Request for advice - buying my next refractor

[g__day (Matthew)]

Hey folks,

I am thinking of buying a refractor this year - and would appreciate pointers as what to buy or avoid. This will be my fifth scope, but only my second refractor (I have a old 80mm Williams Optics Megrez I quite like).

I am planning to give away an old 127 MAK and mount this new scope side by side with my C9.25 in suburban Sydney in a permanent pier in an astro lab. So I will most likely use my Vixen Atlux mount and side by side (Losmandy) mount the C9.25 and this new (or used) scope. My site has fairly evident light pollution and only reasonable viewing most nights.

My budget is anywhere between $2K to $5K. No idea if I eventually wish to do imaging with it or use it mainly for visual (in seeing challenged skies). I haven't looked through many refractors at all - but I do like how tac sharp the WO is compared to an SCT - it just doesn't have much light grasp for visual in Sydney skies.

So I'd been thinking a 120mm - 130mm APO of moderate to high quality. Happy to add after market focuser or flatteners or coma corrector later if I decide to do astro photography with it.

So I am probably not talking a TEC, Televue, Tak or Astro-Physics quality "Ortho-apochromatic" quality scope (to borrow Tak's lovely terminology). I do like the idea of carbon fibre (works brilliantly on the SCT) but I hear conflicting views about whether it helps or hinders maintaining focus on a Refractor (I wonder if it varies depending if is a doublet, triplet or quad or more lens design).

So that leads in to the next question - I don't feel like getting a simple Skywatcher ED quality scope - I want to purchase above this level. Long-Pern and GSO have impressed me with their finder scopes in the past. But I am pondering if a quality Doublet, Triplet or Qaud lens design should be on my must buy feature list.

Too I ponder whether for my needs a 110, 115, 127 or 130mm aperature scope really matters. I see a nice second hand WO refractor in the IIS for sale at the moment - and that's worth considering definitely.

So given this will probably be a scope for 70% - 80% visual initially - and say impressing friends that drop in with sharper views of Saturn, Mars or Jupiter (and whatever else); what advice will folk give me (beyond attend star parties and look through many different scopes.

Many thanks everyone who can help, ask any qualifying questions you recommend for me to better reveal my intentions or choice set limits and I will try an give considered answers!

Matthew

[Poita (Peter)]

I reckon the best bang for buck is a Lomo scope if you can find one second hand. Fantastic optics, along with an actual test so you know what you are getting, solid build quality and as good a views as you will get, for much less than a Tak.
Worth a look.

[dannat (Daniel)]

If you want to consider photography youll need a triplet (unless you buy a tak or televue doublet-the most expensive)

For visual use in the burbs 5" makes sense, but you're talking 3k, for some photography you mit get away with the north group 127triplet vti have for 1200, get a top focuser for 600 & the pkg comes under 2k

Most of the 5" refract are heavy though, something to think of, the skywatcher 120ed with reducer/flattener is still something to think of, add on good focuser & it's still light for visual use also

Are you buying new or used, Amart will have much more choice, eg tmb130

[g__day (Matthew)]

Lomo - I hadn't heard of before!

Triplet or Quad is fine

5" might be a bit too much budget wise (i.e. > $5K) for anything that is good quality

Second hand is fine so long as quality is high and condition is great.

PS

Also reading through the advice in http://www.iceinspace.com.au/forum/a...p/t-50785.html

[Larryp (Laurie)]

Have a good long look at Stellarvue-great scopes and reasonable price

[gregbradley]

If you have a C9.25 and want to do visual then you will be disappointed with suburban views unless you get to around the 130mm aperture. Smaller than that and you really only get widefield views. Use a high powered eyepiece on a 100mm scope and you get really dim views of anything other than the brightest objects. As far as an impressive view of the Planets that would be your C9.25. A 130+ aperture is needed for that in my opinion.

So for visual perhaps the 127mm North Group scope would fit your needs.

A 2nd hand Tak FS125 comes up every now and then. A doublet is not ideal for photography as there is too much chromatic aberration but you can process around that to some degree.

I agree with looking at Stellarvue and also check out APM. He has some nice large aperture cheap doublet visual scopes. Perhaps that is the go.
They were way under $5K.

Greg.

[gbeal]

I think 5" is where you are headed.
North Group ED127 if the budget is tight, Tak TSA120 if it will stretch.
The NG ED127 is a well respected scope, with many followers here. It would also allow a similar 80mm scope if wider than the current 5" FOV was desired.
Don't forget to factor in field flatteners and reducer/flatteners in too, they are essential in some/most scopes.
Gary

[wavelandscott (Scott)]

I'd second the consideration of APM...I really like my APM scope. They have a new line of Chinese made scopes made to their QC standards at a lower price point. It might be worth a look.

[Poita (Peter)]

http://365daysofastronomy.org/2010/1...optics-part-3/

[issdaol (Phil)]

We love our little Tak TSA-120. It is a snap to setup and views are sharp and contrasty even from the backyard in Canberra. It is very light for an APO (around 6.5 kilo) and has good internal baffling. I have read independent tests putting them around .992 Strehl and I could quite easily believe this.

With the favorable Dollar VS Yen you can get one under $5k now.

Noted you were in Sydney so if you feel like the drive down to have a look one evening feel free to bring your fav EP and PM me.

[g__day (Matthew)]

I must say - I am tempted to go larger than a 130mm APO - but mostly likely that will be in 2 years when the kids have finally finished (private) high school; then I will be more finanical - hopefully. So my next telescope is really to ease me into the world of apos.

I have never looked through an APO - so I am a virgin in that respect - not sure what I expect to see versus my C9.25, which is in pretty tip-top condition. Its just that I've outgrown my MAK and think an APO is completely missing from my line up of astronomy tools!

I am unsure whether to go a really high-end smaller apo - then sell it and buy a bigger high-end apo once I'm in the black / or simply start with an mid range apo then upgrade once my mortgage is down a bit.

The next stage for me will be upgrade mount, cameras and OTAs - likely a major financial event; the moment this hobby is about learning and enjoying astronomy as a long term passion!

Poita - thanks for the link - yes it's all the gear I lust for!

[Stardrifter_WA]

Originally Posted by g__day

I must say - I am tempted to go larger than a 130mm APO - but mostly likely that will be in 2 years when the kids have finally finished (private) high school; then I will be more finanical - hopefully. So my next telescope is really to ease me into the world of apos.

I have never looked through an APO - so I am a virgin in that respect - not sure what I expect to see versus my C9.25, which is in pretty tip-top condition. Its just that I've outgrown my MAK and think an APO is completely missing from my line up of astronomy tools!

I am unsure whether to go a really high-end smaller apo - then sell it and buy a bigger high-end apo once I'm in the black / or simply start with an mid range apo then upgrade once my mortgage is down a bit.

The next stage for me will be upgrade mount, cameras and OTAs - likely a major financial event; the moment this hobby is about learning and enjoying astronomy as a long term passion!

Poita - thanks for the link - yes it's all the gear I lust for!

Hi Matthew,

I have been a recent convert to Apo's with the purchase of the Williams Optics FLT110 Flourite Triplet, which came with a bonus field flattener. I am amazed by the views and it has now become my most used telescope, despite the crappy alt/az mount I currently have to use (which will be upgraded soon to a EQ6 GT mount). Although I have an equatorial fork mounted 8" SCT in an observatory, I much prefer the FLT110 Apo. Although the image scale is smaller, for any given eyepiece focal length, the views through the FLT110 are very sharp in comparison, and contrast is considerably better.

When I first started to look at the idea of buying an APO, I had seen through some high end 130mm Apo's from AP and Tak. Awesome they are, however, price considerations dictated that I had to look at something mid range, as the price of the OTA 130/150mm Tak are around $9,000 and $13,000 respectively. And that is not taking into consideration that you would have to buy Tak accessories

I have an Orion 80mm achromat (currently mounted on top of my 8" SCT), which I still think is a great little telescope, and wanted something a little bigger and better, so after some research and cost analysis I decided on the FLT110 Apo, which I bought directly from WO.

I am extremely happy with it, and even though I would like something bigger, however, the price of a great 5/6" Apo's jumps considerably and my bank account simply says no.

Although the 130mm or 150mm Takahashi would be my ideal, however, their price are prohibitive, particularly when considering that you would also require a substantial mount for it. So, when considering the scope size, don't forget to think about the size of the mount you would need.

Had I already had a decent GEM mount, I would have maybe looked at a larger scope. However, having to add a further $5,000 (Losmandy G11 or EQ8) to $10,000 (MX) for a mount put it well out of range.

Hope this is of some help.

Cheers Peter

[beren]

I enjoy the views offered by the refractors I own but more often then not for visual the larger aperture from the compound scopes are far more satisfying. IMO for a refractor up to 130mm it has to serve a dual purpose as either a grab/go scope or for astrophotography. Then you have to decide what focal ratio you'll be happy with which could impact those two functions then obviously what price your prepared to pay which determines the quality of the optics {in theory anyway}. I remember a while back on the forums a beautiful AP130 gran turismo F/6 was put up for sale and brought by a member to be used for visual on a alt/Azi mount. I thought at the time what a great set-up but probably not the most practical for the buyers needs with the scopes purpose more geared for imaging. Not long after the scope was back in the classifieds along with the mount, whether the sale was related to the equipments impracticality to the users situation I can only guess but wow something to ponder before buying given the large investment given.

[gregbradley]

That's my experience Beren. A smallish APO gives spectacular wide field star views but for regular visual only I think it starts at 140mm. That's just my opinion. Otherwise the views are quite a bit dimmer than your 9.25. Sharper and more contrasty but dimmer. I had a Tak FS152 and that was fabulous at a dark site. About the same or slightly better than an 8 inch SCT but a far more engaging view.

Greg.

Originally Posted by beren

I enjoy the views offered by the refractors I own but more often then not for visual the larger aperture from the compound scopes are far more satisfying. IMO for a refractor up to 130mm it has to serve a dual purpose as either a grab/go scope or for astrophotography. Then you have to decide what focal ratio you'll be happy with which could impact those two functions then obviously what price your prepared to pay which determines the quality of the optics {in theory anyway}. I remember a while back on the forums a beautiful AP130 gran turismo F/6 was put up for sale and brought by a member to be used for visual on a alt/Azi mount. I thought at the time what a great set-up but probably not the most practical for the buyers needs with the scopes purpose more geared for imaging. Not long after the scope was back in the classifieds along with the mount, whether the sale was related to the equipments impracticality to the users situation I can only guess but wow something to ponder before buying given the large investment given.

[Steffen]

With a budget like that I'd take another look at Maksutovs. Retire your little toy Mak and get a "real" one, like a 7" or 8" Intes-Micro RuMak type

I agree with Greg and find APO refractors too small for most visual use, unless you hit the 5-6" mark and associated price tag.

Cheers
Steffen.

[Kunama]

Send a PM to UniPol (Steve) he had a WO 132 triplet with Starlight Instruments 4" Feather Touch R & P focuser, WO RDF, WO tube rings, WO dovetail & saddle plate, WO 2" dielectric quartz diagonal, in the classifieds recently around the $3300 mark but withdrew the ad. An immaculate scope apparently.
He might still be prepared to sell it.

[issdaol (Phil)]

Originally Posted by Kunama

Send a PM to UniPol (Steve) he had a WO 132 triplet with Starlight Instruments 4" Feather Touch R & P focuser, WO RDF, WO tube rings, WO dovetail & saddle plate, WO 2" dielectric quartz diagonal, in the classifieds recently around the $3300 mark but withdrew the ad. An immaculate scope apparently.
He might still be prepared to sell it.

Steve's Gear is well looked after gear so worth the time to investigate.

He also has experience across a wide range or equipment including WO and Tak so probably a good source of real practical advice.

[Kunama]

I have only had 30 minutes at the eyepiece of my Takahashi TSA120 but that 30 minutes confirmed that I made the right choice, sharp and CA free optics, just a superb scope.

[David Niven (David Niven)]

Just luv this triplet apo and especially the price.
you can get this babe for just $1299 from VTi Optics.

[raymo]

Steffen is absolutely right. I had a 150mm Skywatcher Mak. It was
a first class scope. I could clearly see the bright blue/green companion
of Antares with it; something I cannot do with my C-8, my 200mm
Newt, or my 250mm Dob. The stars were pin sharp, and the contrast was great; and it was nice and compact. A larger one would be a great
scope, and have a focal length suitable for higher power imaging,
and also be better for visual work, having a much larger aperture
than an APO. Just my opinion.
raymo