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JR1987

Is a 80-ED refractor a good investment?

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I currently image with a Skywatcher 200pds and HEQ5 mount. I get on with that fine and as a scope I love it. But ive had my eye on a skywatcher ED80 refractor for a little while as people who own them have alot of praise for them and produce lovely images.

Is it worth adding it one to the imaging arsenal, perhaps for wider FOV shots? ive used a FOV calculator and I can see the north america nebula requires a much smaller scope to capture the whole thing in the frame anyway,  is this the only DSO at that size??

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I also have a S/W 200 PDS, but bought a S/W Evostar 80ED a year ago. In addition to using it on Deep sky targets, I made a simple MDF mount, and use it frequently for quick grab and go lunar and white light solar imaging. This year, I have managed 140 imaging sessions, many with the 80ED on the MDF mount.

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Edited by ArmyAirForce
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one thing you will happy with using a refractor is that there`s no collimation problems and easier to handle on the mount.

FOV will depend on the focal length of the scope and the chip size on the camera, you`ll need a flatner for anything bigger than an Atik 314 chip with an 80 mm lens.

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Yea, I figured id need the field flattener...which is a pain as they are expensive for what they are. But its fine, like anything in astrophotography its never cheap.

I use a DSLR canon 100d at the moment. 

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Don't get too upset about the flattener-reducer prices until you've seen the equivalent prices from TEC, Takahashi and others. In truth making a good flattener/reducer is a significant optical challenge (which is why some manufacturers make a mess of it fairly regularly.) Making a visual scope is pretty easy compared with making a faster scope with much larger flat field. The ED80 with flattener is a remarkably good scope for the price. Does it have a sufficient reduction in focal length from your Newt to offer what you want? Only you know.

My own choice of focal lengths with the large format cameras I have would be 500mm, 1000mm and 2.5 metres. To quote the song, 'Two out of three ain't bad!'

Where's Santa when you need him??

Olly

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Another vote for the 80ED with Skywatcher's purpose made field/flattener

http://www.firstlightoptics.com/reducersflatteners/skywatcher-85x-reducer-flattener-for-ed80.html

Add FLO's purpose made Camera T mount which screws direct into the flattener and you have a really nice, solid imaging rig.

http://www.firstlightoptics.com/reducersflatteners/skywatcher-dslr-m48-ring-adapter.html

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Just about to press the button and buy one myself, so I hope it is worth the investment.

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I have been delighted with mine - there's a LOT of people using them and we cant all be wrong!!

According to FLO's imaging calculator I am way undersampling by using an Atik 314l+ with it but I have been entirely satisfied with the results.

In retrospect I wish I had bought a better quality ED80 than the bargain basement one - in the end I gave upon the standard focuser and fitted a Moonlite which absolutely transformed it. Hindsight is a wonderful gift though!

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Hind site is a wonderful thing. We all get it at times. Always after we have convinced ourselves that we have done the right thing and bought our ultimate and best/latest acquisition.

If only we got it before the purchase. :)

Derek

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I'm sorry to buck the trend on this, but after doing the standard draw tube mod and fitting a cheap Skywatcher Autofocuser,

http://helixgate.net/ed80mods.html

http://www.firstlightoptics.com/misc/skywatcher-auto-focuser.html

I've never had any problems with the focuser. It's now completely trouble free - it holds a DSLR hanging off the back just fine and there's no slop in the draw tube.

Whilst I'm sure it's not the best 80mm refractor out there, it's plenty good enough to not be the limiting factor on the quality my imaging for many a year.  One of the best £249 I ever spent.

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Love my ED80 had many an imaging session with it, I did have to adjust the focuser due to some camera slippage but apart from that all is fine, there's plenty of larger targets it can be used with, Rosette Nebula, Elephants Trunk Nebula, Horsehead Nebula, M31 to name a few.
Mine is definitely a keeper & works well using the Altair Astro 0.8 reducer.

Edited by tich

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About 2 months ago I bought a 5000 series Meade 80ED from eBay for £435. I think it has a modified focusser as its duel speed and originally they were single speed. However, given the rubbish weather since I got it, I've used it for all of about 20 mins looking at the moon and 10 mins at the sun through a sun filter. Here's hoping it's a worthwhile investment.

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The ED80 is a doublet, right? How bad is the CA on bright stars?

Yes, I believe it is a doublet but performs very well indeed.

Sent from my phone using Tapatalk

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It is a doublet. Mine only has very minor CA and I only ever see any in photos without the reducer (and even then I have to look for it to find it). I never see any visually. 

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The synta Ed80 variants have very good chromatic aberration control, I can remember once using a sub £30 25mm eyepiece in one observing the full moon on one night, there was no CA visible on the outer edge of the moon, even if there was it was not noticeable.

Without getting into glass types and crowning elements, the ED80 scopes are good value for money and certainly give a good run for performance and money compared to other cheaply 80mm manufactured triplets out there with cheaper equipped glass.

I wouldn't be surprised imaging with an ED80 that it would become your main imaging scope.

Al.

Edited by Skyline

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I'm going to offer what may be a controversial piece of advice for an imager looking for a beginning refractor, but its one that I've come to over many nights of amateurish fumbling with imaging setups;

Do not bother trying to image above f/7 native

I know, I know, thousands of people do it well and someone's almost certainly doing it right now, but honestly, focal ratio is the single most irritating and immovable obstacle to satisfying imaging as a beginner, at least in my case. I see the value of RC and Cassegraine setups at extreme focal lengths for really high resolution, but very rarely is the beginner in possession of the craft and experience to handle that kind of setup. A beginner needs simplicity, and a setup that aids the learning process rather than impeding it with a panoply of possible failure modes.

With a fast scope of f/6 or lower, you will accumulate data like nobody's business. One single night of imaging will yield twice as much data, or twice as many targets, as a similar experience at f/8. As a beginner, particularly considering a refractor (I own far too many refractors, I love em :) ), I advise you to look into faster optics.

William Optics do some lovely ED scopes at f/6, as do Altair Astro, with reducer/flatteners available to get you down closer to f/5 even. This will allow you to pull more light and detail out of your target faster, and all else being equal that is always a good thing.

As others have said, the 80ED is a cracking scope and gives wonderful views, but it has always struck me as a refined 'classic refractor' concept for visual work rather than an imaging platform.

Edited by Stratis
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I like your advice on f-ratio. I use a Canon 300 mm tele lens at f/4 and when using a teleconverter making it f/5.6 I find even that to be painfully slow [emoji4]

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I like your advice on f-ratio. I use a Canon 300 mm tele lens at f/4 and when using a teleconverter making it f/5.6 I find even that to be painfully slow [emoji4]

Oh absolutely... I do my photography between f/1.8 and f/4 and even going up to f/4 bothers me when I shoot raw and see all that extra noise.

Even with a cooled CCD, every f/stop you advance is not so much robbing signal as it is adding noise. Your final images will always be that much muddier, requiring that much more processing, more subs, more time to bring them to the standard they could have been already in half the time. 

There are plenty of imagers able to overcome this and process truly spectacular vistas out of data captured at f/8 and above, but they walk a very difficult road, and generally have observatories ;)

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Oh absolutely... I do my photography between f/1.8 and f/4 and even going up to f/4 bothers me when I shoot raw and see all that extra noise.

Even with a cooled CCD, every f/stop you advance is not so much robbing signal as it is adding noise. Your final images will always be that much muddier, requiring that much more processing, more subs, more time to bring them to the standard they could have been already in half the time. 

There are plenty of imagers able to overcome this and process truly spectacular vistas out of data captured at f/8 and above, but they walk a very difficult road, and generally have observatories ;)

This is a very vaild point to think about... especially as ive been imaging at 4.6 with my 200pds + comacorrector/reducer...

However, the idea for me to get an 80ED was the option of having a wider field. Yes the 80ED is slower so it means more subs to create a good image.. however taking a mosaic with the 200pds is going to take x2 x3 more subs anyway to create the FOV desired.. but with added collimation/guiding/wind issues that the 80ED would be much more forgiving with.

What do you think?

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[....]

What do you think?

Well, alright.

Personally I think a small frac is always going to be easier for the beginner than a medium-sized newt, for the reasons you mention. Narrow FoV, wind and balance issues, collimation, all that jazz. Yes, I advise you to go for a small refractor, they are excellent and vanishingly easy to use. Your setup time is halved, your troubleshooting time is near-zero because there's only about three screws on the whole thing.

If it's an 80ED or bust, then yeah, go for it but make sure you have the 0.85x r/c, as far as I'm concerned that is an essential item. You will get good data out of it at a low price.

Buuuuut....

If I can persuade you to look into f/6 scopes, I think you will have an easier road of it. With a standard 0.8x R/C unit (also essential...you DO need one) that goes way down to f/5 or thereabouts. 

You will be able to create lovely images with the SkyWatcher so please don't feel like you can't buy it or that it'll let you down; it won't. But I also know that if you can start your imaging train with that extra f stop under your belt, it will make a lot of headaches go away. Also consider that lower f/ratio almost always means a shorter focal length, translating into an even wider field of view. I tend to image between 500 and 700mm and the difference at the lower end is remarkable, although objects do tend to get a bit small.

Either way you'll be better off than mosaics with a large wind-catching tube.... that way be dragons ;)

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OK I give in... I dont think im going to be able to deal with the f6.37 if im used to f4.6

So with the 'buy once, not twice' attitude im looking into bigger budget options. 

Im looking at either the Skywatcher Esprit 80ED or the William Optics GT-81 -  Much faster scopes! 

Opinions? 

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I did a lot of research on the net before I bought a 80 mm refractor to use for AP, and comparing performance and price I ended up with the Explore Scientific (ES) Triplet ED80 (f/6) that costs 454 pounds. I have to say I am very happy with it as it immediately got me hocked on AP, so happy that I soon also bought the ES Triplet ED127. I have no issues with CA either scope. ES also has a very reasonable field flattener. With a 80mm aperture scope at f/6 (=480 mm FL) and your Canon DSLR with an 18 Mp APS-C you are at 1.85"/pixel f/6 (see http://www.skyatnightmagazine.com/field-view-calculator)which should be good. You could get a reducer but then you would be slightly under-sampling but it may not be a problem. I bought a TS Photoline 0.79 reducer/flattner but has so far only used with the ED127 which works great. That reducer/flattner will give you f/4.7 with the ES ED80.

Those complaining that ES use a Hoya FCD001 ED glass (corresponding to Ohara FPL-51) instead of an Ohara FPL-53 are over-simplifying things as far as I understand. These glasses differ in refractive index (and those with the highest index are more expensive to make). The important thing is to match the type of ED glass with the proper combination of other lenses, which is easier to do in a triplet - in doublets the FPL-53 may be necessary and still will not reach the low CA of a good triplet. At least that is what I concluded from reading what knowledgeable people were discussing at length on the net, and together with the price issue this made me go for ES.

(see for example http://www.cloudynights.com/topic/335776-fpl-53-vs-fpl-51/)

Relevant links to the optics I talk about:

https://www.harrisontelescopes.co.uk/acatalog/Explore-Scientific-ED-APO-80mm-f6-Essential.html#SID=1644

http://www.explorescientific.co.uk/en/Optical-accessories/Explore-Scientific-MPCC-Field-Flatt-ED-APO-Canon-EOS-T2.html

http://www.teleskop-express.de/shop/product_info.php/info/p5965_TS-PHOTOLINE-2--0-79x-Reducer-4-element-for-Astrophotography.html

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