AAVSO: American Association of Variable Star Observers

Proposal #368

Proposer (46778) David Gay (1983RiceOwl@gmail.com) obscode: GDAL
Assigned To(3663) Dirk Terrell
Date SubmittedJune 5, 2023

I wish I had known about AAVSOnet back on May 20...but, better late than never. Due to the marine layer in Santa Barbara this time of year, I have had exactly one night when I could do photometry on SN 2023ixf since then. I would like to follow the long term decline in brightness of SN 2023ixf using one of the Bright Star Monitors. Since there is a current proposal (#358 by Francisco Carlos Soldan, AFSA) observing SN 2023ixf using BSM_NH2, I propose that this proposal be assigned to a different BSM (Hawaii?), but with the same weekly observation frequency, and run through the end of 2023, if possible. I would like to collect photometry using BOTH Johnson-Cousins BVRI and Sloan g'r'i' filter sets, and have the data transferred directly to my VPhot account. My AAVSO Observer Code is GDAL. Thank you for your consideration of my proposal!

Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
SN 2023ixf 14.060712 54.31165 14.0–10.0 BSM_NM 5 Dec. 30, 2023 No


(46778) David Gay — June 5, 2023, 9:34 p.m.

After submitting this proposal, I noticed that proposal #359 for SN 2023ixf was denied on May 24 due to perceived overlap with proposal #358. In advance of a similar decision on my proposal by the TAC, I would like to argue that this proposal has additional merits in terms of adding observations in the Sloan bands as well as for an extended duration (6 month) to provide sufficient data to enable accurate determination of the rate of decline of SN 2023ixf for 7 different filter bands. Thank you for your consideration of these additional arguments for approving my proposal.

(46778) David Gay — June 5, 2023, 10:13 p.m.

In order to provide maximum similarity in the instrumental response (i.e. BVRI/g'r'i' bandpass * CMOS spectral QE profile) with any additional measurements that I make at my home observatory over this time period, I ask that this proposal be assigned to a BSM equipped with an ASI183MM Pro, which is the same camera that I use.

(4726) Kenneth Menzies — June 7, 2023, 11:59 p.m.

Committed to NM. Report when getting too faint.

(4726) Kenneth Menzies — June 8, 2023, 12:05 a.m.

NM will have monsoon weather in summer! May want to run on mpo61 even if it has a different camera. Really doesn't need to match your camera.

(46778) David Gay — June 8, 2023, 5:08 a.m.

Thanks for the idea, but I would prefer to keep it on the BSM in NM with similar FOV and same camera as my home scope. That way I can use the same comp stars on both. Clear skies return to Santa Barbara from July to September, so I will be able to fill in gaps caused due to monsoon weather in NM.

I have a couple of questions regarding exposures:
(1) Is exposure time set automatically based on estimated Vmag (currently ~11) and then kept the same throughout the run as the target gets dimmer, or can it be adjusted based on feedback?
(2) Is a single exposure per filter generally sufficient/reliable, or would you recommend scheduling two or three exposures for robustness (satellite trails) and then averaging the good exposures on a given night?

(2108) Arne Henden — June 8, 2023, 10:28 a.m.

I recommend using 3 exposures per filter. Not only does it guard against problems like satellites, but you can use the 3 exposures to derive a much better error estimate.

(4726) Kenneth Menzies — June 8, 2023, 5:52 p.m.

We never collect single images for snapshots. Stack images / average mags as appropriate.

Exposures are initially chosen based on expected magnitude range and scope aperture. If target has a large amplitude and you notice it is getting too faint, advise us with a response to your 'you have data' email. This SN will get very faint. At some point, the initial exposure may not be long enough? Provide feedback.

Comments on this proposal are closed.