Refractor (mainly visual)

[JonC]

I am currently pondering getting a refractor for mainly visual, the main use would be planets, but also as a general visual scope. The slight complication is that I am starting to get in to astrophotography, mainly using the Star adventurer and a canon dslr. After a lot of reading the SW 80ED looks like the ideal candidate for the astrophotography side, but is it too limited for visual? My eyepiece setup is mainly 2", with a 2X barlow.

Looking at for sale adds, ebay and new I can afford

Skywatcher Evostar 80ED DS-Pro OTA (£350 + a star diagonal. This is really over budget)

Lightwave Altair 72ED-R on ebay for £275

Vixen 102m Refractor Telescope OTA (£175)

Starwave Premium F11 Refractor  (£300)

 

I keep coming back to the 80ED because it would small enough to be nicely portable, I could probably get away with mounting it on the star adventurer and take it when  I go camping. I am just unsure how usable it is for visual.

Mount wise I am sorted.

 

Cheers

 

Jon

[John]

If portability is really important then I'd say it probably has to be the ED80. Personally I much prefer the additional light grasp and resolution of a 100mm scope though. I have owned ED80s and 70mm and 72mm ED scopes but they just "run out of puff" too soon for me despite putting up some very nice views, for their aperture.

I'd be happy with the Vixen or the 102mm F/11 but I'd also be considering a TAL 100 at the budget end or (my preference) finding the £'s for an ED100. None have quite the portability of the ED80 though. I've owned the TAL, Vixen and ED100's but not one of the 102mm F/11's.

By the way, I suspect your Meade ETX 105 will deliver planetary performance at least as good as the ED80 and 72mm ED and have lots of portability as well. Have you thought about a 125mm / 127mm mak-cassegrain or even a Celestron C5 ?

 

 

[ollypenrice]

You say you're sorted on the mount but the FL of even the ED80 is very long for the Star Adventurer. The HEQ5 would do well with it, though, ideally autoguided.

Alas there is a fundamental incompatibility between a small 'easy' imaging refractor and one aimed at planetary observing. Like John I prefer to have at least 100mm for observing. But a fast 100mm DS imaging scope is going to be expensive.

Olly

[alanjgreen]

I'm with Olly. Don't expect great planet views from a refractor. Image will be small to your eye.

SCT or Mak is the way to go for planets. That's why they are called "planet killers"

refractors rule for DSO imaging tho.

[Paul73]

Can't help on the imaging side, except to say that I have seen some wonderfull images produced from this comparitively low cost scope. However, I had one until last Monday for purely visual. It is not a planet killer due to its relatively short focal length. Planatary views are very crisp but small.

But for wide views, with buetifully tight stars, it is lovely. If you are used to looking through big scopes, the view is a bit dim. That said, I was very sorry to see mine go.

Make sure that you get one in the aluminium flight case. You can pack in Eyepieces etc and have it nicely protected for travel.

Paul

[John]

54 minutes ago, alanjgreen said:

I'm with Olly. Don't expect great planet views from a refractor. Image will be small to your eye.

SCT or Mak is the way to go for planets. That's why they are called "planet killers"

refractors rule for DSO imaging tho.

Assume you are speaking of small refractors (80mm or less) here Alan ?

Obviously at 100mm and above refractors in either ED or F/10 or slower forms, are superb for planets.

I've heard of mak-cassegrains and mak-newtonians referred to as "planet killers" but not so much SCT's though they do put up pretty good planetary views when in good collimation and properly cooled - about as good as a dob of the same aperture in my experience.

Not ptobably the thread for a "this vs that" type debate though so I'll stop at that

[Stu]

1 hour ago, John said:

Assume you are speaking of small refractors (80mm or less) here Alan ?

Obviously at 100mm and above refractors in either ED or F/10 or slower forms, are superb for planets.

I've heard of mak-cassegrains and mak-newtonians referred to as "planet killers" but not so much SCT's though they do put up pretty good planetary views when in good collimation and properly cooled - about as good as a dob of the same aperture in my experience.

Not ptobably the thread for a "this vs that" type debate though so I'll stop at that

I think a good four inch refractor can do amazingly well for planetary observing. I think I would prefer one vs a compound scope of five or six inches say. Once you get to MN190/C8 territory obviously you get significant better resolution and, for me, colour as the extra brightness kicks in. But a good four frac does very well as John says.

[mikeDnight]

Personally I'd struggle to choose between the ED80 and the Vixen 102. With a binoviewer and 2X Barlow the ED80 is a great scope for lunar observing and reasonable on some planets.It's FPL53 lens can deliver a very punchy view. It will show some of the brighter dso's but often binoculars will do a better job. The ED80 is very popular among imagers!

Visually the Vixen will give very good views of both planets and brighter dso's but perhaps not an imagers first choice. 

May be you should stick with visual until your budget allows you to buy a higher end photo/visual refractor that will suit both your interests.

With regard to SCT's and Mak's, the Maksutov makes a very nice visual scope, and certainly sharper than a Schmidt Cassegrain. I wouldn't entertain a SCT as a visual planetary scope from the UK. Unlike the refractor, both have a narrow field of view!

Mike

 

[JonC]

Thanks for the advice. Going to have a ponder about this, if I did go the ED80 route it would be used as a travel scope on the Star Adventurer, for AP it would be on the HEQ5. For dedicated AP I have a 130PDS, haven't really got to grips with that yet, have been concentrating on using the 1100D with a 135mm prime.

[Pig]

My experience with smaller refractors (80mm) is that they give wonderfully colourful wide field views of the stars when using low power eyepieces, this colour starts to lessen as you go up in aperture. They are also very versatile and can be used for AP, Solar (with the correct filters), a spotting scope and if this isn't enough they are extremely portable and virtually maintenance free.

As for planets my 110mm frac gives better views of planets than both my current 8" and my old 9.25" SCT's.
I had always been very disappointed  with the views of Mars until I used the 110mm frac....

[Gilles]

Hello,

I have a Vixen GP 102mm F10 refractor. It is very good optically. For visual observation, it is perfect. However, for astrophotography, it suffers from the fact that the focus is not quite back enough - the optical tube is a bit too long - hence, I can not reach focus with my Audine CCD camera mounted with the flip mirror for instance. I believe this is because this refractor was designed back in the 1990's, when CCD cameras were not very common, and when accessories such as wheel filters and flip mirror were not available yet.

Another observation I would make is that early SP 102mm refractors such as the one which you mention here for sale have an objective cell with collimation push-pull screws, as opposed to the lastest GP 102mm which does not have collimation screws. However, it may not be an issue after all, the collimation on my late GP 102 telescope is spot on and would not require any adjustment. Vixen designers may have concluded they could achieve a proper objective alignment relying only on the precision of machining, and that collimation screws were not useful, so they got rid of them as a result of a cost-saving exercise.

Gilles