Speckle Interferometry with midsized amateur telescope why not

Speckle Interferometry with mid-sized amateur telescope: why not? Interferometría con un telescopio amateur: ¿por qué no? L'interférométrie des tavelures avec un télescope d'amateur: pourquoi pas ? Florent Losse Société Astronomique de France

Gili Nice 74 cm Refractor Bath 50 cm Cassegrain IAS, Namibia Romero 40 cm Schmidt-Cassegrain Obs. Astronomico de Cantabria Trégon, Castets 60 cm Newton Pic du Midi

Observatory location MPC I 93 Newton Diam=408 mm Foc. =2052. 5 mm First light COU 407 r=0"4 7 img/600 img =1%

2009 Audine Camera F=11960 mm E=0"1552/px KAF-0400 768 x 512 9 x 9 mm Min exposure=60 ms Frame rate=long ! FOV=2'x 1'3 Miracle Imaging

HU 987 r=1"09 Usuable frames 2% Super-Speckles Exposure time too long, focal length too short, Airy disk spans only 2 pixels, no filter …

With super-speckles Classical processing : fails or difficult task 'Speckle interferometry like' processing does the job ~400 frames is enough No manual sorting, no subjectivity Resolution remains limited

2010 Atik 314 L+ Camera ICX 285 AL 1392 x 1040 6. 45 x 6. 45 mm Min exposure=1 ms Frame rate: (128 x 128 px)=4 fps EFL=11400 mm E=0"1167/px FOV=2'7 x 2' Exp : 2 ms OS 413 m: 4. 7/6. 2 r=0"9 exp: 1 ms Lucky images: 3/400 ~1% HU 940 COU 492 m: 9. 2/9. 8 r=0"5 exp: 7 ms m: 10. 2/10. 3 r=0"5 exp: 20 ms

Typical images Near the limit COU 1271 mag 9. 4/10 r=0"34 BU 1127 Audine 60 ms Super-speckles Near the limit HU 1178 Mag 9. 2/9. 3 r=0"38 Best 3 Atik 10 ms Best 4 THE best

Reductions Autocorrelation Quadrant determination Autocorrelation Intercorrelation Spatial image 5 x 5 masking

Sampling Calibration Prime focus With amplification lens EFL = F x dm/df Sampling 206. 265*px/EFL Sampling in arcseconds - EFL= Effective focal length in mm - px=pixel size in mm

E-W axis determination +/- 0° 2

Results Epoch Cameras Nights Nb doubles Nb orbitals Phase I May/Dec 2009 Audine 75 429 41 Phase II Feb/Jul 2010 Atik 63 579 125 138 1008 166

Results Pixel size (0"12 x 0"12) 43 orbitals Grade 1 & 2 Ai ry dis k O-C

Future improvements (could be…) Use filter Increase focal length Minimize speckle overlapping Decrease chromatic effects => Expand observable zenithal distance Airy disk f ~ 5 pixels 100 nm

Conclusion Do we really want to … üobserve every clear night no matter the turbulence üoptimize the use of the instrument üget accurate measurements üreduce quickly and objectively üwork on very interesting population

Speckle Interferometry with mid-sized amateur telescope: YES ! Interferometría con un telescopio amateur: ¡SI!