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djpaul

Telescope for wide FOV

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djpaul

Hi

im looking to buy a telescope for a wide field of view.

Short list is 

W.O 73mm Zenithstar

SW 72ed

TS Optics 80mm photoline

Any thoughts on these and any other scopes would be great 

Regards Paul

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Tweedledee

The shorter the focal length the wider the field you are going to get. Coupled with a long focal length wide angle 2" eyepiece to give a 5 or 6mm exit pupil, you'll get the maximum field of view from the scope. For visual, you will see more with a bigger aperture, but going bigger means longer focal length and narrower fields.

 

The scopes you mentioned have focal lengths of 420mm, 430mm and 480mm. The cheapest one just happens to give the widest field and the dearest the smallest field, but the dearest will gather a bit more light and is better corrected as it is a triplet. They also get slightly heavier as they get bigger and longer.

 

Going a bit dearer and heavier but wider field than any of the above is the 400mm focal length F5 SW Esprit 80ED Pro triplet. I'd love one of those for wide field.

 

Another way of looking at it could be to get the cheaper 72ED and buy a 25mm 100 degree eyepiece totalling about the same price as just getting the expensive TS 80mm Photoline.

 

The 72ED and 25mm 100d will give 16.8x and a massive FOV of 6 degrees.

 

The TS 80mm with your 26mm 82d Nagler will give 18.5x and a FOV of just 4.4 degrees.

 

All the scopes you mention are better than average performers and extremely portable, but who am I to talk with cheap 80mm, 120mm and 152mm F5 achromats. 😁

 

Pay your money and take your choice. 😊

 

Remember that although the wide field eps will give lovely rich wide angle starfields, they'll not show much on planets, double stars and smaller objects, meaning that most of the time you will probably be using higher power eyepieces giving much smaller FOV's.

 

Always compromises. 

 

Hopefully someone with higher end scopes will give another perspectives on this.

Edited by Tweedledee

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Bino-viewer

I think theres more than one way to skin a cat here.....

 

I consider my 12" F4 Newtonian wide field.

 

It won't show a 6 degree FOV like the 72mm / ES 25 100º / 16.5x

 

But it will give me a 1.13º which frames alot of objects very nicely.

For eg the 'Double cluster' fits in this field perfectly.

 

And the best bit is.......i'm using both my eyes here. You can of course go wider with 2" widefields cyclops style,

but that doesn't compare to the 2 eyed view. Thats just my opinion though, 

and i apologise if i'm going off thread and turning my post into a one eyed / two eyed comparison.

But 60x mag 2-eyed views with a 12" mirror from a dark site are something to behold.

I'd love to show it to you sometime.

 

But its all relative.

I still think something like the M45 Pleiades look best through a good pair of binoculars from a dark sky.

 

Its all about a dark sky.

From home M45 with my old 132mm refractor and N31mm (now both sold) always looked washed out with all the light pollution.

 

I think the scopes you've listed Paul are nice choices, if a little short on aperture..... and you may actually prefer the views through your 15x70 binocs

 

 

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Tweedledee

Another perspective Rob, nicely put. 👍

 

Soon Paul will realise that he needs half a dozen different scopes and several pairs of binoculars. 🙂

 

Going to have to try binoviewing on a proper telescope one day, it sounds great. 

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Bino-viewer

Pete : we must meet up at Belper some time for an observing session.

I'm also thinking seriously about joining MSAS, although its a bit of a journey for me from Derby.

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djpaul

Thank you for all your advise.

Obviously im new to this hobby, and have never had the chance to meet up and try other peoples scopes.

Up till now i have just concentrated on upgrading the scope i have, and buying the best possible eyepieces i can afford when they have popped up on ABS .

I have to say im very pleased with all the gear i have at present.

Im going to wait untill the new year before buying another scope and have a good look round and hopefully try out other scopes at a meet up some where'

Paul

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Tweedledee
7 hours ago, Bino-viewer said:

Pete : we must meet up at Belper some time for an observing session.

I'm also thinking seriously about joining MSAS, although its a bit of a journey for me from Derby.

That's a great idea Rob. 👍

 

I think you'd love it at MSAS, they have a fabulous Obsy and lecture room, some great facilities and are a nice friendly bunch. Get your application in, you don't have to turn up on a weekly basis, unless you really want to.

 

I have my MSAS application forms ready to hand in, assuming they'll have me back. 😊 I was member number 28 in about 1971. Luckily Sherwood Observatory is just 4 miles down the road from me.

 

35 minutes ago, djpaul said:

Thank you for all your advise.

Obviously im new to this hobby, and have never had the chance to meet up and try other peoples scopes.

Up till now i have just concentrated on upgrading the scope i have, and buying the best possible eyepieces i can afford when they have popped up on ABS .

I have to say im very pleased with all the gear i have at present.

Im going to wait untill the new year before buying another scope and have a good look round and hopefully try out other scopes at a meet up some where'

Paul

You have lots of time to evaluate your options by the new year, and make sure you get the right equipment for you. 👍

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djpaul

I have put an ad on ABS 

and have been offered a TV85 with 2 inch everbrite . 25mm plossl TV Starview finder and TV soft case.

Bought new and apparently hardly used. Bought new in 2013 from widescreen centre .

I have put an offer in and hope to organise seeing it near London very soon.

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Tweedledee
12 minutes ago, djpaul said:

I have put an ad on ABS 

and have been offered a TV85 with 2 inch everbrite . 25mm plossl TV Starview finder and TV soft case.

Bought new and apparently hardly used. Bought new in 2013 from widescreen centre .

I have put an offer in and hope to organise seeing it near London very soon.

Nice scope, but you'll not want to bother with the 25mm Plossl after the eyepieces you've been used to. 👍🙂

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djpaul

I will sell on the 25mm plossl. 

Trying to organise me going to pick it up hopefully this week.😀

It's the 2013 version without the fine focus option. 

 

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djpaul

Fam I got an email and the seller has now decided he wants to keep the TV85😣

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Tweedledee
1 hour ago, djpaul said:

Fam I got an email and the seller has now decided he wants to keep the TV85😣

Thats a pity 😞

 

Perhaps he used to be indecisive, but now he's not so sure! 🙂

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Bino-viewer

The TV-85 is a very nice scope indeed, but they are certainly pricy new.

Over £2k for what is, at the end of the day a 3.5" (just under) doublet.

 

There are bound to be other options, as good, for a lot less money.

 

 

I'm a bit miffed because i saw a pair of Fujinon 16x70 on there that had been sold. 😩

The hunt goes on.......

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djpaul

Well I'm in no rush I'm sure the right scope will come along at some point. 

Paul 

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djpaul

Okay i have looked at 2 other possible scopes for a wide field of view

Firstly a secondhand Televue Pronto ( old scopes but supposed to be built like a tank ) theres one for sale on ABS £575 inc 2 inch TV diagonal

Secondly Altair Astro 70mm starwave ( new cost £399 ) 

Would the optics be better on the Altair Astro seeing as its an up to date scope.

with my 26mm nagler i would get AFOV of 4.4 with the Pronto and 5.08 with the Starwave

 

Any suggestions would be very helpful

Paul

 

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Tweedledee

Others may disagree, but I reckon the Pronto has had its day and is old and very overpriced. The Pronto is an ED doublet just like the Starwave, but it only has a single speed focuser whereas the Starwave has a dual speed. The difference in the view between the two would probably only be a smaller FOV on the Pronto.

 

Also, like with cars, there is always a better deal just around the corner. 🙂

 

I'm not sure what the right scope is for you're requirements, but of the two, I would go for the new Starwave in preference to the old Pronto and buy a 2" diagonal for it. Better than a mirror diagonal, get a 2" Amici prism use it for terrestrial as well, with the benefit of correct image on the sky. I love the ease of using my refractors with correct image. So easy when star hopping.

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djpaul

Yes I think you maybe correct.

I was going to tring astronomy today but just thought I'd think about it over the weekend. 

I may pop to tring in the week and see what I think of the starwave.

I must admit I should get round 5 degrees afov with it through the 26mm nagler. 😀

 

 

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Tweedledee

Never good to rush into things, ponder a bit longer, ask more questions and hopefully you won't make the wrong decision. I'm doing that this weekend regarding some kit, but expect to push the button on Monday, nearly pushed it today, but glad I held back and will spend the weekend considering precisely which button to push and why. 😊

 

It is easy to be disappointed with astro views in small apertures and let's face it 70mm is small. Have you considered achieving this wide field with binoculars? A good pair of 70mm bins are very portable and will gather as much light as a 100mm scope and may not always require a tripod. Binoculars can provide an easier view using both eyes. I sometimes find it helps to right a list of pros and cons when choosing between kit.

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djpaul

Long story but binos won't do it for me. 

I had serious sight problems leaving a small scar.

After much messing about I finally found my way round my eye problem.

I'm happy with my 8x43 hawke but would prefer a small scope .

Paul

 

 

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Tweedledee

Yes, I do remember your eye problem now Paul. Obviously you need to stick to using just one eye. 👍

 

Hope you find the right scope for you and let us know how good it is. 😊

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djpaul

I will do. 

I'm still seeing a specialist at the hospital but she is confident I'm cured. 

Very bad at the begging.  

Had to stop driving and working. Stuck in the bedroom for weeks with curtains closed as the sunlight hurt so much. 

But all good now and getting better ... 😀

 

 

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