Second attempt at Astro photos, the aperture was 1.2 and the next half step before f2, could someone please let me know what the value of the half stop is?

The Cloud or nedula, i have no idea what it is called in the centre, it looks like crab defending it self. The second shot has a satelitte tracking through it, this was not planned to much, but i am reasonably happy with the results.

Lastly can you stack frames on a MAC, I checked Deepskytracker and all I could see were exe. files available to download?

Tthanks

[gifthorse]

The second image does appear to be the ISS. The aforementioned Stellarium can be configured to show near earth objects such as the ISS and satellites. A very helpful website is heavens-above.com Heavens-Above Under the configuration section you can mark your location on the map and the website will show when and where the ISS and other space objects will appear in the skies. Yet another handy site for the astro/night photographer is the Astronomy Calendar of Celestial Events. Astronomy Calendar of Celestial Events 2015 - Sea and Sky It lists events like meteor showers, conjunctions, eclipses, etc

[gmans]

The second image does appear to be the ISS. The aforementioned Stellarium can be configured to show near earth objects such as the ISS and satellites. A very helpful website is heavens-above.com Heavens-Above Under the configuration section you can mark your location on the map and the website will show when and where the ISS and other space objects will appear in the skies. Yet another handy site for the astro/night photographer is the Astronomy Calendar of Celestial Events. Astronomy Calendar of Celestial Events 2015 - Sea and Sky It lists events like meteor showers, conjunctions, eclipses, etc

Thanks for the handy info, I ran stellaruim backwards after the photo and did not see the ISS in that position of the sky but in saying that it makes me wonder the accuracy of running it backwards and also the positioning variables of location to angle of view in the simulation.

it was easy to see by eye and bright. There was other satellite on that night passed over which were not nearly as bright and I missed seeing them, picked them in checking the photos on the computer.