Ovoids with Mesu and Tak FSQ 85

[swag72]

Not sure how an auto focuser routine such as one that SGP uses will work if one should focus on the corners.

[libraryman]

That's an interesting thread and I've heard of the method before, however if you focus with SGpro multiple star focus surely that would not work but a Bat mask might!

Would a mask show the issue in the corners relative to the centre?

Ray

[strutsinaction]

Would a mask show the issue in the corners relative to the centre?

Ray

That's what I was thinking and something I will try. It just seems odd though.

Regards

John

[Mike Hawtin]

Very late to this thread and perhaps I'm just making the waters even muddier but for what it's worth I have a problem with odd star shapes with a Borg 71FL which I suspect is down to focuser movement.  Attached are two images showing a very variable error over a two hour twenty minute run of twenty minute exposures, the camera used was a QHY9.  Perhaps it might be worth while doing similar in your case, at least it would rule out one of the possible causes.

Regards

Mike

[gnomus]

The latest advice (received today) from my Takahashi dealer (apparently endorsed by the importer) is:

"To assemble the components and expect them to work at this level is not realistic."  

[sharkmelley]

The latest advice (received today) from my Takahashi dealer (apparently endorsed by the importer) is:

"To assemble the components and expect them to work at this level is not realistic."  

Whereas their website (http://www.takahashi-europe.com/en/FSQ-85ED.optics.php) says the following:

"As on the FSQ-106ED, the built-in field flattener, perfectly designed and manufactured, gives an almost homogeneous flat field of 44mm diameter. At prime focus, at the edge of field (22mm from the optical axis), stars remain pinpoints, including on pixels of 7µ width."

Mark

Edited November 16, 2015 by sharkmelley

[Mike Hawtin]

The latest advice (received today) from my Takahashi dealer (apparently endorsed by the importer) is:

"To assemble the components and expect them to work at this level is not realistic."  

That's disgraceful.  I was saving for one of these scopes but I think I'll look elsewhere now.  Gnomus if you are not comfortable with naming and shaming on an open forum I would be grateful if you would let me know who to avoid by pm.

Thanks

Mike

[RobRob]

That's disgraceful.  I was saving for one of these scopes but I think I'll look elsewhere now.  

same here...

[ollypenrice]

The latest advice (received today) from my Takahashi dealer (apparently endorsed by the importer) is:

"To assemble the components and expect them to work at this level is not realistic."  

This is not just disgraceful, it is plain potty. Why on earth should a refractor of around F5 not 'just work?' It is hardly an insanely fast astrograph and that is the whole point of buying an FSQ. It's a 'sanely fast' astrograph and should be simple to use. We really have heard some strange ideas from Gnomus' vendor on this thread. I have literally thousands of hours of DS imaging time logged on three Tak FSQ instruments. The first was my Baby Q, bought new, and now used to well known good effect by Sara (with the very 8300 chip which the retailer considered, bizzarely, to have too-small pixels. It is probably the most-used chip with the Baby Q, world-wide.) The other two scopes are second hand FSQ106Ns belonging to myself and Tom O' Donoghue, the rig which just produced runner up image in the Astrophotographer of the Year competition. To put the second-handedness of my own scope into context, it arrived after Parcel Force had bashed a hole through it's flight case.

Not in the first flush of youth, then? No, not really. But does it 'just work?' Of course it does! So does Tom's. So did my Baby Q. So do the FSQs (two of them) working in my robotic shed on behalf of their owners. (No, one of them needed the focuser tightening, to be fair.) And so did the three visiting Baby Qs belonging to guests here and whose images I helped process (including ones taken with three micron pixels.)

The FSQ isn't a Hyperstar or some other bit of optical madness built without regard to the harsh realities of engineering. It's supposed to work and most of them, in my experience, do work - even after Parcel Force have molested them.

I smell snake oil.

Olly

[Tom OD]

As I having a sneeky read at work I cant go through all the pages, but this is a great thread.

Do we havea stored file of all optical star mis shapes with known fixes anywhere on this forum? We should include unknown issues to I guess.

I brought a 3rd Tak to Ollys last year and set up quickly to get the first night running. I had out of focus stars on the right hand side, and pin point on the left. A lovely gradient in fact left to right. I had forgotten to align the guidescope and camera to the plane of the imaging scope. Potential sag to, but it would be good to be able to access various iamges of defects and fixes, potential causes, etc..

Tom

[michael.h.f.wilkinson]

Ridiculous answer by the vendor. One of the very reasons to use refractors is their ease of use "out of the box" and lack of collimation issues compared to reflectors (as repeated frequently by Olly)

[ollypenrice]

Tom's right, a sticky of cause and effect distortions would be a great resource. To be honest, I couldn't contribute to it because I've imaged with a WO ZS66, TeleVue Genesis (late eighties, F5), Meade 127, Altair Astro 102 and 115 apos, Tak Baby Q, two Tak FSQ106Ns and a TEC140 without ever having encountered any distortion problems out of the box - including some very old boxes... (This ignores visiting 'guest scopes' such as two other Baby Qs and two other 106 Taks, another TEC140 and - quite honestly, I forget the rest. But it does add up to a lot of refractors which just worked.) I could be wrong about the effects of tilt but I use refractors because- sorry to be boring - they just work.

Olly

Edited November 25, 2015 by ollypenrice

[RobRob]

Any news on getting this resolved???

[gnomus]

On 28/11/2015 at 11:57, RobRob said:

Any news on getting this resolved???

Sorry I should have updated this ages ago.

I returned the scope for a full refund minus shipping costs (the retailer and Tak Europe were still insisting that there was nothing wrong with the scope).

Soon after I got a WO Star 71.  My first copy was duff (by which I mean seriously out of collimation - badminton shuttlecocks across the entire field).  This was replaced immediately by FLO (FLO were not the outfit that sold me the Tak).  The replacement scope was fine and gives me round stars in the corners. 

Edited May 8, 2016 by gnomus

[KaiYang]

Hi, this is Kai from California, USA. ;-)

I wish I read this thread before getting my FSQ-85. I also suffer from the eggiee stars at the corners.

The stock focuser was not tight at the beginning -- here is the video I took: 

 

But even after tighten it, I still see the eggieeee stuffs. By rotating the camera (via CAA), I can see the distortion changes a little bit but I cannot draw any conclusion...

Here are some short exposure pictures (STT-8300 CCD, L filter, 10s expo, tracking / guiding) - rotate 0 / 90 / 180 degree each

With or without reducer doesn't seems make any difference... ;-(

Not sure what to do. Not sure if getting an Feather Touch focuser will resolve this...

Any suggestion?

 -Kai

[gnomus]

My view is that if this expensive scope is not performing as you expected (and as Takahshi promised), you should return it.  

[ollypenrice]

6 minutes ago, gnomus said:

My view is that if this expensive scope is not performing as you expected (and as Takahshi promised), you should return it.  

Without doubt.

Olly

[gnomus]

Let me expand.  I am no expert but the stars in your sample images are all heading off in different directions - that is they are radiating outwards from the centre (except perhaps in the bottom left corner).  To my mind, that cannot be 'Tilt' and it must point to an optical defect.  As such, I don't see how a new focuser is going to help.

[ollypenrice]

9 minutes ago, gnomus said:

Let me expand.  I am no expert but the stars in your sample images are all heading off in different directions - that is they are radiating outwards from the centre (except perhaps in the bottom left corner).  To my mind, that cannot be 'Tilt' and it must point to an optical defect.  As such, I don't see how a new focuser is going to help.

Nor do I.

I host a robotic FSQ85 which did a recent first light and, with an 8300 chip, the corner stars were not perfect, they were elongated radially from the centre a tiny bit. A pixel peeper would have been disgruntled (and in view of the price one can understand that!) but I'm a pragmatic imager and I'd have bought that scope and camera for my own use. It wasn't far from perfect and I think you'd be taking a risk in swapping it for something else in its class. Yours is far worse and I would not accept it. I do think Takahashi have a problem with the Baby Q.

As an aside, I now use a couple of old FSQ106N fluorites, mine and Tom's, worth about £2K a pop and they have no trouble at all with full frame sensors. Quite a bit cheaper than a new Baby Q....

Olly

[KaiYang]

Thank you guys for the quick reply.

Unfortunately I got this used (well, the guy never open the box, consider new) so probably no way to return to Takahashi... ;-(

[kirkster501]

Holy thread revival......

Following the issues encountered by the Steve's in this thread, here is yet another Steve's contribution.

Here is my Ha NA Nebula 30 mins with FSQ85 and reducer stretched to within an inch of its life to make it easier to see for the purpose of this thread.  This is on a NEQ6 which has "good enough" PA because I am not spending an age getting it perfect with drift alignment as I am awaiting my MESU.

My results look pretty good I'd say?

Steve

[ollypenrice]

1 hour ago, kirkster501 said:

Holy thread revival......

Following the issues encountered by the Steve's in this thread, here is yet another Steve's contribution.

Here is my Ha NA Nebula 30 mins with FSQ85 and reducer stretched to within an inch of its life to make it easier to see for the purpose of this thread.  This is on a NEQ6 which has "good enough" PA because I am not spending an age getting it perfect with drift alignment as I am awaiting my MESU.

My results look pretty good I'd say?

Steve

Yes. Sigh of relief!

Olly

[steppenwolf]

This is, of course, the frustration with both this brand and others - consistency! If you get a good'un then life is great if you get a duff'un then the dream is spoilt! Opticaly, the FSQ 85 may be tapping on the boundaries but clearly, it can perform well - as usual, I guess that this is a QA issue but one would have hoped that at this price level, top notch QA would be included in the price? I'm saddened that my dream 'scope didn't deliver on its promise but I'm always pleased to see the results of one that does.

[kirkster501]

Glad to hear it guys, thanks for looking at it for me.

Steve (Steppenwolf), I seem to recall us PM chatting about this a few years ago - indeed, you advised me about the dovetails etc.  I think we bought our FSQ's at a similar time.  Do you recall what serial number yours was?  Wonder if it was a batch of duff ones and I just made it... ?  Then again, I took my FSQ to Steve (Gnomus) in August 2015 to show him the scope and his was a duffer......, two years after ours.....  Possibly just luck that I got a good one. 

 

[gnomus]

3 hours ago, kirkster501 said:

....

My results look pretty good I'd say?

 

Kirkster (I would have used Steve, but there's too many of us about on this thread), you have triggered some PTSD flashbacks with your post.  Aaaaaaargh.  OK - I'll bite......

I have looked at quite a few subs and completed images from these FSQs.  I have seen many that have star defects in the corners - many more than I  would have expected.  It seems that some folks find their corners acceptable whilst with others it bothers them quite a bit.  I guess that it is a personal thing, and who am I to rain on anyone's parade.  (For the avoidance of any doubt, my stars were outside of the limits of 'acceptable'.)  I do wonder about these Petzvals, though, I was attracted by the fact that I didn't have to bother with 'spacing'.  But with a triplet, a flattener (or a reducer) and the correct spacing (which I only have to do once) I get round stars in the corners, not 'acceptable' stars, or stars that I can "live with", or any other euphemism.  

Turning to your image, people who know they have odd corner stars will often say that these round out when stacked.  I don't know if you have posted a stack or a single sub.  The other thing I noticed is that the posted image is only 908 x 711 pixels.   I think your camera is around 2800 x 2200 pixels, so the posted image is significantly reduced and this would tend to mask any abnormality.  100% crops would be better ... BUT .... it doesn't really matter what I or anyone else thinks - the issue is are you happy with them?  If so, then why bother looking for issues? 

1 hour ago, steppenwolf said:

This is, of course, the frustration with both this brand and others - consistency! If you get a good'un then life is great if you get a duff'un then the dream is spoilt! Opticaly, the FSQ 85 may be tapping on the boundaries but clearly, it can perform well - as usual, I guess that this is a QA issue but one would have hoped that at this price level, top notch QA would be included in the price? I'm saddened that my dream 'scope didn't deliver on its promise but I'm always pleased to see the results of one that does.

I was prepared to accept some Q&A issues.  But at this price point I expect to have any issues properly addressed.  What was unacceptable to me was the attitude of the retailer and the importer/distributor.  If you read my story, you will remember that at one point the retailer (having seen my examples) was going to get me a replacement.  It was Tak Europe who said they would not do this.  I could buy a Tak from a different retailer - maybe they would have lobbied Tak Europe harder on my behalf.  But I am still at the mercy of the importer/distributor.  I will not buy another Tak for this reason - well certainly not a new one - no company can achieve 100% perfection and there is always the risk of problems of one sort or another.