example image for new-ish apo and new-ish achromatic scopes

[silv]

Hey :)

could you maybe upload un-edited example photos of your 80- 120 mm achromatic or apo refractors?

As in: if someone posts a mostly un-edited photo of the object xyz taken with an achromatic 80mm scope, the owner of an 80mm APO looks in their collection and posts a mostly unedited capture of the same object?

And please, if there were other devices in the focal path, could you please list them?

Thanks a million!
Annette

[Poita]

I could try an image through my 80mm achro and my 80mm APO and the 105 triplet.

Do you just want raw single captures from each?
What is it for?
Cheers

-Peter

[silv]

oh, peter, yeah!

I want to SEE for myself how much of a difference it really makes, nowadays, to spend so much more money.

I have never looked through a refractor - and of course never taken an image with one. (photography being my preferred observing method).

Your photos - and list of additional devices in the focal path, if any, - would give me insight what to expect regarding color false-ness.

that would be soo awesome! thanks!

[Poita]

If the weather is good I can take images through all three this weekend.

It will be using a QHY8 cooled CCD, I won't put anything else in the imaging chain and will do short exposures.

I'll see if I can grab jupiter or Saturn with the 5x powermate as well.

-Peter

[silv]

excellent!

I'm not interested in planets. but somebody else might well be.

that's exactly what I was hoping for. you're a star!


"short exposures" means in your book?
I mean, we need to see something, right?

re no editing:
some stretching is probably necessary or otherwise we won't see any colors, at all, on any of the images?

[Poita]

What targets do you want? Just starfields or something else?

[rolls05]

Howdy all. May I second that request.As a total newbie,I'm sure there are others like me thinking of getting a refractor but unsure of the quality of the achro compared to the apo. I know through the threads that the apo rules, but would a achro do for a first scope. I dont know. All I know is the price of the apo's are restrictive. Anyway, good thread Silv. A side by side comparison of the two would be great. And thanks Peter also.

[silv]

glad you benefit, too, rolls.

peter, something with colors would be helpful.

so the planets - yes.
and a nebula.

not sure what the fov would be for NGC 3372 .
that would be a nebula I already know from my scope.
so I could compare that 8" newt, too, to all 3 of your refractors .

[will upload a frame shortly.]

[silv]

NGC 3372 , 8 seconds, ISO1600 , Sony Nex-5N. (mounted on the empty focuser barrel, not even with T-ring-adapter kit, only 2 rubber bands :o)
exported to fit 640x640 JPG
scope: 8" newtonian 1000mm f/5 Eden Optics


1. unaltered RWA

2. luminance shifted - a lot - in "Aperture 3"
(that's an Apple photo library software with some basic adjustment capabilities)

3. same as 2, cropped

Don't look at the quality of the image, though. 'kay? ;)

[rolls05]

That's pretty good silv. Not a lot of people have nailed this one from what I've seen. Bit more exposure time and some p.s work and you would be pulling some colour out of it for sure.

[Poita]

After two weeks of clear nights, it is now pouring rain here, but as soon as it clears, I'll get onto it.

[silv]

" two weeks of clear nights" - lucky you, peter. I'll bump this thread once in a while, then. thank you!

[silv]

rolls, the frames are for comparison of the pure capture, not a post-processing contest.

btw: longer exposures are impossible with EQ5 with iOptron motor and GotoStar + 8"newt. 9kg load is too heavy.
eventually will have to either get a lighter scope or a sturdier mount.
that's part of the reason why I would like to have an impression of current achro models vs apo and 80 to 120 mm.
money is tight. maybe I can live with the results of an 80mm achro? or maybe, god forbid, it would have to be a 120mm APO for me?

there hasn't been a star party in months, now, and with this weather there won't be one any time soon. no chance for in-field comparison. :)

peters photos (or someone else's?) would be perfect!

[cjamo9]

hi, yeah id like to see pics from the same scopes as you as well. hoping itll help me decide what gear to go for next. i like the second shot youve got there, the nebula looks heaps clearer than i can get in 40 seconds even.

[silv]

bump :)

[jjjnettie]

You'll get a better idea of what CA is inherent in each scope by shooting a bright object.
The Moon's terminator would be ideal.

[silv]

Thank you :)
Sounds like a sound and scientific approach.

But the moon is not be what I will be imaging.
I would like to see the comparison in that NGC 3372.
That's the practical, intuitive approach.

Can I live with NGC 3372 as imaged through an 80mm achro?
Compared to Apo of same or bigger size?
And compared to my current 8" newt?

Thank you :)

[loki78]

If you're imaging, I would think there are so many factors that will dictate the quality of the image apart from what scope you're using it will be hard to give you a comparison. Location, camera, expertise being just 3 that will differ wildly.

If you're after an idea of how things will be framed, this site (http://www.12dstring.me.uk/fov.php?aperture=100&flength=900&barlow=1&pxsize=4.31&pxwidth=5184&pxheight=3456&binningw=1&binningh=1&day=5&month=8&year=2012#) might give you a rough idea

[cjamo9]

i cant see any difference between apo and same size acro on this site. why such a cost difference. i tried one of the scopes in my stable on this site and what i see dont look anything like that. dont think this site is very accurate.:P

[silv]

I'd like to see images, single frames, un-edited (apart from more light) of NGC 3372, taken with any camera prime focal on a not too old 80 achro and an 80 Apo - if there are more different sizes, all the better. The exposure should mimik what I would be able to get - like 15 seconds (or like the 8 I did on mine.)

I don't see why someone else must doubt the validity of this wish. :)
Did you read the posts, at all?

Thanks.

[loki78]

There's no need for that, yes I did read the posts. I was just trying to infer that unless the same person takes the photos with the same imaging gear from the same location, it wouldn't really give you an accurate compare between the scopes.

Ie suburbia, cheap camera and an apo won't compare favourably to a good dark sky location and good camera with an achro.

From a scientific standpoint, to give you the most accurate info and answer your first question, ideally, the same person will have all the gear and take the photos back to back with all other variables the same.

cjamo9, i think that site is just to give you an idea framing, ie with a certain scope/camera combo how the image will frame, or in other words how big the object will show in your photo.

[silv]

loki, that's a fine thought. albeight not feasible.

getting example images here on IIS is the next best thing.
and I'm fine with the inherent differences.

:)

[loki78]

We might get lucky yet, there are a lot of guys out there with a lot of different gear and might be able to do all of it. Cross your fingers!

I'm curious too, also about the difference between a top quality achro vs a lower end apo. I wonder if it is as cut and dry as 'apos are better' and that's it? I suspect not.

[Poita]

I will get onto this as soon as the moon buggers off and I get a clear night.

[silv]

yes loki :)

Peter, I'll bump the thread again, later :thanks:

[ZeroID]

Confess I'm interested as well. The $$ difference is substantial APO vs ACHRO and I'm impressed with what I've seen posted with just 80mm APO scopes. I have an 80mm Achro and I am quite impressed with just how well it does work but I suspect photographically the faults will appear.
I am going to try some solar pix hopefully soon through Baader film. Being almost monochromatic, colour abberation should not be an issue and will let me see how good the scope is in that role.
I'd like an APO but ... :shrug: we'll see.

[Shiraz]

Silv, know you are not interested in solar system imaging, but others seem to be and you invited input from that area. will remove post if you think it too far from the thread theme.

Achros are pretty much as good as APOs if you restrict the waveband and many solar system objects can be imaged OK in monochrome. The attached images are all with bottom end achros and a QHY5 colour cam - a fun combo. Standard Registax stacking was used for all images.

Venus transit through Celestron 80mm f11? achro - Celestron solar filter + green filter. 4 panels stacked and much detail lost fitting it into posting limits (its actually 4x this area)

moon and Venus through super low cost Meade 90mm f8.8 achro (and 2x Meade Barlow from fading memory). Images assembled from green data only.

Really looking forward to Peter's results

regards Ray

[silv]

Shiraz, you have a livelong permit jumping into any of my threads! ;)

Of course, I'm happy to extend the subject to solar system, incl moon and sun.
Peter I think already made the point about planetary interests.
All for the greater good. :lol:

As long as the images are not an editing contest and as long as the imaging path is well described, no fancy device being used is preferred. (And I have no idea what "assembly from green data" refers to. That's running under "fancy" in my book. ;) )

(And as long as someone gives me light frames of NGC 3372. :o )

I'm really happy that the comparison is of interest to others, too.

And thank you for your contribution, Shiraz!

[silv]

you can't mount your camera to it, can you? that's a pity.
although - it would probably take you half a year to come up with example images, given the weather we suffer from here in Auckland. :lol:

[Shiraz]

(And I have no idea what "assembly from green data" refers to. That's running under "fancy" in my book. )

naah nothing fancy at all - when converting colour images to B&W, most software allows you to specify how much each colour contributes to the luminance - need to set red and blue to zero to remove colour fringing from the achro image.

just to be sure - are you asking for comparison images of NGC3372? - I think that is what your image shows.

[bojan]

I think you just need a well focussed raw photos of the bright open cluster, for example Hyades, so that you can see the star image difference in centre and in the frame corners.
This will give you all the information you need, applicable to planets, stars, nebulae... You will be able to determine and compare the amount of coma, CA, astigmatism, field curvature for each optical system.
Yes, there is a lot of water muddying when comparisons between various optical systems are concerned - sometimes people feel they have to protect their investments (mostly from themselves). It is bad feeling you paid k$ for something that doesn't perform ..
Of course, general rule definitely applies here - "You get more music for more money..."

[silv]

ah, not fancy at all. my book gets new pages everyday. :)

and yes, it IS NGC3372. sorry bout that! thanks for correction, too. have edited posts accordingly.

[silv]

cheers bojan. :)
That's a grand idea. Do you have single frames of short-ish exposure of it, captured through a newish achro or apo or both?
Might well be very useful!! Thank you!


However, I'm a noob. I can't tell anything from seeing an open cluster. My sole "experience" is a colored nebula - NGC3372, as I now know. I've captured/seen it with a 200mm lens and with my 8".
Well, and Orion - but only with the lens in pre-telescope times.

Now, I need to do something with my setup - which means spend money. :(

So, I'd like to see the difference in colorful big objects of achro and apo, 80mm and bigger. Maybe I can live with what I would get through an achro? That's what I want to try and find out.

And other noobs might be interested in planets and the moon and the sun and would appreciate a comparison in these objects before they spend all their money on an APO :)

[bojan]

Annette ,
The thing with open cluster is, it consists of stars, more or less randomly distributed.
Stars are point-like sources of white (more or less) light - and ideal optical system will produce images of stars which are point-like, across all the frame.
The real systems, however, will produce images which will be distorted - that means, those images will not be points, and each wavelength from their spectra will produce it's own image more or less at the same place on the frame.

So, it will be immediately visible which optical system produces closer to ideal star images.

Anything else (any other target - nebulae, or planets or Moon) will not be able to show you that, simply because those light sources are not point-like.

[silv]

ah, thank you!

so people interested in pointlike stars will want to see examples. :)

I'm still interested in whether I can live with the outcome of colorful nebula, or not. I'm not in it for the "art of perfect imaging". I want to discover. That's all.

Let's open the imaging subjects completely, shall we?

[bojan]

Then go straight to achromatic lens - you will live just nicely ;).
If not, you can always reduce the aperture for one stop (and take 2x longer exposures) this will do the trick for you.

[silv]

Mostly unedited,
single frames
of short-ish exposures
taken through new-ish achro
and apo refractors
of 80mm +
with little to nothing else in the imaging path.

Object: Anything goes.

:thanks:

[silv]

bojan, that's not helpful at all. :)

If you don't see the merit in this then - that's okay. Just don't spoil it for me, 'kay?

[cometcatcher]

I posted these images in my ED80 thread but I'll put em up here again.

The Jewel box and Mimosa in Crux comparison. Pic4 is from a 71mm achromat and pic5 is from an Ekinox ED80. As Bojan mentioned, achromatic scopes can't focus all colours at the same focal plane. You can focus red, green and blue individually but not all at the same time when shooting one shot colour. What happens is one or more of the colours will be out of focus in the achromat and bloat, giving a red, blue or violet fringe.

On the other hand ED or APO scopes do a better job at focussing all the colours at the same focal plane.

I've included a close up of halos caused by the red plane out of focus using a 4 inch achromat.

[silv]

whooaaah, awesome, Kevin! Thank you!

so far, only 3 pics show up.

could you make sure that you have not given any of your spectacular post-processing skills into them and that they are single frames?

what was the exposure time?

I'm a bit confused now which one was from the Equinox ED80 and which one from the 71mm achro?
How old and what model is the achro?

Is the red image cropped?
Could you post the full frames, too, and also name the camera you used and any additional devices in the imaging path?

Great! Really so much appreciated! :-*

[bojan]

I didn't try to spoil it for you..
I just tried to stress the fact that no instrument is ideal, but all of them are useful for this or that purpose.
You will have to decide for yourself what's good enough for you - so going for cheap(er) option is not necessarily bad step for the start.
The worst scenario is spending a lot of money and discovering that even APO has limitations.. because of expectations set too high.

I am still using my MTO1100A for nebulae and I am happy with results.

[silv]

Yup. That's the point, here. :)

[cometcatcher]

There's only 3 pics.

I can't post full frames here because of the 200kb limit. The full frame tiffs are about 100mb!

They are not single frames but the circumstances are similar. Same goes for post processing.

Since we are comparing apples to oranges anyway, the thing that matters most is to get focal length and f ratio as close as possible, which I have done, eg: the 71mm is 400mm f5.6 and the ED80 440mm f5.5. The 4 inch achro is 550mm f5.5 roughly. The 4 inch achro is a crop of another image to illustrate red halos.

There was no filter in the focal path of any of the scopes, all straight through.

Camera was an unmodded Pentax K-x.

The ED80 is the second one (pic05).

[silv]

ah, "pic05" refers to the filename, I see.

how old is the 71mm achro? and what brand?

"full frame" - I meant un-cropped. Could you add an uncropped version of the orange pic?

Thank you ;)

[cometcatcher]

The 71mm is Tokina. It's > 20 years old.

Here's a full frame from the 4 inch achro. It's a Ricoh. It's also > 20 years old. But.... the 4 inch has a Lumicon Deep Sky filter in the focal path as I shoot mostly with filters.

[cometcatcher]

Using the same photo, I've split the channels into red and green to explain more about focus and achromatic refractors.

You will see in the red channel the stars are all bloated and look like blobs. They are out of focus.

With the green channel the stars are all tiny and well focussed. Why? Well human eyes have peak sensitivity at green, so I focussed my camera for my eyes.

If I had somehow managed to focus the red channel properly, (which I could have by taking short exps to test) then the green channel would be out of focus.

Such is the life of a fast (F5) achromatic refractor. They improve as the F ratio rises, say to F15, or if special glass is used to make the objective. Hence why everyone loves APO's.

Edit, an achromatic refractor can still take good pics with all colours focussed, but you have to shoot each colour separately and combine them later in software. Or be happy with monochrome.

[silv]

thanks a lot for the explanation and the uploads, too. :thumbsup:
Your words together with your examples already help a lot.


while "20 years" is not "new-ish"
and the fact that these are stacked and post-processed images from long exposures do not meet my criteria,
(I would not be able to reproduce your skills this well so I can't tell whether or not I'd be happy with my result - hence the "single frame" etc. criteria)
I don't dislike the full frame image. Very useful for me. Thank you.

- on that note:
could you guys please help in the way I asked for help? thanks a million.


Now, I'm really - and even hopeful - looking forward to images from new-ish achro scopes in comparison to APO.

[silv]

Mostly unedited,
single frames
of short-ish exposures
taken through new-ish achro
and apo refractors
of 80mm +
with little to nothing else in the imaging path. If anything, please specify.

Object: Anything goes.

And if you could list the model and age of your refractors, too? Awesome!

Cheers :)

[bojan]

You have to understand what simple processing (stacking) does to a picture:

1) it reduces the noise introduced by camera
2) it reduces the effects of the atmospheric turbulence
3) it does not affect much the local visibility (LP, transparency and so on)
4) it does not affect the optical operformance of the system

Also, you will find (in time) that 20 years or even 50 does not mean much when optical design is concerned - APO from 20 years ago is very similar if not the same performance-wise to APO design done with the help of all that high performance computer software from today - because it uses the same mathematical solutions, that were done 100 year ago, and it uses the same glass materials...
The difference from 20 years ago and today is, today the design of optical systems is faster (because it runs on computers.. 20-30 years ago it was done on a piece of paper with the help of slide rule and pencil and book with logarithmic tables) and manufacturing is today somewhat cheaper. But the assembling and testing is not - it is still done manually and individually for each product.
Also, some new exotic optical materials are available today that were not on the market 50-100 years ago, but optical elements made of those materials are still very expensive, and most likely not affordable by most (myself included).

So, reasonably processed images will show you what you want and need to know - is APO better than achromat and by how much.
Kevin's images (post #39 of this thread) are exactly what you needed - side by side picture of the same object (star-like) and there you can see chromatic aberration of the achromat at work.

[silv]

I didn't know what I really want and why until you cleared that up for me. :lol:

good one! classic! :thumbsup:

[silv]

PM sent

[cometcatcher]

I don't have a new achromat sorry.

What is the exact reason you want the comparison? Do you want to save money buying a new achromatic scope instead of an APO? Do you think a new achromat will be better than a cared for 20 year old achromat? Do you want to use it for visual, photographic or both?

For me, I know what I'm in for if I buy a new fast f ratio achromat. I reckon I could live with it for wide field visual use if combined with a fringe killer or semi-APO filter. But for me, for single shot colour photography they are not good enough. Your taste may be different. If you can live with one colour being constantly out of focus like in post #45 then go for it!

[silv]

yup, kevin, you answered your questions yourself, sort of. :)
the first page of this thread explains it several times in detail.

[cometcatcher]

So bear with me for a minute. I'm slow. ;)

Just to clear things up, basically you believe a new achromat will be superior to an older model. You want to use it for both visual and photographic use. You will be shooting single shot colour. You want performance similar to an APO.

Correct?

[Visionoz]

I think Silv wants to know if the new-ish achromats can will give her the results (when compared to a "more expensive" APO of similar size/FL) that she can live with primarily for imaging as well as some visual work

I think her request is pretty good as it allows newbies to get a "feel" of how things work out in the real world without having to make the "mistake" by spending the money first to find out that an ahromat will not cut it based on one's own expectations - however there is nothing wrong at all if one is happy to accept that certain colors will always be out of focus and the $$ spent is within one's means!

MHO only - no offence or slight meant

HTH
Cheers
Bill

[cometcatcher]

That I understand, and is fair enough. My story is similar. Let me explain from my point of view.

Optical physics hasn't changed over the last 20 years. Present day achromatic doublet refractors bear the same disadvantages that they did 20 years ago. If this wasn't so we wouldn't bother buying APO scopes. If everyone hasn't done so already, google "refractor chromatic aberration".

In past years of "classic" refractors, we would never see fast F5 optics. They were usually F11 - F15. But now China has decided to flood the world with big lens diameter cheap F5 refractors. While they are awesome to look at, they are not so awesome for astronomy! I think they may be more directed at terrestrial use.

In the days of film we could get away with it. Film was slow, grainy and lacked the resolution of digital. The funky coloured bloats were absorbed in the process and never made it to print. Enter the digital world and everything has become more critical.

Basically that's my story. I used to shoot deep sky on ISO 800/1600 film with fast optics. The fringes never showed up on print. Then I went digital and the chromatic aberration of the achromats was there in all their glory!

Like Silv I wanted a cheap way out. Because I've been doing astrophotography for something like 30 years+, I didn't want to have to abandon my old achromats. They cost too much back then! I did some major research to find a loophole for single shot colour. What I found was this. There are compromises. One, forget fast F5 optics and go with something with a higher F/D ratio, the higher the better to reduce CA. Problem. F11 - F15 has reduced CA but is painfully slow for photographing deep sky. Great for visual use though. Some claim a good F15 achromat has similar CA to a F7.5 APO.

If you want a cheap achromatic scope for visual use only, get a long tube high F/D ratio type. They work better at higher power and have less CA.

For single shot colour photographic use for deep sky, there is no loop hole. I buckled and bought an ED80.

[Visionoz]

And I totally agree! :thumbsup:

Cheers
Bill

[silv]

your discussions are probably helpful for some.

however, since I have read enough elsewhere about how bad achros are, oh, so bad!, but never seen images made with achros that are currently on the market, and can't compare those never seen images to never seen images taken with Apos,

I'd like to propose a change of rules in my thread:

attach an image to each of your posts.
an image that meets the help requirements:

Cool. thanks :thumbsup:

[rolls05]

Well,a friend sent me this link as he new I was asking about how good an achro might be on dso. I think you might be impressed.http://www.astronomyforum.net/astro-imaging-forum/144251-achro-scope-imaging.html

[silv]

I am!
Thank you - and your friend! :thumbsup:

[silv]

Andromeda (http://www.flickr.com/photos/astro_allie/7834087792/in/photostream/) through this Skywatcher 102/500mm (https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2685_Skywatcher-Startravel-102-OTA---Gro-feldrefraktor-102-500mm.html)
- without anything in the imaging path - no filters like fringe killer or sky glow. for 198 eruro.

M42 (http://www.flickr.com/photos/18581997@N00/2099293610/in/photostream/) with sky glow and fringe killer through this Skywatcher Startravel 80/400 (http://www.teleskop-express.de/shop/product_info.php/info/p3553_Skywatcher-Startravel-80-OTA-Rich-Field-Refractor-80-400mm.html) . for 122 euro.

Another M42 (http://www.flickr.com/photos/von_gollum/6777457169/in/photostream/) with unknown filter, possibly fringe killer, through the SW ST 80/400.

[irwjager]

Annette,

As Bojan correctly suggested, your question cannot be answered and your dilemma cannot be solved with simple comparison images.

The continuation of this thread is doing a disservice to Newbies with the same question - any conclusion anyone would draw from any comparison would be wrong and false.

As pointed out, an achromat can attain the quality of an apo with filters and you can easily find apos with worse optics than a good achromat. Age has nothing to do with it and the prevalence of the chromatic aberration effect of an achro varies depending on the subject, seeing, exposure time and processing and a host of other variables.

The best I can do for you is simulate the optics of a perfect virtual apochromat and then show you the effects of an achromat with the exact same specification on the same artifical point lights under laboratory conditions.

In the first image, you will see 4 equally sized point lights, diffracted by the aperture of an 80mm F5 scope. I purposefully chose big fat stars, as the effect of an achro is the most pronounced on these. The stars are pure white (e.g. contains the same energy in all wavelengths) to demonstrate the effect the best.

With perfect focus on the green channel, I chose a mild inability to focus the redder and bluer wavelengths, resulting in a mild chromatic aberration.

As you can see in the 2nd image, the stars have a purplish quality to them and if you push the saturation and stretch a bit more (as you would do during any sort of normal processing), you'll notice a purple halo forming.

This is the only difference between an achro and an apo; the achro is less able to bring all wavelengths to focus at the same time. What you're seeing is the blue and red wavelengths slightly out of focus, with the green wavelengths perfectly in focus (I could have chosen a different wavelength). The apo is better in this area (but not perfect!). And this attribute is what you are paying for, nothing more.

How the above will manifest itself exactly in your images, will depend on a myriad of different factors too numerous to list. But, as already pointed out, because you can chose which wavelength you wish to bring to focus and filter out all other wavelengths, you can easily attain better than apo-quality with an achro by using color filters if you want.

Please end this thread, as, again, the comparisons you ask for will not answer any of your questions or reveal a universal truth about apo vs achro refractors.

Cheers,

[silv]

Thank you Ivo for your kind contribution and good wishes.

I did find the help I needed in the linked images from Rolls' link and from those in my last post.

I am very impressed by those pics and feel a really big relief .

Some people here did understand the kind of help I needed. Some of these people then helped out in a helpful way or offered to help. Helpful according to the help I needed.

Some other people could not understand and kept telling me what I should want to know.

I acknowledge that they were meaning well.

They can go and look at Roll's link.
Go and look at the Andromeda in my link.
Look at cometcatcher's nebula through a 20 year old lens.

Then they might understand why those images helped to solve my problem.

In case a newbie is interested in solar system imaging he has found some answers in Shiraz' kind and helpful contribution.
Go and have a look at those images, too.

And if Poitr should still dare to contribute with his kind offer, then those images will be helpful, too. And very much appreciated! :)

However, I could understand if nobody else wants to chip in, anymore.

They'd be risking to look stupid in front of those other people who have verbosely defined that those example images of nebula and planets are not helpful, anyway. And it's rather silly of me to ask for them, too.
"Don't answer silly questions or you look silly, too!"

***

Go, have a look at those links, Ivo. Can you understand why they are truly helpful? If not then that's okay. But you surely are open minded enough to allow somebody else to find answers in them.

***

I invite everybody who wants to tackle the problem theoretically to go and open their own thread.

- and thank you for not continuing to write off-topic in mine.

This one is meant for Example Images.

[silv]

hmm.

maybe it is a good idea to open a second thread.

this practical approach to the subject is of interest to newbies.

a second thread, completely clear of the theoretical side and clear of the discussion , could be a nice, continuing collection.

I shall refrain from opening that new thread for tactical/psychological reasons :lol:

but if any other people think that it would be a good idea to have a clean thread: please do so and open a second one.

I'd be contributing soon with images taken through my brand new achro :D

[rolls05]

And thank you all for a great thread , Enjoyed it immensely. I found what I wanted to know even tho it was on the back of silv's thread. And thanks Ivo for your incite. Very informative.

[irwjager]

Congrats on your decision Annette (an achromat would have been my choice too ;) )

If you ever start running into problems with the chromatic aberration, know that there are a lot of ways to eliminate it, both using hardware and using software.

The Internet is a free place and silly questions don't exist. It'd be sillier to not ask and remain wondering or doubting!

It's hard enough for beginners as it is, so personally, I really want to keep the beginners section factual, informative and free of confusing misinformation. My main concern is simply that (other) beginners might make bad decisions based on bad information, asking the same wrong questions and/or making the same wrong comparisons when they are in the shop to buy their next scope. This is why I (and other IIS members) tried to tell you that the questions you ask were rather pointless for the purposes and motives that you stated at the start of this thread. It is certainly your prerogative to ignore any advice given and be headstrong about things - on this or any other forum for that matter. However, please remember that other people may read the same thread and draw conclusions based on its content.

Good luck with the new purchase & all the best,

[Regulus]

Thanks Silv. An absolutely fascinating thread. Enjoyable and informative in so many ways.

I think it's a great idea (as are other similar comparison subjects) for an ongoing, or occasional, thread.

Enjoy the new scope, and post a piccy or two for us.

Trevor