Proposal #497

Proposer	(45802) Mikhail Ashchepkau (ashchepkau@gmail.com) obscode: AMIF
Assigned To	(3663) Dirk Terrell
Date Submitted	March 29, 2024
Status	Allocated
Priority	Normal
Proposal	Systematic BVRI observations of two-hump mira NSVS 2572317 is provided now with BSM telescopes according to proposal #469. I propose to complement them by low-resolution spectroscopy in order to getting data on absorption lines changes during pulsations. I suppose, one spectral observation per month may be enough, if total duration will be 12 months or more. Gotten spectras will help in better understanding of nonstationar condensation processes in overcooled stellar shell.

Targets
Target	RA (H.HH)	Dec (D.DD)	Magnitude	Telescope	Observation Frequency	Expiration Date	Proprietary Term
NSVS 2572317	10.604814	59.93597	15.2–12.3	BSM_TX	20	April 15, 2025	No

Comments

(3663) Dirk Terrell — April 2, 2024, 2:53 p.m.

BSM_TX can do low resolution spectra. The TAC would like you to get a few test exposures and see if they will suit your needs before committing to the full project.

(4848) George Silvis — April 3, 2024, 4:58 p.m.

I'll put this in with a daily cadence until we sort out the focus and placement of the grating spectra.

(4848) George Silvis — April 7, 2024, 7:49 p.m.

I'll increase the exposure to 100
And try a couple different focus offsets
I've shared a sequence with you on VPhot.
Please review to make sure the target is properly identified.

(4848) George Silvis — April 12, 2024, 2:52 p.m.

Advice from Scott Donnell is that we should not be flat fielding. We'll try to get that setup.
The last shots had different focus settings. Are any of them better than the rest? We can continue to adjust
We need to also image an A and a Miles star. Please select and post their coordinates and mag here.
George

(45802) Mikhail Ashchepkau — April 12, 2024, 3:54 p.m.

Scott Donnell asks to make 600 s exposure due to absense of blue end.
I suppose one 600 s image instead of three shorter ones will be enough.

(45802) Mikhail Ashchepkau — April 12, 2024, 4:02 p.m.

Thank you, George! I've asked Scott about defocussing (but I guess, defocus on 240411 images is too excessive).

(45802) Mikhail Ashchepkau — April 12, 2024, 4:36 p.m.

I can not help with Miles, but maybe pair of A-type stars will suite?

V0341 UMa
10 35 38.18 +58 15 49.1 (158.90910 +58.26364)
Variability type RRAB
Spectral type A
Mag. range 13.18 - 14.20 V

UU Boo
15 17 05.26 +35 06 56.5 (229.27192 +35.11569)
Variability type RRAB
Spectral type A
Mag. range 11.5 - 12.81 V

(45802) Mikhail Ashchepkau — April 12, 2024, 4:40 p.m.

Scott's answer:
Defocusing is not necessary or desired. I was not able to make out any part of the spectrum on the 100 second exposures. Let's try to get the exposure correct and then we can move on to focus and other items.

(45802) Mikhail Ashchepkau — April 16, 2024, 4:51 p.m.

Scott's message:
The target you have chosen for this study is very faint and requires a large aperture telescope and long exposure times. The only telescope in the AAVSOnet with a spectroscopic grating filter (i.e. SA200) is the one you are tasking. However, this telescope is a 4 inch aperture and the camera has a limit of 180 sec on the exposure time. My analysis of the spectrum on the 100 sec exposure image for NSVS 2572317 shows a signal to noise ratio of about 4.5 - too low to identify spectral features.

So I have to reject proposal #497, sorry and a lot of thanks for test images.

(4848) George Silvis — April 24, 2024, 3:19 p.m.

Good try.
Alas, none of the larger scopes have gratings.
I'll retire this project

Comments on this proposal are closed.