Which refractor ?

[halli]

Hi All

I am looking at a Skywatcher Evostar 80ED DS  Pro (F7)  (£450 for outfit) or Evostar 100 ED DS Pro (F9) with 0.85 focal reducer (£625 for outfit).  I am obviously tempted by the 100ED but it  has a greater focal ratio but comes with a reducer which makes it a F7.65 .

The 100ED seems a very good price and is this therefore  a no brainer as I cant see any disadvantage in  choosing this or am I missing something !?  Want to use for imaging and I presume that for DSOs the 100 with the focal reducer will have more flexibility than the ED80 - do you agree ? Not concerned about the extra £175 if it is good value and the right way to go.

What do you think ?

Thanks in anticipation

[GuillermoBarrancos]

If it´s a scope for pure DSO imaging purposes, I would rather look at the Equinox 80 ED Pro to be honest. It´s faster at F/6,25 and mechanically better.

The little increase in aperture of the 100 ED won´t make much of a difference when it comes to imaging, but the Scope is slower, even with the reducer. ( F/7,65 reduced compared to native F/6,25 for the equinox).

The 100ED Pro is a bit of a different duck in the pond so to speak with these Scopes and was intended more for visual use (Lunar / Planetary). Hence, the longer focal length and F/9 ratio.

The 80ED Pro and 120ED Pro are faster and more intended for imaging.

If you are looking for a refractor for both Visual and Imaging purposes and find the 80ED too small, I would rather jump towards the 120ED Pro. It has the same focal length as the 100ED Pro, but has a much faster focal ratio. F/7.5 native compared to F/9 native.

Both 80ED Pro and 120ED Pro can be reduced as well, making them even faster.

[nmoushon]

For imaging you actually have it backwards. The ED80 with reducer is a much better fit than the ED100 with reducer because of the faster F/Ratio. Both of them are a bit slow for imaging. Especially if you are wanting to image nebula type objects. For that you want as fast optics not long focal lengths and slow optics. For example the Equinox ED80 has a native F/6.25 and with a reducer its drops to F/5. Its a bit more expensive that the Evostar 80ED but its chearer than the Evostar 100ED and much faster. Also what kind of mount to you plan on putting these scopes on?

[halli]

Thanks for your advice guys - I guess the message is that fast optics are best for imaging even at the expense of the increase in aperture.  Point taken.

I  think the 120 would be a bit above my budget which is a shame.  

Also I hadn't spotted that the Equinox range were faster and therefore better for imaging DSO so thanks for pointing that out as well.

I am returning to astronomy after quite a while and I am definitely interested in imaging because of the dramatic improvement in techniques/equipment  and available software but perhaps also in a bit of observing of planets.  I suppose it wont be until I spend some time with a scope doing a bit of imaging and observing whether I understand whether I just want to specialise in imaging DSO or am happy to just have a dabble in a few areas - to this effect I think I am tending to keep options open.   Hence I feel that although the 100 does not appear to be the best choice for imaging, as you are advising,  I will be able to use it to do a bit of everything with the help of the focal reducer so that I can eventually decide what I want.  However this will mean potentially spending more money at a later stage for faster optics  !  

With regard to the stand - I need to get one of these as well !  The three I am considering are Advanced VX, HEQ5 or NEQ6.  The latter will allow me to perhaps get a bigger scope at some stage so may be a better investment.   If I went the HEQ5 or NEQ6 route I would consider getting the SynTrek versions and using EQMOD for the Go To although I need to do some more research on this !  The AVX gives the impression of being easier to polar align and perhaps is more portable which is an attraction..........

I am trying to get to a final position after a  visit to a shop to  look at some of the gear this Saturday. 

I have a camera already - Canon 1100D and have experimented with it alone on a tripod and have done enough to know I want to go further with a scope.

Too many decisions - but your input is helping me to inch closer to a decision so thanks again - any further advice is welcome ! 

[nmoushon]

You should really buy the book Make Every Photon Count. FLO has it on their website and you need to read that before you buy anything for imaging. It will explain everything you need to know and will really help you make a good decision and not waste money. Even if money isnt an option. 

In regards to the mount if you are wanting to ever upgrade I would suggest at least the HEQ5. If you really want to future proof yourself go with the NEQ6. This will allow you to have lots of upgrade options. The AVX will work well but you dont have much room to upgrade. 

[halli]

Thanks Nmoushon -  I have ordered the book from FLO.

 I am quite interested in  the Equinox ED80 because of the faster optics than the Evostar.  I notice that it is generally sold without accessories and see that you own one - I would appreciate any advice you or any one else  may have on Finder sope, diagonal and tube fittings etc.  I guess I will aim to go guided at some stage !

Thanks 

[nmoushon]

The book will really help explain a lot. So that will clarify most things. The diagonal is only need if you plan to view out of it, I have one b/c sometime I feel like viewing instead of imaging. They are pretty cheap second hand and any will do. The finder scope is up to you. I bought a 9x50 with bracket second handle for like 20 dollars. I have since converted it to be my finderguider. I am one of several people on here that use the EQuinox and all of us are very happy with it. The only downside, its the downside of almost every scope, is that the focuser isnt the best. Its better the your other picks but under heavy weight of even a DSLR or a CCD you will need to tighten it down otherwise it will slip while imaging. I havent had any flexture issues with it which would be a bigger problem. Really read the book a couple time before making any purchase you wont regret it.