These two TV models the Genesis 500mm. f.5 and the 540mm. f.5.4 SDF could someone tell me which is the better choice for visual observing? thank you, John M
Are these true APOs ?
Started by Midnight Sun, 01/20/2010 03:08PM
Posted 01/20/2010 03:08PM
Opening Post
Posted 01/20/2010 11:40PM
| Edited 01/20/2010 11:42PM
#1
I bought my TV Genesis SDF about 5 years ago after doing a lot of research on the 101mm series of TeleVue scopes and came to the same conclusion as Mark Rieck. I have not been disappointed. Even though the G-SDF does not say "APO" on the OTA, it certainly performs like one. I've compared it to my TV-76 (APO) and a friend's TV-102 (APO) and cannot tell the difference in terms of control of color fringing. I've not had the opportunity for a side by side comparison with a TV-101 or NP-101, but doubt there would be enough difference to make me trade "up".
The only (minor) downside I can see with the Genesis SDF is it's length (and weight). It's 29.5" long OTA is noticeably longer than the Genesis 500/f5, 3" longer than the TV-101, but 1.25" shorter than the TV-102. That hasn't been an issue for me.
Since all of these scopes are pretty "fast" and focusing is critical, I found the addition of the Feather Touch TVRFB Focuser Pinion assembly, with 10:1 fine focus, a worthwhile modification. I'm a visual observer and the ability to easily fine tune the focus is a real plus.
The only (minor) downside I can see with the Genesis SDF is it's length (and weight). It's 29.5" long OTA is noticeably longer than the Genesis 500/f5, 3" longer than the TV-101, but 1.25" shorter than the TV-102. That hasn't been an issue for me.
Since all of these scopes are pretty "fast" and focusing is critical, I found the addition of the Feather Touch TVRFB Focuser Pinion assembly, with 10:1 fine focus, a worthwhile modification. I'm a visual observer and the ability to easily fine tune the focus is a real plus.
Attached Image:
Funding Member
