Sky-Watcher Evostar 72ED DS-Pro

[alexbb]

3 minutes ago, RayD said:

I have a feeling they were in the dark with this as much as we were, and were also expecting a dedicated corrector.  I'm sure they are trying to find out as much as possible, and also keeping an eye on our testing as it is all a bit of an unknown at the minute.

Of that I'm pretty sure too. But if they act upset, maybe SkyWatcher could lean an ear towards them and maybe tell them some additional information. I've a feeling that if I asked SkyWatcher directly, I would receive no answer.

TS state that their 72ED with the 0.79x reducer/flattener works with a 65mm backfocus. I hope I will be able to test next week the 6/8/10mm M48 spacers and see which one fits better.

But I also do wonder if SkyWatcher do actually test their products. I mean, did they take at least a picture through this scope and the flattener? How did it look like?

This might be the last of the SkyWatcher products I buy new, maybe only if I find some tested sh bargains.

It's a pity that FLO need to provide extra check and fix for some of the scopes or that we need to sort out how a new product works. It is expected that we don't read the manual, but at least provide all the needed parts.

[RayD]

16 minutes ago, moise212 said:

Of that I'm pretty sure too. But if they act upset, maybe SkyWatcher could lean an ear towards them and maybe tell them some additional information. I've a feeling that if I asked SkyWatcher directly, I would receive no answer.

TS state that their 72ED with the 0.79x reducer/flattener works with a 65mm backfocus. I hope I will be able to test next week the 6/8/10mm M48 spacers and see which one fits better.

But I also do wonder if SkyWatcher do actually test their products. I mean, did they take at least a picture through this scope and the flattener? How did it look like?

This might be the last of the SkyWatcher products I buy new, maybe only if I find some tested sh bargains.

It's a pity that FLO need to provide extra check and fix for some of the scopes or that we need to sort out how a new product works. It is expected that we don't read the manual, but at least provide all the needed parts.

I'm certain that FLO get as frustrated as we do when things don't fit together, especially when they are from the same manufacturer.

I think the pressure was on SW to release a FR for this 'scope, so they felt utilising the 80ED one would be the best solution.  However, as you rightly say, some accurate spacing details would have been useful for sure.

I notice now that TS has relegated the SW corrector to options rather than recommended.  I wonder if this was a conscious decision?  It will get ironed out, I'm sure, and a small run of clear skies will enable me to get a definitive spacing requirement.  I'm sure there is someone out there who can calculate it, but I didn't even get an E in A level maths, so that's beyond me.

[FLO]

1 hour ago, moise212 said:

I wonder if @FLO has more priority to get an answer from SW about the correct distance for the 72ED + flattener.

We are doing our best to find the info ? 

1 hour ago, RayD said:

I have a feeling they were in the dark with this as much as we were, and were also expecting a dedicated corrector.  I'm sure they are trying to find out as much as possible, and also keeping an eye on our testing as it is all a bit of an unknown at the minute.

@RayD is right ^ ?

Will post details as soon as we have them. Promise. 

Steve 

[Susaron]

One more thing to add. The usual FLO compression ring suitable for the ED80/ED100 etc. does not fit into the ED72, as the internal drawtube thread is M54, you need to use the compression ring for the SW newtonians, so instead of using this:

https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-synta-skywatcher.html

Use this one:

https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-for-skywatcher-newtonians-m54.html

Regarding the reducer spacing I have checked my numbers with my QHY168, (another nightmare of camera with a lot of spacers), and it gives me around 56.5mm, when I use the camera with the Baader Mpcc I need around 57 to 57.5 mm to eliminate the coma, I will see what happens with the ED72.

Cheers.

[RayD]

5 minutes ago, Susaron said:

One more thing to add. The usual FLO compression ring suitable for the ED80/ED100 etc. does not fit into the ED72, as the internal drawtube thread is M54, you need to use the compression ring for the SW newtonians, so instead of using this:

https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-synta-skywatcher.html

Use this one:

https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-for-skywatcher-newtonians-m54.html

Regarding the reducer spacing I have checked my numbers with my QHY168, (another nightmare of camera with a lot of spacers), and it gives me around 56.5mm, when I use the camera with the Baader Mpcc I need around 57 to 57.5 mm to eliminate the coma, I will see what happens with the ED72.

Cheers.

There are actually a few custom adaptors that FLO has had specially made specifically for the 72ED due to the thread cut of the draw tube.  You can find the compression one here and there is also a M42 (T) and M48 one, which are all very good and work well with this OTA.

[alexbb]

15 hours ago, Susaron said:

Regarding the reducer spacing I have checked my numbers with my QHY168, (another nightmare of camera with a lot of spacers), and it gives me around 56.5mm, when I use the camera with the Baader Mpcc I need around 57 to 57.5 mm to eliminate the coma, I will see what happens with the ED72.

I'm interested to see what you get with 57.5mm, but I have a feeling that we need more. I'm afraid 2.5mm is not that much. Maybe you can get away with the QHY168, as the 4/3" sensor is smaller than the APS-C sensor which is quite wider.

15 hours ago, RayD said:

There are actually a few custom adaptors that FLO has had specially made specifically for the 72ED due to the thread cut of the draw tube.  You can find the compression one here and there is also a M42 (T) and M48 one, which are all very good and work well with this OTA.

I've a few 2" compression adapters for my Newtonians and the adapter for the 72ED. They are identical.

[RayD]

6 minutes ago, moise212 said:

I've a few 2" compression adapters for my Newtonians and the adapter for the 72ED. They are identical.

I don't doubt that for one minute.  Equally I have several M54 fittings here that I have tried and they don't fit, so anyone buying an adaptor who doesn't have newt ones to try, or doesn't want to play a game of hit and miss, is probably better getting the FLO ones, I would have thought.

[alexbb]

1 minute ago, RayD said:

I don't doubt that for one minute.  Equally I have several M54 fittings here that I have tried and they don't fit, so anyone buying an adaptor who doesn't have newt ones to try, or doesn't want to play a game of hit and miss, is probably better getting the FLO ones, I would have thought.

I would say that's wise.

OTOH, I waited a few months for this adapter to become available, while the one for the Newtonian was already available for long. I also waited a few weeks for an AZ-EQ5 Berlebach tripod, while one for HEQ5 was already in stock and actually on mine it is written HEQ5. Not to mention for how long I waited for the flattener for the 72ED...

Hopefully this info comes up on search engines. It would be useful also if FLO and others updated their offers to reflect this.

[RayD]

23 minutes ago, moise212 said:

I would say that's wise.

OTOH, I waited a few months for this adapter to become available, while the one for the Newtonian was already available for long. I also waited a few weeks for an AZ-EQ5 Berlebach tripod, while one for HEQ5 was already in stock and actually on mine it is written HEQ5. Not to mention for how long I waited for the flattener for the 72ED...

Hopefully this info comes up on search engines. It would be useful also if FLO and others updated their offers to reflect this.

Yes I fully understand what you're saying.  

Unfortunately in many cases, as with the corrector, retailers like FLO have the same information as us so only get to see the product when it arrives, just as we do.  To be fair to @FLO, as soon as they were aware this was the same corrector they immediately updated their site and even offered a refund to those who bought one and already had one for their 80ED. You can't get better or fairer than that in my book.  I suspect that they would do the same wherever this applies, or at least would confirm that the alternative was the same fit.  Naturally I can't speak for other suppliers (I'm not speaking for FLO either, just my experience of them), but this is just another reason why I prefer to use FLO as my experience shows that they are totally honest and do the right thing.

In industry it makes commercial sense to reuse parts where possible.  Take a look at the motoring industry for a clear example of this, where underneath the badge of one car lies a completely different one (Jaguar and Ford Mondeo springs to mind).

 

Edited August 31, 2018 by RayD

[alexbb]

4 minutes ago, RayD said:

Yes I fully understand what you're saying.  

Unfortunately in many cases, as with the corrector, retailers like FLO have the same information as us so only get to see the product when it arrives, just as we do.  To be fair to @FLO, as soon as they were aware this was the same corrector they immediately updated their site and even offered a refund to those who bought one and already had one for their 80ED. You can't get better or fairer than that in my book.  I suspect that they would do the same wherever this applies, or at least would confirm that the alternative was the same fit.  Naturally I can't speak for other suppliers, but this is just another reason why I prefer to use FLO as my experience shows that they are totally honest and do the right thing.

In industry it makes commercial sense to reuse parts where possible.  Take a look at the motoring industry for a clear example of this, where underneath one car lies a completely different one (Jaguar and Ford Mondeo springs to mind).

 

I'm not trying to argue in any way, I apologize if I left this impression.

I was just trying to mention that there are alternatives to some items and this is not obvious at first glance. While the info about the flattener was added indeed by FLO to the site, the info about the other parts I was referring to is only on the forum.

[RayD]

6 minutes ago, moise212 said:

I'm not trying to argue in any way, I apologize if I left this impression.

I was just trying to mention that there are alternatives to some items and this is not obvious at first glance. While the info about the flattener was added indeed by FLO to the site, the info about the other parts I was referring to is only on the forum.

No not in the slightest, that was the furthest thing from my mind.  It's a good thread in general and is giving me information which I never knew on compatible parts too.

[Skyline]

On 30/08/2018 at 16:26, Susaron said:

One more thing to add. The usual FLO compression ring suitable for the ED80/ED100 etc. does not fit into the ED72, as the internal drawtube thread is M54, you need to use the compression ring for the SW newtonians, so instead of using this:

https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-synta-skywatcher.html

Use this one:

https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-for-skywatcher-newtonians-m54.html

Regarding the reducer spacing I have checked my numbers with my QHY168, (another nightmare of camera with a lot of spacers), and it gives me around 56.5mm, when I use the camera with the Baader Mpcc I need around 57 to 57.5 mm to eliminate the coma, I will see what happens with the ED72.

Cheers.

You are correct, The thread size on the ED72 draw tube is M54. I Could not reach focus using the standard thick 12mm collar fitted on the ED72 using a SW 0.85x reducer with a 2" pushfit adaptor. I have to use a pushfit adaptor instead of the screw on method due to using a IDAS 2" LPR filter. However I did overcome the focusing issue by replacing the standard collar to a low profile collar which I use on my 130PDS to reduce the draw tube intruding into the light path, which measures 8mm thick compared to the standard collar of 12mm .

Cheers.

[alexbb]

On 26/08/2018 at 12:51, FLO said:

We have learned the Evostar 72ED’s 0.85x reducer is the 0.85x reducer for Evostar 80ED, with a thread adapter. They are the same. So if someone already owns the reducer for 80ED then they need only our FLO 2” nosepiece adapter to use it with the 72ED. 

HTH

I tried yesterday to increase the backfocus distance. I used an m48->m42 and an m42->eos adapters. The total backfocus increased by ~8mm. The problem was that I could not reach focus anymore. The m54->flattener provided by SkyWatcher adds 6mm between the focuser and the flattener. So that's a no go. Even more, I can't unscrew the m48->m42 adapter from the m42->eos adapter, yay.

I tried then to make another spacer from a beer holder. This adds 2-3mm to the backfocus and it seems to be about enough after last night's tests. But with this I'm left with not much focus space. So 2-3mm of added backfocus + 6mm the SkyWatcher adapter and there are just a few mm left. I'm afraid that with the lynx 2" compression adapter and with the custom 2"->flattener FLO adapter, you might not be able to reach focus, especially if you want to increase the backfocus distance for rounder stars.

I don't know how much the FLO custom 2" to flattener adapter adds, but someone please check if possible.

The first image is where I can't reach focus, the second is in focus.

If I was not clear enough, I apologise, I'm on the phone. I can come back later.

[Skyline]

The 2nd pic shows how much distance +2 mm extra is left when using my low profile adaptor with the reducer and push fit.

Edited September 2, 2018 by Skyline

[Ben Ritchie]

On 27/08/2018 at 12:02, RayD said:

I would say that SW probably intend for this to be use with 2" eyepieces, especially at low powers, and is why it is only supplied with a 2" thumbscrew adaptor on the draw tube (this is only an assumption). 

Low-power browsing with a 2" eyepiece should be a natural use-case for it, but there are some slight frustrations - it's very focuser-heavy and hard to balance with a 2" diagonal and a heavy 2" eyepiece, as the short dovetail doesn't give much room for adjustment.

I find mine a bit easier with a lighter max-FoV 1.25" eyepiece (I have a 24mm Meade SWA, but a 24mm Panoptic would be great too), and that seems to be a good combination and gives wide fields with less weight. Haven't had time or clear-enough skies to really test mine out properly - only arrived from FLO a couple of weeks ago, and life's been busy! - but first signs have been pretty positive, and i'm pleased with the purchase. 

Edited September 5, 2018 by Ben Ritchie

[Stu]

1 hour ago, Ben Ritchie said:

Low-power browsing with a 2" eyepiece should be a natural use-case for it, but there are some slight frustrations - it's very focuser-heavy and hard to balance with a 2" diagonal and a heavy 2" eyepiece, as the short dovetail doesn't give much room for adjustment.

I find mine a bit easier with a lighter max-FoV 1.25" eyepiece (I have a 24mm Meade SWA, but a 24mm Panoptic would be great too), and that seems to be a good combination and gives wide fields with less weight. Haven't had time or clear-enough skies to really test mine out properly - only arrived from FLO a couple of weeks ago, and life's been busy! - but first signs have been pretty positive, and i'm pleased with the purchase. 

I agree with that Ben. The views with a widefield long focal length eyepiece in theae scopes will be lovely, but as you say, very back heavy! The 24mm Pan makes a very good match with it weight-wise though as you say, and still gives plenty of sky to enjoy.

[alexbb]

OK, I put the ASI1600 on the little scope for some serious imaging (intended at least).

I increased the backfocus distance to 60mm and I'm left with 1-2mm focus distance. The stars don't look good enough around the corners and there's not enough focus distance to increase the backfocus. Meh..

You could probably get away with a small decrease in resolution or larger pixels. Mine's are 3.8um, an 18MP Canon APS-C sensor has 4.2um wide pixels.

Attached are a pic of the camera + adapters at the focus distance and an integration of 4h in Ha. No flats applied yet so the image was flattened in processing. A simple HT with STF parameters applied.

[Adam J]

I was giving serious consideration between this scope and a TS72 / WO ZS73. Guess I just got my answer.

 

[alexbb]

If only I knew...

[Skyline]

My efforts:

Using 55mm spacing on a skywatcher reducer

[Skyline]

That is a full sensor image of a Atik 314L+

[alexbb]

2 minutes ago, Skyline said:

That is a full sensor image of a Atik 314L+

I only see it at 1391x1039

[Skyline]

Thats the size of the resolution area

[Skyline]

My setup:

 

[alexbb]

I wasn't aware of the sensor size of your camera, I thought it was larger. Indeed, you will notice that the correct backfocus is not 55mm only with a larger sensor and smaller pixels. My pixels are 3.8um wide and I have 4656 of them on width.

Edited September 19, 2018 by moise212