The Dutch Open Telescope at the Roque de los Muchachos Observatory

Multi-wavelength fine structure and mass flows in solar microflares

“…The SOHO joint observing program JOP 171 included the operation of selected instruments onboard SOHO and the transition region and coronal explorer (TRACE; Handy et al 1999). The space instruments were supported by the ground-based Dutch open telescope (DOT; Hammerschlag & Bettonvil 1998). DOT provided tomographic (nearly simultaneous) filtergrams of the Sun's photosphere and chromosphere in the blue and red continuum (432 and 651 nm), the G Band (430.5 nm), the Ca ii H line (396.8 nm) and the Hα line (656.3 nm, ± 0.35Å).…”

DOT tomography of the solar atmosphere

“…Over the past years the instrumentation concepts were tested extensively, an elaborate multi-wavelength post-focus re-imaging system has been developed, and multichannel speckle-burst data acquisition has been implemented. More detail is given in conference proceedings (Hammerschlag 1981(Hammerschlag , 1983Hammerschlag & Bettonvil 1998;Rutten 1999;Sütterlin et al 2001a;Rutten et al 2001a;Bettonvil et al 2003;Hammerschlag et al 2003), in , and on the DOT website 2 which also furnishes DOT photographs and most speckle-restored DOT movies taken so far. Example images from the DOT are shown in Lower panel: Ca  H (low chromosphere).…”

Ba ii 4554 Å speckle imaging as solar Doppler diagnostic

“…This paper describes a test which combines the principal alternative to adaptive optics, namely post-detection speckle reconstruction, with a tunable Lyot filter selecting narrow passbands in a specific line, namely the Ba II resonance line at λ = 4554Å. The test was done in the context of developing focal-plane instrumentation for the new Dutch Open Telescope (DOT) on La Palma (Hammerschlag & Bettonvil 1998;Rutten et al 2001a). The DOT is presently being equipped with an advanced multi-wavelength imaging system (Sütterlin et al 2001) that exploits the well-established speckle-masking image reconstruction technique Lohmann et al 1983; von der Lühe 1993) for large-volume tomography of the solar atmosphere (Rutten et al 2001b).…”