Show us your Vixen Scope or mount

[JeremyS]

7 minutes ago, IB20 said:

 

That extender looks ace on the 60. I thought about getting it for the 76 but by some reports it doesn’t change a lot. It would also make a lot of my eyepieces redundant and add 40cm on the FL which makes the scope a lot more unwieldy. Happy to keep the Starbase for the longer F ratio.

I find the extender has a bigger effect on the FS60 than the FC 76. 
I do like Tak’s extender range for its different scopes though. Here’s what I use on the TSA 120, FC 100DZ and FS 102 (l to right). I never got on with Barlows.

[IB20]

4 minutes ago, JeremyS said:

I find the extender has a bigger effect on the FS60 than the FC 76. 
I do like Tak’s extender range for its different scopes though. Here’s what I use on the TSA 120, FC 100DZ and FS 102 (l to right). I never got on with Barlows.

Why is there no drool reaction? 🤤

[Franklin]

2 hours ago, Sunshine said:

Though the small counterweight catches my attention, is it enough? my eyes are telling me it is small.

1kg counterweight is the smallest Vixen offer. They also do 1.9kg, 2.8kg and 3.7kg all fitting a standard 20mm bore. The little 1kg was meant for the Polarie and the AP as a star-tracker but do come in useful for getting things balanced. It is supplied as standard with the AP mount. I think Vixen switched to lighter weights after the release of the Sphinx series of mounts because these mounts use the motor housing to add weight as well.

[mikeDnight]

On 24/04/2022 at 15:43, Franklin said:

SP FL102S f/8.8. Don't really know much about the history on this one, other than it originated from the French market (Perl Vixen). Oh, and it knocks the socks off my achros.

 

It will knock the socks off many apo's and ED's too! Congrat's on finding such a beautiful vintage classic.

The Vixen fluorite have optics made by Canon Optron same as Takahashi, and like many of the earlier Tak fluorites, the Vixen rear fluorite Steinheil element remained uncoated. The front element is multicoated.  Takahashi, or more likely Canon Optron, later developed a method of hard coating their fluorite elements and coated some later versions of their original FC100 series. Then Tak brought out the FS series with a front (hard multicoated) fluorite element with a Fraunhofer design. Tak claimed the FS was a better design, but in reality the only advantage it offered was a thinner, and therefor less expensive to manufacture, fluorite element. The FS series never quite matched the level of colour correction of the Steinheil  (Vixen or early FC100's), and both even today have an almost cult following among lunar and planetary observers, and lovers of fluorite optics.

 The choice of a Steinheil objective may most likely have stemmed, initially at least, from the need to protect the uncoated fluorite element from moisture and repeated cleaning. But the Steinheil has another advantage over the Fraunhofer design, in that the Steinheil offers better colour correction at shorter F ratio's. For example, the FS lower limit was F8, below which the scope nolonger can be said to be apochromatic. (The Sky 90 was not part of the FS family and has a different lens design).  And so all things considered, the Vixen fluorite apochromat's are among the best 4" class refractors ever made, with excellent continuity of quality thanks to Canon Optron. The modern incarnation of the FC Steinheil's by Tak do have fully hard multicoated optics at F7.5, F8 and F9, and though they might keep pace, but I doubt any could noticeably outperform the Vixen in side by side comparison.

 I imagine your Vixen standing at the end of your garden set against a starry background sky, and being all the telescope you'll ever need. 

 

[Franklin]

16 minutes ago, mikeDnight said:

It will knock the socks off many apo's and ED's too! Congrat's on finding such a beautiful vintage classic.

The Vixen fluorite have optics made by Canon Optron same as Takahashi, and like many of the earlier Tak fluorites, the Vixen rear fluorite Steinheil element remained uncoated. The front element is multicoated.  Takahashi, or more likely Canon Optron, later developed a method of hard coating their fluorite elements and coated some later versions of their original FC100 series. Then Tak brought out the FS series with a front (hard multicoated) fluorite element with a Fraunhofer design. Tak claimed the FS was a better design, but in reality the only advantage it offered was a thinner, and therefor less expensive to manufacture, fluorite element. The FS series never quite matched the level of colour correction of the Steinheil  (Vixen or early FC100's), and both even today have an almost cult following among lunar and planetary observers, and lovers of fluorite optics.

 The choice of a Steinheil objective may most likely have stemmed, initially at least, from the need to protect the uncoated fluorite element from moisture and repeated cleaning. But the Steinheil has another advantage over the Fraunhofer design, in that the Steinheil offers better colour correction at shorter F ratio's. For example, the FS lower limit was F8, below which the scope nolonger can be said to be apochromatic. (The Sky 90 was not part of the FS family and has a different lens design).  And so all things considered, the Vixen fluorite apochromat's are among the best 4" class refractors ever made, with excellent continuity of quality thanks to Canon Optron. The modern incarnation of the FC Steinheil's by Tak do have fully hard multicoated optics at F7.5, F8 and F9, and though they might keep pace, but I doubt any could noticeably outperform the Vixen in side by side comparison.

 I imagine your Vixen standing at the end of your garden set against a starry background sky, and being all the telescope you'll ever need. 

Wow, thanks for all the info Mike. I was told by the previous owner that the fluorite element was at the rear, so that all fits in. Going to Google "Steinheil" now and find out more about this amazing scope. Had it out the other clear night and the difference to what I'm used to seeing is noticable, even to someone with limited experience of these types of scopes such as me.

[Deadlake]

22 minutes ago, mikeDnight said:

It will knock the socks off many apo's and ED's too! Congrat's on finding such a beautiful vintage classic.

The Vixen fluorite have optics made by Canon Optron same as Takahashi, and like many of the earlier Tak fluorites, the Vixen rear fluorite Steinheil element remained uncoated. The front element is multicoated.  Takahashi, or more likely Canon Optron, later developed a method of hard coating their fluorite elements and coated some later versions of their original FC100 series. Then Tak brought out the FS series with a front (hard multicoated) fluorite element with a Fraunhofer design. Tak claimed the FS was a better design, but in reality the only advantage it offered was a thinner, and therefor less expensive to manufacture, fluorite element. The FS series never quite matched the level of colour correction of the Steinheil  (Vixen or early FC100's), and both even today have an almost cult following among lunar and planetary observers, and lovers of fluorite optics.

 The choice of a Steinheil objective may most likely have stemmed, initially at least, from the need to protect the uncoated fluorite element from moisture and repeated cleaning. But the Steinheil has another advantage over the Fraunhofer design, in that the Steinheil offers better colour correction at shorter F ratio's. For example, the FS lower limit was F8, below which the scope nolonger can be said to be apochromatic. (The Sky 90 was not part of the FS family and has a different lens design).  And so all things considered, the Vixen fluorite apochromat's are among the best 4" class refractors ever made, with excellent continuity of quality thanks to Canon Optron. The modern incarnation of the FC Steinheil's by Tak do have fully hard multicoated optics at F7.5, F8 and F9, and though they might keep pace, but I doubt any could noticeably outperform the Vixen in side by side comparison.

 I imagine your Vixen standing at the end of your garden set against a starry background sky, and being all the telescope you'll ever need. 

 

Is there any particular reason why Takahashi or any other vendor does not come out with a fast doublet 4" (around  f6 ish), even for visual a smaller scope has some advantages.

Modern EP's even mid priced can cope with the field curvature so not a valid argument.

The f 7.9 doublets are capable, however compared to the Vixen fluorite do to its speed creates a noticeably larger exit pupil which for a dark site visit will pay back in spades. APM lens are made of ok-1/ok-4 which is fluorite like but you have the weight penalty of a triplet, returned with that brightness of the lens and contrast.

I presume why the Vixen is a one and only fluorite scope of this type is due to the glass available at the time.....  

[mikeDnight]

3 hours ago, Deadlake said:

Is there any particular reason why Takahashi or any other vendor does not come out with a fast doublet 4" (around  f6 ish), even for visual a smaller scope has some advantages.

Modern EP's even mid priced can cope with the field curvature so not a valid argument.

The f 7.9 doublets are capable, however compared to the Vixen fluorite do to its speed creates a noticeably larger exit pupil which for a dark site visit will pay back in spades. APM lens are made of ok-1/ok-4 which is fluorite like but you have the weight penalty of a triplet, returned with that brightness of the lens and contrast.

I presume why the Vixen is a one and only fluorite scope of this type is due to the glass available at the time.....  

Vixen used to offer a superb 102mm F6.5 ED doublet that had excellent colour correction, and delivered great planetary views when called upon to do so. Today Takahashi's FC100DC and DF have a ratio of 7.4, which is probably the lower limit while retaining its Apochromatic credentials. The Sky 90 was a fluorite doublet having an F ratio of 5.5 I think. 

Technosky offer an F7 ED doublet and there is Tak's super expensive FSQ 106 ED quad.

The performance gap between true fluorite and some modern ED glasses has closed considerably over the last 20 years or so, so fluorite isn't the only option.

I think if i were looking for a fluorite doublet with a low F ratio I'd go for the Tak DC or DF at F7.4. They are awesome under a dark sky. But if I wasn't too bothered about fluorite, I'd just grab myself a 102mm Starfield or Technosky.

[Stu]

4 hours ago, Deadlake said:

Modern EP's even mid priced can cope with the field curvature so not a valid argument.

Which eyepieces correct for field curvature?

[Deadlake]

9 hours ago, Stu said:

Which eyepieces correct for field curvature?

I was thinking of modern multi lens EP’s, say 20 mm upwards where the effects of field curvature would be more noticeable, usually termed as astigmatism.

Take a 20 mm XWA or maybe a 21 E these EP’s have been designed to work with F4 scopes to produce a flat image, of course the manufacturers do not put a spec on the EP, usually have to wait for observer reports like this one

Here Jerry is reporting the lack of astigmatism in the EP.

I take your point if you want a flat field then go with a Petzval design of add a field flatter to a scope, however placing the correction the EP to reduce astigmatism maybe a more practical approach.

 

[Stu]

22 minutes ago, Deadlake said:

I was thinking of modern multi lens EP’s, say 20 mm upwards where the effects of field curvature would be more noticeable, usually termed as astigmatism.

Although potentially related in certain systems, Astigmatism and field curvature are different effects so should be discussed separately. Good, wide afov eyepieces correct for edge astigmatism even in fast scopes.

Field curvature in refractors at least is worst at shorter focal lengths. The field curvature in the eyepiece can either reinforce or cancel out (or leave the same) the native field curvature of the scope. This means some combinations work well, others don’t.

I believe (though may be wrong), that the XWs were designed for Pentax’ spotting scopes which are short focal length so are likely to show less FC in refractors.

Some general discussion here:

https://www.cloudynights.com/topic/686030-field-curvature-and-eyepieces/

One key point made in here is that in order to design an ideal eyepiece, you really need to know the scope it is going to be used in. That’s generally not possible so I guess plenty of compromises get made.

My Genesis certainly has a very good, flat field and works beautifully with a 31mm Nagler. Interestingly a 30mm ES showed FC in the Genesis implying it had some curvature itself, or at least the combo was not optimal.

[Deadlake]

4 hours ago, Stu said:

My Genesis certainly has a very good, flat field and works beautifully with a 31mm Nagler. Interestingly a 30mm ES showed FC in the Genesis implying it had some curvature itself, or at least the combo was not optimal.

Using a flat field *might* need a completely different set of EP's.

An XWA 20 mm from memory seems a little flatter at the edges in a APM 105/f6.25 compared to a APM 130/f6. 
 

[plyscope]

This is my old GPD2 mount on a Berlebach Uni 18 set up for some lunar viewing with the Starfield 102 f7.

[MalcolmM]

I've put this mount on this thread before but this time the 100DC is on it. Very impressed how stable the whole setup is. Virtually no settling time after knocking the scope or focusing. For high powered lunar viewing a very quick and rough polar alignment is easy and sufficient.

Malcolm

[JeremyS]

1 hour ago, MalcolmM said:

I've put this mount on this thread before but this time the 100DC is on it. Very impressed how stable the whole setup is. Virtually no settling time after knocking the scope or focusing. For high powered lunar viewing a very quick and rough polar alignment is easy and sufficient.

Malcolm

Stunning 👍🏻👍🏻👍🏻

[F15Rules]

On 06/05/2022 at 14:07, plyscope said:

This is my old GPD2 mount on a Berlebach Uni 18 set up for some lunar viewing with the Starfield 102 f7.

"This is my old GPD2 mount"

Thanks for posting this..It seems odd to read of the GPD2 as being "old"..I think of the Polaris, Super Polaris (SP) and Great Polaris (GP) mounts as being "old"...your GPD2 still looks very modern and cool to my eyes 😎👍

That's a lovely setup!

Dave

[plyscope]

Hi Dave,

Not so old I agree, only in comparison to the Starfield 102 which is just a month or so.

I think I bought the GPD2 back around 2008.

Andy

[Pixies]

5 hours ago, MalcolmM said:

I've put this mount on this thread before but this time the 100DC is on it. Very impressed how stable the whole setup is. Virtually no settling time after knocking the scope or focusing. For high powered lunar viewing a very quick and rough polar alignment is easy and sufficient.

Malcolm

@MalcolmM - may I ask which model Berlebach tripod that is?

[MalcolmM]

Hi @Pixies, it's a Uni 8. It's very solid, very portable but it's maximum height is only 83cm. I compromised a little on the height in order to save a few kg in weight.

Malcolm

8 hours ago, Pixies said:

@MalcolmM - may I ask which model Berlebach tripod that is?

 

[Stu]

On 06/05/2022 at 14:07, plyscope said:

This is my old GPD2 mount on a Berlebach Uni 18 set up for some lunar viewing with the Starfield 102 f7.

What a great combination. The Starfield scopes look really nice, and reports sound like they perform really well too 👍.

It’s hard to beat a simple but solid EQ for high power planetary and Lunar observing. Nice!

[Franklin]

Thanks to everyone who replied to my "MT-1 spares" wanted ad, allowing me to get this vintage Vixen SP FL102S back to its original spec.

 

[900SL]

That's a great looking set up. Congratulations! 

[MalcolmM]

Every refractor man is allowed one reflector

This is right on the stated limit for this mount but I think it'll cope with it. Be interesting to check out it's stability under high power, though I've had no clear sky for weeks now!

Regardless, I think it looks a lovely combination

Malcolm

[F15Rules]

21 hours ago, Franklin said:

Thanks to everyone who replied to my "MT-1 spares" wanted ad, allowing me to get this vintage Vixen SP FL102S back to its original spec.

 

Just bloomin' gorgeous Tim!!

Dave

[F15Rules]

4 minutes ago, MalcolmM said:

Every refractor man is allowed one reflector

This is right on the stated limit for this mount but I think it'll cope with it. Be interesting to check out it's stability under high power, though I've had no clear sky for weeks now!

Regardless, I think it looks a lovely combination

Malcolm

Looks great..and at least you view through it like in a proper scope!😂😂

Dave

[Franklin]

10 minutes ago, MalcolmM said:

This is right on the stated limit for this mount but I think it'll cope with it

Lovely setup Malcolm, if the AP struggles in EQ mode you should try it in AltAz mode. You'd only need to buy the APZ base adaptor and it will transform the AP into the APZ (using the same AP weight bar). I did this and haven't regretted it at all, super slick AltAz grab n go and it puts the weight capacity up a notch.