ASASSN-V J181654.06-202117.6 campaign - Alert Notice 710 and 723

This campaign notice is also available in the Campaign & Observation Reports thread

In the Campaign & Observation Reports thread, Erik asked whether Airmass > 2 observations are useful, to which I replied, yes right now we just want as much data as possible so we can catch all the details in the eclipse. We can sort through systematics at a later stage.

Hi everyone,

Just wanted to let you know that I obtained data from ATLAS, which lines up with the deepest part of the eclipse (along with data from VMT). I also have data from ASAS, which seems to show a similar dip in the past (more analysis needed). I'm working on reducing the LCOGT data to see if we can get more data to fill out the eclipse, and I'll keep you posted! Thanks all for staying on board

Kind regards,

Dirk

Just wanted to thank you all for observing J1816 and provide a very basic plot. I just took all the AAVSO, ASAS-SN, ASAS, and ATLAS data (I've been on holiday so didn't have the time to reduce the LCOGT data yet), and just removed the median for each observer and filter to get a kind of first order plot. It looks like the object is still crossing in front of the star, so if you can keep observing this would be much appreciated.

For some reason I can't seem to upload the file here, so I made a GitHub repository with the plot in it (basic_plot.png found at https://github.com/dmvandam/j1816)

Cheers,

Dirk

Hello thanks to everyone for continuing to make observations of this interesting star. I'm "kind of" on holiday so won't be able to do any in depth analysis for now, but did want to share with all of you some new plots. So I've posted a plot of the possible ring system and the theoretical light curve obtained on the github page (https://github.com/dmvandam/j1816). I hope this keeps everyone motivated. This could be a very very interesting system. Let's keep our hopes up!

Hello Everyone,

Thank you for your continued support on J1816, it looks like we're approaching pre-eclipse levels. I'd like to ask you to keep monitoring J1816, because 1) I don't believe we're quite at quiescent levels, 2) I hope that this is half of the eclipse and that we'll see two similar dips as we continue to observe the star.

Cheers,

Dirk

Hello everyone,

I just wanted to thank you all for supporting us throughout this campaign. It looks like the star is approaching its quiescent level. I'm still hoping for another dip - reflection symmetry - that could show rings! Asking you all to monitor intensively seems unfair, so instead I would like to ask all of you to monitor the star twice per night (at least an hour apart). If you see a large drop in brightness, please report this to me or on this forum, so we can start up the intensive monitoring again. I'll keep everyone informed on the progress on the modelling as this goes on.

Thanks all,

Dirk

Ok everyone,

This is what I was hoping for! It looks like J1816 is dropping again. If everyone could resume their original cadences that would be excellent, maybe we can fully capture the eclipse this time (if that is what we are looking at now - fingers crossed).

Cheers,

Dirk

Hello Everyone,

I just wanted to let you know that I've updated the GitHub page to include lots of plots animations and the basic story of J1816. Feel free to explore the whole repository, but the main information of interest will be found at https://github.com/dmvandam/j1816/tree/master/public

Cheers,

Dirk

AAVSO Alert Notice 723 announces a new, second campaign on the UXOR ASASSN-V J181654.06-202117.6 (the previous campaign was announced in Alert Notice 710). Please see Alert Notice 723 for new instructions (including spectroscopy), a beautiful light curve incorporating your data, and other information.

To stay informed about this campaign, particularly regarding any modifications to instructions from the astronomer, subscribe to this forum thread (option 1 under Subscribe in the first post in this thread) -  see feedback from the astronomer,  comments and questions from observers, and notes from AAVSO HQ. Add a post yourself  -  join in the discussion about this interesting target!

There is also a thread on this campaign in the Campaigns and Observation Reports) forum.

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ