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Old 15-06-2013, 08:13 AM
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δ Scorpii in HA

I have been waiting for any bit of cloud free sky to test the latest modification to my system. Managed to get some last night.

Below is an image of the rear of the optic train. I have added two turnbuckle tensioned wires to try to stop flexure. The bar the wires are attached to bears directly on the dovetail holding the ITS that holds the camera. This all then forms a stable triangle with no extra strain on the dovetail.

Does it work?

Large image 3x16 min in 3nm HA 7MB

http://d1355990.i49.quadrahosting.co.../dsco_test.jpg


Bert
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  #2  
Old 15-06-2013, 08:23 AM
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strongmanmike (Michael)
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Looks like it

...God I love your imaging setup

Mike
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Old 15-06-2013, 09:23 AM
cfranks (Charles)
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You must have been looking at my wiring setup! I hadn't thought about turnbuckles and G clamps though!

Love it!

Charles
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Old 15-06-2013, 10:16 AM
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Wow Bert,
Looks like an industrial monster, are the rusty G-clamps going to be a permanent feature?

Trent
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Old 15-06-2013, 10:54 AM
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Quote:
Originally Posted by trent_julie View Post
Wow Bert,
Looks like an industrial monster, are the rusty G-clamps going to be a permanent feature?

Trent
They are just like me, old and rusty and rough around the edges but they can still do the job!

One is to hold the bar to stabilize it. The other is just my way of fine tuning mount balance. I may buy some new shiny G clamps when I get the chance.

I do not go for looks. I go for performance!

Those very old G-clamps belong to the very talented cabinetmaker that works in the very large shed in my backyard. I nicked them while he was not looking from his very large collection. They were most probably screwed tight before I was born!

Bert

Last edited by avandonk; 15-06-2013 at 11:17 AM.
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Old 15-06-2013, 11:05 AM
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Originally Posted by strongmanmike View Post
Looks like it

...God I love your imaging setup

Mike
The image says it all Mike and stop calling me god!

Bert
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Old 15-06-2013, 11:07 AM
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Originally Posted by cfranks View Post
You must have been looking at my wiring setup! I hadn't thought about turnbuckles and G clamps though!

Love it!

Charles
My next move was a whip!

Bert
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Old 16-06-2013, 02:33 AM
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dvj (John)
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I would bet the flexure is coming from the rear tip-tilt plate of the RH-200. The Altas should be able to support the CFW and Camera, but I don't like the mechanics of the RH tip-tilt plate. It's a thin piece of aluminum.

Your image looks very good corner to corner. Too bad it took that much mechanical modification to get this little bugger too work.

Everyone I know who has purchased this instrument knows the pain!

jg
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Old 18-06-2013, 10:25 AM
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You still seem to have flexure related problems. Stars are not round at full res in every corner, but are very close. It makes me wonder what is going on here if you need to go to this extent to solve star shapes. Is the back of the scope not capable of supporting the load? Is the FLI gear flexing (most like as I have heard this before from other guys) particularly at the connections to the filter wheel? Or are you getting flexure from the dove tail setup. Also why not go 30 minutes on your subs? Doing subs at 1 minute, then 5 minutes, then 10 minutes, then 15 minutes, then 20 minutes, then 25 minutes and then finally 30 minutes will give you a clear idea of what is going on. Each image you have produced in the last 6 months has had elongated or odd stars near the corners. This one is about the best with stars approaching round, but still slightly elongated. I would be very reluctant to buy one of these scopes having seen these issues with a very expensive scope. Just my opinion though and each to their own.
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Old 18-06-2013, 10:57 AM
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Great field. The rig scare the hell out of me though.
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Old 18-06-2013, 04:05 PM
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It seems you eventually tamed your scope Bert, my compliments on the dedication on optimizing all the little details and get it fully operational

Regards
Marco
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Old 20-06-2013, 07:22 AM
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All the problems with flexure is due to one thing, F3. At F3 focus is very terse with a CFZ of about 10 to 20 micron.

The fully corrected field of a RH200 is 42mm diameter. The FLI PL16803 camera has a diagonal of 52mm. This further constrains how much flexure can occur before it is noticeable at the corners.

This then means that an OAG is not a practical proposition if there is ANY flexure present with this configuration.

I knew all this before I ordered the new system. The elimination of all flexure was the only way to go.

Nearly all the flexure I had was due to the weight of the focuser CFW and camera. I had flexure between the camera and RH200 and what was even more disturbing the dovetail holding the RH200 and ITS was twisting due to gravity with mount movement. In fact EVERYTHING was flexing. Blaming it on one component is self delusion.

I have not touched the factory alignment of the RH200 and as you can see by the almost flexure free images this alignment is still spot on!


Below is a picture where I have modified the steel plates at the end of the bar the turnbuckles are attached to. The tiny amount of flex due to bending in those plates were allowing the ITS with camera to move.

I now have almost no movement. The second image is of the output of DSS of four 32 minute exposures of Beta Centauri in 3nm HA without dither.

Note the DX and DY columns denoting movement between frames. This tells me I have about one pixel movement in two hours!

Here is a full res image 7MB

http://d1355990.i49.quadrahosting.co...3_06/bcent.jpg


Bert
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Last edited by avandonk; 20-06-2013 at 09:30 AM.
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  #13  
Old 20-06-2013, 07:36 AM
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Here is another test. NGC 6357 with a little mate 5x32 minute exposures without dither.

Full res image 4MB

http://d1355990.i49.quadrahosting.co...06/6357_HA.jpg


Below is the DSS output showing the amount of movement.

Bert
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Last edited by avandonk; 20-06-2013 at 08:34 AM.
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  #14  
Old 20-06-2013, 08:16 AM
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Here is an unstretched stack of 7x32 min 3nm HA dithered of the Helix Nebula. 15MB


http://d1355990.i49.quadrahosting.co...HN_HA_7fr_.zip


With far more data I think this will show more faint stuff.


I would be interested to see what anyone else can squeeze out of this data.


Bert
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Last edited by avandonk; 20-06-2013 at 09:42 AM.
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Old 20-06-2013, 09:17 AM
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that is already very deep Bert - much more and you are going to be seeing the blue end of the CMB! I have enough trouble at f4 and can only imagine how unforgiving of bendy metal f3 must be. That is the price you must pay for sensitivity though and your system has that in spades.

Last edited by Shiraz; 20-06-2013 at 10:00 AM.
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Old 20-06-2013, 10:52 AM
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Dear Ice In Spacers,

As the owner of one of Australia's leading astronomy products suppliers, and exclusive Australian distributor for the Officina Stellare RH200 telescope that is being considered in this thread - I usually stay well away from adding to threads on Ice In Space.

I regard it as unsuitable for suppliers to comment on this forum - though some - particularly one - do it all the time.

Bert has done a leading job with getting this "system" to where it is today.

The magic word here is - "system".

John's comments from the US give the impression that this "telescope" is a difficult unit to use, this is not the case.

John knows this telescope unit quite capably - but he unfortunately does not have adequate detail about Bert's full system and what Bert has been doing with it over the last year, and his comments may be misconstrued by you the readers of I In S as criticism.

Without full knowledge and with inadequate data - which Bert and I both have - as we have lived this on a day to day process together for the last year - and thereby know how far "past the design of this system" he is running it, comments are quite unsuitable and misplaced.

Bert is running this system "over" it's design parameters, and is achieving the highest capability results with this system of anyone - globally.

Bert is trying to do something absolutely exceptional, system implementation that has never been actioned before, never attempted before, and never achieved before. With Bert's exceptional talents and capabilities he is achieving heady heights that are simply stated "unique" - never achieved before, globally.

Bert's target strategy is not for us all, as most of us are happy to work within the design parameters & specifications of the systems we select.

Bert is not of this mould, and has custom selected a comprehensive set of products that provide - each and every component - state of the art performance, of which his telescope is merely one component in a "system". The balance of his system is the same - all state of the art gear.

As a specialist globally leading optical physicist that spent his career with CSIRO working on cutting edge global leading technology in optical physics, Bert is in a unique position to stretch the boundaries, and "Go Where No Man Has Gone Before" - which is exactly what he is doing here. His talents are well above anyone that I know globally, and thereby his results reflect his unique capabilities.

The telescope he is using is NOT difficult to tame, it is actually a very easy system to achieve exceptional results.

With this F3 system you need to "vertically" assemble the imaging train, as this is necessary. John's comments are correct for those that do not wish to follow this instruction - and incorrectly assemble their system, and thereby achieve out of round star images. It's simple - if you follow the manufacturer's instructions you achieve the results.

Every purchaser in Australia of this telescope receives instruction as to the correct simple vertically assembly process for the imaging train, and with them doing this - they ALL achieve excellent results very quickly.

And thereby achieve the fastest imaging that is available - with imaging in 1/3 of the imaging duration of your typical f5 ultra premium quality advanced astroimaging system - simple as that

What John is saying may mislead some of you. John has one of these telescopes - but does not have the same full system as Bert.

In my humble opinion - there is an element of stiff cheddar in John's comments, and this is not isolated to this thread, this has been a theme for some time. John is a very experienced and very capable astroimager, but his "system" is not in the same class as Bert's, nor his capabilities with this particular telescope, thereby Bert's images are superior to John's using the same telescope - this is the crux of this issue.

Personally John, your comments are not welcomed on this forum by myself, you seem to be "on a mission" here, as your comments are giving the impression that you are trying to warn people away from this telescope ?

John - may I recommend that you issue a correction, as going around upsetting people, as you have achieved here - I suggest this is not your desired strategy. I suggest that the manufacturer will be less happy than I am when I provide this threads link to them.

Rgds,
Cris Ellis,
Astromelb,
Melbourne,
Australia.
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Old 20-06-2013, 02:10 PM
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Quote:
Originally Posted by Shiraz View Post
that is already very deep Bert - much more and you are going to be seeing the blue end of the CMB! I have enough trouble at f4 and can only imagine how unforgiving of bendy metal f3 must be. That is the price you must pay for sensitivity though and your system has that in spades.

Many years ago my lecturer in mechanical dynamics always started a rigorous mathematical proof with the assumption 'that all bodies are regarded as perfectly rigid'. He then mumbled something about the mathematics falling apart when they flexed. He then said in the real world ALL bodies flex no matter how rigid they seem.

I try to deal with reality and it is not easy. Overcoming the limits of our less than perfect constructions is what it is all about.

This has been a long journey as there are no signposts. I had to make it all up on the way.

Bert
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Old 20-06-2013, 02:32 PM
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Sounds like you have an agenda here too Cris. John has a perfect right in making his statements. I know of several people who have had trouble with this telescope. Your comments seem to suggest an interest in the outcome the capacity to image with this particular telescope.

Bert might well be an optician but his images have for a long time displayed flexure in the system and the steps he has had to undertake are to say the least not conventional for a 10K plus telescope and it is perfectly reasonable to suggest that something is not right if you have to add a turn buckle to a system and a mechanical holder to hold the camera, which are not standard appliances in astronomy imaging. Stability of the imaging train comes through the rear assembly of the scope and all the connections between various components, it is apparent to me at least that is not possible with this telescope. The AP version of this scope carrying the same load does not have this issue at all and required no mechanical control. Certainly going beyond the recommended imaging circle has contributed to this issue and I accept that, but the fact remains AP seem to have this right and everyone I know has had trouble with this particular scope. So people are not imagining things or misrepresenting things.
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Old 20-06-2013, 02:33 PM
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That said it far better than I could Cris.

Cris has been very helpful all this time with my problems that were of my own making.

It was just a matter of identifying every REAL problem one at a time and then solving it.

I do use unconventional methods. One being the KISS method. Keep it simple stupid!

Why add more weight by making a fatter stronger ITS when a a couple of turnbuckles and a bit of stainless steel wire will do a better job.

I was at Woodonga at a vintage fly in and was admiring a beautifully restored biplane. It was all wood and cloth reinforced by piano wire. The 'old' bloke next to me started a conversation about the aircraft. He said his name was John. He seemed to know a lot about flying. It was then I realized he was John Gorton a once Prime Minister of Australia. He flew fighters in WW2. He owes his facial good looks to a crash in one in combat.

If piano wire can hold a plane together surely it can stabilize a mere bit of metal.

Bert
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Old 20-06-2013, 02:54 PM
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Originally Posted by Paul Haese View Post
Sounds like you have an agenda here too Cris. John has a perfect right in making his statements. I know of several people who have had trouble with this telescope. Your comments seem to suggest an interest in the outcome the capacity to image with this particular telescope.

Bert might well be an optician but his images have for a long time displayed flexure in the system and the steps he has had to undertake are to say the least not conventional for a 10K plus telescope and it is perfectly reasonable to suggest that something is not right if you have to add a turn buckle to a system and a mechanical holder to hold the camera, which are not standard appliances in astronomy imaging. Stability of the imaging train comes through the rear assembly of the scope and all the connections between various components, it is apparent to me at least that is not possible with this telescope. The AP version of this scope carrying the same load does not have this issue at all and required no mechanical control. Certainly going beyond the recommended imaging circle has contributed to this issue and I accept that, but the fact remains AP seem to have this right and everyone I know has had trouble with this particular scope. So people are not imagining things or misrepresenting things.

Paul Imaging at F3 is NOT standard.

I have not seen many images from these mythical AP scopes. Even Peter Ward had trouble with orthogonality.

I am not an optician. They make glasses so people with limited vision can see clearly. My background is in Applied Physics. With a very strong emphasis on light optics and x-ray optics.

Standard image trains may work for far slower systems but I guarantee you they flex. You just do not see it.

So please cut out the speculation and misinformation when you do not know what you are even talking about.

Can you give me a list of EVERYONE you know who is having problems? I would like to start a self help group.

By the way F3.0 is far more terse than F3.8! In fact f/3.0 is 60% faster than f/3.8.



Bert
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