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SW Esprit 80ED disappointing first results

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#1 mborland

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Posted 05 September 2020 - 01:52 PM

I got some first results with my new Skywatcher Esprit 80 ED last night, in spite of the full moon. I imaged the area around the North America Nebula and the Pelican Nebula. Imaging train was: Esprit 80ED - SW Flattener - ZWO OAG - ZWO EFW using Optolong L-eNhance - ASI 071 MC Pro. Backfocus is correct to within 0.5 mm, after adding 1 mm for the filter.

 

Although the dimmer stars are sharp, the brighter stars show obvious green halos that are displaced to the left side. Some of the brighter reddish stars show reddish halos displaced to the right side. This suggests something is not well aligned. I suppose it could be in the imaging train, e.g,. the filter wheel, but I haven't had such issues with my other OTAs (SW Esprit 120, 8" LX90) using the same imaging train. I don't see any way to perform collimation adjustment on the scope itself.

 

color-rings-s.jpg

(This image was processed using the Weighted Batch Preprocessing script in PixInsight, then cropped and stretched. Total exposure was 72 minutes.)

 

I'm planning to try some imaging without any filters, next time I get clear skies, just to check the scope. Meanwhile, I'm looking for comments and advice.

 

Thanks in advance!

 

--Michael


Edited by mborland, 05 September 2020 - 01:53 PM.


#2 Echolight

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Posted 05 September 2020 - 01:57 PM

I think the picture looks pretty cool.


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#3 Tapio

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Posted 05 September 2020 - 02:03 PM

Not looking bad at all.

And the biggest halo with brightest star - it's the filter most likely.

What filter were you using ?


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#4 mborland

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Posted 05 September 2020 - 02:19 PM

Not looking bad at all.

And the biggest halo with brightest star - it's the filter most likely.

What filter were you using ?

It's an Optolong L-eNhance. I use it on with my other OTAs without such issues.

 

--Michael



#5 mborland

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Posted 05 September 2020 - 02:41 PM

Here's the image after further processing. I reduced the green halo by desaturating green, which works in this case. The red halos can't be fixed that way.

 

NANPN-small.jpg

 

Full size here

https://www.flickr.c...N07/50308636993

 

--Michael


Edited by mborland, 05 September 2020 - 02:41 PM.

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#6 Tapio

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Posted 05 September 2020 - 04:20 PM

Can you show a sample image of same target taken with another scope and same filter?

#7 mborland

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Posted 05 September 2020 - 04:49 PM

Can you show a sample image of same target taken with another scope and same filter?

Here's one taken with the SW Esprit 120. The brightest star has a similar green fringe, but it is centered on the star. In this shot, I didn't do anything to try to reduce the fringe. I guess I found it less obvious since it was concentric with the star.
Pelican-small.jpg

 

Does this suggest that the filter was slightly canted in the Esprit 80 shot, or could it be a problem with the scope?

 

--Michael


Edited by mborland, 05 September 2020 - 04:49 PM.


#8 Alterf

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Posted 05 September 2020 - 04:51 PM

There is definitely a problem.  Anything that is not aligned properly in the image train could cause it, though.  Troubleshoot by swapping out each thing and taking a picture without each component?

 

Val



#9 gnowellsct

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Posted 05 September 2020 - 04:57 PM

I wonder if you have any other 80mm triplets available for a comparo.  I mean a friend who has one, for example.



#10 mborland

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Posted 05 September 2020 - 05:15 PM

There is definitely a problem.  Anything that is not aligned properly in the image train could cause it, though.  Troubleshoot by swapping out each thing and taking a picture without each component?

 

Val

I'm hoping to try that tonight. Easiest thing is to shoot without a filter. I already know that the problem is not just the LeNhance filter. I also saw it in some other images with the Optolong LPro.

 

I wonder if you have any other 80mm triplets available for a comparo.  I mean a friend who has one, for example.

Unfortunately, I don't know anyone locally with such a scope.

 

--Michael

 



#11 tonyt

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Posted 05 September 2020 - 08:06 PM

A 30 second image of a star field with the simplest possible setup (no filter, etc) will tell you if there's anything wrong with the scope.

Try an image with and without the flattener.



#12 Woodbridge_Dave

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Posted 05 September 2020 - 09:45 PM

The Esprit 80 has a known issue with miscollimation.  In the last 9 months I went through 3 new scopes searching for a good one, but none were collimation properly.  There was a blurry patch of halo off to one side of each big star.  Skywatcher refunded my money directly.  They said they will  address the issue with the factory.  



#13 gnowellsct

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Posted 05 September 2020 - 10:15 PM

The Esprit 80 has a known issue with miscollimation.  In the last 9 months I went through 3 new scopes searching for a good one, but none were collimation properly.  There was a blurry patch of halo off to one side of each big star.  Skywatcher refunded my money directly.  They said they will  address the issue with the factory.  

Well that's a shame.  This was supposed to be the 80 mm that always excelled.  

 

I think that the lens cell is one of the places where the less expensive apo makers cut costs.    But I'm still surprised to read this about the Esprit.



#14 mborland

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Posted 05 September 2020 - 11:40 PM

The Esprit 80 has a known issue with miscollimation.  In the last 9 months I went through 3 new scopes searching for a good one, but none were collimation properly.  There was a blurry patch of halo off to one side of each big star.  Skywatcher refunded my money directly.  They said they will  address the issue with the factory.  

When was your last contact with them? I wonder if they had time to fix it, or if they sold me one of the bad ones. Do you happen to know the serial number of any of the scopes you tried?

 

Thanks--Michael



#15 Tapio

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Posted 06 September 2020 - 03:47 AM

There's a difference that Esprit 120 is a slower scope than Esprit 80.



#16 Alan S

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Posted 06 September 2020 - 11:48 AM

The Esprit 80 has a known issue with miscollimation.  In the last 9 months I went through 3 new scopes searching for a good one, but none were collimation properly.  There was a blurry patch of halo off to one side of each big star.  Skywatcher refunded my money directly.  They said they will  address the issue with the factory.  

 

 

Well that's a shame.  This was supposed to be the 80 mm that always excelled.  

 

I think that the lens cell is one of the places where the less expensive apo makers cut costs.    But I'm still surprised to read this about the Esprit.

Hey Dave-

 

Sorry to hear you went through 3 samples.  I too am surprised to read that there is a "known issue" as I have been considering purchasing one of these myself, and in my limited searches so far have not run across a known issue with poorly aligned optics.

 

Have you seen reports of this elsewhere?  Any further information you can point to about this issue is appreciated-

 

Thanks,



#17 skyward_eyes

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Posted 06 September 2020 - 11:57 AM

Please email support@skywatcherusa.com.

We need an image with and without the filter on a bright star. Short exposures are all we need.
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#18 mborland

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Posted 06 September 2020 - 12:07 PM

Please email support@skywatcherusa.com.

We need an image with and without the filter on a bright star. Short exposures are all we need.

Thanks, will do.

 

--Michael



#19 mborland

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Posted 08 September 2020 - 07:56 PM

Just an update: I've been testing the scope using an artificial star and confirmed the problem. It persists even without a filter. I was suspicious of the connection between the OAG and the filter wheel (that three-pronged affair), so I replaced the OAG with a plain extension tube. The off-centered halos still exist.

 

I'm in touch with Sky-Watcher to see if this can be resolved.

 

--Michael



#20 skaiser

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Posted 12 September 2020 - 08:53 PM

Yikes.

i just received my Esprit 80mm ED a few months ago.

this is my first refractor (had reflectors and SCTs ) up till now.

have not had a lot of imaging time with it so far with weather problems.

now it looks like I will concentrate on getting some images of bright stars with/without the FF and see if mine shows the same issue.

i will then get these to skywatcher support as per posted email above.

i will post here with what I see in images.

take care

steve



#21 mborland

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Posted 13 September 2020 - 11:12 AM

As mentioned above, there was an issue with my OAG not being square, which I found using an artificial star. Even after replacing the OAG with a straight tube, I still see halos, but they seem less prominent (it's hard to say). What I didn't notice before is that they are also all on the outside, pointing away from the center of the field of view, whereas with the OAG they were all off to the same side.

 

I'm planning a second imaging session with the scope tonight (sans OAG), which is (I hope) going to be the first clear night in over a week. I'm hoping that in practical use the scope will show good performance now. SkyWatcher has asked me to send the scope in for evaluation, but I'm reluctant to start down that road since it isn't clear when it ends.

 

--Michael


Edited by mborland, 13 September 2020 - 11:13 AM.


#22 mborland

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Posted 14 September 2020 - 11:08 PM

Unfortunately, the results of the second imaging session were not satisfactory, so the scope is going back to the retailer. SkyWatcher customer service was responsive as always, but since these scopes are on back-order they couldn't offer me an immediate replacement.

 

There are a few other issues I found with the scope. I'm not saying these are typical of this product, just my experience.

  • The mounting foot is inadequate. There's no way to put an imaging train on the scope and get it to balance on the mount. I solved this with a long ADM universal Losmandy-style dovetail plate, to which I bolted the SW Esprit 80 at one end with a pair of screws. I shouldn't have had to improvise like that with a product in this price range.
  • The threaded fittings are not well finished. E.g., when threading the adapter onto the flattener, the threads would turn for a bit, then get sticky, then turn easily again. It seems the pitch isn't constant or the threads aren't clean.
  • The mechanism for rotating the imaging train was similarly difficult to operate. It would bind up and require two hands to get free.
  • I tried to loosen the "boat wheel" in order to rotate the whole focuser body. I couldn't budge it.
  • The rear cap for the adapter doesn't stay on well.
  • I personally don't care for the screw-on front cap, as it is tedious to remove and attach.
  • Every time I pulled the scope out of the case, several of the blue rubber support balls came lose and rolled around. It's kind of funny, once.

If the optics had been good, I'd have lived with these issues. My Esprit 120 has none of these issues, except the last.

 

In fairness, there are things I liked about the scope

  • 80mm aperture and f/5. I was really looking forward to using this with a Starizona APEX ED 0.65 reducer!
  • The focuser didn't shift when I slewed around and had no backlash that I noticed.
  • The locking mechanism did not cause the focus to shift.
  • The scope seemed to acclimate quickly and hold focus for hours.
  • Nice finish on the tube body and focuser.
  • Light weight.
  • Familiar operation for an Esprit 120 owner.

Too bad the optics didn't meet expectations. I really like the 80mm f/5 specification of this scope, but now I'm on the hunt for something else. Suggestions are welcome!

 

--Michael



#23 tonyt

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Posted 14 September 2020 - 11:53 PM

Yikes.

i just received my Esprit 80mm ED a few months ago.

this is my first refractor (had reflectors and SCTs ) up till now.

have not had a lot of imaging time with it so far with weather problems.

now it looks like I will concentrate on getting some images of bright stars with/without the FF and see if mine shows the same issue.

i will then get these to skywatcher support as per posted email above.

i will post here with what I see in images.

take care

steve

Most of the Esprits are fine. Here's a page where the guy tunes some early esprits which had a different cell design; it shows some abnormal and normal halos: http://interferometr...ml?view=sidebar

 

Obviously it's still possible to get a bad one though since extreme care is needed at the factory with initial assembly of the lenses and cell. 



#24 honyi

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Posted 15 September 2020 - 09:29 AM

Unfortunately, the results of the second imaging session were not satisfactory, so the scope is going back to the retailer. SkyWatcher customer service was responsive as always, but since these scopes are on back-order they couldn't offer me an immediate replacement.

 

There are a few other issues I found with the scope. I'm not saying these are typical of this product, just my experience.

  • The mounting foot is inadequate. There's no way to put an imaging train on the scope and get it to balance on the mount. I solved this with a long ADM universal Losmandy-style dovetail plate, to which I bolted the SW Esprit 80 at one end with a pair of screws. I shouldn't have had to improvise like that with a product in this price range.
  • The threaded fittings are not well finished. E.g., when threading the adapter onto the flattener, the threads would turn for a bit, then get sticky, then turn easily again. It seems the pitch isn't constant or the threads aren't clean.
  • The mechanism for rotating the imaging train was similarly difficult to operate. It would bind up and require two hands to get free.
  • I tried to loosen the "boat wheel" in order to rotate the whole focuser body. I couldn't budge it.
  • The rear cap for the adapter doesn't stay on well.
  • I personally don't care for the screw-on front cap, as it is tedious to remove and attach.
  • Every time I pulled the scope out of the case, several of the blue rubber support balls came lose and rolled around. It's kind of funny, once.

If the optics had been good, I'd have lived with these issues. My Esprit 120 has none of these issues, except the last.

 

In fairness, there are things I liked about the scope

  • 80mm aperture and f/5. I was really looking forward to using this with a Starizona APEX ED 0.65 reducer!
  • The focuser didn't shift when I slewed around and had no backlash that I noticed.
  • The locking mechanism did not cause the focus to shift.
  • The scope seemed to acclimate quickly and hold focus for hours.
  • Nice finish on the tube body and focuser.
  • Light weight.
  • Familiar operation for an Esprit 120 owner.

Too bad the optics didn't meet expectations. I really like the 80mm f/5 specification of this scope, but now I'm on the hunt for something else. Suggestions are welcome!

 

--Michael

I've been using an Esprit 80 for two years now, and yes, i would agree with you on some of the above points on the shortcomings, but there are non-complicated workarounds.

I use a 20cm long dovetail bar which i screw to the bottom of the foot with two 1/4" screws. This makes it much easier to balance even with an imaging train.

I had two adapter rings machined (M74 to M72; M72 to M65), which allowed me to use a Takahashi 2.7" rotator (TKA23200) on the tube, instead of the default contra-rotating rings. I agree that the default rotating system is terrible, and causes image shift.

Some of the results i have obtained: https://www.astrobin.com/users/honyi/



#25 skaiser

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Posted 15 September 2020 - 03:49 PM

Ok . It just makes me uneasy when the company seems to agree that the images don’t look right.

i thought I was being picky on a number of “things” on this scope , but like others , I did expect some higher standards at this price point.

agree on the following:

 mounting rail too short

 threads sticky on FF and image train.

 Replaced screw-on font cap with 3D printed cap. (Worried about thread debris)

 A couple of the  case ball sockets were deformed at factory, would not hold balls. Used some spare foam to make missing ball retaining rings.

 3D printed better cap for adapter.

i really like the focuser mechanism. Seems very smooth. 
great finish on the scope.

perfect setup for my canon 60da.

i have already 3D printed adapters for using my asi224mc / 3x focal extender for planetary imaging.

looks like I’ll finally get some clear sky’s this Friday to Do some evaluation imaging .

i really like this scope and hope the optics were properly setup.

i spent a lot of time researching refractors and will hate to do this again.

I will check out Tony’s references but will submit any pictures I get to see what the company thinks.

take care


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