TecnoSky 70/420 ED, Takahashi FS60/355 CB

[Fedele]

I bought a TS 70/420 ED for some tests. As soon as I arrived it became normal for me to mount it very quickly in parallel to my FS60CB (60/360).

In visual the CB wins

[Robindonne]

Its probably a great way to love that little japanese even more. The next big question is: how soon will you put that TS thing for sale?

[Louis D]

19 hours ago, Fedele said:

I bought a TS 70/420 ED for some tests. As soon as I arrived it became normal for me to mount it very quickly in parallel to my FS60CB (60/360).

In visual the CB wins

Can I ask why you bought another scope barely different from the FS60CB aperture-wise?

For my second refractor after my 72ED, I went with a 90mm APO FPL-53 triplet, and it made a big difference in reducing spurious color at high powers.  However, cool down time increased dramatically.  I really like the R&P focuser on the APO for securely lifting heavy loads at high altitudes as well.  The smooth Crayford focuser on the 72ED slips horribly with 3 pound loads in it no matter how much I try to tension it.

[Fedele]

5 hours ago, Robindonne said:

Its probably a great way to love that little japanese even more. The next big question is: how soon will you put that TS thing for sale?

Just TODAY. It not work  with a my specific setup

[Fedele]

2 hours ago, Louis D said:

Can I ask why you bought another scope barely different from the FS60CB aperture-wise?

For my second refractor after my 72ED, I went with a 90mm APO FPL-53 triplet, and it made a big difference in reducing spurious color at high powers.  However, cool down time increased dramatically.  I really like the R&P focuser on the APO for securely lifting heavy loads at high altitudes as well.  The smooth Crayford focuser on the 72ED slips horribly with 3 pound loads in it no matter how much I try to tension it.

1) because of nonsense about Chinese production that "now equals that of Japan" they say a lot, without detracting from their products.
2) because therefore I like to personally check if what I buy is actually TOO USELESS ergo try what I gave up
3) Because, following a discussion between friends in which it was stated that the diameter is everything, I wanted to demonstrate how much this is not entirely true and that it DEPENDS.

[Stu]

I’m assuming the second one is the 72ED? It would be interesting to see them at the same image scale on the sensor. From what I can see the 72 is showing more detail in this comparison, as you would expect due to the increased aperture and better coverage on the sensor.

[Carl Au]

Oh that’s interesting, which one is which?

Edited April 8, 2022 by Carl Au
Spelling

[Carl Au]

1 hour ago, Fedele said:

1) because of nonsense about Chinese production that "now equals that of Japan" they say a lot, without detracting from their products.
2) because therefore I like to personally check if what I buy is actually TOO USELESS ergo try what I gave up
3) Because, following a discussion between friends in which it was stated that the diameter is everything, I wanted to demonstrate how much this is not entirely true and that it DEPENDS.

Doesn’t that scope use Japanese Ohara fpl 53 glass? 

[Highburymark]

I think there are two Tecnosky 70mm EDs - a triplet, and a doublet which I think uses FPL-51 (?). The 70ED was cheaper than the FPL53 Tecnosky 60ED I bought a few months ago, so presume it’s FPL51. If this is a comparison between a fluorite Tak 60 and an FPL51 70ED (which is pretty fast at F/6), you’d expect a clear difference in performance.