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In observations of diffuse emissions like, e.g., the Lyman-$\alpha$heliospheric glow, contributions to the observed signal from point sources(e.g., stars) are considered as a contamination. There are relatively fewbrightest point sources that are usually properly resolved and can besubtracted or masked. We present results of analysis of the distribution ofpoint sources using UV sky-survey maps from the SOHO/SWAN instrument andspectrophotometry data from the IUE satellite. The estimated distributionsuggests that the number of these sources increases with decreasing intensity.Below a certain threshold, these sources cannot be resolved against the diffusesignal from the backscatter glow, that results in a certain physical backgroundfrom unresolved point sources.  Detection, understanding and subtraction of the point-source background hasimplications for proper characterization of diffuse emissions and accuratecomparison with models. Stars are also often used as standard candles forin-flight calibration of satellite UV observations, thus proper understandingof signal contributions from the point sources is important for the calibrationprocess. We present a general approach to quantify the background radiationlevel from unresolved point sources in UV sky-survey maps. In the proposedmethod, a distribution of point sources as a function of their intensity isproperly integrated to compute the background signal level. These generalconsiderations are applied to estimate the unresolved-point-sources backgroundin the SOHO/SWAN observations that on average amounts to $28.9$ R. We discussalso the background radiation anisotropies and general questions related tomodeling the point-source contributions to diffuse UV-emission observations.

Inferring contributions from unresolved point sources to diffuse emissions measured in UV sky surveys: general method and SOHO/SWAN case study