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was not aware that this technique was piccy about what telescope was used
Yeah. The main reason for NV requiring a fast focal ratio for extended objects — f/15 or potentially even slower is viable with globs and open clusters — is that NV produces an image in real time. Imaging and EAA stacking don’t have this specific constraint.
Hi Barry.
Gavin (mentioned above) recently acquired a new current generation Chinese NNVT tube (from Opfor in Canada) for the purposes of evaluating it vs. higher end tubes. He reported his initial findings in this Cloudy Nights thread. Whilst his impressions are positive, and the images he obtained with the entry level tube are impressive, for nebula viewing in particular, the lower gain of the NNVT (and Photonis) tubes does demand a fast setup.
For example, a lower gain tube won’t really work well with my f/7.4 Tak or (reduced) f/7 C11. You need a fast Newt or a refractor reduced with something which will allow you to still achieve focus. But these lower gain tubes should be more than capable of great views when handheld (at 1x magnification) and with non-extended objects like globs and open clusters with scopes like mine.
I managed to acquire a high quality Gen 3 (GaAs) tube secondhand from someone in the UK for a significantly higher price than the entry unit mentioned in that thread. Quite difficult to find a good one TBH.
how do you connebt it to the scopes you are using
There are two main ways of doing this:
– “Afocal” – Essentially bolting the NVD’s objective lens to a regular eyepiece in the scope. This allows one to achieve much faster effective speeds.
– “Prime” – Using the NVD without an objective lens (at the focal ratio of the native or reduced scope).Tele Vue provides an ecosystem for afocal connection to its eyepieces. Details here. There’s a lot to this; I did a lot of research before I bought mine.
All the best,
Joelthere are lots of different ways to do astronomy
Absolutely. I’m visual only and am really liking my new C11 for traditional glass views that my 4″ Tak is just too small to deliver. Night vision is a tool in my arsenal which opens up a lot more when appropriate (which is often); I particularly love it with globs through both scopes.
