Quality Refractor

[TheDecepticon]

Still in the though process at the moment, but have been thinking of upgrading to a larger and better quality refractor.

Ive also had enough of collimation on reflectors and GSO's etc, so easy to use and good quality is what I am after. Some thing I can have for years to come.

Currently using a Megrez 110 that has served me well. I can't go too much bigger due to space, weight and a bad back, so interested in the 130mm range.

That leads me to the Tak 130, the AP 130, Stellarview 130, WO FLT 132 and the Meade 6000 130.

I know I will need a new mount too, but that is easier to figure out, and I should be able to thrash the EQ6 for a while with a 130 and OAG so weight is not too high.

After some serious thought on quality, fit and finish, sharpness etc. Please stick to the subject matter and no slanging off "this is better" type of stuff please.

Thanks,

Gray.:)

[wavelandscott]

I think the big question is how much you are willing to spend?

Depending on your budget, folks can point you in the right direction.

[Profiler]

If you are seriously thinking about a 130 size AP or Tak then you should also at least consider the the TV-127is.

IMHO there is a distinct difference in the quality of refractors which does justify the big price differences - otherwise we would all be buying the same scope variously rebadged and repainted as either WO/Astrotech/Orion and Tak, TV and AP etc woud all be out of business tomorrow.

Ironically, I had a M110 also some time ago and one of my most poignant astronomy experiences was looking through it alongside a humble TV Ranger. I still have the Ranger but I sold the WO long ago.

The moral of the story is that you do get what you pay for and essentially if you are spending big dollars on a genuinely hand-made quality refractor like a Tak, TV, AP etc with very high QC you wont be disappointed with any of them.

[alocky]

I have a WO FLT 132 on loan at the moment, and the quality of the finish and machining is on a par with anything I've ever seen from Tak, AP or TV. I don't think it's fair to lump this scope in the same bucket as the more economical brands. It's not a light scope, the OTA is about 10kg, about the same as my old Meade starfinder 10" with four times the light-gathering ability...
As for the increase in aperture over your 110 - I had this side by side with an old Unitron 4" (@same magnification), and yes, the contrast was a bit better, and I could notice some colour in the old beast after looking through the WO, but it wasn't that different and there wasn't a great deal of detail leaping out of the eyepiece that couldn't be seen in the 4". You'd definitely want to look through and at one of these things before buying it.
cheers,
Andrew.

[issdaol]

hi gray,

It might be worthwhile catching up with a few users on here that own and use each of the scopes you have listed.

I do not own one, but I have used the Tak TOA130 owned by a mate of mine, and I found the fit and finish to be superb.

Sometimes you look at scopes and they appear to have been made from inexpensive mass market materials.

This is not the case with the TOA130 . All of the components look and feel as if they have been custom made for the scope and finished off with that nice pebbly paint finish (this is similar to other Taks like the TOA150 and Mewlon 300).

Visual performance is fantastic as well with pinpoint stars and no sign of any colour effects.

Given the outstanding build quality and performance, this is a scope that I believe could be handed down to the next generation.

I have also been seriously considering one for myself as a traveling "grab'n'go" unit as my Mewlon 300 takes a bit of effort to move around.

[alocky]

Not only that, but since it seems you're interested in astrophotography it's relatively easy to google up examples of images taken with exactly the scope and mount combination (and probably camera) you're considering. I guess the key thing for imaging is focal length, the amount of effort that needs to go into guiding increases quadratically with FL! The FLT132 I have has taken some very nice images on the back of a NEQ6. PM me for the link as it isn't my work.
cheers,
Andrew.

[TheDecepticon]

When looking for quality, I'm not thinking of a price point. When I make my mind up, that will be my budget. I was looking for a bit of feedback to justify up to $8k for a good scope.



Hadn't thought of TV. I'll have a look. Thanks.



It is a small increase I know. But just a bit of this and a bit of that can make the difference to an image,



I hope they pop in here and impart a bit of info.



Will do, thank you.

[wavelandscott]

I own and adore an APM 130 mm refractor and believe that it is the bees knees for me. I balanced quality/availability and size...to me it was the scope to fit the bill. I don't do Astrophotography so I can not speak from experience on it's qualities for that use but for visual it is fantastic.

I would have loved to have gotten an Astro Physics of this size but in terms of availability this was not an option for me. Now that I have the APM I can not imagine how an AP could be better.

[gregbradley]

Hi Gray,

Mr Rhor has done a lot of thorough optical testing of many scopes that is an eye opener:

http://translate.google.com/translate?prev=hp&hl=de&js=y&u=http%3A%2F%2Fwww.astro-foren.de%2Fshowthread.php%3Ft%3D108 01&sl=de&tl=en&history_state0=

To get one that performs through that tough testing has to be very special.

Having had several high quality APOs I think there are 3 main aspects to consider.

One is quality of optics - obviously.

One is quality and practicality of the mechanicals - millions of internet posts about the focusers, reflections etc etc.

One is about your intended use - weight, portability, imaging versus visual etc.

Imaging seems to be more demanding of a scope than visual. CCD cameras detect a wider range than our sight. Flex is not an issue with visual it is with imaging. Weight also is less important for visual except for portability whilst it can be very important for imaging and mounts.

Looking over some of Mr Rohrs tests you will find only really about 3 or 4 makers that make top end optics.

Tak, AP, TEC, APM/TMB. Tak, AP and TEC run around .98-.99 strehl. TEC may be lower strehl in the red channel (.88) and high in the blue (.98) and green(.99).
Tak TOA and AP would be good in all 3, some colours better than others but very high. APM/TMB are sold between -.95 to about .97 and sometimes higher. They are air spaced triplets from LZOS in Russia who make their own exotic OK4 glass which is similar to FPL53.

Its worth looking over the site and checking out the tests. They are often in German but mostly graphics. They are not explained and I guess you look at several and you can tell a good one when you see it. Start with TOA to see an excellent one so you can tell what is not excellent.

AP130GT sell rountinely fairly new for US$7500 on Astromart. Roland must have made quite a few of these last year and is about to make a bunch more so these are the most accessible Astrophysics scope.

Tak TOA are usually fairly available as well.

As far as optical tests go the best seemed to be TOA and AP. TEC is up there as well. The usual complaint about TOA is they are very heavy for their size. The usual complaint about AP is they are not available. I don't read any complaints about TEC. Nor APM/TMB for that matter.
Perhaps also a question mark over the focusers' heavy weight load performance (Tak had to bring out a TOA150B to handle this).

AP has a stainless steel drawtube rather than Aluminium that everyone else seems to use. Grab a 3mm thick aluminium tube sometime - you can make it flex by hand with a bit of force. That or something similar is what most use. AP uses stainless steel. It must be 4x stronger at least.

My experience is AP has the best mechanicals, the best or equal to the best optics (you'd have to be confident with Tak there and also TEC).

AP130GT may be a good match for your needs. Not sure if it comes with a 4 inch focuser which is ideal long term for imaging. 2.7 inch limits you to DSLR sized chips.

My choice would be an AP130, TEC140, Tak TOA130.
It depends on what size camera you are using and types of objects you want to image. None will be great for galaxy imaging except for the larger brighter galaxies and will be ideal for widerfield objects like nebula and globs, larger galaxies, things like Horsehead, Rosette, Eta C, Omega Cent, M42, Pleiades etc.

Greg.

[Waxing_Gibbous]

There are both an AP130 GT and an TMB 130/780 on A-mart at the moment.
Both are terrific scopes and either would be perfect as any optical difference would be minimal and sample specific. Thoughyou stand a better chance of getting that last "Nth" from the AP. The AP is also a bit lighter.
The AP is $US7500, the TMB is $US5900.

While I own a TOA130, it's quite a heavy beast and accessories are expensive. It's also f7.7 as opposed to F6.3 for the AP and F6 for the TMB, so the latter will give slightly wider FoV.

The TEC140 was the first premium refractor I ever looked through and I am still in love with it. Like the TOA It's a little longer FL than the others.

The Stellarvue, while using the same glass as the Astro-Tech 130, should not be sneezed at. SV have very tight QC and their tubes are a thing of beauty.

My choice would be: the AP 1st, the TMB 2nd and the TEC140 3rd.

If it turns out you are unhappy with your choice, I will take it off your hands for a small fee. :)

[clive milne]

What has the world come to when a refractor on a german equatorial is considered the most manageable option? (from a physical size perspective)

I could think of some criteria where an apo excels - contrast transfer function being one of them - which translates to a more pleasing view when there is a bright object in the fov, but the trade off in raw aperture is something that needs to be considered.

If collimation is viewed as an issue (and cost isn't) there are quality telescopes using reflective components where this problem has been addressed.

I know from my experience when I had a choice between an 180mm starfire and a good 12.5" Newtonian. The refractor collected dust while the Newtonian gathered photons.

[gregbradley]

A good quality 12 inch Newt like Mike's is a hard telescope to go past. They just seem to be a bit fiddly and less foolproof than a good APO.

I know what you mean and I think the answer is no one scope is an allround performer for all types of imaging.

Some are more versatile than others.

Faster scopes are more fussy than longer F ratio scopes.

But faster scopes are more productive considering the main hurdle to overcome is getting enough clear skies.

Greg.

[strongmanmike]

Good luck Gray, you seem to have some great feedback (especialy from Bradleys Scope Advisory Service) and look to have it sorted..?

The only thing I'll add is that having now used both the best 6" APO available and perhaps the best fast comercial 12" Newt available, the only thing I would say is that for about the same price and focal length 12" and F3.8 makes mince meat of faint light compared to the 6" F8 APO - which is great for those poor time starved sods like me not established at New Mexico Skies or Paranal. For the pristene quality of star images across a large field though the edge probably still goes to the Starfire.

There really is no truly perfect scope but so far the AG12 has delivered what I was hoping for and the amount of fiddling hasn't been that bad and it's still portable :D

Mike

[sadia]

I can see few good advices already and wanted to add a comment on your initial comment related to OAG



If you want to have OAG please check the backfocus beforehand. I believe QSI is the only CCD with built in OAG and any other CCD will requite an external OAG which will take some additional backfocus.

TEC flatteners have about 78-85 mm backfocus which leaves little or no space to fit a OAG after the flattener.


Regards
Sad

[clive milne]

Is Gary looking for a visual or imaging instrument?

[gregbradley]

Just on that point you can use a 4 inch Tak flattener with the TEC and that gives something like 120mm backfocus and plenty of room for a MMOAG and I have imaged with that setup and it worked beautifully.

In fact it made me wonder if the Tak flattener was better quality than the TEC one (which also works well).

The new SBIG STf8300 has a built in OAG which is a welcome addition to CCD cameras. It would be on my wish list for FLI or Apogee to make something like this. OAGs are definitely the way to go.

Greg.

[strongmanmike]

Perhaps if your mount and polar alignment are a bit dodgy or you have a mirrored scope with plenty of flex spots but not a refractor..? With a quality mount meah, no probs...

I've done quite well at 1300mm FL (similar to most other 6" refractors) for some years now without a selfguide chip or OAG unit in sight :lol:... a little overated IMO ;)... particularly at this FL :shrug:

Not a single AO, self guide or OAG in sight for any of these (http://www.pbase.com/strongmanmike2002/hubble_comparisons) either he he...? :thumbsup:

A good mount (http://www.pbase.com/strongmanmike2002/njp_unguided_exposures) is very useful though :thumbsup:

Mike

[gregbradley]

Mate you are the king of polar scope polar alignment!

I'd say you get your polar alignment within a gnats hair with that. The rest of us mere mortals are not anywhere near as close. Your setup works really well but the best guiding I ever achieved with my TEC180 was with a MMOAG without a doubt. I found a guide scope on my setup (my guide scope was cheap and could be heavier duty for sure) was a tad unreliable. It would give great guiding one trip and the next a bit off.

1x1 binning on a 16803 chip REALLY shows up the little guiding errors.

C'mon Mike you know you want an OAG!

Greg.

[strongmanmike]

Yes, perhaps now because I have a Newtonian with multiple areas that can flex or move but with the Starfire a fixed APO lens in a tube...not really and I think those comparison images speak for themselves really, in fact they suggest that I would still have been able to get high res results at much longer FL :shrug:

Mike

[gregbradley]

Yes your guiding on your AP is 2nd to none.

Greg.

[TheDecepticon]

Thanks heaps guys, great info and advice.

I think I'm on the right track with choices. I would prefer the longer focal ratio, however I want to keep the weight down. If I end up going guide scope insted of OAG, I will make sure it is a solid mounted affair with very little flex, and a decent focuser to prevent flex there also.

I think my choice is coming down to Tak or AP, however, I stilll have a bit of saving to do and time to tease myself by researching each product.

A new mount is in the wings as well, there is no doubt about that either. I have had the chance to be up close and a bit personal with an AP900, which I quite like, I think it would suit me well.

All has been authorized by the High Commisioner for War, so smiles all round from me, especially as I'm still young enough to get this type of gear which will serve me very well for many years and put it to good use.:D

[gregbradley]

Mike I reckon you should experiment with 2 autoguiders if not an OAG.

Use the SBIG STX or the Italian Guys technique. Although he used an STL with self guiding plus a guide scope. Perhaps much the same as an OAG but there are times when an OAG isn't feasible due to lack of backfocus.

Have them out of phase with each other or one short and one long.
One on the dovetail one on your guide scope. The guide scope short and the one on your dovetail long.

Either guide 1 second exposures on your guide scope and 1 minute on the dovetail mounted one or guide scope 1 second and dovetail every say 10 seconds or experiment to find if there is an optimum timing.

Or mount a 2nd guider on your finderscope like the little orion 50mm mini guider package for around $319 at Bintel.

I plan on experimenting with autoguiding over the next several months and come up with improvements to this black art.

I have several ideas.

Greg.

[Mighty_oz]

Can u point me to this person/link so i can see what they do ?

Thanks.

[gregbradley]

If you look in the promo piece for the STX they mention his name. Then google his name and you find his site.

Greg.

[Mighty_oz]

Thanks Greg.