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Advice on 4" APO


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I've read with interest the recent threads discussing APO refractors.
I know how you good folk like to empty others' wallets and invite your help.
I'm looking to acquire a 4" refractor of reasonable quality. My aims are purely visual, no AP, to use on lunar, planets, double stars and later to view solar in white light with a Herschel wedge.
The S/W Evostar 100ED DS Pro caught my eye. Here:- https://www.rothervalleyoptics.co.uk/skywatcher-evostar-100-ed-ds-pro-optical-tube-assembly.html  Your thought please. I'm not adverse to spending a bit more but don't want to go silly. 
If this is your recommendation please suggest a suitable GOTO mount. Bear in mind when making a decision I don't have high end eyepieces and would want to use what I have, see my signature. 
Any comments, suggestions gratefully received.
Thanks in advance.

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I have owned both the ED80 and ED100 from Skywatcher.
They both performed well visually, but the focuser was annoying.
They have both gone in favour of my Vixen ED103s.
If I was buying the SW ED line I would go for the 100 and upgrade the focuser.

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Hi Alan,

Having owned a 100mm DS Pro, I can tell you its a very nice refractor. If you wanted to splash out a little more, but steering clear of the high high prices of Taks etc, I'd suggest you consider the 120mm DS Pro. Either of the above are superb scopes but the 120ED with its greater aperture, has obvious advantages, without increasing the bulk too much. 

GOTO mounts are not my thing, so I'm not able to be of much help here. What I will say is that either of the above scopes can be carried with ease by a standard eq5, AZ4 or similar mounts. With a low power eyepiece they are a joy to use while sweeping rich star fields, and dso's just glide into their stunning wide field. Personally I'd invest in a good rich field eyepiece rather than a goto mount. 

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I also vote 100DS Pro.

Can offer alternative, also very good scope (according to scarce reports):

https://www.teleskop-express.de/shop/product_info.php/info/p9868_TS-Optics-PhotoLine-102mm-f-7-FPL-53-Doublet-Apo-with-2-5--Focuser.html

Also know as:

https://www.stellarvue.com/stellarvue-sv102-access-ed-apo-refractor-telescope/

(same scope, different branding, more reviews available in stellarvue flavor).

I think F/7 scope will optically be at least as good as 100DS Pro, and will have some advantages - easier wide field due to shorter focal length, easier to mount again because it's shorter, retractable dew shield, collimation lens cell, and very good focuser (probably no need to change it). Maybe you will find these advantages worth extra cost.

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30 minutes ago, Alan White said:

If I was buying the SW ED line I would go for the 100 and upgrade the focuser.

Thanks Alan, what did you consider wrong with the original focuser and what would be a sensible upgrade?
Thanks again, I guessed I'd get a response from you.

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Hi Alan

The SW dual speed focuser had slip and with careful adjustment was ok, but when at zenith, it slowly slipped down.
The ED100 was used so had some wear from use, the ED80 was new and far, far better.
Never did upgrade the focusers, chose my targets away from zenith.

Upgraded the scopes to the 103 Vixen for the build quality and slightly wider FOV in a 100mm ED.

With either scope you will get good presentation of targets, but the step from 80 to 100 was visible to me.
The ED80 is also mounted in the same tube as the ED100 so over sized for the objective size, so it comes up 
larger than you might expect for an 80mm.
That said my Vixen is in an oversize tube too and does not bother me.

The ED doublet optics are great, especially for the money, the 80 especially.
Bought that new from FLO and felt I had stolen it for what I paid ?

Neither will be as bright as the 8" Dob you have, but somehow the refractor view has something special.
I speak as a 10" Dob owner as well as a refractor lover.

Good luck with your choice, it's a tough one.
 

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Another vote for the ED100 DS Pro from me. Generally I've found 100mm the minimum aperture that I find delivers satisfying observing capability that sustains the interest.

Interesting review from Roger Vine here:

http://scopeviews.co.uk/SW100EDPro.htm

Plus a group report on 4 inch APO's here from the same author:

http://scopeviews.co.uk/FourInchBG2017.htm

 

 

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Altair Starwave 102ED would get my vote.

https://www.altairastro.com/Starwave-102ED-FPL53-Refractor.html

More robust focuser than the stock SW one.

As for a GOTO mount, SW HEQ5 would be my choice.

Your existing EPs will be fine. In fact you will be hard pressed to find any difference between these X-Cels and any TVs on a f/7 or slower scope except for FoV.

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Just as a question but why are you limiting yourself to a refractor for doubles, moon and planets?  If you were interested in widefield views then I would agree, but for your targets an SCT would be better.  The higher the magnification you can use from the larger aperture, the more you will see.  

For example there are two 9.25" SCTs for sale second hand on UKastrobuyandsell within 'spitting' distance relatively (Kings Lynn and East Anglia) at prices similar to a new ED100.  These, once collimated will give you much better views on your targets of interest.

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Just to toss a different idea in the mix, I'd almost be inclined to consider a shorter 100mm like the esprit 100 triplet if it's financially feasible? The rationale being that a highly corrected triplet  will work very well on planets and doubles if coupled with a good barlow but at the same time, with a 30mm 80° 2" EP it will offer up to 4.5° fields of view, which virtually no other telescope can!  I use mine in the "super wide" mode a lot because that's what it does exceptionally well (better than my big scope) but it's also superb for showing high mag stuff when our club does outreach events. If down the track you did decide to do some astrophotography too, this would be spectacular choice for that :)

 

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48 minutes ago, timwetherell said:

Just to toss a different idea in the mix, I'd almost be inclined to consider a shorter 100mm like the esprit 100 triplet if it's financially feasible? The rationale being that a highly corrected triplet  will work very well on planets and doubles if coupled with a good barlow but at the same time, with a 30mm 80° 2" EP it will offer up to 4.5° fields of view, which virtually no other telescope can!  I use mine in the "super wide" mode a lot because that's what it does exceptionally well (better than my big scope) but it's also superb for showing high mag stuff when our club does outreach events. If down the track you did decide to do some astrophotography too, this would be spectacular choice for that :)

 

I do miss my 4 inch F5 Genesis for precisely this reason. I could have an enormous FOV for such delights as the entire Veil, the Double Cluster with Stock 2, the Rosette etc.

Olly

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