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nicoscy

SkyWatcher 72ED just arrived

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Posted (edited)

It appears I snagged the last SW72ED at FLO (a customer return without it being opened) and after a wholly unnecessary but most welcome discount by FLO, DHL just dropped like 2 hours ago a lovely SW72ED. My first transaction with FLO and Steve was most awesome to deal with!

I have plans for this scope. The price to performance proposition is superb and this will be my do-it-all mighty midget. Travel scope, short focal length EAA scope, spectroscopy scope (yes, I know mirrors are better for this, but the SW will do well enough), grab 'n go for quick sessions and generally a nice lightweight all rounder.

Will put it through its paces this weekend on the moon, some doubles and maybe EAA time permitting. Interested to see how it will perform on DSO and I have fitted a 2" field flattener (the TS model) to a TV diagonal I have prepped for this scope. The field flattener worked wonders on my Borg 55FL, yielding a visually flat field at f4.5, so it should iron out any field curvature with ease on the SW72ED (I belong in the old school where anything faster than 7.5 is too fast). 

More feedback to be provided when testing takes place! Note that both Mr. Spock and the 2 Buddhas gave their seal of approval to this scope 😋

SW27ED.jpg

Edited by nicoscy
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My impressions of unpacking:

The aluminum case has 2 slots for eyepieces, one for filters and one for the diagonal. Quite sturdy, but a bit heavy with scope and accessories in it. I will use a small padded back I have for the scope and a small camera bag for visual accessories.

Scope measures just under 420mm in length, so easily within cabin luggage restrictions. Dunno why some people discussed in the past the removal of the dew shield to reduce length for travelling.

The focuser is - gasp - buttery smooth! In my current lineup I have a 2" FTF (Crayford) and a 3" FTF R&P. I daresay that this focuser is close enough. In an email I sent to Steve earlier I said: "Surprised at the quality of the focuser as the basic SW focuser is - pardon my French - crap and needs a lot of work to be serviceable. It is buttery-smooth, and I wish SW implemented whatever they did with this focuser, throughout their range of achros and ED doublets. I was honestly taken aback with the focuser. I fully expected to have to work on it and had resigned myself to just having a so-so focuser at the scope's price point, but I am so glad to be proven wrong."

Fit and finish WELL above what I expected. SkyWatcher is definitely upping their game with this scope. Focuser travel around 40mm so I hope it works ok with my eyepieces.

More later...

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This is definitely on my Want List for my SA!

Nice descriptions @nicoscy

:)

 

 

 

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Not all is rosy in SW Land though. Some small design flaws do come up:

Dovetail and rings: rings must be placed as far back as possible to allow balancing with 2” diagonal and eyepiece (and I use a lightweight one too). The dovetail is not made in a way to allow moving the rings closer together to allow for part of the dovetail to be further back. A dovetail with a groove in the middle running all the way through would be preferred.

Findershoe location: Scope is drilled only to the left side for a findershoe (an extra hole on the right wouldn’t kill SW mechanics / designers) and also placing it at say 11 o’clock would be more helpful. Also, the findershoe cannot be swapped for another as the drilled hole is located at a point too close to the beveled area of the focuser adapter.

Relevant photos attached but these are pet peeves. However, in the interests of fairness, all must be reported. Testing on moon and a couple of doubles later in the evening.

6B10BDC2-FD41-4882-8FF8-47DC54181413.jpeg

88162DA1-4452-4548-98B4-9D2DAD6E325F.jpeg

F5C644F6-092B-4545-9DB0-11336697E6D7.jpeg

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Posted (edited)

Last night was not the best to test the scope. Too much humidity. Despite the obvious refraction effect from this (even just eyeballing the moon showed a halo from high altitude humidity), what little chromatic aberration was seen, I can definitely attribute it to this and not to the optics. Of course more testing will be done when weather conditions are better.

A tentative thumbs up for the optics, but one very serious design flaw. Using my Tele Vue 2” diagonal, Tele Vue 7mm T6 and Astro Physics 2x Barcon, I could not reach focus. Not enough in-travel. So, I was stuck at 60x with the 7mm by itself.

I can bypass this by using an eyepiece with shorter native focal length, but this is a serious design flaw by Skywatcher and arises out of the fact that they made the OTA too long and allowed only about 40mm focuser travel. I suspect that this was done to make sure the focuser would not be overtly stressed by extending out too much.

I am now seriously worried that I could have issues reaching focus with my 2” solar wedge and 7mm T6 (without Barlow, 60x is perfect for white light solar viewing), or that I could face lack of in-travel with my 0.79x reducer and ASI183 camera.

Currently on stand by for the sun to come up a bit more so that I can set up in my back yard...

Edited by nicoscy

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Very interesting comments Nicos. Thank you. I have the TS Optics 72mm which I guess is a reasonably close competitor of the skywatcher albeit about £100 more expensive. The R&P focuser on the TS has a lot of travel (over 100mm) and although I’m not an imager,TS state on its website that it can be used fine with reducers etc.

I guess it’s not likely to happen soon (unless I make that trip to Cyprus 😊) but it would be interesting to see a side by side of the TS and skywatcher done some day.

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Gavin,

Mostly interested for EAA with this scope as well as spectroscopy (yes, mirrors are better for the latter but whatever).

If I can reach focus with my camera and reducer, I will keep it. The solar thing is a non issue I just decided, because if there is a worthy sunspot to observe, I would prefer the additional resolution and focal length of my FS128.

Re the Barlow thingie, I can always get another eyepiece in the future, but this scope is to be used for wide field views of the sky, not for high magnification work as again, my FS128 provides jaw dropping views of the moon and planets.

But, I will test the solar wedge in a bit and post my results and later today mount my camera and reducer and see how that goes...

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Your choice of the TS gets you better rings and dovetail, better focuser and better optics. The only thing in common between these scopes is the aperture ;)

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Posted (edited)

Ok, with my APM 2” Herschel wedge and 7mm Nagler T6, I can reach focus with (drum roll please) one millimeter to spare!

Nice contrasty views of the sun, with granulation easily visible on the limb and around a piddly little thing that calls itself a sunspot. 60x is a nice place to be for solar viewing. 

Next this evening,  is to point the scope to some bright star or other and see if I can reach focus with the reducer. A bit concerned as the focal length will go down from 420 to 332. Them 88mm in- travel could theoretically cause an issue, but I think it will be ok and again, very close to the focuser being racked in. 

The optimal space of the flattener to scope is 65mm and there is an additional 40mm from the body of the reducer. However, since Imaging is done sans diagonal, and since I can reach focuser with a 2” diagonal which takes more than 105mm of travel, I should be good to go. 

If so, and based on what I saw visually last night, it will make a cracking scope for wide field EAA views and for spectroscopy. If it performs well, I am revising my original thought of getting a smaller padded case for it and I will move the camera, filters, flattener and extensions to the metal case that came with the scope and keep everything together as a set :)

As the gold standard, I keep in mind my former FC76 in more or less the same aperture, but a much more gentle focal ratio of 7.5. The SW is about 7 times cheaper,but the views are 85% - 90% of what I got with the Tak.

The value / performance ratio is incredible as long as you do not need to alter anything on the scope. The focuser will do for my ASI183 + reducer weight. The dovetail despite its shortcomings will balance along nicely with the camera + reducer. The finder shoe is a non issue for my style of EAA as I do not need guiding or much troubled by its location for visual and I can always rotate the scope to have the findershoe at my preferred 11 o’ clock position. The scope is short enough for travel purposes and light enough to go on the smallest decent EQ mount I have in mind (IOptron EQ Pro +). 

The only change I did was to replace the visual back with the non-marring one on offer by FLO. I detest screw markings and chalk that down to the negatives of the scope design - it should have been non marring to start with.

Soooooo.... with one more test to go, the TS that Gavin referred to is the better scope, but at a different price point to take into consideration most of the nags I mention about the SW.

The point though is that SW built a scope for those who are more or less ok with these nags and consider them non issues.

BTW, one can always use a 1.25” diagonal and Barlow and reach focus. I have both so again, the focusing thing is a non issue - I just have to go to my storage unit and dig up that Barlow!

Edited by nicoscy

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A nice perk is that my reducer (which I got as a gift from a friend - yay, saved some for more astrostuff - is this one from TS. Removing the visual back allows me to thread it on the focuser drawtube. Eliminating the visual back out of the configuration ensures a better fit and stability (assuming the drawtube is orthogonal to the optical elements of course to begin with).

So, at M54x0.75, for anybody interested, TS has 3 interesting adapter to T2, M48 and mix T2 and M48, this, this and this. Usually SkyWatcher Crayford focusers are M54x1 so this one is a bit different and needs a different adapter. 

 

Reducer.JPG

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Nicos that is an excellent review of this new scope from Skywatcher. You have covered so information with the pros and cons associated with this scope and have answered many questions I wanted covered.

Thanks again

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Most welcome Mark :)

Unfortunately I may not be able to test the scope if it focuses with the reducer and camera combo. My ZWO adapters need to be reversed to put the T2 thread ahead of the M48 (they are the other way round now) but the parts got stuck! 

30 minutes of WD 40 didn’t to anything and they are currently in the fridge cooling off. Hopefully by lowering their temp the contraction will allow me to unthread them. Otherwise, a 10 day wait for me as I already ordered a second set of these adapters from ZWO.

On the subject matter of SW72ED Vs TS72ED, If someone wants an all rounder, the TS is better and more versatile, at a reasonable increase in cost over the SW72ED as I explained above. For my specific needs, the Skywatcher will do without feeling that I “sacrificed” too much.

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Very helpful review, thanks for posting. :)

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After 3 rounds of WD 40 and 2 rounds in the freezer and using tools from the local DIY store to secure s form grip, it was impossible to pry the parts separate. However, I found a T2 to 2” adapter, which enabled me to test the backfocus.

Instead of being plagued with in-travel issues, the exact opposite happened! Focuser drawtube too short and I need a bit more to reach focus. This can be sorted out though...

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It also appears that Baader Planetarium has come up with a Clicklock Clamp for this particular scope. As mentioned earlier, the threads on the focuser drawtube are female 54mmx0.75 Vs 54mmx1 for the standard SkyWatcher Crayford focuser. 

They have added a new SKU in their product lineup#2956253 NEW 06/18 M54i x 0,75-ClickLock (Bresser / Omegon / Explore Scientific)

I think I want to treat the little SkyWatcher to one of these. I fired off an email to Baader asking about compatibility (measure twice, cut once) and will update accordingly :) 

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Good to see Baader have added new sizes and a form to request a type they don't yet produce. Every scope should have click locks. :)

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Sigh,

Just got a response from Baader. Their clicklock is indeed the correct size but it is also female. So, a M54 Male to Male adapter is required. Checking around to see if I can find something!

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On 18/08/2018 at 06:21, nicoscy said:

Gavin,

Mostly interested for EAA with this scope as well as spectroscopy (yes, mirrors are better for the latter but whatever).

If I can reach focus with my camera and reducer, I will keep it. The solar thing is a non issue I just decided, because if there is a worthy sunspot to observe, I would prefer the additional resolution and focal length of my FS128.

Re the Barlow thingie, I can always get another eyepiece in the future, but this scope is to be used for wide field views of the sky, not for high magnification work as again, my FS128 provides jaw dropping views of the moon and planets.

But, I will test the solar wedge in a bit and post my results and later today mount my camera and reducer and see how that goes...

@nicoscy you have peeked my interest in spectroscopy! I know nothing about how to do it apart from a brief web search after reading your post and I'm looking for a bit of advice about what kit I need to get into it. I fancy having a go but I'm wondering how easy it is for a complete beginner to get reasonable results.  I have an Altair Astro 80mm ed with star discovery alt az goto mount and a Meade etx 125 which I could use on the star discovery mount too.  I have no camera and have no Astro photography experience. What else will I need to get started? Anyone else do spectroscopy, feel free to comment, all advice gladly accepted! 

Steve 

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13 minutes ago, Trikeflyer said:

@nicoscy you have peeked my interest in spectroscopy! I know nothing about how to do it apart from a brief web search after reading your post and I'm looking for a bit of advice about what kit I need to get into it. I fancy having a go but I'm wondering how easy it is for a complete beginner to get reasonable results.  I have an Altair Astro 80mm ed with star discovery alt az goto mount and a Meade etx 125 which I could use on the star discovery mount too.  I have no camera and have no Astro photography experience. What else will I need to get started? Anyone else do spectroscopy, feel free to comment, all advice gladly accepted! 

Steve 

Steve, it is probably best to start a new thread to get what you need so this one doesn't get diverted. Thanks :)

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When there is a will (and some money to spare for such trinkets) there is a way. After an email exchange with Baader, I settled on this and this. Yes, I know, I could have gone for the TS72mm f6 in the first place, but I have lusted after the little SkyWatcher ever since it was announced, so I am pretty happy with the extra spending.

The Lynx adapter from Flo is certain to introduce some sag when plugging in my camera and the original visual back has screws (hate screw marks on my gear), so Baader Clicklock it is since the scope is primarily destined for non-visual use.

Having done some measurements last night, the additional 31.5mm light path "stolen" by the two adapters is offset by swapping with the Lynx adapter of 11.7mm (12.2mm for the factory one), resulting in a net reduced in travel of 19.8mm. With a 1.25" diagonal, I will have (yay!) precisely 3.5mm travel available to reach focus with my Nagler T6 13mm. Certainly not with a 2" diagonal, but I can always swap visual backs if necessary.

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On 18/08/2018 at 18:28, nicoscy said:

After 3 rounds of WD 40 and 2 rounds in the freezer and using tools from the local DIY store to secure s form grip, it was impossible to pry the parts separate. However, I found a T2 to 2” adapter, which enabled me to test the backfocus.

Instead of being plagued with in-travel issues, the exact opposite happened! Focuser drawtube too short and I need a bit more to reach focus. This can be sorted out though...

Having battle with trying to decide the optimum drawtube length for a scope, for use with EPs, diagonals and cameras, the answer is 'ridiculously long'. The basic problem is that focuser length doesn't change with scope focal length...  and so short focal length scopes need impractically long focusers with impractically short tubes. Compromise is inevitable.

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Posted (edited)

Neil,

It's not so much the OTA length as much as the short focuser travel. 39mm IS on the short side, but I understand the rationale as extending it further would really strain this lightweight yet very capable focuser. But another 20mm wouldn't extend that far out. Of course it would create balancing issues and would require a longer dovetail ;)

As this scope has been purchased to spend about 90% of its life mated to a camera, I don't much care about how it works with eyepieces. As a 1.25" eyepiece set, I have a Pan 24, Nagler 13mm T6 and Nagler 7mm T6, plus a Baader 2.25x barlow element which covers most magnifications I want.

If I want to use a 2" eyepiece, I can use my 2" diagonal with my very lightweight Edmund Scientific 32mm (the Nagler 31mm I have, I consider too much weight-wise for the scope, but the ES has of course pronounced aberrations Vs the Nagler which I accept as a compromise) and still reach focus, as the ES  goes nearly in its entirety in the 2" diagonal, releasing much needed focuser travel. Here's a review of the ES Vs the Nag on CN - it's an interesting eyepiece! 

Basically, I am good with this scope as is - with the addition of the Clicklock, which I am really fond of and have on my other refractor as well. BTW, just received today the extensions needed from ZWO for the 183 (WD40, why have you forsaken me?) and despite a full moon this weekend, I plan to see what this scope does just for fun on wide field targets for EAA. Plus I changed laptops and need to "certify" the system to ensure hardware talks to software and vice versa.

It could be that I am not happy with the performance of the ASI183MC and decide to use my AS294MCPro. Second one is more sensitive, first one gives better sampling at such short focal lengths. Your last words ring true, "Compromise is inevitable", a fact of life in every endeavor.

P.S. I see you dabble in a lot of hobbies - interesting website you got there...

Edited by nicoscy
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Some more info as I was asked to measure this: Closest focus for terrestrial viewing is precisely 8 meters.

Oh, I found the right name for the scope. First, it's a boy and it's name is "Truffles". Was planning to go with "Pig" but a friend mentioned "like a pig who eats truffles" and well, Truffles kinda stuck. I also found some silly stickers in my storage that were destined for another scope that I sold and I am debating if I should stick one on the dew shield. So, aggressive look with the black one or cute look with the one that has the black outline? Problems, problems ;)

3.jpg

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