Proposal #549

Proposer	(8107) James DeYoung (deyoung_james@yahoo.com) obscode: DEY
Assigned To	(3663) Dirk Terrell
Date Submitted	Sept. 5, 2024
Status	Allocated
Priority	Normal
Proposal	I have started observing USNO-B1.0 1295-0410006 a DCEP with a 10.2865-d period. I have been doing a program of observing and obtaining transformed light curves for over 60 long-period cepheids sampled over the last 5 years or so. Most have been observed in four-colors, B, V, Rc, and Ic. A grand tome with color indices, times of maxima, DC DFT determined periods, and Fourier coefficients for the phased LCs is in final writing stages covering 53 of them. I am currently observing 8 DCEPs and one CWA. A sequence has recently been generated by the sequence team and UID assigned, 000-BPY-764. I'm using my portable observing setup Atik490EX + Esprit 100. This object is very reddened and I'm not able to get any signal in B for this DCEP. I am getting good V, Rc, and Ic measurements with my small system. Proposal goals: 1. Johnson B & V, 2. one observation in each filter every clear night, 3. until the end of current observing season or upon notification from the proposer if sufficient phase coverage is obtained sooner. I would like to get Johnson B & V with an SNR of at least 10 or better higher that are transformable to the standard system. I use simple linear coefficients to transform for my home systems and would prefer to use my software tools here at home to extract and reduce the photometry from the images. I use Aperture Photometry Tool and excel to do the transforms. I need good sampling at all phases to be able to generate good times of maxima and allow Fourier fitting of the phase-folded LCs. The V overlap with my small telescope system will allow any bias to be determined between observing systems. Best regards, DEY

Targets
Target	RA (H.HH)	Dec (D.DD)	Magnitude	Telescope	Observation Frequency	Expiration Date	Proprietary Term
USNO-B1.0 1295-0410006	20.422353	39.58822	17.58–16.84	MPO61	0	March 12, 2025	1 Year

Comments

(3663) Dirk Terrell — Sept. 6, 2024, 5:51 p.m.

We might not be able to get B data either because the object is so faint, but the TAC suggests looking at it with MPO61 or TMO61 and seeing what the first images look like before committing further time.

(8107) James DeYoung — Sept. 6, 2024, 6:52 p.m.

That will work... Looking forward to a B test image.

(8107) James DeYoung — Sept. 10, 2024, 3:30 p.m.

2460563.5 I took a 600s B filter image with the Atik490EX + Esprit 100 and got no signal, not even a hint, Moon not esp. a problem, transparency good and little forest fire smoke here this night.. B limit somewhere around 19.1 so in B this object is fainter than that and B-V greater than +1.4. V at 17.7 magn. FYI.

(4726) Kenneth Menzies — Sept. 13, 2024, 8:55 p.m.

Committed to MPO61. I assume you know that our scopes are not guided?

(8107) James DeYoung — Sept. 13, 2024, 9:19 p.m.

No I don't know much about MP061 except what is on its web page.

If the psfs are not round from sidereal tracking but reasonable I can deal with that with an elliptical aperture.

What is its typical sidereal tracking performance?

Bright period observations probably aren't the optimal. What exposure time are we expecting to get?

It may be that VRI is all I will get for this object with my home system. I can live with that! If we are lucky to get one positive B observation with the test image that will at least fix the B-V value.

Thanks.

(8107) James DeYoung — Sept. 29, 2024, 12:37 p.m.

Downloaded the B & V images. Quick inspection shows the variable but only a hint in B. Will stack what I received and check phase and let you know if it worth trying again, perhaps just around B maximum times at most.

Btw, the current Filezilla installer contains malware/adware according to windows security. Winscp is a better option for windows ftp'ers. Guest login doesn't work but anonymous login does.

More to come...

(8107) James DeYoung — Sept. 30, 2024, 1:27 p.m.

The 4x stacked B image had SNR of 7 for the variable, around 19.1 B. B-V is now fixed and known. That SNR is probably sufficient but since the total exposure time is so long I don't think it is especially worth getting more phase coverage to fill in the B light curve.

Unless! You have lots of unused telescope time that can be allocated. If that is the case then the original proposal is still valid. The V-band doesn't need 4 images for stacking, single images are plenty good enough and would cut down total exposure time significantly.

Comments on this proposal are closed.