Proposal #689

Proposer	(16309) Helmar Adler (eagle.astro@gmail.com) obscode: AHM
Assigned To	Dirk Terrell
Date Submitted	April 19, 2026
Status	Allocated
Priority	Normal
Proposal	Name: Helmar Adler Code: AHM This is my first proposal - please be gentle... Use of Data: Submit to AAVSO Database after VPhot analysis Please send data to Vphot. Target Star: EQ CMa Magnitude Range: 12.05 - 13.2 V mag Comp Stars: from X42135EVS chart – no comparison stars available, yet. Need to ask the "Team" or look up via SIMBAD etc. Observation Cadence: 1X per day to start with (not that much seems to be known about this star…, period: 2.29 d) Filters Required: B, V, R, (I) (not sure about the number of filters since this is supposedly (VSX) an EA/RS star, but see below). According to: The Astronomical Journal, 156:241 (49pp), 2018 November, “A First Catalog of Variable Stars Measured by the Asteroid Terrestrial-impact Last Alert System (ATLAS)”, Heinze et al., https://iopscience.iop.org/article/10.3847/1538-3881/aae47f/pdf, ”… appear(s) to show pulse-like variability interrupted by narrow eclipses. We refer to these as notched stars... They cannot actually be pulsating variables in eclipsing binary systems, because the pulsation and orbital period would have to be perfectly in phase , which is not plausible. EQ CMa is classiﬁed in VSX as an RS CVn star (a spotted rotator), but its light curve is far from typical for that class.” I.e., this seems to be an interesting, dynamic star that has some controversial classifications(?). Number of Exposures per Run: 3X per filter Exposure Times: Site owner's best guess initially, will review following 1st observing run Start Date: ASAP End Date: TBD

Targets

Target Name	RA (H.HH)	Dec (D.DD)	Magnitude	Observation Frequency	Expiration Date	Proprietary Term
EQ CMa	6.814339	-16.30103	13.2–12.05	1	May 1, 2027	No

Plans currently in place

bsm_berry/AAVSO_P689_AHM_AUTO.csv

# $Id: AAVSO_P689_AHM_AUTO.csv 5839 2026-05-16 13:31:45Z MZK $
#PROPOSAL=689
#REQUESTER=AHM,,vphot
#target,hh,mm,ss.ss,dd,mm,ss.s,desc,priority,monitor,maxX,nrepeat,bin,[filter,exposure,nexp],[filter,exposure,nexp]
EQ_CMa,6,48,51.62,-16,18,3.7,EQ_CMa,50,1,2,1,1,B,120,3,V,60,3,SR,60,3,I,60,3,EarliestTime=2026-04-19T00:00:00,LatestTime=2027-05-01T00:00:00

Comments

Kenneth Menzies — May 16, 2026, 1:32 p.m.

committed to Berry,

Helmar Adler — Sept. 4, 2026, 9:02 p.m.

I'd like to follow up on my first request.
After I received the first data set (thanks!) I used VPhot for data analysis. The target appeared to be challenging in various aspects:
1. Not many comp stars in the field of view;
2. The star Sirius, even being out of the field-of-view, radiated noticeably into the image (I was wondering at first if it was amp glow...);
3. Available comp stars were mostly close to the image border; not many closer to the target;
4. The target is fairly red - (B-V) ~ -1.0; even less available comp stars showed that (B-v) value.

Thanks to the Sequence Team I got promptly additional comp stars after my request for an improved sequence ((thanks Michael!). Still, red(dish) comp stars are hard to find in the fov.
Nevertheless, I was able to get first calibrated/transformed measurements uploaded and would like to ask for more images now. We could limit the filters to B, V and I (I am not sure if Sloan-r would be of any real value; please let me know. If yes, please add that filter, too).

The period of this target is 2.29 days. I am not sure what a good temporal sequence for the observation would be. E.g., several observation per night, distributed over a night, and then repeated over some nights. Or observation at the same time, but at many nights in a row. Maybe one of you could chime in with a more useful suggestion?
I am asking again for a minimum of three images per each B-V-I filters. The current exposure times led to SNR of 40-60, not great, but usable. I do not know where in the period the first measurements were taken, so I could give feedback as soon as I get the next measurements (this time earlier, though).

Thank you all!
- Helmar

Comments on this proposal are closed.