Two Infinities
Sun, 06 Jul 2025
STELAR group at Mt Wilson Observatory
This report is a slice of data acquired Thursday, May 22, 2025 with the Hooker 100" telescope on Mt Wilson.
Richard Bell operated the telescope. Target stars were selected by Leon (and Nick remotely) using the NINA plugin. Reference stars were selected by NINA from a list provided by Tom S. The list of targets was developed in cooperation with Russ: multi-peak fraction < 80 on Thursday, multi-peak fraction > 80 on Wednesday. Filter selection was guided by Geoff who provided autocorrelation images from the first 100 exposures of the targets.
The first goal was to estimate what portion of Gaia 2-parameter astrometric solution stars are multiple stars. Back in November, Geoff had identified a possible triple system from October observations, and in response to a question about the system, Cécile Loup of SIMBAD had said "There is no astrometric solution in Gaia DR2 nor DR3 [for TYC 2761-582-1], which probably means that this star is double." The idea was to estimate what that probability might be.
It turned out that each of our targets exhibited signs of multiplicity. Some quite obvious; others less so. Separations were roughly measured to be between about 0.1 and 0.3 arcseconds based on a plate scale estimated at 0.0117 arcseconds/pixel. More precise results may be available from Geoff's bispectrum reductions using Dave's Speckle Toolbox.
Three images are displayed for each target: first the power spectrum of the reference star, second the power spectrum of the target, and third the quotient of the target power spectrum by the reference power spectrum à la Labeyrie. All images were taken through the IR-pass filter except for the first reference star where the Sloan I filter was used.
The parallactic angle of each target star at time of observation was computed to guard against any obvious distortion by atmospheric refraction. Such refraction must occur given the non-zero zenith angles and the wide bandwidth of the IR-pass filter, but it did not appear to affect the first order approximations.
Lastly, a summary of filters and exposures used is tabulated along with filters with which fringes were detected and the range of measured separations for filters and methods.
Filters
Gaussian high pass and low pass filter profiles. Theoretical resolution limit occurs at about 52.7 pixels out. See the circle in the G2PS193 power spectrum below.
G2PS010
G2PS018
G2PS055
G2PS078
G2PS102
G2PS120
G2PS132
G2PS161
G2PS179
G2PS193
G2PS209
| Target | RA | Dec | source_id | Gmag | FDBL | GOFHA | BREX |
|---|---|---|---|---|---|---|---|
| str7 | float64 | float64 | int64 | float64 | int64 | float64 | float64 |
| G2PS010 | 185.14 | 30.60 | 4013740572694929408 | 10.29 | 71 | 0.31 | 67.54 |
| G2PS015 | 187.27 | 9.53 | 3903824800447407232 | 11.35 | 44 | 0.20 | 11.92 |
| G2PS018 | 189.90 | 31.95 | 1514419835236108032 | 9.50 | 56 | 0.17 | 21.23 |
| G2PS019 | 190.00 | 11.16 | 3928344150265115520 | 11.34 | 25 | 0.21 | 2.08 |
| G2PS055 | 202.89 | 11.20 | 3738443614381976448 | 10.34 | 53 | 0.14 | 43.08 |
| G2PS078 | 208.67 | 12.82 | 3728535399707693696 | 9.10 | 1 | 0.02 | 4.23 |
| G2PS102 | 214.11 | 19.89 | 1252031418311733120 | 10.51 | 39 | 0.16 | 11.17 |
| G2PS120 | 218.37 | 26.57 | 1280208735939184000 | 6.19 | 47 | 0.25 | 47.26 |
| G2PS132 | 222.69 | 22.26 | 1265524006532379392 | 10.92 | 57 | 0.39 | 58.84 |
| G2PS161 | 231.83 | 18.08 | 1208848889404284416 | 8.19 | 73 | 0.29 | 106.01 |
| G2PS179 | 235.27 | 16.69 | 1196966295444346368 | 9.94 | 64 | 0.35 | 42.10 |
| G2PS193 | 238.63 | 15.12 | 1193174354721344384 | 10.62 | 47 | 0.24 | 8.59 |
| G2PS209 | 243.18 | 22.07 | 1205620826343661696 | 11.24 | 40 | 0.21 | 23.03 |
| G2PS215 | 245.24 | 7.43 | 4451820571100096640 | 11.19 | 35 | 0.13 | 6.38 |
| Target | obstime | sidereal | HA | p-angle |
|---|---|---|---|---|
| deg | deg | |||
| str7 | Time | float64 | float64 | float64 |
| G2PS010 | 2025-05-23T03:38 | 177.62 | -7.52 | 13.73 |
| G2PS015 | 2025-05-23T03:56 | 182.00 | -5.26 | 24.60 |
| G2PS018 | 2025-05-23T04:41 | 193.30 | 3.39 | -6.05 |
| G2PS019 | 2025-05-23T04:16 | 187.04 | -2.97 | 12.75 |
| G2PS055 | 2025-05-23T05:11 | 200.96 | -1.94 | 8.37 |
| G2PS078 | 2025-05-23T05:34 | 206.70 | -1.97 | 7.63 |
| G2PS102 | 2025-05-23T06:01 | 213.33 | -0.78 | 2.09 |
| G2PS120 | 2025-05-23T06:18 | 217.75 | -0.62 | 1.29 |
| G2PS132 | 2025-05-23T06:36 | 222.26 | -0.43 | 1.04 |
| G2PS161 | 2025-05-23T07:09 | 230.59 | -1.24 | 3.59 |
| G2PS179 | 2025-05-23T07:23 | 233.89 | -1.38 | 4.28 |
| G2PS193 | 2025-05-23T07:34 | 236.75 | -1.88 | 6.34 |
| G2PS209 | 2025-05-23T07:58 | 242.79 | -0.39 | 0.94 |
| G2PS215 | 2025-05-23T07:52 | 241.19 | -4.05 | 23.21 |
| Target | filt_ir_exp | filt_lu_exp | filt_sg_exp | filt_sr_exp | filt_si_exp |
|---|---|---|---|---|---|
| s | s | s | s | s | |
| str7 | float64 | float64 | float64 | float64 | float64 |
| G2PS010 | 0.06 | 0.04 | -- | -- | -- |
| G2PS015 | 0.14 | 0.08 | -- | -- | -- |
| G2PS018 | 0.06 | 0.04 | -- | -- | -- |
| G2PS019 | 0.09 | 0.06 | -- | -- | -- |
| G2PS055 | 0.06 | 0.04 | 0.06 | 0.06 | 0.06 |
| G2PS078 | 0.06 | 0.04 | 0.06 | 0.06 | 0.06 |
| G2PS102 | 0.06 | 0.04 | -- | -- | -- |
| G2PS120 | 0.02 | 0.02 | 0.06 | 0.06 | 0.06 |
| G2PS132 | 0.06 | 0.04 | -- | -- | -- |
| G2PS161 | 0.03 | 0.02 | 0.02 | -- | -- |
| G2PS179 | 0.06 | 0.04 | -- | -- | -- |
| G2PS193 | 0.06 | 0.04 | -- | -- | -- |
| G2PS209 | 0.09 | 0.06 | 0.06 | 0.06 | 0.06 |
| G2PS215 | 0.09 | 0.06 | 0.06 | -- | -- |
posted at: 14:05 | path: | permanent link to this entry
