Testing a little objective prism

[Paolo Berardi]

Not tonight but some days ago... During a star party which took place in Gran Sasso mountain I brought a lightweight portable setup consisting of a small refractor with a little 3 degree prism placed in front of the lens.

This was just a test that will let me know the results with such a tool. The diameter of prism is only 2 inch (you can see it on the Pentax 75)



Working...



Some celestial objects observed on 17 july 2015 (from 21 to 23 UT):

Messier 57 Ring nebula, 120 sec exposure:



Wolf-Rayet 136, 30 sec exposure:



Nova Oph 2015, 20 mins exposure:



Nova Sgr 2015 #2, 20 mins exposure:



Just for fun! Perhaps useful for any surveys? Maybe with a larger prism diameter...

Paolo

[Robin Leadbeater]

Nice Paolo

Mike Harlow has also been experimenting with a 100mm diameter 12 deg objective prism belonging to the BAA and getting some nice results, here for example
https://britastro.org/node/6551
http://forum.oasi.org.uk/download/file. ... &mode=view

Robin

[Paolo Berardi]

Thank you Robin! Obtained with a large prism and a long focal length, they are very nice 2d spectra. The "stretched" blue part of spectra for the non-linear dispersion is captivating... We're used to see a "crowded" world in the UV region!

Paolo

[Robin Leadbeater]

Yes indeed. In "the old days" prisms and blue sensitive films must have made a perfect match !

Robin