Bunter Vaasa #winter #winterwonderland #wintertime #city #cityphograph #cityphography #cityphoto #retrolenses #retrolens #retrophoto #retro #vintagelensphotography #vintagelens #vintage #helios44 #gelios #vasa #vasafitness #finland #finland_photolovers (at Vaasa, Finland) https://www.instagram.com/p/CnoUSqCohAp/?igshid=NGJjMDIxMWI=

Traveling through Kansas to Omaha for the holiday weekend and loving working with some vintage and retro lenses on the road less traveled. X-Pro3 Various lenses Heartland of Kansas #10yearsofxmount #myfujifilmlegacy #vintagelenses #retrolenses #roadlesstraveled #backroads #forgottenmainstreet #roadtrip (at Kansas) https://www.instagram.com/p/CfoU0Ber-oc/?igshid=NGJjMDIxMWI=

Shooting under a spotlight outside my building one late evening with my partner in crime @lizzie989 . . . #bnw #bnwphotography #downlight #bnw_city_streetlife #bnw_life #bnwlife #bnw_city #bnwmodel #latenightinspiration #bnw_planet #bnw_silhouettes #jetsetter #jetsetlife #tucson #tucsonaz #pnw #portland #portlandoregon #sonya6000 #retrolenses

Gas street basin walk Olimpus om20 Fomapan 100 #olympus #olympusom20 #fomapan #fomapan100 #film35mm #film35 #film35club #film35mmphotography #bw #blackandwhitephotography #blackandwhite #manualfocus #manualfocuslens #manualfocuslenses #retrocamera #retrocameras #retrolens #retrolenses #retrolensclub #birmingham #gasstreetbasin #streetphotography #city (at Gas Street Basin) https://www.instagram.com/p/CgsWKalKYF3/?igshid=NGJjMDIxMWI=

Winter Forest #winterforrest #winterwonderland #winter #forest #forestphotography #vaasa #winterfinland #finlandia #pictorialism #pictorials #pictorialpicture #manualfocus #manualfocuslens #manualfocuslenses #helios44m #helios #helios44_love #jupiter135 #jupiter135mm #retrolenses (at Ravintola Seglis) https://www.instagram.com/p/Cey0vSSIQly/?igshid=NGJjMDIxMWI=

Retrolensing by a wormhole at deflection angles $\pi$ and $3\pi$. (arXiv:1701.09169v2 [gr-qc] UPDATED)

The deflection angle of a light ray can be arbitrarily large near a light sphere. The time-symmetrical shape of light curves of a pair of light rays reflected by a light sphere of a lens object does not depend on the details of the lens object. We consider retrolensing light curves of sunlight with deflection angles $\pi$ and $3\pi$ by an Ellis wormhole, which is the simplest Morris-Thorne wormhole. If an Ellis wormhole with a throat parameter $a=10^{11}$ km is $100$ pc away from an observer and if the Ellis wormhole, the observer, and the sun are aligned perfectly in this order, the apparent magnitudes of a pair of light rays with deflection angles $\pi$ and $3\pi$ become $11$ and $18$, respectively. The two pairs of light rays make a superposed light curve with two separable peaks and they break down time symmetry of a retrolensing light curve. The observation of the two separated peaks of the light curves gives us information on the details of the lens object. If the observer can also separate the pair of the images with the deflection angle $\pi$ into a double image, he or she can say whether the retrolensing is caused by an Ellis wormhole or a Schwarzschild black hole.

from gr-qc updates on arXiv.org http://ift.tt/2kOvzMU

Retrolensing by a wormhole: $\pi$ and $3\pi$ in the sky?. (arXiv:1701.09169v1 [gr-qc])

Deflection angle of a light ray can be arbitrary large near a light sphere. The time symmetrical shapes of light curves of light rays reflected by a light sphere of a lens object does not depend on the details of the lens object. We consider retrolensing light curves of sun lights with deflection angles $\pi$ and $3\pi$ by an Ellis wormhole which is the simplest Morris-Thorne wormhole. If an Ellis wormhole with a throat parameter $a=10^{11}$ km is at $100$ pc away from an observer and if the Ellis wormhole, the observer, and the sun are aligned perfectly in this order, the apparent magnitudes of a pair of the light rays with deflection angles $\pi$ and $3\pi$ become $11$ and $18$, respectively. The two pairs of the light rays make a superposed light curve with two separable peaks and they break down time symmetry of a retrolensing light curve. The observation of the two separated peaks of the light curves gives us information on the details of the lens object. If the observer can also separate the pair of the images with the deflection angle $\pi$ into a double image, he or she can say whether the retrolensing is caused by an Ellis wormhole or a Schwarzschild black hole.

from gr-qc updates on arXiv.org http://ift.tt/2kOvzMU

Light curves of light rays passing through a wormhole. (arXiv:1607.01120v3 [gr-qc] UPDATED)

Gravitational lensing is a good probe into the topological structure of dark gravitating celestial objects. In this paper, we investigate the light curve of a light ray that passes through the throat of an Ellis wormhole, the simplest example of traversable wormholes. The method developed here is also applicable to other traversable wormholes. To study whether the light curve of a light ray that passes through a wormhole throat is distinguishable from that which does not, we also calculate light curves without the passage of a throat for an Ellis wormhole, a Schwarzschild black hole, and an ultrastatic wormhole with the spatial geometry identical to that of the Schwarzschild black hole in the following two cases: (i) "microlensing," where the source, lens, and observer are almost aligned in this order and the light ray starts at the source, refracts in the weak gravitational field of the lens with a small deflection angle, and reaches the observer, and (ii) "retrolensing," where the source, observer, and lens are almost aligned in this order, and the light ray starts at the source, refracts in the vicinity of the light sphere of the lens with a deflection angle very close to $\pi$, and reaches the observer. We find that the light curve of the light ray that passes through the throat of the Ellis wormhole is clearly distinguishable from that by the microlensing but not from that by the retrolensing. This is because the light curve of a light ray that passes by a light sphere of a lens with a large deflection angle has common characters, irrespective of the details of the lens object. This implies that the light curves of the light rays that pass through the throat of more general traversable wormholes are qualitatively the same as that of the Ellis wormhole.

from gr-qc updates on arXiv.org http://ift.tt/29vEXn5