C9.25 vs GSO RC 8" vs VC200L vs 8" LX200-ACF

[troypiggo (Troy)]

Interested in gathering some thoughts on the above scopes, primarily for planterary and DSO imaging with DSLR and/or CCD. As a side-comment, also interested in how they'd go for viewing occasionally as well (planetary and DSO).

They all seem to fall within the same ballpark of price. I know their focal lengths differ. I'd be trying to mount them on my HEQ5PRO for the moment with ED80 as a guidescope. Pushing the limits of the mount, I know, but if I can get away with it I will.

Celestron C9.25 - this has consistently been recommended in many reviews as a great imaging scope. 2350mm focal length, with barlow/powermate certainly capable of planetary imaging. f/10 - too dark for observation?

GSO RC 8" - newish on market. Good first impressions, but read that you need to spend a bit more money on it to improve/correct some distortions or optical errors?

VC200L (or is VMC200L better) - heard this one highly recommended as well.

LX200-ACF - read good reviews on these too.

Can I please have your 2 cents' worth? If you have one of them and were faced with the same dilemma, what made you choose X over Y etc?

[rat156]

Originally Posted by troypiggo

Interested in gathering some thoughts on the above scopes, primarily for planterary and DSO imaging with DSLR and/or CCD. As a side-comment, also interested in how they'd go for viewing occasionally as well (planetary and DSO).

They all seem to fall within the same ballpark of price. I know their focal lengths differ. I'd be trying to mount them on my HEQ5PRO for the moment with ED80 as a guidescope. Pushing the limits of the mount, I know, but if I can get away with it I will.

Celestron C9.25 - this has consistently been recommended in many reviews as a great imaging scope. 2350mm focal length, with barlow/powermate certainly capable of planetary imaging. f/10 - too dark for observation?

Never used one or even looked through one. But as it's an SCT it will have coma at the edge of field unless a Focal Reducer/Field Flattner is used. Should be great for planetary work (Bigger aperture means shorter exposure time, longer FL for image scale. For DSO's will be difficult to get effective guiding at long FL, even with a FR in the image train. Will need a better mount. Visually f-ratio is less important than aperture.

Originally Posted by troypiggo

GSO RC 8" - newish on market. Good first impressions, but read that you need to spend a bit more money on it to improve/correct some distortions or optical errors?

See ongoing threads on this scope. Seems to be good for DSO's. Visual and planetary may suffer due to large central obstruction and smaller aperture. Only available in 8" ATM. Light, so won't overtax your mount. Focusser needs upgrading, requires FR for flat field, several have been tried, but none are made specifically for this scope.

Originally Posted by troypiggo

VC200L (or is VMC200L better) - heard this one highly recommended as well.

Flat field is great for DSO's, not seen too much planetary work done with these, again may suffer from larger CO. Very fat spider so large diffraction spikes and square stars if you don't oversample. Reasonably light so mount should be up to it.

Originally Posted by troypiggo

LX200-ACF - read good reviews on these too.

Assume you mean the 10"er OTA. Same arguments as for C9.25" regarding f-ratio and FL. Flat field, so FR shouldn't be a FF as well, although in practice the f6.3 has been used. I would reccomend the AP0.75 FR as it's great on my RCX, Optec 0.5 induces coma at edge of field so off-axis or self guided cameras have problems with this FR. Great visual scope.

Originally Posted by troypiggo

Can I please have your 2 cents' worth? If you have one of them and were faced with the same dilemma, what made you choose X over Y etc?

In general, one scope can't do all of these things, as usual there will have to be a compromise between uses. Pick which one you are going to concentrate on and pick the best scope for that, then put up with the limitations of the other uses.

For planetary, aperture is king, it gives better image scale as it usually comes with longer focal length. Mount is unimportant, you can even use an Alt/Az fork mount. Collimation of the optics is essential.

For DSO's, the optics are relatively unimportant, the mount is King. You need low PE or consistent PE, other than that f-ratio is important if imaging under light polluted skies. Collimation of the optics is essential.

Visually, the optics are important, aperture rules, image scale is defined by your eyepiece, larger aperture allows more magnification. Again mount is not very important, but pointing accuracy and ease of setup become factors.

Hope this helps, of course other may have different opinions.

Cheers
Stuart

[TrevorW]

A number of these types of threads have been run before on varying sites and in all honesty each scope has their good and bad points and in my opinion at our level there is no such thing as the perfect scope.

A lot of buying a scope is reading what others have said about them, what your main interest is and how much money you have.

A lot is also trail and error, you may purchase something and find it doesn't suite you or doesn't live up too your expectations.

Like a car you'll buy it thinking well if I add this and that will it perform better.

As a purchaser of a GSO RC the only issue appears to be the focuser although some say it's ok but others are changing it but this is not an uncommon thing even on the other scopes you have listed.

Cheers

[troypiggo (Troy)]

Originally Posted by rat156

Never used one or even looked through one. But as it's an SCT it will have coma at the edge of field unless a Focal Reducer/Field Flattner is used. Should be great for planetary work (Bigger aperture means shorter exposure time, longer FL for image scale. For DSO's will be difficult to get effective guiding at long FL, even with a FR in the image train. Will need a better mount. Visually f-ratio is less important than aperture.

See ongoing threads on this scope. Seems to be good for DSO's. Visual and planetary may suffer due to large central obstruction and smaller aperture. Only available in 8" ATM. Light, so won't overtax your mount. Focusser needs upgrading, requires FR for flat field, several have been tried, but none are made specifically for this scope.

Flat field is great for DSO's, not seen too much planetary work done with these, again may suffer from larger CO. Very fat spider so large diffraction spikes and square stars if you don't oversample. Reasonably light so mount should be up to it.

Assume you mean the 10"er OTA. Same arguments as for C9.25" regarding f-ratio and FL. Flat field, so FR shouldn't be a FF as well, although in practice the f6.3 has been used. I would reccomend the AP0.75 FR as it's great on my RCX, Optec 0.5 induces coma at edge of field so off-axis or self guided cameras have problems with this FR. Great visual scope.

In general, one scope can't do all of these things, as usual there will have to be a compromise between uses. Pick which one you are going to concentrate on and pick the best scope for that, then put up with the limitations of the other uses.

For planetary, aperture is king, it gives better image scale as it usually comes with longer focal length. Mount is unimportant, you can even use an Alt/Az fork mount. Collimation of the optics is essential.

For DSO's, the optics are relatively unimportant, the mount is King. You need low PE or consistent PE, other than that f-ratio is important if imaging under light polluted skies. Collimation of the optics is essential.

Visually, the optics are important, aperture rules, image scale is defined by your eyepiece, larger aperture allows more magnification. Again mount is not very important, but pointing accuracy and ease of setup become factors.

Hope this helps, of course other may have different opinions.

Stuart - thanks for the very detailed thoughts. I realise there will be some compromise. I'll have to mull over this some more, and check out some of the other thoughts.

Originally Posted by TrevorW

A number of these types of threads have been run before on varying sites and in all honesty each scope has their good and bad points and in my opinion at our level there is no such thing as the perfect scope.

A lot of buying a scope is reading what others have said about them, what your main interest is and how much money you have.

A lot is also trail and error, you may purchase something and find it doesn't suite you or doesn't live up too your expectations.

Like a car you'll buy it thinking well if I add this and that will it perform better.

As a purchaser of a GSO RC the only issue appears to be the focuser although some say it's ok but others are changing it but this is not an uncommon thing even on the other scopes you have listed.

Thanks Trevor. I have done some reading of individual posts about these scopes. That's how I have narrowed things down to this list.

Regarding the focuser on the GSO RC - do you have one in mind? I've been reading about those moonlite focusers being very nice and with focuser replacement being recommended for that scope wondered if they might be a nice solution?

[JohnH]

Re the VC200L I have used this scope and can confirm it is not great for planetary imaging due to the large central obstruction and fat spider- the resultant images lack contrast, it is ok not but not up there with the C9.25 from what I have experianced.

It is F9 which with a DSLR on the back and a guidescope on top is going to be a massive ask of your HEQ5, I think you might be in for a lot of frustration. You will be imaging at 0.75" /pixel meaning you will want your mount to deliver +/- 1.5" accuracy. At the very least you will need the VC200L FR which I have also used, unfortunately I found that reduced the image flatness somewhat and meant focus could never be reached visually (ie it is not compatible with the flip mirror or OAG), still I did get some very good results with this setup on a similarly rated SXW mount so it can work out well. The weakest part of the scope is often reconed to be the focuser (because it is R&P) and lock which can cause image shift if not adjusted correctly. The R&P is actually a very good unit but it is a little coarse making critical focus hard to achieve but here the big spider does you a favour as the diffraction spikes soon let you know quickly if you are not on the sweet spot.

The other unusual features you might hear about is the VISAC design - open tube like the R-C which is good as your primary is unlikely to dew up (but your secondary might is really damp conditions) and the corrector/flattener which is in the focus draw tube meaning you cannot use 3rd party focusers/reducers etc. The mirror has a unique figure and can only be re-finished by Vixen. Collimation is more complex than other SCTs due to the need to align the pimary,seconday and corrector not for the faint hearted. Fortunately it seems pretty much set and forget (that industrial grade spider is doing it's job!)- I never touched mine once the shop got it right for me.

Visually the scope works very well and as an all rounder I think it is a good choice. With with a big flat field for AP I recon it is a winner there but I am pretty sure you will need a bigger mount if you are going to enjoy the imaging...and having said all that I must point out that I have not looked through or imaged with the other scopes on your list.

[troypiggo (Troy)]

Thanks for the details and experiences with the Vixen, John. It's all good info.

[dpastern (Dave Pastern)]

Troy - my honest thoughts - go with a refractor for planetary imaging, and one of the other OTAs for DSOs.

The Celestron 9.25 has an almost legendary reputation for its optical quality, Meade units less so imho. The Vixen also has a good reputation. The GSO is new on the market - looks promising, but the focuser does look insufficient. I'm not keen on the primary mirrors being glued in place and much prefer the costlier implementation by Deepsky instruments with an electric focuser set up on the secondary mirror.

One other thing - from everything I've read, a 4" refractor will provide better quality planetary images than a 4" reflector etc. The same comment can be applied to any size comparison. Obviously a 10" reflector will show more detail than a 4" refractor due to the larger light gathering abilities of the primary objective/mirror.

I'd go with the Celestron myself - it's a proven optical/quality setup.

I don't expect Meade to last much longer to be honest - I predict that they'll go bust within the next 15-18 months. They are showing all of the warning signs already. Meade optics have a horrid reputation for either being good, or well, bad. And getting Meade to fix the problems is both a timely and costly problem.

Dave

[TrevorW]

Moonlite are apparently already making them and should be advertised on their site in 2 weeks

I've heard Moonlite are VG

Cheers

[troypiggo (Troy)]

Thanks Dave, but aren't the costs of refractors with the focal lengths and apertures required for planetary pretty scary? Surely something like a reflector/SC/Mak is a much more economical way of achieving aperture and focal length?

[troypiggo (Troy)]

Thanks Trevor.

[Terry B]

I have a VC200L on an EQ6 with a 127mm refractor as a secondary imager/guide scope. It handles it well. I have a reducer but rarely use it.
Not sure about an HEQ5 though to carry 2 scopes.
f ratio is totally unimportant for visual as you vary the magnification with your eyepiece fl. The only difference is that a longer fl eyepiece will achieve the same mag if the f ration is bigger. 8mm eyepieces seem easier to use than 4mm one etc.
Lots of people comment about the spider but for deep sky it is not noticable at all. For planets the VC200L isn't optimised. It is a very well corrected astrograph with a flat field to the edge of a 35mm film frame.
I can't comment on the SCT scopes except that I someimes use our clubs 14".
It has much better light grab but dew is a real hassle- something that rarely affects the VC200L

[TrevorW]

f ratio is totally unimportant for visual as you vary the magnification with your eyepiece fl. The only difference is that a longer fl eyepiece will achieve the same mag if the f ration is bigger. 8mm eyepieces seem easier to use than 4mm one etc.

Terry not quite correct

the F ratio determines the field of view so a scope with a large f ratio will have a narrower field of view and will be useless for wide field views of star fields although perfect for planetary.

This won't change unless you use a focal reducer.

Cheers

[rat156]

Originally Posted by dpastern

One other thing - from everything I've read, a 4" refractor will provide better quality planetary images than a 4" reflector etc. The same comment can be applied to any size comparison. Obviously a 10" reflector will show more detail than a 4" refractor due to the larger light gathering abilities of the primary objective/mirror.

snip

I don't expect Meade to last much longer to be honest - I predict that they'll go bust within the next 15-18 months. They are showing all of the warning signs already. Meade optics have a horrid reputation for either being good, or well, bad. And getting Meade to fix the problems is both a timely and costly problem.

Dave

I don't think so Dave (to quote a well known computer).

The speculation about the future of Meade Instruments is largely irrelevant. If it goes belly up, the name (and IP) will be sold to a Chinese (or even Mexican) company in all likelihood. They DO have a good name and DO produce quality products, hence their reputation for optics is at least equal to Celestron, which BTW aren't manufactured in the USA either. So we'll end up with Meade made by GSO, which is pretty much the same as Celestron.

On the comments on the quality of Meade optics, I say show me some proof. I have had two Meade scopes (including the problem child RCX) and have never had a problem with the optical quality. I can't remember seeing too much negative on the forums about optical quality. Support could be better, and may become so once the company goes through renewal. The ACF scopes are generally regarded as one of the best bang-for-buck visual scopes on the market. These aren't SCT's, they are better, don't just take my word for it, ask Theo.

There's only one comparison between a 4" refractor and a 10" reflector, and that's price. In order to get the same light gathering power from a refractor you're up for the price of an RC, not a GSO RC either.

In summary;

• Meade optics aren't rubbish, infact they may be superior to the Celestron equivalent.
• If you have dewing problems, buy a dewshield! (another thread)
• Comparisons between refractors and reflectors for imaging aren't valid, refractors for widefield, reflectors for long FL (unless you have a large bank balance)

Cheers
Stuart

[Alchemy (Clive)]

vixen vc200l, lightweight probably the lightest of the four (unless the gso offering is light), supposed to have tight flat field, at f9 or thereabouts the DSLR uses will struggle on faint stuff unless they are cooled. not much chop for planetary.... ive had one. and the FR didnt fit even though it had vixen written all over it.

gso rc, new kid on the block, first results from paul heases shot of eta look promising, problem is that a bright object and so far no-one else has really produced the goods that make me say yes ill buy one. time will tell ( but id want the 10 inch) focuser probs easily rectified. same goes for the dslr at f8, i will wait for those that have one and a DSLR to realize this, then there might be a cheap one available.

meade rcx well i leave that to rat he has produced exeptional results with his... but he does use an adaptive optics thingy which helps too. plus FR readily available which helps dslr users

celestron 9.25 proven performer and does a reasonably good job of deep sky AND planetary. again FR available. at the moment this is the one i would choose... but watching closely the RC

Rats comment of widefield... refractor , long focal length some kind of reflector is fair comment.

[PeterM]

Hi Troy,
Thank goodness someone else is sticking up for Meade here. I will follow suit with my experiences. Too many people have based opinions over the years on what they have read - largely service issues - not the 'scopes optics and not always from ownership or use and perhaps they used them not well collimated, I just dunno. I have used Meade SCTs & now "R" telescopes for many years. I have looked at side by side comparisons with other 'scopes and the Meades are always equal/superior to other SCTs. The ACF once setup well (ie good focuser), will outclass its competition completely and the ACF is bang for buck no doubt about it.
So before anyone starts asking for my images to prove it, I will just let it rest on my 2 Supernova discoveries at mag17.5 & 17.6 using a Meade 12inch LX200R (ACF) each with a single 25 second image (sure great camera also in the Starlight Xpress SXVH9). The optics are sharp and that's a proven fact. Meade going bust "soon", hmmm that was supposed to have happened a year ago and then a year before that and ... As far as repairs go you have a couple of the best techs in Australia working at a store in Sydney - they know these inside out, there is little that can go wrong with an OTA - unless you drop it.
It is getting close to Astrofest, if you can wait until then go along and do some comparisons most people are very helpul.
See you at Leyburn again soon.
PeterM.

[TrevorW]

Pete good one, I think Meade, Celestron and the rest all come out of China or Taiwan nowadays so all the lens will be done by machine, some will be good, some will be average the same goes for the GSO RC.

Clive this is a link to Centaurus A taken by me with my RC, this is uncropped

http://www.iceinspace.com.au/forum/a...se.php?a=57379

it's a lot dimmer than Eta amd IMO has potential

Regards

[troypiggo (Troy)]

Thanks again for your input, all.

I must say that before I posted this thread, I had in my mind that the C9.25 would be a good "all rounder" and probably top of the list, with the Meade being second - based on my criteria.

I have not attempted planetary stuff, obviously, with the gear I have. But I do want to get into it eventually, so the capability of it is important to me. I will always want to do DS stuff - I love nebulae and galaxies.

I'm gonna be up for a mount upgrade, aren't I...

@PeterM - I'm planning on going to Astrofest at least for a couple of days. And Leyburn is definitely on the cards in the next few months, depending on work.

[Paul Haese]

Some interesting comments to be had here. From my perspective.

C9.25 - great planetary scope, crap for DSO imaging. Not a flat field nor coma free. The stars end up being too blobby when using a reducer. Main strength planetary.

GSO RC - DSO imaging telescope only. Not designed for viewing and is likely not to have the goods for planetary. The optical design is just not setup for planetary imaging. Contrast and sharpness is likely an issue.

VC200L - never owned one, but a confirmed performer for DSO imaging. Design does not lend itself to planetary imaging.

Meade ACF - older meade scopes with the exception of the rare f6.3 were utter crap, star were blobby and not good for planetary at all. The ACF version is however very sharp and flat fielded. A DSO performer but I have read that the central cone of light which is important for planetary imaging is not as sharp as the Celestron SCT's. Nearly all the great planetary images come from a Celestron SCT. Lester is the only person I have seen planetary imaging with a Meade LX200 and producing very good results. Must be an aberration. The ACF is king for DSO imaging though. RCX is probably better still.

Refractors for planetary imaging (standard sized models) - not in a million years. These telescopes have no where near the light grasp nor the focal length to gain the same image scale or resolution. Only if you were very rich could you afford a 12 inch apo which would equal a 14 inch SCT. Having said that, refractors are superb for DSO imaging.

So to rap up each design has it strengths and weaknesses. A telescope that will work for you on all levels is just not really possible. If I had to pick out of all of them, I would hedge my bets by going with the ACF. It will be great for DSO and could potentially be very good for small scale planetary imaging (not certain but I have seen some good views of the planets through them). If I were just interested in Planetary and wanted to just dabble with DSO I would go with the C9.25. The other telescopes are just for DSO imaging really. So what do you want to use it for the most? That is what you need to ask yourself.

[rat156]

Shameless plug...

BTW my RCX is for sale...
http://www.iceinspace.com.au/forum/s...ad.php?t=41192
Only so I can buy Theo's bigger one!

/Shameless plug

Stuart

[coldspace]

I will second Pauls comments on the various scopes.

Troy, you need to look through a few more scopes and decide if there is one major area you want to pursue or a couple of different uses.
I will second Peter M's comments in that there is a few of the best scope tech's here in Aust.that know the ACF's inside and out. Meade is a too valuable trade Mark that won't be thrown away if the company sells or winds up. There is soooo much Meade gear out there in this world someone would love to take over with parts and patents.

Alot of the negativity of the service issues came about mostly in the USA where most warranty work had to be sent back direct to Meade which caused alot of back issue problems then it became a bashing company game between what seemed like only a few individuals on the forums. The service with Meade gear here from my experience over the years have been first class. Meade has changed alot in the way they do things in the states and if you follow the forums there they have made big improvements in customer service now there is very little bashing going on.
Alot of people make comments about products that they know nothing about or have never used for along time to make a fair judgement about. So be carefull when reading forums here and overseas about things untill you are sure they are correct. I nearly been caught out sometimes from misinformed comments.

I own a 12 inch 200R ( same as ACF) and let me say when it is colimated properly and cooled for an hr or two the views through it both planetary and DSO are very sharp. I used a nice sharp 5 inch Mak on the planets for awhile which gave almost refractor like views but always ran out of light when the magnification was cranked up where the 12 r never ran out of light on the planets and the image was as sharp as the Mak.
I used this same scope to follow up PeterM's first S/nova discovery at over Mag 17.5 in my light polluted back yard suburban Brisbane with a 28 second intergration using a Mallincam video all this was through thin high level cloud. This scope performs the way it was designed and intended for.

Great alround scope for the $ and with a dew strap no problem ever with dew allnight.

You will never get 1 total alrounder as each scope serves a design requirement but the ACF scopes come close for the money.

I may be taking it out to Leyburn either end of June or July with the Mallincam to put it through its paces in pure dark sky. Talk to PeterM and he will let you know and you are welcome to come to Leyburn and have alook through the scope with eyepieces or with the camera on the monitor.
You will see most of these scopes up at astrofest but if you are like me it took about 6 months to take the plunge and I am very happy with what I got.
Good luck deciding which way to go.

Regards Matt.