Vixen VSD100 f3.8 5-element Apochromat

[FLO]

The new Japanese-made Vixen VSD 100 f3.8 5-element apochromat is shaping up to be a very desirable telescope.

It is essentially an upgrade of the Pentax 4-element SD100 with an additional lens element and new lens coatings for a higher level of optical performance. The 5-element design is made from Japanese Ohara glass and includes an SD and ED element for very high colour correction. The new lens coatings have been specially developed for the individual glass types.

The flat, evenly illuminated field will cover even 645 medium format sensors.

A large precise helical focuser is also included.

A 3-element focal reducer (0.79x) and a 4-element tele-extender (1.58x) will also be available. When used with these accessories, the VSD100F3.8 can be transformed to an even faster 300mm f3 astrograph or a versatile 600mm F6.0 telescope for both imaging and visual astronomy. 

UPDATE: The Vixen VSD100 f3.8 has arrived  

[FLO]

A close-up to whet your appetite

[jnc71106]

that looks very nice....oh and expensive

[NickK]

It looks like Vixen have attempted to really make a go of this series.

I think they don't mean a tele-extender to 300mm when the scope is naturally 380mm!

[Earl]

OOO looking like a dream imaging scope !!!

[DaveS]

So are we looking at Tak price levels?

Can't afford one yet, but when I retire.....

[FLO]

It looks like Vixen have attempted to really make a go of this series.

I think they don't mean a tele-extender to 300mm when the scope is naturally 380mm!

You are right, of course

It would have been easier if I had simply cut/pasted the description from our website. A 3-element focal reducer (0.79x) and a 4-element tele-extender (1.58x) will be available. When used with these accessories, the VSD100F3.8 can be transformed into a super-fast 300mm f3 astrograph or a versatile 600mm F6.0 telescope for both imaging and visual astronomy. Otherwise the specification is 380mm f3.8 (which is still plenty fast enough for most people).

Steve

[FLO]

that looks very nice....oh and expensive

So are we looking at Tak price levels?

Yes, I am sure we are. The Vixen is a modern Japanese-made astrograph.

[NickK]

That's a nice scope - the 105SDP does 670mm at f/6.38 .. so the tele-extender really will make it a flexible scope (even at "only" f/6!).

[DaveS]

On my retirement list then. When I downsize I should have funds for a serious astrophotography rig.

Looks like it could be used on an Astrotrac......

[dmahon]

Do you have to use a specific spacing to get a flat frame, and if so, is it more than the 55mm that some manufacturers hamper their scopes with?

Is it easy to motorise t focuser?

[E621Keith]

Any news on the price yet?

The price tag of Pentax scopes used to made Tak's looked cheap, but this is a Vixen so it will probably be more affordable.

I don't think it will cost a lot more than a FSQ106, but I also doubt it will be much cheaper. I guess £5k for the OTA and around £1.5k for the reducer.

Do you have to use a specific spacing to get a flat frame, and if so, is it more than the 55mm that some manufacturers hamper their scopes with?

.....

A flat field scope like the SDUF and FSQ have flat focal planes. These scope have no field curvature when they are in focus, so there is no need to worry about spacers.

[Naemeth]

I'd love one. Afraid it might be a while before I can afford one though .

[NickK]

it takes after the SDP.. adding a 2x televue powermate 2" actually adds some curvature..

The focuser will be a boon for robo-focusing too.

[FLO]

Any news on the price yet?

Not yet, but we'll update our website and post details as soon as they come in.

The price tag of Pentax scopes used to made Tak's looked cheap, but this is a Vixen so it will probably be more affordable.

We hope you are right. The Vixen VSD 100 is a telescope designed and manufactured for performance, not price. This is not a budget telescope.

A flat field scope like the SDUF and FSQ have flat focal planes. These scope have no field curvature when they are in focus, so there is no need to worry about spacers.

Spot on. You only need to attach and focus your imaging sensor or eyepiece for optimum performance. Easy

it takes after the SDP..

The Pentax heritage is clear, which is why we are so excited to see this model enter the market. Pentax and Canon optics are behind many of the very best brands

[Naemeth]

The ETA is described as Autumn, is it more likely to be mid-September / October than this month - or do you have no further details on that?

[E621Keith]

I just noticed in the Vixen announcement, it claimed the Strehl intensity of the VSD is 10% better than a 4 element Petzval. If I remembered correctly, Pentax Petzvals had Strehl ratio of 0.96 or better, so what could this 10% mean? Obviously it's impossible to have a Strehl ratio of 1.06

[Naemeth]

I just noticed in the Vixen announcement, it claimed the Strehl intensity of the VSD is 10% better than a 4 element Petzval. If I remembered correctly, Pentax Petzvals had Strehl ratio of 0.96 or better, so what could this 10% mean? Obviously it's impossible to have a Strehl ratio of 1.06

Keith, could this be against 'budget' Petzvals like this?

http://www.telescopehouse.com/acatalog/Revelation_62mm_Four_Element_f8.4_Achromatic_Refractor__Black_.html

[FLO]

The ETA is described as Autumn, is it more likely to be mid-September / October than this month - or do you have no further details on that?

We don't have an official ETA but are predicting October. I will be surprised if it is any later than that because the busy season begins October when the nights become long and dark.

[dmahon]

it takes after the SDP.. adding a 2x televue powermate 2" actually adds some curvature..

The focuser will be a boon for robo-focusing too.

I'd have thought there were far more auto focus units already developed for regular focusers - were there many adapters for the SDUF?

[ollypenrice]

This is good news. I've seen the older Pentax in action here and, although excellent and incredibly fast, it didn't have the FSQ level of colour correction. A redesign and an extra element might easily sort that. If it can hold focus during cooldown it will certainly challenge the Tak 106. At F3 it would surely be the fastest production apochromat in history, no? The later FSQs reduce to F3.6. When you consider the extreme difficulties associated with these F ratios in reflecting designs then something like this stands out clearly. F3 that just worked? Yes indeed!

Olly

[E621Keith]

Keith, could this be against 'budget' Petzvals like this?

http://www.telescope...or__Black_.html

Good point. May be they compared the VSD with their DED-108SS rather than Pentax's 100SDUF

SA,CA, pinched optics. The DED-108ss had it all.

http://homepage3.nifty.com/cz_telesco/vixen%20DED108SS.JPG

[melsky]

"At F3 it would surely be the fastest production apochromat in history, no?"

Hmmmm 300mm and fast, it's a nice looking scope but how much better would it be than a secondhand Canon 300mm F2.8?

Mel

[ollypenrice]

"At F3 it would surely be the fastest production apochromat in history, no?"

Hmmmm 300mm and fast, it's a nice looking scope but how much better would it be than a secondhand Canon 300mm F2.8?

Mel

This remains to be seen, but fair point... Camera lenses can be great but there are a few issues, I think, and while you do pay for things you don't need with lenses you also don't get things you do need, like focusers fine enough for astronomical use at these F ratios. Using lenses with CCD does take a fair bit of improvising while a scope is made for that one job.

Olly

[E621Keith]

... At F3 it would surely be the fastest production apochromat in history, no? ...

Borg made a 125mm F2.8(native) a few years ago, so this is not the fastest 'apo' astrograph in history, but it is probably the fastest in production.