Friday, November 10, 2017

shot HR 8 longer

With the Burke-Gaffney Observatory, I tried imaging the multi-star system OΣ 549 (or HR 8) again. Gah. Nothing...

Visually observed this system from the Carr Astronomical Observatory with a NexStar 11 on 24 Sep '16. Split A and B. Could see the other stars, C and D, but in mediocre seeing they were merged.

Did some digging on 30 Sep '16. I learned of the E star on referring to the Washington Double Star index. But the LAF 21 entry looked odd: the E was noted having a magnitude of 17.2 while A was 4.6. What? Other WDS entries said 6; SkyTools 3 Pro said 6.

Decide to image this target with the Burke-Gaffney Observatory in Halifax. Received my first photograph on 14 Jul '17. Searched for more companions. Happily, I spotted the C star, very close to D, albeit, in a slightly different location compared to the chart display in ST3P.

But I could not see the E element even though the WDS said it was over 10 arc-seconds away. Yes, it was very dim but other mag 17 stars were visible in the 4 second exposure. Was it caught in the glare of the bright primary?

On 1 Sep '17 I decided to shoot the system faster, twice as fast, to better see the C and D partners and maybe reveal the E. Received a decent image but still E was hidden.

Tried faster again, down to 1 second, on 9 Sep '17. No E star. I was starting to seriously doubt the quality of the entry in the WDS.

Tonight, BGO aimed at the system again (using GSC 01735-0996). Following my directive, it exposed longer—8 seconds. And still no E star emerged.

Perhaps I should send a report to the JDSO stating that the E star data does not seem to be accurate.

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