Takahashi FC100DF focus question

[mikeDnight]

I've just had a question paused to me by a Tak FC100DF owner, but my scope is a DC and so not quite the same.  He recently bought a brand new DF, but while using a 14mm Explore Scientific 2" eyepiece and a TeleVue 2" diagonal, found he couldn't obtain focus. Has anyone experienced this problem and if so, how was it resolved?

Edited March 27, 2020 by mikeDnight

[mikeDnight]

Problem solved! 

[Rainmaker]

How?

[mikeDnight]

It's a secret! 

Go on then, I'll tell you.   Apparently the 2" ES 14 needed more back focus, so he retracted the eyepiece a couple of millimetres and it snapped into focus. Perhaps a spacer ring for that eyepiece would be the way to go, though it shouldn't be needed if Tak had designed the focuser properly in the first place. There's simply not enough travel in both directions, which is something that could so easily be resolved by shortening the main tube and lengthening the draw tube by a small amount. May be they do it on purpose so you buy Tak eyepieces? 

I still love Tak though! 💙

Edited March 28, 2020 by mikeDnight

[JeremyS]

3 hours ago, mikeDnight said:

I still love Tak though! 💙

Funny, I thought your jury was still out about Tak, Mike.

[John]

A shortage of outward travel is easier to solve than a shortage of inward travel.

My DL focuser seems to have ample travel for a very wide range of eyepieces - does the ES 14mm have a particularly extreme focal point ?

 

 

[mikeDnight]

53 minutes ago, John said:

A shortage of outward travel is easier to solve than a shortage of inward travel.

My DL focuser seems to have ample travel for a very wide range of eyepieces - does the ES 14mm have a particularly extreme focal point ?

 

 

I've not used the ES 14 myself. I sold a 7.5mm Parks Gold to the gentleman and the next news he'd bought a FC100DF. I think most people struggle at first in one way or another with the Takahashi back end, with its adapters. It's all very old school compared to the more modern high end focusers I suppose. Anyhow, he phoned me last night to say he'd been able to get the eyepiece to come to focus.  It did seem strange that a 14mm struggled to focus as its a middle of the range focal length. I could understand it better if it was either very long or very short. None of this has phased him though, as he's blown away by the Tak's performance on the Moon and Venus. 

[Rainmaker]

Takahashi Seisakusho have always had a very particular ethos, they design their scopes as part of a system that works incredibly well as a system.  All their components are of high quality and work because they are designed and intended to be used with other Takahashi components.  They don't cater for ES or TeleVue or Morpheus because they already have a selection of eyepieces and other components like prisms and diagonals that are of a high quality.  They make their  mounts, focusers and rings in their traditional way, sandcasting them,  I doubt that will ever change....

Their draw tube travel in each model is sufficient to allow the use of any of their own eyepieces...... but lately they have softened their approach a little to try to accommodate individual preferences...