First: Thanks for the compliment about the images. To get the posted pictures into my gallery, it's necessary to select a lens from the choices POTN offers. But telescopes aren't listed in the choices for the lens used, so I picked a lens that was obviously not what I had used. I used the Meade ETX 125 telescope.
Second: You're right! The telescope with the short T-Adapter for my camera has a 1900mm focal length, but the adapter has an extension tube that increases the focal length to 2310mm. Then, I added a 1.4x teleconverter to that, which increased the focal length to 3234mm.
The image below is a screen capture from the manual for the Meade ETX telescopes, with the focal lengths listed with the short adapter and with the extension inserted... And that's how my photos were taken at 2310mm and 3234mm focal lengths. Also, the focal lengths given in the manual are for 35mm cameras. Since my camera has a smaller sensor, it has a 35mm equivalent conversion factor of 1.5... So if that is factored in, the 2310mm focal length converts to 3465mm, and the 3234mm focal length is equivalent to a photo taken with a 4851mm telephoto lens on a 35mm camera!!! The numbers just keep getting bigger and bigger.
forum: Astronomy & Celestial
Thank you very much for your explanation!
This is the first time i know about that extension tube can increase the focal length, in astronomy gear i know that only a Barlow can increase the focal length of the telescope not the extension tubes.
Second, i didn't know that you can use a Teleconverter with a telescope, but no wonder as long you use a Canon DSLR then tha won't be a problem, i use an astro camera so only Barlow can be used here if i use a telescope, unless if i use a teleconverter with Canon lenses then i can use a T-adapter in this case.
I am not good in those calculations, so good image and well done with whatever gear you use, soon i will do the same too.