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Sky-Watcher Evostar 72ED DS-Pro


FLO

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1 hour ago, FLO said:

Some of the comments in this thread suggest a problem with the telescope or its reducer but our experience here at FLO suggests the opposite. 

Since launch the Sky-Watcher Evostar 72ED Pro has been hugely popular, outselling even the long established 80ED Pro. So far we have experienced only two customer returns (one for dust behind a lens element and the other because the customer believed his draw tube was misaligned). As for the 0.85x Reducer/Flattener, only one return. My colleague, Grant, is getting along nicely with his and there are some nice images posted here at SGL. 

From where we sit the telescope and reducer are performing well and owners are pleased. We certainly haven't noticed a need for third-party reducer/flatteners. 

Is it pixel-peeping (the 72ED Pro a £265 doublet) or are we missing something? 

Steve 

Hello, Steve!

Maybe I pixel-peep, but the 0.85x SkyWatcher reducer/flattener and the OVL non reducing flattener don't give perfect results around corners with APS-C and 4/3" format sensors at the expected 55mm backfocus distance. I found that the image quality improves at ~60mm, but with the mentioned flatteners, at 60mm, you're just at the focus limit and stars are still not perfectly round at corners. Increase the backfocus distance more, and you won't be able to focus anymore.

Here's an image shot with a Canon 550D (APS-C sized sensor) at 55mm backfocus (just the M48 -> EOS adapter used) and the SkyWatcher flattener.

And below an image shot with the same flattener, but this time with a "spacer" about 3mm wide. The stars have a better shape at corners, though not perfect.

M42_2019-01-07_DSLR_RGB_p07.thumb.jpg.723db2a79d755dbab68cb899183cf3cb.jpg

And here's an image shot with an ASI1600 (4/3" sized sensor) at ~60mm backfocus, same flattener. The sensor is smaller, but the pixels are smaller too so they should emphasize any distortion.

 

How good is good enough? That depends on each person.

I don't think there's anything wrong with the optics, just that the backfocus distance should be more than 60mm and there's not enough focus travel distance to play with with those flatteners.

One day I will try the TS as it seems that one is (or can be) fully inserted in the drawtube. Of course, I will post the results.

Hope this is useful!

Alex

Edited by alexbb
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2 hours ago, FLO said:

Is it pixel-peeping (the 72ED Pro a £265 doublet) or are we missing something? 

You aren't missing anything.  This telescope performs excellently, particularly given the price point.   For me it seems pretty evident that it was never designed specifically for imaging, but as a decent quality portable item for visual use that would also perform perfectly adequately for imaging.

I think, perhaps, some of the frustration I am seeing comes from people who are trying to sort out the spacing to the FF as none of them are specifically designed to work with this OTA, so it does need a little bit of fettling.  Also most that I see are using it with a DSLR with pretty large sensors, so almost inevitably the field isn't absolutely perfect across it.  I have not had issues with using either the SW one or the OVL one (with the nose cone removed and screwed to the draw tube) other than the well documented short inward travel of the draw tube, but that isn't insurmountable in most cases. 

TS do some very nice Photoline products, designed with imaging in mind, as do SW in the Esprit model of course, but these are not available at the cost that this one retails for.

Edited by RayD
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5 minutes ago, alexbb said:

Hah! Did I miss that?

It works well.  The nose cone unscrews and you then use the M48 adaptor (I am at work so I will check this later as there are a few) which FLO supply, and screw it to the draw tube.  For me it gave a little better performance than the SW one, but both seem to work.

I did a short video here, and have more to upload with it in use.

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6 minutes ago, RayD said:

It works well.  The nose cone unscrews and you then use the M48 adaptor (I am at work so I will check this later as there are a few) which FLO supply, and screw it to the draw tube.  For me it gave a little better performance than the SW one, but both seem to work.

I did a short video here, and have more to upload with it in use.

This one https://www.firstlightoptics.com/adapters/lynx-astro-m48-adapter-for-sky-watcher-72ed.html

Indeed, that should allow for a more inward focusing.

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35 minutes ago, Skyline said:

That's a good adaptor, but might have to adapt this to have an internal 2" filter fitting 

Yes, a filter would need to go elsewhere in the imaging train.  I use mine with a SX mini wheel, so this wasn't an issue.

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Unfortunately one way around this would be buy a IDAS EOS Clip filter, but I am just thinking if I was to buy a Baader Protective EOS T Ring adaptor, then use my 2" IDAS into it, then I would have to use a Lynx adaptor to make the scope for better inward focus using a DSLR with the OVL flattener, as this is my preferred camera for imaging.

I am wondering, would this combination work ?

Edited by Skyline
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19 minutes ago, Skyline said:

Unfortunately one way around this would be buy a IDAS EOS Clip filter, but I am just thinking if I was to buy a Baader Protective EOS T Ring adaptor, then use my 2" IDAS into it, then I would have to use a Lynx adaptor to make the scope for better inward focus using a DSLR with the OVL flattener, as this is my preferred camera for imaging.

I am wondering, would this combination work ?

I can't see why it wouldn't.  I get enough inward travel with my EOS 450D and the OVL flattener screwed to the Lynx adaptor.

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On 16/02/2019 at 08:10, RayD said:

This is how I fit my OVL to mine with unscrewing the nose cone and using the M48 adaptor.  This is with the camera in focus, so there is a bit of play.

20190215_203123.jpg.72835443e54e8287e102e8c9b418a5c3.jpg

 

Ray,

am I right in assuming that because the FF is screw fitted to the scope draw tube and the Canon is bayonet (obvously fixed points) that you have to rotate the whole scope for image framing?

 

Tim

 

 

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Just now, Cozzy said:

 

Ray,

am I right in assuming that because the FF is screw fitted to the scope draw tube and the Canon is bayonet (obvously fixed points) that you have to rotate the whole scope for image framing?

 

Tim

 

 

That's correct, Tim.  An unfortunate down side.  You can have some control with the positioning by adding delrins between the adaptor and the draw tube if you find the focuser fouling your mount.  I use a long dovetail with a weight at the front, so my focuser is clear of the mount.

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6 minutes ago, Cozzy said:

just found this link whilst having a search, could be very useful, what do you think?

Superb idea, Tim.  Thanks for that.

You know I need to check my Baader one as looking at this I have a feeling I may be able to do this with that one!

Cheers :thumbright:

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  • 2 weeks later...

Well, Got my 72 ED this week, Also went for TS FF/fr. I have had a quick set up pay in the house but as usual the weather not letting me test it. Also for those interested the  SW auto focuser fits no problem. I have set the spacing for the FR to 65mm for the first test, does that sound about right? Im using a ZWO 1600 mm pro and narrow band filters for this set up so wish me luck!

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On 18/02/2019 at 10:37, RayD said:

Superb idea, Tim.  Thanks for that.

You know I need to check my Baader one as looking at this I have a feeling I may be able to do this with that one!

Cheers :thumbright:

Ray

have you tried this system yet?

I have just recieved two packs (4 in each) of 2.5mm thumb screws from China so will have a go at swopping out the grub screws on the DSLR-M48 Ring Adapter and Canon EOS T ring adapter. Not sure what size the grub screws are for the Canon EOS T ring adapter, do you have any idea what they are?

 

Tim

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On 02/03/2019 at 09:09, simmo39 said:

Well, Got my 72 ED this week, Also went for TS FF/fr. I have had a quick set up pay in the house but as usual the weather not letting me test it. Also for those interested the  SW auto focuser fits no problem. I have set the spacing for the FR to 65mm for the first test, does that sound about right? Im using a ZWO 1600 mm pro and narrow band filters for this set up so wish me luck!

That's good news, it's a great scope.

hope all goes well with the testing.

sorry can't help with the spacings, I will be using a Canon 450D and OVL FF, and just ordered a threaded 5mm spacer, so like you will testing when it arrives along with the great UK weather.

 

Tim

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4 hours ago, Cozzy said:

That's good news, it's a great scope.

hope all goes well with the testing.

sorry can't help with the spacings, I will be using a Canon 450D and OVL FF, and just ordered a threaded 5mm spacer, so like you will testing when it arrives along with the great UK weather.

 

Tim

Thats it, no good weather for at least a month then! lol. good luck hope it all works out well.

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7 hours ago, Cozzy said:

Not sure what size the grub screws are for the Canon EOS T ring adapter, do you have any idea what they are?

One here is M3, and takes a 1.5mm allen key.

Good idea to swap out for thumb screws, who needs a rotator?

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33 minutes ago, Stub Mandrel said:

One here is M3, and takes a 1.5mm allen key.

Good idea to swap out for thumb screws, who needs a rotator?

Neil,

thanks for the info much appreciated. 

just swapped out the grub screws for thumb screws in the DSLR-M48 adapter, works a treat.

Now to order some M3 thumb screws for the DSLR -T2 adapter.  Much much cheaper than a bought rotater! 

A big shout out 'Nice one Grumman'

 

Tim

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M48 adaptor fitted to focus tube, OVL FF and 5mm spacer fitted (pack of spacers available in case I need more, to fine tune), grub screws replaced with thumb screws.

So good to go??, thanks for the info all.

Ok who sorts the weather out then.:clouds2:

 

Tim

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