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  #1  
Old 21-05-2020, 02:29 PM
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Andy01 (Andy)
My God it's full of stars

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Welcome to my nightmare....

I think you're (not) gonna like it....
Apologies to Alice Cooper

Long post ahead - apologies...


In January, I was overjoyed to win a nice new large format camera. However, in short, this meant replacing my Newt with a full frame ready OTA. I was lucky enough to be offered a nice pre-loved Takahashi TOA 130 with reducer, flattener & Feathertouch focuser. Woohoo - happy days! I then sourced 2" Chroma filters from the USA and had a couple of adapters made to connect the camera and off I went imaging, or so I thought...

Now I realise that I’m kinda fussy and I'm using a camera with a much bigger chip but wow From first light onwards, my stars have been sooooo far out, defocused and distorted in all four corners and in different directions - a perfect storm of tilt & eccentricity errors....

I tried really hard to eliminate the tilt with a feeler gauge, alfoil etc. packing out different corners but I just couldn’t make the adapters work, so in frustration I took the whole shebang to ASV member Stefan Buda (he builds telescopes) - who inspected, measured and diagnosed them on his lathe.

Turns out the adapters were uneven, the threads were too loose and and the camera OAG/tak 72mm adapter was out by 50 microns on one corner.

Stefan re-machined this and remade a new adapter & spacer for the reducer and I tried again.

There was significant improvement in the image, but there were still distorted stars in two corners.

Back to Stefan again, this time with the entire focuser! By spinning the entire focuser on the lathe all the issues were very clear to see. Turns out that the thing was poorly made, the FT/Tak adapter was way out of round, the focuser was wobbly and don't even get me started on the built in Captain's wheel rotator which wouldn't lock flat in the same place twice!

Seems that a top brand does sadly not always equal top quality.

Stefan also ran his laser over the reducer which he suspects is also causing problems.

He has since re-machined the OAG/Tak adapter, both ends of the FT/Tak adapter, both internal faces of the rotator mechanism, and is making a new spacer/adapter for my flattener. Stefan is a really meticulous master craftsman who works in microns!

Having now sorted out the rear mechanicals, any possible remaining issues now have be optical ie: the reducer itself - (hopefully not the Tak lenses themselves needing collimation eek!)

The new flattener adapter will be ready for testing soon under clear skies.

I just want round stars!

So anyway, I've cobbled this image together from my endless series of tests. Probably not the best time to try semi-automating my capture method by using Ekos for auto focussing, but I'm sure it'll all be ok in the end!

1) 5 hrs of 5nm ha with dodgy stars removed using Starnet++ https://www.astrobin.com/a1lt2n/0/
2) HaRGB with above data + just 20mins ea. of RG&B - https://www.astrobin.com/full/a1lt2n/B/

DISCLAIMER: I have used Startools to rectify the stars eccentricities!
Attached Thumbnails
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Click for full-size image (Ha_Starless_NR_iis.jpg)
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Click for full-size image (HaRGB2_NR_iis.jpg)
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Last edited by Andy01; 21-05-2020 at 02:33 PM. Reason: missing links
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  #2  
Old 21-05-2020, 02:49 PM
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Joshua Bunn (Joshua)
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Hi Andy,


I totally hear what you're saying. I've done some diagnosing on astro parts and gear, and sometimes things are not always square
Good to hear you're on your way though.



Josh
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  #3  
Old 21-05-2020, 02:50 PM
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Atmos (Colin)
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Stefan really does beautiful work doesn’t he

Regardless of your star issues, you have a great amount of detail within the nebula with some fine contrast showing up.
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  #4  
Old 21-05-2020, 03:05 PM
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strongmanmike (Michael)
Highest Observatory in Oz

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Good luck with it all Andy, I'm sure it will all get sorted soon

Nice Lobbie

I see you have Gepetto on the job

Mike
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  #5  
Old 21-05-2020, 04:03 PM
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The_bluester (Paul)
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I can understand the frustration, even some simple commercial gear is not really up to snuff. Discussing your trials and tribs sent me out to my lathe to whack the dial gauge on a heap of mostly commercial off the shelf bits I have. A quick machine on both ends of an old socket to make sure it was as parallel as I could make it followed by rotating it in the chuck and checking again says my lathe is not perfectly flat, probably 10 microns or so away (It is just a cheap Chinese thing I bought to shorten bolts and make non critical stuff for my race car etc) but whack the commercial extension tubes in and suddenly I was seeing 25 microns of runout. Put one of the "well known brand" plastic spacing adjusting rings in between two extension tubes and suddenly it was 100 microns and more!

I want a better lathe now so I can make my own bits and if they are not straight, know who is to blame...

That said, for all the issues, the first light image of Ara is pretty flash and as Mike said, nice Lobster!

Last edited by The_bluester; 21-05-2020 at 05:56 PM.
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  #6  
Old 21-05-2020, 04:24 PM
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codemonkey (Lee)
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That sounds about right to be honest. This hobby is for either the obsessive or the easily impressed... hardly anything ever works out of the box. Don't get me wrong, I fully sympathise and wish it was not the way that it is, but I'm not at all surprised.

Really hope your gear is swiftly fixed and you're able to spend less time problem solving and more time imaging!

As for the image; wonderfully sharp detail, great composition and overall contrast... I'm less sure about the colour... looks a bit too red to me.
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  #7  
Old 21-05-2020, 05:20 PM
Placidus (Mike and Trish)
Narrowing the band

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A tale of woe, and of almost endless thwarting and frustration, but great victory at the end.



(One good thing about our CDK-20 with its 3.5 metre focal length and rather generous sweet spot is that at only 660 meters altitude in rather ordinary seeing, one doesn't have to be too meticulous about squareness. Droop, and differential flexure, on the other hand, is a nightmare).


Speaking of nightmares, the Lobster always looks very scary.


I reckon you're up and running now. The RGB stars look faultless.



Well done!
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  #8  
Old 21-05-2020, 05:24 PM
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gregbradley
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Looks like you have a good head start on ironing out any bugs. Be prepared though to ditch the TAK focuser and put a Feathertouch one on it. There are models made for the FSQ so perhaps they would also work on a TOA. Its a common handling for FSQ focuser issues.

TOA optics may require a trip to Japan to collimate. I did read on some promo about TOA that you can collimate them at home but I am not so sure about that.

CCDinspector may be a clue to see if the optics need collimating or not.

TOA optics seem to be the best of any scope when everything is aligned.

Tak have dropped the ball several times in the recent past which is why there is an FSQ106EXiv as the previous 3 sometimes had issues, mainly with the focuser. Yes and the captains wheel was handy on the BRC250 but on the FSQ it seemed to be a liability. It most likely is the same part as the older FSQ106EDX's had.

Your Ha Lob is the most detailed Lob I have seen.

Good luck with the upgrading.

Greg
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  #9  
Old 21-05-2020, 06:01 PM
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The_bluester (Paul)
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Andy's actually has a FT focuser fitted, several of the problems are related directly to the Tak to FT adapter (Which I don't know if it is a FT item or custom machined) but it was not machined parallel end to end, and the captains wheel arrangement to rotate the focuser on it was not right either, every time you changed the camera angle the tilt would change both in orientation and severity!
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Old 21-05-2020, 06:27 PM
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ChrisV (Chris)
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As Wayne and Garth said to Alice, "we are not worthy!" Lovely image.
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  #11  
Old 21-05-2020, 07:15 PM
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multiweb (Marc)
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Sounds like a combination of problems with parts that should be already machined to tight tolerance. I'm surprised to hear this from a TAK. That's usually what you pay for. Piece of mind. I'm not familiar with newer models but both TAK I own I've pulled apart. They are quite old and surprisingly simple designs with very few pieces. But the bits have incredibly tight fittings. Very solid and not much room for play. I'm also surprised to hear there are that many issues with newer models.
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  #12  
Old 21-05-2020, 09:59 PM
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Andy01 (Andy)
My God it's full of stars

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Hi folks, thanks for your concerns & thoughts!
In case I wasn’t clear in my OP, these issues are so far related to the aftermarket adapters and the Feathertouch focuser, and Joshua is correct in saying that small errors can really add up when parts aren’t actually square. (and maybe, possibly with the Tak reducer too).

Stefan has just advised that the new flattener adapter is ready, and that the Tak 67 flattener is in itself a beautiful, well made piece of engineering! (Very high praise indeed) so weather permitting, I’m desperately hoping for decent results with it over the next few days!

It might happen, and as Wayne said- “Yeah, and monkeys might fly out of my butt.”
Patience Grasshopper....

As to the image itself, yes Lee- it’s a bit overcooked, but as Greg & Colin remarked, there’s a lot of detail there, a surprising amount of Ha surrounds the Neb itself.
Oh, and the only reason the stars are round at all is the use of Startools remarkable ability to artificially repair them.

Last edited by Andy01; 21-05-2020 at 10:11 PM.
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  #13  
Old 22-05-2020, 10:05 AM
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The_bluester (Paul)
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Fingers crossed.
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  #14  
Old 22-05-2020, 06:37 PM
jamespierce (James)
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The central details here are really nice... I for one, am very much looking forward to seeing the results from the finely tuned end result. There is nothing like Tak stars.
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  #15  
Old 22-05-2020, 06:59 PM
spiezzy
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Hi there Andy glad Stephan sorted your issues out and you will be back on track .
what concerns me though you fork a lot of money out for these adapters and equipment and it should just work as advertised without the purchaser having to modify everything to make it work as advertised its a real shame in my opinion .
BTW i washed you interview the other day very inspiring actually watched it twice well done you have put a lot of work into your imaging and they are exceptional
cheers Pete
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  #16  
Old 23-05-2020, 03:26 AM
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Ant0nio (Tony)
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I feel your pain Andy,
your current ordeal totally resonates with me. Lee nailed it with this reply;

Quote:
Originally Posted by codemonkey View Post
That sounds about right to be honest. This hobby is for either the obsessive or the easily impressed... hardly anything ever works out of the box.
That's it right there , at least that's been my experience.
Reading this thread has given me some heart in knowing these issues are part & parcel of the pursuit & when I'm satisfied with my own setup I'll start posting again
instead of throwing images in the vault.(after I've fixed stars in Startools, I feel dirty )
That said, an excellent image Andy & thanks for posting.
CS,
Tony
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  #17  
Old 23-05-2020, 10:16 AM
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Andy01 (Andy)
My God it's full of stars

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Paul, Pete, James & Tony - cheers for the sentiments guys.

It's both amazing and incredibly disappointing to me that tippy top brand quality is missing in such highly rated and expensive gear.
My previous experience with Skywatcher, William Optics, Stellarvue and Sidereal Trading was completely the opposite, their stuff all just worked!
Not so amazing though to Stefan who has seen this before with commercially made stuff.

Anyway, seems that Sunday nights' forecast is clear so the next chapter of testing resumes then - fingers & toes crossed, lucky sox & undies on, prayers said etc...
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  #18  
Old 23-05-2020, 10:29 AM
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Peter Ward
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An eye pleasing rendition just the same.

Can't say I have had a bad experience with either my FSQ85 or FSQ106...though I must admit with a STX16803 the focuser on the 106 was not happy lifting the half tonne or so of camera. The fix was a FLI atlas, which also significantly helped nail the focus.
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