Micro Focuser for Takahashi 100 DZ

[Mr Spock]

1 hour ago, Franklin said:

The DZ has two adjustment grubscrews either side of the lock-knob.

There are three with that focuser. You have to unscrew the focuser to see the third 

[johnturley]

2 hours ago, mikeDnight said:

 

 Sometimes I think the best way to look at any Tak purchase, is that you're paying for the optics. Tak throw the tube and focuser in as a bonus.

Sounds a bit like the early (pre-Starfire) Astro Physics Refractors, which had very basic focusers.

John 

[John]

The focuser seems to have been a weak link in quite a few brands / models that I can think of over the years 🙄

 

[MalcolmM]

Regarding the stiffness, I have tweaked the three grub screws on the top of the focuser to get it 'just right' as best I could. I have heard that each should be tweaked an equal amount so as not to unbalance the focus (image shift). The stiffness of the focus is very sensitive to these grub screws so a tiny turn on each should be all that's needed. I put a tiny amount of locktite on the grub screws when finished, to hold them in place.

This is what I have done based on information I read either on this forum or on Cloudy Nights, and have been very pleased with the outcome. Unfortunately I can't remember the link, but I'm sure a Google search would throw up some hits. It does however sound like it would not be the right thing to do if the middle grub screw was simply to hold the pad in place as mentioned above.

I find the stock Tak focusers excellent, very smooth, and easy to 'snap to' focus when adjusted well.

I did put an MEF3 on a 60CB, then moved it to my 100DC (my 60CB did not fit in my travel case so well with the MEF3). Very easy to install and brilliant! At high magnification, I can tweak the focus with no vibrations when on a lightish mount/tripod combination. It really does give me confidence I have got good focus.

Caveat is I have no experience with other focusers, but I really like the stock focusers, and really really like the MEF3! Oh, the other caveat is I'm very biased towards anything Tak 🙂

I hope you get a solution one way or the other. 

Malcolm 

[Franklin]

4 minutes ago, MalcolmM said:

It does however sound like it would not be the right thing to do if the middle grub screw was simply to hold the pad in place as mentioned above.

That was from a Vixen focuser adjustment instruction on the web, it stated to NOT touch the middle grubscrew but without giving a reason. I shouldn't worry, these old school R&P focusers are a very basic design and there's nothing that can really go wrong, they just need setting up properly but unfortunately they don't always arrive from the factory that way. Once you know how they work it's quite easy to set them up. They actually work really well and it's only because of the popularity of imaging in recent times that dual-speed-focusing has become all the rage, people expect to get a dual-speed these days but for visual they're a luxury not a necessity. 

[MalcolmM]

8 hours ago, Franklin said:

Once you know how they work it's quite easy to set them up. They actually work really well

 

8 hours ago, Franklin said:

but for visual they're a luxury not a necessity

Perfect summary 🙂

Malcolm 

[mikeDnight]

On 26/11/2023 at 21:50, John said:

The focuser seems to have been a weak link in quite a few brands / models that I can think of over the years 🙄

 

It's amusing to think back at some of the junk focusers I've used over the years, some of which had ATM origins, and I know I'm not alone in this. Yet they worked in a fashion and I, like many, I was thrilled to have a telescope. Tak focusers are a world apart from those nightmarish contraptions. I'm only thinking out loud but may be we're going just a bit soft expecting focusers to work? It's similar with eyepieces today. If an eyepiece doesn't have a 300° apparent field we go into meltdown, complaining it's like looking through a straw. Next we'll be expecting clear skies! I jest of course, but the truth is that Tak focusers are a long way from being bad, they're just old school.

Edited November 28, 2023 by mikeDnight

[Stu]

On 26/11/2023 at 23:26, Franklin said:

people expect to get a dual-speed these days but for visual they're a luxury not a necessity. 

That’s interesting. I actually find them invaluable for visual, and they really enhance my enjoyment. Particularly for, say, Solar white light observing where a tenth of a turn on the fine focus can make the difference between granulation being just being visible and really popping. But then I’ve always been a sucker for a Feathertouch. What do they say about a fool and his money? 🤣🤣

[Mr Spock]

3 hours ago, Stu said:

That’s interesting. I actually find them invaluable for visual,

Same here. I find achieving perfect focus to bring out the finest detail requires an almost imperceptible touch on the micro focuser.

I'm not commenting on the money side of it. When I look down my account with FLO there's enough there to buy a new car... 

[Franklin]

3 hours ago, Stu said:

That’s interesting. I actually find them invaluable for visual, and they really enhance my enjoyment. Particularly for, say, Solar white light observing where a tenth of a turn on the fine focus can make the difference between granulation being just being visible and really popping. But then I’ve always been a sucker for a Feathertouch. What do they say about a fool and his money? 🤣🤣

 

12 minutes ago, Mr Spock said:

Same here. I find achieving perfect focus to bring out the finest detail requires an almost imperceptible touch on the micro focuser.

I'm not commenting on the money side of it. When I look down my account with FLO there's enough there to buy a new car... 

I agree as well, finding perfect focus, especially under demanding conditions is made much simpler with a dual-speed but in years gone by before fine focusers were available, were amateur astronomers unable to achieve focus? No of course not, it was just a more frustrating experience! Back in those days folk came up with their own solutions like screwing a jam jar lid to the focus knob😁, the Robinsons fine-focuser!

[Mr Spock]

With my early model OMC-140, which had one of the worst focusers in history, I used a Meade 6.4mm Plössl for high power. What I would do was part unscrew the top, focus with the focuser as close as I could, then fine focus with the eyepiece thread. Had some fabulous views of Saturn when it was nearly overhead at x313.

[josefk]

I would put a finer focuser on my fine focuser if i could (not joking). I may yet still add a bit of pipe lagging or similar to expand the circumference on my GnG set-up. When my hands get cold i think i pass quite a bit of tremble onto my lightly mounted GnG when trying to get that last bit of sharpness.

 

[Franklin]

34 minutes ago, Mr Spock said:

What I would do was part unscrew the top, focus with the focuser as close as I could, then fine focus with the eyepiece thread.

Those Baader fine focusing eyepiece holders work well too.

[John]

I'm ambivalent about the need for 2-focusers. 4 of my scopes have them, 2 don't. I find the focal ratio of the scope makes a difference to how easily things "pop" into or out of focus though. As I understand it, steeper light cones (faster scopes) have a narrower zone of apparent sharp focus than slower scopes do. 

 

 

[mikeDnight]

Here's my micro focuser. Its very precise and has no spongey feeling to it. Although its helical in design it can even be used with binoviewers, as the movement needed is slight and makes negligible difference to the angle of the viewer. I used this baader helical focuser with the 1.6mm Vixen HR plus 2X Barlow on my DZ. Simply awesome! And as cheap as chips - almost!!

 

[JeremyS]

I use an MEF-3 on two of my Taks (FC 100DZ and TSA 120). Not that I need to, but because I can 😊.

More seriously tho, I find the greatest benefit when using an unpowered mount. In such situations, the lighter touch needed with  the MEF-3 is less likely to impart vibration of the whole setup 

[johnturley]

1 hour ago, mikeDnight said:

Here's my micro focuser. Its very precise and has no spongey feeling to it. Although its helical in design it can even be used with binoviewers, as the movement needed is slight and makes negligible difference to the angle of the viewer. I used this baader helical focuser with the 1.6mm Vixen HR plus 2X Barlow on my DZ. Simply awesome! And as cheap as chips - almost!!

 

That's interesting, as you say quite cheap at just £40 from FLO, I'll give that idea some thought, but it looks like I would also need to purchase a 'Baader T' Prism Diagonal (£90), plus a 2in Nosepiece (£30), but you can buy the two combined for £117, and FLO currently have this in stock (unlike the Tak MEF3 Micro Edge Focuser) , and would work out about half the price of Tak MEF3, and avoid the fiddly job of fitting one of these or the More Blue version. I was also thinking of asking Rother Valley Optics (from whom I bought the 100 DZ) to fit an MEF3 if I bought one from them, don't know whether they would charge extra for fitting.

Baader T-2 90° Prism Star-Diagonal with Focusing Eyepiece Holder & 1.25" Nosepiece | First Light Optics

This would mean however that I would need to swap diagonals to use 2in eyepieces (I currently have a spare Baader Click Lock Dielectric Diagonal), but I probably won't use the 100 DZ much with 2in eyepieces, as my Esprit 150 is probably better suited to low power wide field views. I was however thinking of getting a Tak 1.25 Prism Diagonal anyway, as I think that @Mr Spocksaid this noticeably improved the visibility of the Jovian Cloud Belts over the Baader 2in Dielectric Diagonal. I don't know whether the Baader T2 Prism Diagonal would be as good, but I do know that several observers think quite highly of this diagonal.

John 

 

Edited November 28, 2023 by johnturley

[johnturley]

1 hour ago, JeremyS said:

I use an MEF-3 on two of my Taks (FC 100DZ and TSA 120). Not that I need to, but because I can 😊.

More seriously tho, I find the greatest benefit when using an unpowered mount. In such situations, the lighter touch needed with  the MEF-3 is less likely to impart vibration of the whole setup 

That's was the problem when I tried to view Jupiter for the first time through my 100 DZ, turning the focusing knob imparted vibrations to the setup making it difficult to try to achieve correct focus. Viewing conditions however weren't very good at the time, and it probably didn't help with the mount and tripod being place on decking, although I didn't find the latter a problem when I had my CPC 9.25. 

At the moment trying to decide between the Baader Focusing Eyepiece Holder (and T2 Prism Diagonal), the Tak MEF3 Micro Edge Focuser, or the More Blue version of the latter.

John 

[Mr Spock]

I'm currently waiting for a Baader Zeiss T2 prism to arrive (should be here this week). It's enough with the 2" fitting to accommodate my 30mm UFF. That will replace completely my Baader 2" dielectric and Tak 1.25" prism. Makes sense just to have one quality diagonal.

[johnturley]

On 26/11/2023 at 16:15, Franklin said:

The adjustment grubscrews are on the top of the focuser on both Vixen and Takahashi scopes. Older Vixen scopes in the hammered green livery had side adjusted focusers back in the early 90's. The DZ has two adjustment grubscrews either side of the lock-knob.

 

Managed to slacken off the two grubscrews shown above, I needed to use a bit of nail varnish remover and WD40 to remove the glue and get the Allen key to fit in .The focusing mechanism now moves a bit more freely, I didn't however access the 3rd grubscrew that @Mr Spock mentioned, as I gather you have to unscrew the whole focuser mechanism to access this, which I didn't really want to do. Incidentally if anybody wanted to know, its a 1.5 mm Allen key that fits these grubscrews.  

I had the opposite problem with my Esprit 150, the focusing mechanism was too slack and needed tightening up, I had problems with the focuser racking out on its own when viewing objects at high elevation, and in particular using 2in eyepieces. It was also a bit of a problem trying to find out how to do this, as like with the 100DZ, there were no instructions regarding how to do this in the manual that came with the scope. 

Edited November 28, 2023 by johnturley

[johnturley]

1 hour ago, Mr Spock said:

I'm currently waiting for a Baader Zeiss T2 prism to arrive (should be here this week). It's enough with the 2" fitting to accommodate my 30mm UFF. That will replace completely my Baader 2" dielectric and Tak 1.25" prism. Makes sense just to have one quality diagonal.

Agree, presumably you also need to get a T2 to 2in eyepiece holder, and that this doesn't cause any vignetting with the 30mm UFF (which I also have), and which I think has a field stop of about 36mm. 

P.S. Just been looking on FLO's website again, and noticed that there are actually two different T2 Diagonals, one type, including the version with the built in helical focuser, has just a 1.25in prism, the other (which I assume is what you have on order) has a larger (I assume about 42mm prism), but you have to buy the nosepiece and eyepiece holder separate. 

Baader T-2 Prism Star-Diagonal | First Light Optics

This latter version  Baader T-2/90° diagonal features a prism manufactured to Zeiss specification from BaK4 glass, multi-coated, inside a solid metal case, and I assume can be used without vignetting with the 32mm UFF. Am I right in thinking that this has a better quality prism , and will be more comparable with the Tak Prism Diagonal quality wise, although of course the latter only has a 1.25 prism.

John 

Edited November 28, 2023 by johnturley

[MalcolmM]

6 hours ago, Franklin said:

screwing a jam jar lid to the focus knob

Now where would I get a jam jar lid that would compliment my Tak? 🙂

Malcolm 

[Mr Spock]

1 hour ago, johnturley said:

Agree, presumably you also need to get a T2 to 2in eyepiece holder, and that this doesn't cause any vignetting with the 30mm UFF (which I also have), and which I think has a field stop of about 36mm. 

P.S. Just been looking on FLO's website again, and noticed that there are actually two different T2 Diagonals, one type, including the version with the built in helical focuser, has just a 1.25in prism, the other (which I assume is what you have on order) has a larger (I assume about 42mm prism), but you have to buy the nosepiece and eyepiece holder separate. 

Yes, three parts. It's the eyepiece holder I'm waiting for - they were quoting 3-4 days when I ordered last week.

[John]

59 minutes ago, johnturley said:

Agree, presumably you also need to get a T2 to 2in eyepiece holder, and that this doesn't cause any vignetting with the 30mm UFF (which I also have), and which I think has a field stop of about 36mm. 

According to Baader the T2 Zeiss prism diagonal has a clear aperture of 35mm.

The non-Zeiss Baader T2 prism diagonal has a clear aperture of around 32mm I think.

 

 

[johnturley]

13 minutes ago, John said:

According to Baader the T2 Zeiss prism diagonal has a clear aperture of 35mm.

The non-Zeiss Baader T2 prism diagonal has a clear aperture of around 32mm I think.

 

 

Do you think that there is much difference in quality between the T2 Zeiss prism diagonal, and the non- Zeiss version apart from the different size. As mentioned, I was thinking of getting the latter with a built in 1.25in helical focuser, as an alternative to fitting a MEF3 Micro Edge Focuser. 

Note: I do have a Baader 2in Dielectric Diagonal I can use for low power wide field views, where focusing is not so critical.#

John