA and Sep:

separation calculated 9.9 arcsec

position angle calculated 329.4 degrees

Wow. I'm off by quite a bit. Still, my image clearly shows that the target star is not the double in question.