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Esprit 100 Pinched optics?


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12 hours ago, Adam J said:

Ok just posting this now for interest as if there was any doubt that the stars are hexagonal take a look at what they look like when I combine LRGB as opposed to just Lum, not much data but I think its still very telling:

 

As you can rotate the focuser compared to the optical tube you could do this and re-orientate the camera.  If the pattern stays the same then it is likely something to do with the optical tube.  If the pattern rotates then it is probably something to do with the focuser.  However, it does look like pinched optics to me.  These things happen and FLO is good at helping sort the issue.

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14 hours ago, Adam J said:

Thanks for the suggestion but fortunately I know better lol. I would not touch the colimation screws on a triplet with a barge pole. The tolerances are incredibly fine.

Yes I appreciate that. I wouldn't be happy about having to do it myself. But if it was going back anyway to be checked by a professional then i might be tempted to take the nip off the screws to alleviate the problem and it might serve to be of use over Christmas. If it goes back this week you might have to do without. It's a bad time of year for this for sure. Are you using a dew band btw?

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1 hour ago, henry b said:

I can now see a customer with a fully operational scope over the festive holidays, I have used some harsh words for which I will apologise openly, Skywatcher products have served our hobby very well and I will always acknowledge this fact.    Henry B.

 

16 minutes ago, henry b said:

Pass the buck or deal with the issue, which one is it ?  Henry B

I wonder if you could make up your mind whether to accept that you have misjudged this situation and let Adam and FLO deal with it, or continue to be rude and interfering for no reason?

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Guys, I am getting this sorted so no need to be concerned for me, I can take care of myself just fine. :)

I posted this thread purely to confirm my diagnosis of the problem with experts in the community so that I did not waist time and money returning a scope unnecessarily.

As such this thread should not be miss interpreted as a complaint, or even an attempt to get FLOs attention via the forum, though I am grateful for their assistance here.   

I would rather not get this thread locked / removed as it would be nice to share the resolution with everyone and this can be preserved as an example of pinched optics in an Esprit scope for future reference.

A trawl though Astrobin shows that this is not a common problem with the Esprit line but its not totally unique either and the Hexagonal shape being different from the triangle normally associated with pinched optics probably means people don't correctly diagnose the issue. 

thanks everyone. 

Adam 

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On 14/12/2019 at 14:30, henry b said:

I do not believe as  a  customer receiving a new product delivery from a supplier that you should have  the need to have it checked by a  third party!  However i am sure FLO will resolve the issues.       Henry B.

And they would probably be just fine out of the box. But if you bought a new car and had the chance to get it fine tuned and checked by the country's top mechanic for a just a few extra £££, would you not take that option?

 

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On 14/12/2019 at 10:52, Adam J said:

................... More integration mind you.

You really need to look at a single, short image using a mix of bright and medium stars. Stacked multiple images will not be accurate enough and may add variables/elements to the situation that are unrelated to the telescope.

 

EDIT: Just re-read this, that the integrated image was your friends, sorry. Is your original single star pic a single exposure?

Edited by Tim
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17 minutes ago, Tim said:

You really need to look at a single, short image using a mix of bright and medium stars. Stacked multiple images will not be accurate enough and may add variables/elements to the situation that are unrelated to the telescope.

 

EDIT: Just re-read this, that the integrated image was your friends, sorry. Is your original single star pic a single exposure?

Its an integration because it shows it better but the effect is still visible in individual LRGB subs and even in a couple of Ha subs that I shot while testing, but less obvious in the smaller Ha stars.

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  • 1 month later...
On 15/12/2019 at 19:51, Adam J said:

.

A trawl though Astrobin shows that this is not a common problem with the Esprit line but its not totally unique either and the Hexagonal shape being different from the triangle normally associated with pinched optics probably means people don't correctly diagnose the issue. 

thanks everyone. 

Adam 

I think the triangle shape is more with 3 clips distortion,  if the esprit has 6 and they're all having a slight effect on the star..

I'd agree that a single filter sub will show more of what is actually happening rather than a multi filter stack as all sorts of things can be introduced to the mix..

I remember reading that you saved, and saved for this scope, I  hope it gets sorted, FLO have been first class on sorting problems for me, above and beyond customer service but not on this level of instrument.. the esprit is a amazing scope, no doubt..

Edited by newbie alert
Damn phone
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53 minutes ago, FLO said:

A replacement telescope was dispatched to Adam some time ago. We are assuming no news is good news... 🙂 

Steve 

Ah awesome! I can never fault FLO's customer service but just wondered what was the cause of these stars and what had fixed them but a replacement scope and no news means Adam is happy :)

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13 minutes ago, souls33k3r said:

Ah awesome! I can never fault FLO's customer service but just wondered what was the cause of these stars and what had fixed them but a replacement scope and no news means Adam is happy :)

It was pinching caused by low temperature (a lower temperature than when Es tested it).

When it comes to low temperature pinching it can be difficult sometimes to determine what is/isn't acceptable. I.e. should a telescope never pinch, regardless of temperature. Or is a 'little' pinching acceptable below freezing if a dew-heater tape solves it. I favour the former but I know other retailers routinely claim the latter. They might be right... 

Anyhow. Adam has received a replacement telescope and we haven't heard from him so are assuming all is good 🙂 

Steve 

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13 minutes ago, FLO said:

It was pinching caused by low temperature (a lower temperature than when Es tested it).

When it comes to low temperature pinching it can be difficult sometimes to determine what is/isn't acceptable. I.e. should a telescope never pinch, regardless of temperature. Or is a 'little' pinching acceptable below freezing if a dew-heater tape solves it. I favour the former but I know other retailers routinely claim the latter. They might be right... 

Anyhow. Adam has received a replacement telescope and we haven't heard from him so are assuming all is good 🙂 

Steve 

A dew strap holding the objective at ambient +4c  was used for my test images on the original scope, ambient temperature was about -2c.

35 minutes ago, souls33k3r said:

Ah awesome! I can never fault FLO's customer service but just wondered what was the cause of these stars and what had fixed them but a replacement scope and no news means Adam is happy :)

Yes I cant fault the service from Steve and the rest of the team at FLO. 

So far the replacement scope is looking much better than the original one. I have not made a comment here yet as I have not had the opportunity to do more than a few test exposures as on the first couple of nights with the scope I had guiding issues that would have obscured any problems, however now those are resolved test exposures are showing round stars with complete halos.

Once I have taken a proper image I will report the results here. In light of the problem with the old scope I also want to ensure that it performs ok on a lower temperature night before fully claiming victory.

I will complete a full scope review in a separate thread once I have a couple of images completed with it. 

Adam

 

 

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I enjoyed reading this thread and now have a better appreciation of Pinched Optics and what to look for. As I continue learning, these forum threads provide a valuable source of information which is not readily available in books or videos.

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  • 8 months later...

Apologies for reviving this thread but I appear to be having a similar problem with my new Esprit 100.

This has only shown itself on the colder nights, so last night (~7 degrees ambient) I decided to run a test sequence on Vega to try and characterise the issue.

I've attached a 1:1 crop of a 20 minute stack of Vega, taken with my Canon 6D.

image.png.d2ca65f56f21b39900d78f4d4320522f.png

This looks, as discussed earlier in the thread, like the six lens clips are very slightly pinching the objective lens. 

For reference I shot this with my dew heater running at 100% to try and combat the issue.

I've already sent an email to FLO about this but just wanted to see if anyone else had any suggestions?

Cheers

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Is it the 'lighthouse beams' you are referring to emanating from the bright star? I was under the impression that all refractors exhibit this phenomenon to some degree on bright stars, even Taks(!) Here is Alnitak through my AA 102 mm APO.

3E9659F9-A5FC-445C-BB0F-C8404F9FD70B.jpeg.f5216324bdc15a076f144db3eeca07f4.jpeg

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3 hours ago, Spongey said:

Apologies for reviving this thread but I appear to be having a similar problem with my new Esprit 100.

This has only shown itself on the colder nights, so last night (~7 degrees ambient) I decided to run a test sequence on Vega to try and characterise the issue.

I've attached a 1:1 crop of a 20 minute stack of Vega, taken with my Canon 6D.

image.png.d2ca65f56f21b39900d78f4d4320522f.png

This looks, as discussed earlier in the thread, like the six lens clips are very slightly pinching the objective lens. 

For reference I shot this with my dew heater running at 100% to try and combat the issue.

I've already sent an email to FLO about this but just wanted to see if anyone else had any suggestions?

Cheers

You need to upload a full resolution image I feel like that is a down sampled, but perhaps its just the big pixels on the 6D?

But from what I see I don't really see the effect I had in this image. My problem showed up in much lower brightness stars, Vega is one of the brightest stars in the sky and although you have some indentation in the halo that is not uncommon on refractors in general and your star really is not that bad. The often those lines are much much darker and more distinct.

You would do well to test by pointing at something like m45 as there are is quite a range of star colour and brightness in that target, if you are not seeing something on the seven sisters then this is not something to worry about unless it gets much much worse as temperatures drop. But you cant assume that is going to happen. In terms of the light house beam effect I have seen much worse from an Esprit 100.

100-550_Nr11_orig-Flattener_Eos600d.JPG

Above is an example shot from interferometer blog. If you search google for Esprit 100 interferometer blog you will find many examples of what is normal for a Esprit 100. As you see above the halo has dark lines in it just like yours (purple due to baader filter). 

What I had on mine was very different and resulted in clear spikes / hex shaped stars that when combined in LRGB produced odd chromatic artefacts in the star halo. I also felt that it was not snapping to a fine focus. 

Bottom line is that I don't see anything immediately concerning in your image. 

 

Adam

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5 hours ago, Spongey said:

Apologies for reviving this thread but I appear to be having a similar problem with my new Esprit 100.

This has only shown itself on the colder nights, so last night (~7 degrees ambient) I decided to run a test sequence on Vega to try and characterise the issue.

I've attached a 1:1 crop of a 20 minute stack of Vega, taken with my Canon 6D.

image.png.d2ca65f56f21b39900d78f4d4320522f.png

This looks, as discussed earlier in the thread, like the six lens clips are very slightly pinching the objective lens. 

For reference I shot this with my dew heater running at 100% to try and combat the issue.

I've already sent an email to FLO about this but just wanted to see if anyone else had any suggestions?

Cheers

Vega looks well controlled to me, very nice.   
 

The diffraction type spikes in the image are quite normal. I get a similar effect with my fsq. I think they are caused by the clips which hold the lens cell in place. At least that is what I concluded with my fsq 85. Not an issue. 
 

Actually the star is very well controlled and I’d be very pleased. 

ken 

 

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I have similar with my Espirt100, I contacted FLO and got this response:-

"Es thinks it is almost certainly caused by the peripheral lens adjustment screws being slightly too tight at lower temperature.

We have seen this quite a bit on the Esprit and various Taks as well. There is no easy answer, we can have Es loosen them but then in warm temps you run the risk of one of the elements moving slightly and introducing coma into the image.

Personally I would leave as is."

So I did and remain very happy with the scope....  

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