-Roger Pitre- 1 X 7 binocular MN65, Nexstar 8SE, SV70ED, Lunt 60 PT EQ6 Pro, Vixen GP2, Canon 50D, Modified XSi, SBIG ST-2000XM, 70-200 f/4L, BackyardEOS "He's got shoulders on him like a smelt..."--Anonymous <a href="" target="_blank">https://www.facebook.com/pages/AJP-Observatory/462651307139970?ref=ts&fref=ts</a> http://ajpobservatory.is-great.org/
I have a doublet TV 102, so what's your issue?
Quote:I confirmed this with a simple but all-telling star test, where I once compared a TV 101 with a TV102. The 102 won hands down and showed a level of SA correction < 1/8th wave ptv. The 101 was more like 1/5th wave, which is enough to take the edge off fine planetary detail.
400mm f/4.46 self made Dobsonian on Tom Osypowski equatorial platform Skywatcher 130mm f/5 BlackLine (finder, widefield scope and solar continuum scope) Sumerian 250mm f/4.8 Alkaid (as travelscope without platform and on Tom O. platform above).
On the matter of the TV 101, it has already been asserted that the 102 has sharper optics than the Genesis SDF (see the astromart review comparing them both)and that critical assessment by observers I trust (Ed Ting and Phil Harrington) both agreed that the 102 was sharper optically than the 101(despite it having marginally better color correction). As my threads already discussed, I confirmed this visually on Jupiter by comparing both the 102 and 101 images on the same night. Both gave excellent images, but the 101 was slightly softer IMO. No amount of optical theory can alter my own conclusions. Or, in the immortal words of the celebrated English poet John Keats, " Nothing is real until it is experienced"
No doubt about it, Nagler has done it again. The NP101 is an amazing optical accomplishment setting bar by which all other apochromatic refractors are judged.
This level of excellence does not detract from the TV102, which is an exceptional performer in it's own right. But in side by side tests conducted at Riverside Astronomy Expo, I found it is not in the same league as the NP101.
You do not need a parachute to skydive, you only need a parachute to skydive twice...
Quote:But this is really off-topic: if you want a discussion about this, the ATM and Optics forum is the place for it, or you can try Astromart if you feel like getting spanked by Roland himself.
Quote:The key was to observe and study the contrast between the components and observe the strength of the light in and around the airy discs, particularly the E and F component stars. In some of the refractors I tested, a good number of them did not direct a strong amount of light in the airy discs of the fainter E and F components compared to others
My point is that three scopes with three slightly different star tests will all have a different level or degree of contrast.