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SW72 ED can it be beaten?

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#26 houndsbourgh

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Posted 11 January 2020 - 08:29 AM

So SW72ED it is. Will be picking it up next week. How vital is the reducer/flatener right now?

Always a good idea to have a feild flattener/reducer in the imaging train on a small wide field scope. If the target is smaller and centered in the field of view not a big deal. More field of view used more important it becomes. Really it's up to you. Without the flattener/reducer in there you will need to run a 50mm ish spacer stack to reach focus with the camera. You will also need to decide if you want to use the compression/set screw ring to hold it or thread it all together. That's where the FLO adapters come in.


Edited by houndsbourgh, 11 January 2020 - 08:33 AM.


#27 stars n planets

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Posted 11 January 2020 - 08:35 AM

Has anyone been to the Astrofest uk in kensington? There is one at the end of this month. Do the exhibitors sell kit at the stands such as small refractors or is it all demo and show only? Cash or payment facilities? Sorry silly question but ive never been.

If they do sell i may hold out as most of the uk distributors will be there.

#28 houndsbourgh

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Posted 11 January 2020 - 09:12 AM

Here is a shot of mine all threaded together. My SW 72ed is an early version so the SW dedicated flattener/reducer was not available. So if you like options or you just want a flattener in there like my set up adapters are your friend/enemy. I can't remember the brand of flattener I have but I got it from FLO as well. Being threaded on both ends It can run a 2" eyepiece end or threaded adapter. Threading it all together will reduce the probability of misalignment. Looking back on it the SW flattener/reducer would have been a lot less hassle. It threads right into the focuser tube. No adapter needed.

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Edited by houndsbourgh, 11 January 2020 - 09:18 AM.


#29 25585

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Posted 11 January 2020 - 09:13 AM

Has anyone been to the Astrofest uk in kensington? There is one at the end of this month. Do the exhibitors sell kit at the stands such as small refractors or is it all demo and show only? Cash or payment facilities? Sorry silly question but ive never been.

If they do sell i may hold out as most of the uk distributors will be there.

Might go to that...  no FLO there though.



#30 Uranotopia

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Posted 11 January 2020 - 12:01 PM

Has anyone been to the Astrofest uk in kensington? There is one at the end of this month. Do the exhibitors sell kit at the stands such as small refractors or is it all demo and show only? Cash or payment facilities? Sorry silly question but ive never been.

If they do sell i may hold out as most of the uk distributors will be there.

I would like to recommend you to go to the stands and ask for these scooes, try to watch through these refractors and make your own estimation!

But I wouldn't buy it too soon, with the exception, one seller would give you a very good price.


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#31 houndsbourgh

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Posted 11 January 2020 - 04:51 PM

I forget to mention the SW 72ED produced after Dec 2019 is different. Known as a “short tube version” looks like SW has tweaked the design to better accommodate the focuser travel. Very hard to fined any info on the change but FLO mentions it in the rotating camera adapter page.


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#32 kel123

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Posted 12 January 2020 - 09:27 AM

I forget to mention the SW 72ED produced after Dec 2019 is different. Known as a “short tube version” looks like SW has tweaked the design to better accommodate the focuser travel. Very hard to fined any info on the change but FLO mentions it in the rotating camera adapter page.


Was it possible that they didn't test the focus travel in the original version? I am surprised at how some of these big manufacturers fail at simple QC.

#33 houndsbourgh

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Posted 12 January 2020 - 10:10 AM

Every scope has its quirks. Trying to accomidate all the different eyepiece and diagonal designs in such a small package gets difficult. In my experience using the SW 72ED I get the feeling a diagonal with adjustable culmination was part of the idea. Diagonals with the adjustable surface use an extra 8-10mm of focuser travel right off the bat. Using my Meade diagonal on a Baader Mark III I get about 5mm of back focuse. Close but it works. With my ES diagonal I get about 15mm. Shortening the tube may just put it the other way. The design surely narrows your options. If they had included a diagonal originally some users confusion could have been avoided.


Edited by houndsbourgh, 12 January 2020 - 10:11 AM.


#34 michel deromme

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Posted 12 January 2020 - 11:07 AM

Was it possible that they didn't test the focus travel in the original version? I am surprised at how some of these big manufacturers fail at simple QC.

The Skywatcher 0.85 reducer for 80 ED is the same as for the 72 ED, but there is a focus travel problem with the 72 ED, it's missing about 5mm, you need the adapter for the 72 ED. Rotating camera adapter didn't help, was too long.The problem has been traced at Skywatcher and my french distributor, optique unterlinden, sent me the right adapter, so I'm not surprised that Skywatcher has released a short tube travel

picture with rotating camera adapter, target at 950 meters, unable to focus

72ED SW rotating adaptor.jpg

 

picture with good adapter, same target, focus now

72ED shorter adaptor.jpg


Edited by michel deromme, 12 January 2020 - 11:21 AM.

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#35 Uranotopia

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Posted 13 January 2020 - 04:26 AM

The Skywatcher 0.85 reducer for 80 ED is the same as for the 72 ED, but there is a focus travel problem with the 72 ED, it's missing about 5mm, you need the adapter for the 72 ED. Rotating camera adapter didn't help, was too long.The problem has been traced at Skywatcher and my french distributor, optique unterlinden, sent me the right adapter, so I'm not surprised that Skywatcher has released a short tube travel

picture with rotating camera adapter, target at 950 meters, unable to focus

attachicon.gif72ED SW rotating adaptor.jpg

 

picture with good adapter, same target, focus now

attachicon.gif72ED shorter adaptor.jpg

Very interesting news about this scope, thx a lot!

I guess, these facts are of great importance for terrestial observations. like bird watching.



#36 Trevor N

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Posted 13 January 2020 - 05:06 AM

I've found the FLO field flattener works OK. It doesn't reduce the focal length but the scope is fairly fast anyway. Attached image is with a canon 1000D using the flattener.

 

Cost is about £70 so much cheaper than the dedicated SW reducer. I can't recall FLO being at astrofest but their on line service works very well. Trevor

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  • Cali neb ed72 canion 1000D.JPG

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#37 Astrodymium

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Posted 15 January 2020 - 02:21 AM

Nothing comes close in terms of cost. Something to be aware of with this telescope (if you are using it for imaging) is that there will be purple fringing. This can be  seen on Astrobin images and ones I have taken myself personally. I highly suggest you get a doublet that has FPL 53 glass instead for imaging.

 

The reducer/flattener for this scope is also overpriced and at that point you may as well buy the TS72 instead.

 

As for visual, I've never looked through it but it seems to do the job well according to everyone else.


Edited by Astrodymium, 15 January 2020 - 02:30 AM.


#38 Trevor N

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Posted 15 January 2020 - 07:56 AM

I agree. There is evidence of fringing but I didn't find it too bad. The same issues seem to be appearing with the ED150 looking at images so far produced. For the cost though, the ED72 would be hard to beat. It wasn't that many years ago when refractor imaging was a nightmare. Not now !



#39 aa6ww

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Posted 15 January 2020 - 01:17 PM

Did they shorten the tube so there is finally more range of "in-focus?" With a 2" opening, I would have guessed this scope should have been able to accommodate any 2" diagonal and eyepiece combo. Apparently this wasn't the case with the original version.
I know a 2" eyepiece/diagonal combo isn't very practical on something this small, but if its got a 2" opening at the tail end of the scope, why not make it so it can take advantage of every option available.

I unfortunately, bought into the hype that the in-focus was a deterrent and opted not to get one.

I found a used FC-60 in excellent condition that has filled my tiny scope requirements.

...Ralph



I forget to mention the SW 72ED produced after Dec 2019 is different. Known as a “short tube version” looks like SW has tweaked the design to better accommodate the focuser travel. Very hard to fined any info on the change but FLO mentions it in the rotating camera adapter page.



#40 Shorty Barlow

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Posted 15 January 2020 - 01:30 PM

Did they shorten the tube so there is finally more range of "in-focus?" With a 2" opening, I would have guessed this scope should have been able to accommodate any 2" diagonal and eyepiece combo. Apparently this wasn't the case with the original version.
I know a 2" eyepiece/diagonal combo isn't very practical on something this small, but if its got a 2" opening at the tail end of the scope, why not make it so it can take advantage of every option available.

I unfortunately, bought into the hype that the in-focus was a deterrent and opted not to get one.

I found a used FC-60 in excellent condition that has filled my tiny scope requirements.

...Ralph


 

I found that any eyepiece or combination with less than about a 3mm focal length didn't have enough in-focus with 2" diagonals on mine. This was generally with a regular 2" Baader Amici however.

 

med_gallery_249298_10284_152588.jpg

 

I've recently decided to use this Baader dielectric predominantly for weight reasons. When I get the opportunity I will try to see if using a mirror makes any difference to in-focusing with small focal length EP's.



#41 houndsbourgh

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Posted 15 January 2020 - 01:57 PM

Mine plays nice with the ES collection I have. This is at focus on a cell tower 3 miles away. ES 2” diagonal and 32mm eyepiece. When I drop my Badder Mark III in there the back focus gets cut down to 5+mm.

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  • 08F886EC-EEE3-4E0A-88AB-29C67FA376FA.jpeg

Edited by houndsbourgh, 15 January 2020 - 02:03 PM.


#42 Shorty Barlow

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Posted 17 January 2020 - 12:14 PM

Well basically the mirror makes no difference. I couldn't achieve enough in-focus with a 5mm orthoscopic and a 2.5x Barlow with a 2" diagonal. 



#43 jeffmac

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Posted 18 January 2020 - 11:26 PM

Using a low profile 2" to 1.25" adapter in the diagonal will greatly improve the number of eyepieces that can achieve focus with this scope.



#44 Shorty Barlow

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Posted 19 January 2020 - 01:29 PM

Using a low profile 2" to 1.25" adapter in the diagonal will greatly improve the number of eyepieces that can achieve focus with this scope.

It might, although I just switch to a 1.25" diagonal which solves the problem for me.




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