Can a Takahashi 100 DZ Outperform a Non Premium 120-127mm ED Refractor

[johnturley]

13 hours ago, dweller25 said:

@JeremyS The issue with SCT’s is optical variability, it sounds like you have a very good one that works as a 9.25” should, perhaps @johnturley’s is not quite as good.

I can say with 100% confidence that the C9.25 I owned was the worst telescope I ever looked through - it really was a lemon that had gone rotten !

Stupidly I bought a C8 years later - it was a stunner ! 🙂

My C9.25 gave quite good results on planets, although I don't think it was as sharp as the Esprit 150, but unfortunately I never got round to comparing them side by side, partly because my wife had 'boxed it in' in the conservatory with some quite large house plants.

Sounds like you were unfortunate by getting a bad sample with your C9.25, some claimed that the C9.25 provided superior planetary views even compared to the C11, because of the longer (f2.5) focal ratio of the primary compared to the C8 and C11. Did you check the collimation, Rother Valley Optics checked mine before I purchased it.

John 

 

Edited January 22 by johnturley

[dweller25]

6 minutes ago, johnturley said:

Did you check the collimation

 

Oh yes over and over again ! 

The C8 that replaced it needed collimating but was then excellent 🙂

Edited January 22 by dweller25

[johnturley]

21 hours ago, Deadlake said:

The issue with the SCT is it needs a night of good seeing to use and also needs to acclimate to be usable. 

In the end I run out of time to use the C11, I just go for the APO as it's ready to use in thirty minutes.

The SCT has more image scale, however it's never as sharp or has the contrast of my APO.

The MTF of the APO I have just pulls away when looking at planets compared with the SCT.

Why do I have the C11, it's great on DSO, it just goes so deep on the stars I can see.

My back yard is SQM 21.

Sounds like I was never going to get the best results from my C9.25 with storing it in the conservatory (which can get quite warm in sunny weather even in winter), and then bringing it out just before use. My Tak 100 DZ, which is stored in the same place, will cool down and acclimatise much more quickly.

My Esprit 150 is stored in a wooden observatory shed (piggybacked on my 14in Newtonian) where the temperature will be much closer to the ambient, although it can get quite warm in summer. The need for the C9.25 substantially diminished anyway after I purchased the Esprit 150, although it would have been potentially better for planetary photography, having more than double the focal length.

John

Edited January 22 by johnturley

[Deadlake]

On 21/01/2024 at 21:36, dweller25 said:

Is your C11 reflectix wrapped ?

No, but I thought that only helped with stopping tube currents with large temperature swings. Is it really that good in helping out stopping tube currents forming?

[dweller25]

1 hour ago, Deadlake said:

No, but I thought that only helped with stopping tube currents with large temperature swings. Is it really that good in helping out stopping tube currents forming?

I don’t want to hijack this thread so will PM you 👍