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V339 Del fading in B faster than in V??

WGR's picture
WGR
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Joined: 2010-08-17

Hello

Did a short run last night, and V339 Del was fainter in B than in V by 0.2 mags.  If real, this is another big change and a challenge for the Pro's to explain.  Cannot wait for other postings in B and V this morning.  Could also be a dreaded systematic.  No changes on my end, that I know of.

Gary (WGR)

Nova Del
TCB168's picture
TCB168
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Joined: 2010-07-26

WGR wrote:

Hello

Did a short run last night, and V339 Del was fainter in B than in V by 0.2 mags.  If real, this is another big change and a challenge for the Pro's to explain.  Cannot wait for other postings in B and V this morning.  Could also be a dreaded systematic.  No changes on my end, that I know of.

Gary (WGR)

I took measurements of the Nova last night-admittedly 12 hours out from your "last night" due to me being in Oz.

Transformed BV measurements using an ensemble gave B-V of -0.154

This is the reverse of what you have described.

A simultaneous spectra does not show any brightening of the blue end of the continuum from my measurments taken 4 days earlier.

Hopefully this is helpful.

Cheers

Terry B (BHQ)

V339 Del
Stan Walker's picture
Stan Walker
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Joined: 2010-10-05

I had a brief look a the data on this star after reading Arne's earlier post and the discussion elsewhere over sequences.

It's very noticeable that the scatter in B is about half that in V. I didn't bother looking in detail any further but this suggests that those observers who use two filters and calibrate their equipment are getting better results than the single filter people This would be expected but not to the extent seen here.

This star is not as strange as HR Del - which was the first noiva I ever observed - but it still has an interesting slow light curve.

Regards,

Stan Walker

My results for 26/10 had B
PJOC's picture
PJOC
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Joined: 2012-12-01

My results for 26/10 had B around .12 fainter than V.

cheers

Jonathan (PJOC)

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484