Change in R MON (NGC2261)

Affiliation

American Association of Variable Star Observers (AAVSO)

Tue, 02/20/2024 - 18:48

Hi all,
Recently, I visited an old friend... The R MON star (NGC2261).
After treatments, I realize that there has been a change in the color indices since the end of 2022.

Date B V R I B-V V-R R-I B-I V-I
2022-11-04 11.5775 10.878 10.1104 9.9258 0.69945 0.7676 0.1846 1.6516 0.9522
2024-02-06 10.9085 9.7787 9.9696 8.8091 1.1298 -0.1909 1.1605 2.0994 0.9696

JBD

hambsch

Affiliation

Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)

Wed, 02/21/2024 - 20:58

R Mon

HI,

I have been following R Mon since Nov. 22, 2023 when it was requested to observe it in BVRI filters. There is variation of about 0.2 mag in each filter over the about 100 nights I have data submitted to the AAVSO.

Regards,

Josch Hambsch (HMB)

bskiff

Affiliation

American Association of Variable Star Observers (AAVSO)

Sat, 02/24/2024 - 17:36

Change in R Mon ?

Since Josch has taken the lion's share of the recent data, for consistency it will probably be important to know what measuring aperture he is using. The amount of 'fuzz' the surrounding nebula contributes to the integrated magnitude will vary considerably depending on seeing, image scale etc. Thus apparent changes in magnitude and color may be masked (or caused by) various sizes of measuring apertures. This has been a long-time problem with active galactic nuclei for nearby objects where the host galaxy is well-resolved.

\Brian

hambsch

Affiliation

Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)

Sun, 02/25/2024 - 20:39

Measuring aperture

Hi Brian,

since I use a CMOS camera with small pixels in 4x4 binning (pixel scale 1.15 arcsec). I run an aperture of 6 pixel (about 7 arcsec) routinely on all my targets except when close by stars interfere. My FWHM is between 3 to 4 arcsec.

I hope this helps.

Regards,

Josch

bskiff

Affiliation

American Association of Variable Star Observers (AAVSO)

Mon, 02/26/2024 - 01:08

Measuring aperture for R Mon

Good; thanks. I note there is similar coverage over recent seasons by ASAS-SN in one filter. Their reduction scheme is probably not simple aperture photometry, however.

\Brian

hambsch

Affiliation

Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)

Sat, 03/02/2024 - 19:27

Reply not possible to your e-mail address

Hi Brian,

I tried to reply to your e-mail sent to me concerning photometry software. I got each time I try to reply to your e-mail or forward to your e-mail address bas at lowell dot edu a delivery failure notification.

Hence I guess you never got my reply..

If you sent me another mail with a different address, I could try again.

Thanks,

Josch