I realised I have been neglecting my Tec160fl. I’ve either been using my c11 for viewing smaller objects or my Tak Epsilon 130 for larger ones. As a refractor man this felt wrong so last night I dusted off my tec and went out for a mixed normal glass and night vision session.
First point to note is that I was in London so skies were very lp. Sqm measured 17.9 at start and got to heady heights of 18.3.
I used an astro physics 0.75 photo visual reducer and switched between a 55mm plossl (system speed f2.5) and 41mm panoptic (system speed f3.3).
The 55mm plossl gave some fairly poor edge stars (linear!) whereas the 41mm pan gave sharp points to the edge (first time I’ve used the pan with the tec).
On nebulae the 55mm was generally better if you ignored the edge stars (which were nullified by the 3nm ha filter to some extent). The North America was rather nice considering the skies- not as in my face as I get at a dark sky but some good detail and nice subtlety. The crescent was a bit disappointing - I have seen much better with the c11 from the same site - maybe transparency wasn’t as good last night, thinking about it I think that was the case.
Sagittarius was low down as always in the UK 🙁 about 15 degrees. And the nebulae were disappointing again compared to views I got with the c11 a few weeks ago. The swan was the best of the lot but the c11 gave me real detail previously whereas I just got the broad outline last night. Eagle, trifid and lagoon were basically just disappointing smudges with no detail to make out (I could just make out the lane in the lagoon). Eastern veil was very nice though - some nice detail visible which surprised me.
Switching to the 642 astronomik (nice filter even with Lp)
This was more successful. With the less filtered stars, the 55mm edge distortion was really showing up so I used the 41mm panoptic most of the time which gave very aesthetic views across the fov. M13 was lovely as always with the propellor obvious. Even the tiny ngc6229 glob was nice. In fact every glob was good including m92 and several others. M81/m82 as good as normal with the dark lane visible in m82. Oddly I couldn’t see the needle galaxy at all though!! Yes transparency issues again..
I didn’t put the pier extension on so for the high clusters was sitting on the lawn to see through the eyepiece! C11 wins here!!
In summary the tec performed very well as expected. With normal glass last night I really enjoyed the 200x lunar views and the double double at 200x and the carbon star t lyrae was a stunning red.
With night vision the tec was nice with the reducer and 41mm panoptic. On reflection, transparency was disappointing I guess so nebulae didn’t really show like I am used to.
However, it reinforced my view that the tec sits between two stools - not enough fov for the bigger objects and too much for the smaller ones. If you only have one scope then the tec is a good compromise for nv. But the extra aperture of the c11 really helps on the smaller objects - I think the c11 is noticeably better just because of the aperture and the fact that at low mag the c11 doesn’t need to be fantastic optically to give lovely views. For larger objects my smaller scopes such as the baader 95mm refractor or Tak Epsilon 130 are better since they frame say the veil or the North America nebula much better. The tec just didn’t have enough fov even with the reducer and 55mm plossl (only around 2.5 degrees whereas I get 4 degrees with the other scopes).
For nv my preference is definitely the two scope one. One for large objects with a fov of 4 degrees at 10x and one for smaller objects with a fov of 1 degree and mag of 40x.
But on the moon with normal glass the Tec160fl is king!!
Edited by Gavster, 09 June 2019 - 04:56 AM.