Michel Makhlouta:
Hi Moustafa,I've started this hobby with a C8-N, so I will share my experience. For newtonians, you will need a coma corrector. As you've done, the only way to reach focus with the celestron newt is by screwing directly that part of the focuser into the t-ring. If you want to use a coma corrector, that will screw in the tring and you won't be able to reach focus anymore. The solution for that, is to cut a piece of the tube (3.5cm in my case) and bring the primary mirror closer to the secondary. You may also want to consider upgrading the focuser, a low profile focuser might save you from modifying the primary position.
Newts also require to be collimated, this is something you need to put some time on to learn and perfect, from centering the secondary in the tube and in the focuser, all the way to aligning the primary mirror with the secondary. A Bahtinov mask is a must for reaching proper focus. One you've focused, try to refocus every hour or so, to check if the focus is shifting.
Looking back at my experience, I am glad I went through this, as a learning experience. But I would have gone with an 80mm refractor if I had to start all over. I am not saying the newt was useless, I've had some decent images with it, but it's up to you to weigh the pros and cons. Celestron newts weren't designed for astrophotography as a primary concern.
Hi Michel,
Thank you for the through explanation. Really helpful. Honestly, I like newts because of the star diffractions
. I realize now that its going to be painful to get this right. I will probably buy the Orion Astograph 6' or 8', comma corrector and bahinov mask. I have no problems with the collimation, I have done it multiple times using a laser collimator.
I will keep my C6-N for visual. BTW, I tried the 80mm refractor and OMG - Everything was like 10x easier got good photos of M51 with it, will share it next week once I'm done shooting since we have got a lot of clouds here.
Thanks again
