Calvera is an unusual isolated neutron star with pure thermal X-ray spectrum typical for central compact objects in supernova remnants .
On the other hand , its rotation period and spin-down rate are typical for ordinary rotation-powered pulsars .
It was discovered and studied in X-rays and not yet detected in other spectral domains .
We present deep optical imaging of the Calvera field obtained with the Gran Telescopio Canarias in g ^ { \prime } and i ^ { \prime } bands .
Within \approx 1 ^ { \prime \prime } vicinity of Calvera , we detected two point-like objects invisible at previous shallow observations .
However , accurate astrometry showed that none of them can be identified with the pulsar .
We put new upper limits on its optical brightness of g ^ { \prime } > 27.87 and i ^ { \prime } > 26.84 .
We also reanalyzed all available archival X-ray data on Calvera .
Comparison of the Calvera thermal emission parameters and upper limits on optical and non-thermal X-ray emission with respective data on rotation-powered pulsars shows that Calvera might belong to the class of ordinary middle-aged pulsars , if we assume that its distance is in the range of 1.5–5 kpc .