共查询到3条相似文献，搜索用时 234 毫秒
1.
We present a characterization of two narrow band filters commonly used in Infrared Astronomy. Our study mainly quantifies the effect of temperature and tilt angle on the central wavelength and width of the transmission bands of such filters. This allows to evaluate some important effects that must be taken into account to have good quality astronomical images. Effects as the limitation of the field of view and the presence of OH sky lines in the final image are quantified. 相似文献
2.
Yuvraj Harsha Sreedhar Karl Rakos Gerhard Hensler 《Journal of Astrophysics and Astronomy》2014,35(1):55-68
Evolutionary models form a vital part of stellar population research in understanding their evolution, but despite their long history of development, they are often misrepresented and the properties of stellar population observed through broadband and spectroscopic measurements are also misinterpreted. With growing numbers of these synthesis models, model comparison becomes an important analysis to choose a suitable model for understanding stellar populations and model up-gradation. Along with model comparison, we reinvestigate the technique of modified Strömgren photometry to measure reliable parameter-sensitive colours and estimate precise model ages and metallicities. The assessment of Rakos/Schulz models with GALEV and Worthey’s Lick/IDS model find smaller colour variation: Δ(uz ? vz) ≤ 0.056, Δ(bz ? yz) ≤ ?0.05 and Δ(vz ? yz) ≤ 0.061. The study conveys a good agreement of GALEV models with modified Strömgren colours but with poor UV model predictions and observed globular cluster data, while the spectroscopic models perform badly because of outdated isochrone and stellar spectral libraries with inaccurate/insufficient knowledge of various stellar phases and their treatment. Overall, the assessment finds modified Strömgren photometry well suited to study different types stellar populations by mitigating the effects of age-metallicity degeneracy. 相似文献