Friday, March 05, 2021

worked on Struve 1327 (Halifax)

Imaged Σ1327 (HD 79552) again in Cancer. Surprised to get a ping from the BGO in Halifax. I thought they were clouded out. 

Struve 1327 in luminance only

Luminance only, 4 seconds subexposures, 10 stacked shots. FITS Liberator, GIMP. North is up; east is left.

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I didn't discover the notice until some time later.

The Clear Sky Chart at the time looked grim.

Clear Sky Chart for Halifax Friday night

Cloud: 90% covered; ECMWF: cloud 95%; transparency: too cloudy to forecast; seeing: too cloudy to forecast! Wow.

Checked Twitter to see it was really running. Nope. Too cloudy; waiting for it to clear. But then I noted that BGO said "at 22:32 (AST), I just took this image for Gustav Holmberg of V0351GEM (ID 13824) in the V filter!" That was 10 minutes after my job and his looked great!

I was buoyed.

When I downloaded the FITS data, everything looked good so I quickly made a colour image.

Struve 1327 in colour

FITS Liberator, Photoshop.

Imaged this is 27 Jan '18 to get some good colour data but I didn't use the right ratio, 3 to 1, for the LRGB data (still trying to shake off bad advice).

This colour image is made with LUM 4x12, RED 12x12, GRN 12x12, and BLU 12x12.

Visually, I assess the colours to be: 

A - yellow
B - orange
C - orange.

But they are VERY subtle.

And that bright star to the east-south-east to be blue-white. SkyTools says that is HD 79595, an F class star, F2 specifically.

And since we're talking about classes, ST4VP says HD 79552 is F8. It's definitely warmer than 79595.

F is one class to the blue-white end of the scale, a notch above our G class Sun.

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Near the top-right of the image, south-west of 1327, is the faint, almost equal pair of SLE 482. The northern star is orange. My first impression of the southern partner was blue. A pale blue. But maybe it's yellow? Or white? ST4VP says A is south. Huh. It is mag 12.5 while B, brighter, is mag 11.8.

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