TAK FSQ Fluorite versions

[kirkster501]

Hi, the older FSQ-106N fluorite version.  How do they compare to a 106 you could buy now?

Another question?  I notice many folks "upgrade" their 85 to 106.  I see loads of folks have done that.  Why is that?  Its a narrower FoV so potentially less useful I would have thought?

Thanks.

[swag72]

Olly has the older fluorite version of the 106, I'm sure he'll be a long soon! My understanding from him is that the older 106 hold focus better than the current model and only needs a tweak once a night!

I would say that most people move from the FSQ85 to the 106 for sheer imaging circle illumination. I don't think there's a chip made yet that the 106 can't cover, it has a massive circle of 80 odd mm, whereas the FSQ85 is in the 40's. This means if you want to use a 11000 for example, you will not get full illumination on the chip as the imaging circle is not big enough.

I am certain that had Olly not moved to a large chip 11000, he would have kept his FSQ85.

[ollypenrice]

Do people regularly move from 85 to 106? I did so very reluctantly indeed and for the reason Sara suggested; the 85 wouldn't quite cover the big Kodak chip which is actually larger than 35mm 'full frame' film. Also the 9 micron pixels are a bit big for the FL of the Baby Q. And another factor, for me, is that Tom (the famous Tom as we should now call him!  ) was about to install his own 106/11000 here so two identical scopes seemed like a good idea.

The older Flurorite scopes (Fluorite Super Quadruplets) are a pure design. The later ones, introduced because Tak wanted to stop using Fluorite, are a modified design. They are even better corrected and they can come down to F3.6. The 106N cannot be focally reduced. However, everyone I know who uses the 106ED (Flatfield Super Quadruplet) says that refocus between subs is pretty much essential. The use of automated focusing is almost universal with this instrument. Since I'm allergic to too much IT in the observatory I wouldn't fancy that. 

A word of caution; the refocus issue and the theory that the 106N is less affected is an 'Olly and Tom' concoction and shouldn't be taken as gospel. We find that our 106Ns hold focus quite well, needing one or two adustments per night. We know this is not true of the ED. Maurice Toet made a video of focus drift in his ED 106. I think, in fact that he made it here, under familiar conditions. So our theory is factually-based but not at all rigorous. Yves, who has had both 85 and 106EDs doesn't buy it, for instance. I'm convinced, though.

Although the 106 is bigger, and although all FSQs are excellent, I feel the 85 is the pick of the bunch. It really has no vices. A small pixel camera in an 85ED would quite possibly beat my present rig sampling at 3.5 arcseconds per pixel. However, the stunning FOV and high speed arising from the coarse sampling rate do make me love the new rig as well.

Once refunded £450 by Parcel Farce for poking a hole through the Tak flight case my 106N came it at under £2K. Since it clearly takes more than a fork lift truck in full flight to hurt an FSQ I'm going to declare myself happy!!!

Be aware that the 106 is a big scope. Short but very hefty.

Olly

[kirkster501]

Thanks guys.

Wow, the 106N cannot have a FR?  Really?  Well, that's good to know, thanks for pointing it out.  But that would mean one cannot cover wide fields easily with the 106N, and wide field is my intended purpose.  Thinking cap on.....

I am on the lookout for a FSQ to use with my 460, I got a good bonus this month.  They are like hens teeth they are so rare when used.

Steve

[ollypenrice]

Well, you can do widefield with the 106N... and the 11 meg. It covers a whopping 3.9 x 2.6 degrees. I'd call that wide!!  But, as you say, it won't be that wide with the 460. The 460 at 328mm (ie reduced) in the Baby Q would give you 2.18 x 1.74, so 3.79 square degrees (as compared with 10.14 square degrees from the 106N/11 meg.)  However, the sampling rate for the 460/reduced Baby Q would be fast at 2.86 arcsecs per pixel and yet reasonably resolved. Tom and I accept lost resolution at 3.5 arcsecs per pixel but we eat up signal, particularly narrowband, like there's no tomorrow.

With a Baby Q you'd be wasting quite a lot of that expensive flat field in the 460 but, on the other hand, you'd be using an exquisite camera in an exquisite telescope, as Sara is rather good at demonstrating! It is also an incredibly productive combination since guiding errors would have to be bad to get you with a small short FL scope. And here's a thought; take your widefield image in HaLRGB or whatever with the reducer. Then whip out the reducer and shoot some more luminance at native 450mm for such parts of the image as cary intense fine detail. (Trapezium in M42, galaxy cores, etc etc.) Then use Registar to resize the 450mm data to overlay onto the widefield. Works like a charm.

Yes, you need a Baby Q    and there is nothing at all out there which can compete with it. I can't think of another instrument for which you can say this. (Eg the TV NP101 takes on the FSQ106.)

lly

[gingergeek]

So Olly what would be the best CCD to partner a FSQ85 and use as much of the flat field as possible ?

[kirkster501]

Thanks for the commentary Olly.  How would the 106ED compare then?  The one that *can* take the 0.73 FR?  That'd give some useful combinations with and without the FR.  I still like the idea of the 85 though.  That sure ticks a lot of boxes.

[ollypenrice]

So Olly what would be the best CCD to partner a FSQ85 and use as much of the flat field as possible ?

Maybe an 8300 with smallish pixels and a decent chip size? Atik 383 or the more luxurious QSI?

Thanks for the commentary Olly.  How would the 106ED compare then?  The one that *can* take the 0.73 FR?  That'd give some useful combinations with and without the FR.  I still like the idea of the 85 though.  That sure ticks a lot of boxes.

You'd be spending even more on an even more enormous flat field that you weren't going to use. The 106 has an 88mm diagonal. That is mind blowing and you are paying for it but not using it. That's the drawback. The 85 has a 44mm circle and can be reduced to F3.9. That's not radically different from F3.6. The 85 also seems to hold focus better than the ED106. I found mine often ran all night without a refocus.

Olly

[steppenwolf]

Maybe an 8300 with smallish pixels and a decent chip size? Atik 383 or the more luxurious QSI?

The QSI 683WSG/FSQ85 is the combination I'm looking into right now  - all the boxes are ticked so far but I still need to make sure that it will all work with the 0.73x reducer and I believe that this would make for a killer combination.

[ollypenrice]

The QSI 683WSG/FSQ85 is the combination I'm looking into right now  - all the boxes are ticked so far but I still need to make sure that it will all work with the 0.73x reducer and I believe that this would make for a killer combination.

Are you thinking that it might vignette, Steve? I don't think it would because the QSI has the filters so close to the chip. I've imaged with two visiting QSI 583s in the 85 but unfortunately I can't remember if we ever used the reducer. Given that we'd have needed to get the chip spacing right I rather doubt that we would have done so. I wonder who might be able to give chapter and verse on this? Dave_Galera uses an Atik 383L/Baby Q but has 2 inch filters. I think Yves may have tried the combination though. I'll ask him.

There's an image taken here by Chris Baker using our 85 and a 583 on Ian King's site. It's the Elephant Trunk about half way down. That was at 450mm.

http://www.iankingimaging.com/show_gallery.php?id=50

Olly

[kirkster501]

I need a sanity check re the FSQ85 and CCD chip size please then Olly/Steve....

Point taken about the 106 having such a large diameter light cone that it would be wasted somewhat with a Atik460.  Yes that makes sense.  But then you also say much of it will be wasted from a 85 as well Olly?  So does that mean a FSQ telescope is rendered  "wasted* unless you have a huge, HUGE chip?  Lets face it, a Atik 460 is not exactly a cheap or small chip! Where is the tipping point in this chip/light cone discussion do you think?

My other thinking here is that a 85 or 106 - especially the 106 - would also make a superb refractor instrument as well for lunar observation, one of my great interests.  There is something magical about refractors for lunar observation in my opinion.  That said, the 106 is silly money and a bit more than I am prepared to spend - certainly as brand new. I am 99% certain that the 85 is the way to go and as such I am on the lookout for one.  I don't believe there is a single box it does not tick for wide field.  That would give me best of both worlds: a great wide field scope and also a RC scope to get a little closer.

Thanks, Steve

[ollypenrice]

Yves tells me he hasn't tried his QSI with reduced Baby Q but thinks flats would sort it.

I don't think anyone else can tell you what is reasonable flat field 'waste,' really. The 460 has, I think, a diagonal of 19.42mm. The 85 has a native circle of 44mm and a reduced one of 42mm (clearly overkill) whereas the 106 has a native circle of 88mm. That is more like mass extinction than overkill! The largest chip currently used by amateurs has a diagonal of 50.9mm (lucky devils!) so that gives some perspective on CCD sizes.

Don't buy a 106N for visual. It doesn't have enought backfocus for a diagonal. Well, the Japanese hava a tradition of viewing 'straight through' but I'd find that crippling! You can use a diagonal with the shorter 106EDs though, and with the Baby Q. I've looked through the Baby Q quite regularly. The view is simply perfect for the aperture and the contrast fantastic, allowing the Hamburger in the Leo Triplet to show fairly easily.

Oh, there is also a thing called 'The extender Q' which extends the FL of all of the FSQs. I have one of these but am entirely at a loss as to how it works! I doubt it will see much action but you never know.

Olly

[Velvet]

I have the 106 FSQ ED with H694  and it is a peach  i dont seem to have the focusing issues mentioned above until after about

3 hours imaging.  There is a bit of drift then but not much. 0.73 reducer gives a good wide field. The 85 is also very good as a friend of mine has one with the Atik 460.

i would recommend either, but really its personal choice and depth of pocket

velvet

[ollypenrice]

Good that you don't get the focus drift, Velvet. One thing I do every night is run the dew heater permanently in hopes of it slowing the cool down. I don't know if it helps but I do it anyway, and might try heating the rear element in winter as well.

Olly

[Astroscot2]

Don't buy a 106N for visual. It doesn't have enought backfocus for a diagonal. Well, the Japanese hava a tradition of viewing 'straight through' but I'd find that crippling! You can use a diagonal with the shorter 106EDs though, and with the Baby Q. I've looked through the Baby Q quite regularly. The view is simply perfect for the aperture and the

Olly, you sure about that?  my own FSQ focuses perfectly well with a diagonal on the back .  Not having a goto mount I would often visually check my FOV and position prior to attaching the camera.  Ive had some great views though my 106N with diagonal in-situ. .

[Jessun]

The best wide field camera for short FL scopes is not yet shipping...

Look out for the KAI-29050 chip! Full frame, small pixels...

/Jesper

[ollypenrice]

Olly, you sure about that?  my own FSQ focuses perfectly well with a diagonal on the back .  Not having a goto mount I would often visually check my FOV and position prior to attaching the camera.  Ive had some great views though my 106N with diagonal in-situ. .

Aha, no, I was just told that this was so. I should be more careful. Thanks for this correction. However, you'd need to be mighty careful not to touch the rear element with the nosepiece of many diagonals, I think? It really is close to the back.

Still, I look forward to trying the Veil Complex in the FSQ since at 530mm I can fit it all in with a Nagler.

Cheers,

Olly

[Astroscot2]

No worries Olly,  yes you need to be careful when inserting diagonals or barlows,  have a look through your FSQ next chance you get.

Mark

[melsky]

I need a sanity check re the FSQ85 and CCD chip size please then Olly/Steve....

Point taken about the 106 having such a large diameter light cone that it would be wasted somewhat with a Atik460.  Yes that makes sense.  But then you also say much of it will be wasted from a 85 as well Olly?  So does that mean a FSQ telescope is rendered  "wasted* unless you have a huge, HUGE chip?  Lets face it, a Atik 460 is not exactly a cheap or small chip! Where is the tipping point in this chip/light cone discussion do you think?

I'm sure Olly won't like this but you could do as I do with my FSQ85, my sensor of choice is all wrapped up inside a DSLR body

Mel

[perfrej]

29050... Available and shipping from FLI and Apogee... Soon from QSI - with filter wheel as always! On my short-list!!!

Droooooool!

/per

[Jessun]

Aha! Didn't know...

But QSI is on the forefront on this. Software assisted CCD adjustment, built in memory for calibration frames, network.....

Thread creep warning.... but I'm sure OP Steve doesn't mind - we're both firmly planted in the 460EX camp now for the foreseeable future...

/Jesper

[steppenwolf]

Are you thinking that it might vignette, Steve? I don't think it would because the QSI has the filters so close to the chip.

Hi Olly, thanks for this observation and the other detail that followed in your post. It was not so much the risk of vignetting that concerned me (although I could do without it (!) but I would hope that flats would resolve this if there was any), it was more a case of the physical spacing. A figure of 72.2mm has been quoted by both Sara and now from data I have found on Anacorte's website but this diminishes rapidly when you include the (required) Takahashi adaptor (CA35 M56 to M54).

[swag72]

You'd have more than enough space Steve I'm sure of it. I've got an adapter in there after my reducer thing that you mention, a couple of Delrins and a seperate filter wheel.

[ollypenrice]

Maybe Steve's thinking about back focus with the QSI's built in OAG though? I don't know the camera's 'front to chip' distance in this configuration.

Olly

[Brian Nordstrom]

Well, you can do widefield with the 106N... and the 11 meg. It covers a whopping 3.9 x 2.6 degrees. I'd call that wide!!  But, as you say, it won't be that wide with the 460. The 460 at 328mm (ie reduced) in the Baby Q would give you 2.18 x 1.74, so 3.79 square degrees (as compared with 10.14 square degrees from the 106N/11 meg.)  However, the sampling rate for the 460/reduced Baby Q would be fast at 2.86 arcsecs per pixel and yet reasonably resolved. Tom and I accept lost resolution at 3.5 arcsecs per pixel but we eat up signal, particularly narrowband, like there's no tomorrow.

With a Baby Q you'd be wasting quite a lot of that expensive flat field in the 460 but, on the other hand, you'd be using an exquisite camera in an exquisite telescope, as Sara is rather good at demonstrating! It is also an incredibly productive combination since guiding errors would have to be bad to get you with a small short FL scope. And here's a thought; take your widefield image in HaLRGB or whatever with the reducer. Then whip out the reducer and shoot some more luminance at native 450mm for such parts of the image as cary intense fine detail. (Trapezium in M42, galaxy cores, etc etc.) Then use Registar to resize the 450mm data to overlay onto the widefield. Works like a charm.

Yes, you need a Baby Q    and there is nothing at all out there which can compete with it. I can't think of another instrument for which you can say this. (Eg the TV NP101 takes on the FSQ106.)

lly

Hi Olly , I have a mate down here that's just got  a beautiful Vixen  DED108SS  direct competition to the Takahshi  FSQ106  I believe ? , its a sweet AP rig that's for sure , as good as his FL102S visually as well , so now there are 3 in the ring the  FSQ , NP and DED  cool ,

But I  also hear the Vixen have a  101mm f 3.9 coming , based on the Pentax ?  all the best for AP , if you can afford  (find) one .

Brian.