From jop at astro.columbia.edu Fri May 7 06:30:46 2021 From: jop at astro.columbia.edu (Joe Patterson) Date: Fri, 7 May 2021 06:30:46 -0400 Subject: (cba:news) AM CVn... one last push Message-ID: Hi CBAers, Apologies for the (proverbial) radio silence. I recently returned to regular classroom teaching after a year's break... and what seemed so natural in 2019 now seems Herculean. Half the students scattered around the world, half live (seated in a vast room with 90% of seats blocked), cameras reducing me to insect-size, and practically no opportunity for feedback. Masks, distancing, computers monitoring all buildings - and we thought PC was bad! It's even more grim for students... but on the bright side, we effusively thank each other for helping us with our slow, uncertain emergence from isolation. I'm sure that many of you have similar stories - which I'd be interested in hearing. The last (at least for now) piece of the AM CVn puzzle is the two drifting superhumps. Do they drift in phase, in anti-phase, or uncorrelated? Physics seems to demand "anti-phase". But this year - our best, and therefore anyone's best - suggests"in phase". The drift is SLOW, so you really need a full oberving season (~5 months) to get the answer. We're close... but restoring AM CVn to high-importance (=> LONG nightly runs) would much more accurately define the signal phases in this last month of observation, before short summer nights stop us. I really, really want to nail this down! Weekend respite coming up... and I'll comment on the wider list of good targets. Mostly old novae, supplementing ENrique's mostly-IP list.) joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/ From jop at astro.columbia.edu Tue May 18 09:44:28 2021 From: jop at astro.columbia.edu (Joe Patterson) Date: Tue, 18 May 2021 09:44:28 -0400 Subject: (cba:news) stars for May-June Message-ID: Hi CBAers, Pardon my long silence. I'm teaching every day now, with 50% in-class students and 50% remote. Really impossible to serve both audiences simultaneously! So research time is limited. Nevertheless... On clear nights, we still need to keep the pressure up on AM CVn - taking it all the way to ~2 airmasses. The 1011 s signal (the negative superhump) went faint on us a few weeks ago... and it take a lot of effort to measure the phase of a signal which is down to 0.002 mag. Yet that's what the PHYSICS question (the relation to the positive superhump) requires. CI Aql is another super choice - both hemispheres, and for at least the next two months. Recent novae: V1974 Cyg, V4743 Sgr, and V1494 Aql OV Boo. Paper just about ready to go. A couple more eclipses would be great. 19th mag, only suitable for big scopers. Nova Sco 1437. Really beguiling light curve! And some IPs (Enrique might want to add/subtract among these): V2306 Cyg, V1223 Sgr, AO Psc joe ____________________________________________________________ Center for Backyard Astrophysics (CBA) mailing lists https://cbastro.org/communications/mailing-lists/