Tak FSQ 85 set up questions

[gnomus]

Apologies for starting another FSQ85 thread, but I'm a little uncertain as to how I should integrate the Tak into my existing set up. The telescope will be housed in a ROR observatory. Currently, I have an ED80 for imaging and an ST80, which sits atop the ED80, for guiding. For the moment I have a CGEM mount.

The Tak can come with a clamshell-style bracket (not sure if that is the correct term). This looks great but seems to allow only one fixing point for a guide scope. Therefore, should I forego the Tak bracket and get rings? If so which ones? An alternative would be to use the Tak bracket along with a side-by-side mounting arrangement. This would allow me to keep the ED80 in the system. I could use the ED80 (and its better focusser) as a guide scope. I could also continue to use the ED80 with the Quark for solar observing/imaging (for now I am a little nervous about pointing my expensive Tak straight at the sun!!!).

I already have 3 finder-scopes, including one RACI. I don't think I need the Tak finder-scope. Will my Skywatcher finderscope fit in the Tak finder-scope bracket? If not, can I get an adapter of some sort?

For imaging, the Tak will be attached to an Atik EFW 2 and 383L. What connectors will I need to connect the two together? Also, will I need any sort of extension tube to achieve focus with the camera?

For the moment, I will probably not buy the reducer given that the 383 has a relatively large chip. I may add this at a later date, however.

I would be very grateful for thoughts.

Regards

[steppenwolf]

Therefore, should I forego the Tak bracket and get rings? If so which ones?

Most users buy a set of Parallax Instruments tube rings designed for this particular instrument. Ian King sells them and they work but boy are they overpriced and very averagely finished!

Will my Skywatcher finderscope fit in the Tak finder-scope bracket? If not, can I get an adapter of some sort?

I had to modify a Sky-Watcher finder base to fit the Tak 85 - not a difficult task as I recall.

For imaging, the Tak will be attached to an Atik EFW 2 and 383L. What connectors will I need to connect the two together? Also, will I need any sort of extension tube to achieve focus with the camera?

You are in for a treat here (NOT!) Takahashi will require you to buy several different adaptors to get you to the right place and as I don't have my Tak 85 any more, I no longer have the details to helpyou myself but I suspect that someone with up-to-date info will be along shortly.

I hope you enjoy your purchase.

[ollypenrice]

Here's a picture of how I did it. (I do know that's a solar scope on there, not a guide scope, but the system allowed me to swap solar and guiding in a jiffy!)

I attached a Baader mini saddle plate to the top of the clamshell using an appropriate bolt. (Altair Astro do a nice mini saddle as well, a bit beefier.) Both solar and guide scopes then had Vixen dovetails allowing for quick change and very easy adjustment of  balance in Dec. Slide the piggyback scope fore and aft.

This is shown without reducer so, as you can see, you need an extension from Tak to reach focus. I'm afraid I cant remember how long it was but Sara will know. Or you could measure the main scope tube on the image and get a scale from that, allowing you to estimate the focal distance. Camera plus FW added about 38mm.

Also note the Tak offset foot for the clamshell. The scope is very rear-heavy so needs to be offset forwards. You don't need the Tak offset foot as seen here. If you have a long Losmandy dovetail you can put the clamshell near the front of it and gain the offset that way. (Edit. I think. Hmmm, maybe on the 85 the focuser would foul the plate because the clamshell isn't tall enough on its own. Easy enough to check that, though.

Some will advise against a clamshell for imaging but mine worked fine and Tom's FSQ106 is happy with exactly the system above as well.

Olly

[DirkSteele]

I could also continue to use the ED80 with the Quark for solar observing/imaging (for now I am a little nervous about pointing my expensive Tak straight at the sun!!!)

Regards

Unless the Quark uses a front aperture energy rejection filter do not use the Tak as the rear elements in the FSQ could be damaged by the focused sunlight.

[gnomus]

So no love for the side-by-side option featuring FSQ85 and ED80?

[Chris]

"for now I am a little nervous about pointing my expensive Tak straight at the sun!!!"

I'm glad Dirksteele gave you the heads up regarding rear element scopes, if I melted a babyQ I would sob like a baby    

[gnomus]

"for now I am a little nervous about pointing my expensive Tak straight at the sun!!!"

I'm glad Dirksteele gave you the heads up regarding rear element scopes, if I melted a babyQ I would sob like a baby    

I'm glad he did too!!!!!!!!

I wonder if this strengthens the argument for a side-by-side arrangement...

[steppenwolf]

Nothing wrong with a side by side arrangement, I sometimes use one myself:-

[gnomus]

Do you have a particular recommendation as regards a dual saddle?

[ollypenrice]

Nothing wrong with a side by side arrangement, I sometimes use one myself:-

dual_1.png

I use side by side as does Steve, but I wouldn't entirely agree that there's nothing wrong with it.

The thing I dislike about it is that you can't image past the meridian for as long because the width of the payload makes it collide with the pier earlier. Also, if you have obstructions like an observatory wall or trees or rooves, etc, the scope which is offset to the west will be blinded rather earlier than it would if in the middle.

I greatly prefer a piggyback arrangement where possible but with a pair of FSQ106 OTAs I think it would be pushing our luck... 

Olly

[steppenwolf]

Do you have a particular recommendation as regards a dual saddle?

I researched this very carefully before buying and decided that the ADM unit was the best one - it is not the prettiest but it is the sturdiest as far as I discovered at the time (about 3 years ago).

[steppenwolf]

The thing I dislike about it is that you can't image past the meridian for as long because the width of the payload makes it collide with the pier earlier.

This is a fair comment BUT if you are going to make a meridian flip at some time during your session, why not just bite the bullet and do it when the time comes? I just know that a can of worms has now been opened but, I'm up for learning new stuff as always!!

[ollypenrice]

This is a fair comment BUT if you are going to make a meridian flip at some time during your session, why not just bite the bullet and do it when the time comes? I just know that a can of worms has now been opened but, I'm up for learning new stuff as always!!

Indeed. On occasion (and more often than by random chance because of the way stars rise and set and the sun spoils the party) you may not get all that long after the Meridian and the time you can use can be exploited by tracking through fliplessly. This applies particularly when imaging at low elevation when it's often possible to run long enough past the Meridian to have the counterweights well up in the air.*

The reduction of width isn't always important but in my own observatory I've noticed that the dual Tak is in need of significantly more flips than was the single 14 inch when that was on the same mount.

Olly

*Edit. I may see this more than many UK based imagers because I can image very close to the horizon.

[steppenwolf]

That's an interesting explanation, Olly, I knew there would be something in it - sadly though, not for me as a low horizon is something I never see from my location

[ollypenrice]

That's an interesting explanation, Olly, I knew there would be something in it - sadly though, not for me as a low horizon is something I never see from my location

...and I dare say you've mastered an accurate and automated flip which solves the problem by another means. With our Argonavis setup we still do a manual flip which takes a while.

Olly

[steppenwolf]

...and I dare say you've mastered an accurate and automated flip which solves the problem by another means.

There is that too ....... :grin:

[gnomus]

Yikes, that all seems a bit complex. My own situation is that I live in a very flat area. I can get to my eastern horizon (just about). No other horizons are available to me.

The fact that I cannot use the Tak for solar does make me lean more towards a Tak & ED80 arrangement of some sort. I can then swap these out to use my SCT, as and when required. I am seriously thinking about one of these Mesu-jobbies at some point in the future, but will need to persist with the CGEM for now.

It would still be helpful to know the part numbers I will need to connect the Tak to my Atik gear (and achieve focus). Can anyone help with this?

[Barry-Wilson]

Steve,

The Tak charts are helpful, http://www.takahashi-europe.com/en/FSQ-85ED.systemcharts.php, and Ian King can supply the CA35 (Sky 90) and the aux ring: Ian will gladly advise you.  Without reducer, as the Tak has a native flat field, you can connect the EFW2 by a number of means, eg using the nosepiece of the EFW2, the Tak wide t-mount as per system, or add the Baader click lock for Takahashi, and simply focus.

If using the reducer, you need a different CA35 (TSA102) the Tak wide T-mount (which converts the M54 thread into a male T2 and has an optical thickness of 12mm) leaves too little space for a T2 spacer to connect to the EFW2 using the 383L+ (this isn't a problem with the 460EX which has a backfocus of 13mm, but losing the additional 4mm with the 383L+'s backfocus of 17mm only leaves about 3 mm or something from memory).  Telescope Express do a thinner M54 to T2 which I purchased and then I could use T2 spacers to get the required 72.2mm + third filter thickness metal/metal backfocus, http://www.teleskop-express.de/shop/product_info.php/language/en/info/p203_TS-Adapter-from-M54-to-T2---low-profile-for-Skywatcher-Crayford-focuser.html.

As Olly said, the OTA/ccd combination is very rear heavy and a long losmandy does help.

HTH

Barry

[steppenwolf]

the OTA/ccd combination is very rear heavy and a long losmandy does help.

This is good advice - I had to mount my Parallax Tube Rings towards the front end of the Losmandy bar and mount the rear of the bar in saddle clamp to achieve balance.

[gnomus]

Steve,

The Tak charts are helpful, http://www.takahashi-europe.com/en/FSQ-85ED.systemcharts.php, and Ian King can supply the CA35 (Sky 90) and the aux ring: Ian will gladly advise you.  Without reducer, as the Tak has a native flat field, you can connect the EFW2 by a number of means, eg using the nosepiece of the EFW2, the Tak wide t-mount as per system, or add the Baader click lock for Takahashi, and simply focus.

If using the reducer, you need a different CA35 (TSA102) the Tak wide T-mount (which converts the M54 thread into a male T2 and has an optical thickness of 12mm) leaves too little space for a T2 spacer to connect to the EFW2 using the 383L+ (this isn't a problem with the 460EX which has a backfocus of 13mm, but losing the additional 4mm with the 383L+'s backfocus of 17mm only leaves about 3 mm or something from memory).  Telescope Express do a thinner M54 to T2 which I purchased and then I could use T2 spacers to get the required 72.2mm + third filter thickness metal/metal backfocus, http://www.teleskop-express.de/shop/product_info.php/language/en/info/p203_TS-Adapter-from-M54-to-T2---low-profile-for-Skywatcher-Crayford-focuser.html.

As Olly said, the OTA/ccd combination is very rear heavy and a long losmandy does help.

HTH

Barry

Barry

Thanks very much for pointing me towards these charts.  So, if I understand correctly, for attaching my EFW2/383L to the Tak (without reducer), I need (from Camera to Scope), the following:

Wide T Mount (needs to be bought separately)

CA35 (TSA-102) [TKA 23201] (needs to be bought separately)

Aux Ring (FB) [TKA23250] (needs to be bought separately)

CAA [TKA23200] (supplied with scope)

Coupling (DT) [TKP37001] (supplied with scope)

Are the bits in square brackets the Takahashi part numbers?

Does that seem about right?  Seems a bit complicated but ho-hum....

Regards

Steve

[gnomus]

This is good advice - I had to mount my Parallax Tube Rings towards the front end of the Losmandy bar and mount the rear of the bar in saddle clamp to achieve balance.

I can do that.  If I go side by side I will get the clamshell, otherwise I will try to source some of these rings.

Will the forward limit be dictated by the camera or will it clear all of that?

[steppenwolf]

Will the forward limit be dictated by the camera or will it clear all of that?

The forward limit may well be dictated by the camera - either the camera or filter wheel *may* foul the mount but this is quite simple to fix. I use an adjustable balance weight comprising a piece of Vixen dovetail bar and an old counterweight as shown below to allow the telescope/camera combination to move backwards. When I am reviewing cameras of different weights, this little counterbalance system becomes invaluable and on my latest system it is infinitely variable because I have a Vixen saddle clamp attached to the top of the tube rings of my imaging telescope and I simply slide it to get the correct balance.

[Barry-Wilson]

Barry

Thanks very much for pointing me towards these charts.  So, if I understand correctly, for attaching my EFW2/383L to the Tak (without reducer), I need (from Camera to Scope), the following:

Wide T Mount (needs to be bought separately)

CA35 (TSA-102) [TKA 23201] (needs to be bought separately)

Aux Ring (FB) [TKA23250] (needs to be bought separately)

CAA [TKA23200] (supplied with scope)

Coupling (DT) [TKP37001] (supplied with scope)

Are the bits in square brackets the Takahashi part numbers?

Does that seem about right?  Seems a bit complicated but ho-hum....

Regards

Steve

Essentially, yes.  It does take a while to understand the Tak system I must admit.

I would however not purchase the Tak wide T mount.  Whilst it will work without the reducer, if you choose at a later date to use the reducer, the Tak wide T mount is too thick to use with the Atik 383L+ and EFW2 combination.  Using the Tak wide T mount I found I only had about 3mm (or something like that, might have been 4mm can't remember exactly: the point is it was too little in practical terms to make up - too short for a spacer, too long for delrin rings) between EFW2 and the T2 thread on the Tak wide T mount.  This is insufficient space to insert a T2 spacer and use up all of the thread length on the wide T mount.  So I purchased the Telescope Services M54 to T2 adapter instead (linked to in my post above).  This has a shorter length allowing you more 'space' to insert T2 spacers when you use the reducer.  The TS adpater will of course work fine in the optical train without the reducer at the native F5.3.

To aid in imaging near the zenith, when I used the EFW2, I set up the EFW2 with the cable connection side upper most, thereby enabling the underside of the optical train to get closer to the pier without contacting it.  The ccd attachment method of the EFW2 allows you to set the ccd at any angle to the EFW2.

HTH

Barry

[gnomus]

Barry

I won't quote your extensive post, but thanks again for your assistance. This is helping me greatly.

Steve

[Barry-Wilson]

No problems Steve.

For mounting, I know you're considering all of your options, however, I would be tempted to forego a dual side-by-side mount and mount a guide scope (whether ST80 or finderguider) on a dovetail on top of the FSQ.  This will be symmetrical and will aid balance.  For long subs at fast focal ratios my preference would be to minimise any possible flexure, minimising components in the system to aid balance, guiding, rotation artefacts etc.  It will mean more swaping and changing I appreciate, and there are many folk who have eliminated potential gremlins in dual mounts, of course: there's always more than one way to skin a cat.

Good luck!

Barry