Monday, September 07, 2020

tried for SEI 1197 (Halifax)

I suspected some space would be available in the queue with the... Moon. So I looked up some "old" double stars, previously known as "neglected doubles."

Found SEI 1197 from 1895 near GSC 03153-0148. A pair of mag 11 stars with a PA of 174 and sep of 14.7 with precise coordinate value of 203755.47+380520.1.

neglected double SEI 1197

Luminance filter, 2 seconds subexposures, 12 stacked shots. FITS Liberator, GIMP. North is up; left is east.

With a position angle of 174, that would be nearly vertical in the image.

GSC 03153-0148, at the centre of the image, is mag 11.8, according to SkyTools.

The J2000 coordinates of the GSC star are 20h37m59.2s and +38°05'20". The Washington Double Star database coordinate would be very slightly right of the GSC star. Where there's nothing...

Those two equal horizontally oriented stars at 32 arc-seconds apart. So, looking for something about half that...

TYC 03153-0574 1 is intriguing. It's the medium bright star to the the south-east, 7 o'clock, with the fainter companion directly above. Magnitudes are wrong, position is wrong, but the separation looks right.

I do not see a pair of tight vertically arranged mag 11 stars anywhere...

I should pull up a proper motion chart...


Hold the phone! When I zoom into the image, I see a star below and left of GSC 03153-0148! Is that it?!

It's 15" away.

The position angle is 151°.

But it's MUCH dimmer.

SkyTools shows J203759.8+380506 at this location at magnitide 16.3.

Which corresponds to other mag 16 stars in the area...

Is that it?

Begs the question, how low does SEI go?

Could it be that Scheiner, J. saw the mag 16 star but accidentally marked it with the mag value of the primary?


OK. Ran a query on the 18-24 segment of the WDS and searched for the "max" mag on the secondary: 15.3! So he does go pretty low.

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