ATIK 320E?

[lukebl]

Hi all,

OK. I know I'm reviving an old debate, but I need to clarify a few things in my simple brain.

I know there've been one or two threads in the past questioning the 320E, which few people seem to possess, but I've just been thinking if it has any potential advantages, apart from being considerably cheaper than the 314L.

The usual response is simply 'save a bit more and get the 314L', and any objections to the 320 seem to be rather anecdotal (primarily based on the fact that no-one seems to have one). But the smaller pixels of the 320 would surely result in a higher-resolution image, and I have seen some superb images taken with one on one of Olly's threads. I know smaller pixels means less sensitivity, but some of the images I've seen look superb, and has anyone measured the difference in sensitivity. Smaller pixel chips are often cited as being ideal for shorter-focus fracs for widefield images, but it's just that I'm particularly interested in imaging smaller DSOs such as planetary nebulae (i.e I'm really not bothered with wide fields), and surely smaller pixels would be an advantage in terms of resolution, and I'm not particularly bothered about the smaller field of view. Basically, I could get a 314, and the field of view would be wider, but the resolution would be lower.

I know the 314L is a better all-rounder, but the 320E seems to have potential advantages. Does anyone out there actually possess one of these and is prepared give an honest judgement of its performance, and how much less sensitive is the 320 chip over the 314?

So before you all cry 'Get the 314L!' (I know you will) or 'The fact that no-one has a 320 should give you a clue!', I'm really just after a bit of objective analysis from anyone who has directly compared the two.

[riklaunim]

know smaller pixels means less sensitivity,

That's not precisely true. If you compare response to light at the same resolution for small and big pixels of two different CCDs then result may be any.

320E and 314E use older generation of Sony CCDs than 314L = they are noticably less sensitive in IR (H-alpha in terms of DSO imaging). Beeing older also makes them cheaper... And that's it

[FLO]

The Atik 320E has more (smaller) pixels but is less sensitive. The Atik 314L-Plus has greater sensitivity (particularly in Ha and Red) and less noise. It's larger pixels also makes it suitable for a wider range of telescopes.

Personally speaking I feel there should be a larger price difference between them. Currently there is less than £300 difference so the 314L-plus is the firm favourite.

HTH,

Steve

[lukebl]

The Atik 320E has a larger sensor and more (smaller) pixels but is less sensitive. The Atik 314L-Plus has greater sensitivity (particularly in Ha and Red) and less noise. It's larger pixels also makes it suitable for a wider range of telescopes.

Steve

Thanks Steve. Much as I thought. What's your delivery time on a 314L at the moment?

[FLO]

We currently have both mono and colour versions in stock for overnight delivery. If you did catch us out of stock you would receive one in around 7 days. We sell more 314L-Plus than all the other models combined...

HTH

[riklaunim]

320E isn't bigger than 314L (both are bigger than 314E)

2/3" - 10.2 mm (H) × 8.3 mm: for Atik 314L+ (ICX285)

1/1.8" - 8.50mm (H) × 6.80mm: for Atik 320E (ICX274)

[FLO]

You are right. I said larger sensor, I should have said higher resolution. I have corrected my post

Thank-you

Steve

[Black Knight]

The Atik 320E has more (smaller) pixels but is less sensitive. The Atik 314L-Plus has greater sensitivity (particularly in Ha and Red) and less noise. It's larger pixels also makes it suitable for a wider range of telescopes.

Personally speaking I feel there should be a larger price difference between them. Currently there is less than £300 difference so the 314L-plus is the firm favourite.

HTH,

Steve

Do you mean the 314L+ ought be more expensive or the 320E cheaper. Just curious, I've often wondered about the relative merits of these two cameras myself.

[riklaunim]

314L+ has Sony ICX285 CCD sensor. It's exview HAD (320/314E aren't exview), which gives more sensitivity (exview part). It's also the biggest mono CCD Sony makes (and one of best). That and more makes this CCD hot for various scientific and machine vision usage. That uses most of the stock and increase the price even more.

There is lesser demand in ICX204, 205, 274 (as they aren't that good, and are older) so they are cheaper (and thus cameras are cheaper). Also Sony released ICX445, ICX625 which are successors of those sensors and take now a part of the market for CCDs with small pixels

There is a successor for ICX285 - ICX674 -> maybe in the next years the prices for ICX285 will start to fall (or we get cams with newer sensors). Also EXMOR CMOS sensors may kick in and replace those CCDs even in astrophotography.

[Glider]

When you say that the 314E is less sensitve than the 314L/L+ what does that mean on a night by night imaging basis.

Are we talking the 314E needs double the exposure time of the 314L/L+ or is it that a 10 minute sub needs to be 11 minutes instead.

If it's the latter then that 1 extra minute makes £300 extra look pretty expensive.

[FLO]

Do you mean the 314L+ ought be more expensive or the 320E cheaper. Just curious, I've often wondered about the relative merits of these two cameras myself.

Speaking from a purely marketing perspective, I would like to see the 320E sell for less. No doubt there are practical costing reasons why they don't. The Titan, 314L-plus and 383L-plus are the best sellers.

HTH

[riklaunim]

QE comparison looks like so (from airylab.net):

So you have 20-25% of QE difference for H-alpha It's very hard to tell how it will impact the exposure time as that would require doing test images for the same image scale (measuring response to light, not raw QE). For planetary imaging ICX618 vs ICX098 is very noticeable difference.

But... even so with the "E" cams you can do this: W poszukiwaniu z?otego grala taniej astrofotografii – kamera Atik 314E | Astrofotografia i astronomia

[FLO]

When you say that the 314E is less sensitve than the 314L/L+ what does that mean on a night by night imaging basis.

Are we talking the 314E needs double the exposure time of the 314L/L+ or is it that a 10 minute sub needs to be 11 minutes instead.

If it's the latter then that 1 extra minute makes £300 extra look pretty expensive.

We were discussing the 320E but the 314E is broadly similar. Generally the 320E is 1/3 less sensitive than a 314L-plus. The difference increases to about 2/3 when imaging in the Ha or SII regions.

HTH

[lukebl]

Still getting my head around a few things!

Take the image below, taken with my Starlight Xpress MX716. The chip is 6.3 x 4.76mm, with 8.2µM pixels in a 752 x 580 array. Therefore this area comprises c.436,000 pixels.

If it was taken on the Atik 314L the overall image would cover a much wider field of view, but because of the smaller pixel size (6.45 µM) this detail area would be covered by c.705,000 pixels. i.e. greater resolution.

If it was taken on the Atik 320E, the overall image would also cover a wider field, but the even smaller pixel size (4.40 μM) would result in this detail area being occupied by c. 1,514,000 pixels. i.e much greater resolution.

So, the 320E seems to offer the opportunity for imaging of smaller DSOs (which is what I'm interested in) at a much better resolution. So, aside from anecdotal opinion, and based on measurable factors, how much less sensitive is the 320E compared with the 314L. Surely there is an advantage in resolution and a crisper image with greater scope for enlargement.

Awaiting Olly's rant at my stupidity shortly!

[Glider]

I think Rik's graph gives a good first order approximation that it's a case of double the exposure rather than add a minute or 2. Thanks Rik.

I think you are right about the resolution Luke.

[shaunster]

I had the sensitivity issue when going from 314 to 383, in reality though I havent noticed it significantly and the small pixels provide an amazing level of detail. If it were me I wouldnt get too hung up on all the graphs and papers on this as in the real world things are never as bad as they look in a graph IMO

I can assure you its not a case of doubling the exposure times it doesnt really work like that. Once you factor in all the seeing conditions etc etc then the graphs really do become meaningless

[riklaunim]

Resolution depends also on the scope. With C11 even at f/6.3 would give 0.75 "/pixel for the 314L (and 0.54 "/pixel for 314E). So the small pixels are usually advised for short-focal refractors.

I had the sensitivity issue when going from 314 to 383, in reality though I havent noticed it significantly and the small pixels provide an amazing level of detail.

383 is similar to 314 in terms of QE. What's different is the pixel well depth (pixel charge capacity). Kodak CCDs have higher charge capacity which allows to catch fainter elements while still not overexposing the brighter ones (it's easier for them to get higher dynamic range).

[Glider]

Cheers Shaunster, I can see where you are coming from. I don't suppose there is someone on SGL who has both 314L and 314E?

[shaunster]

383 is similar to 314 in terms of QE. What's different is the pixel well depth (pixel charge capacity). Kodak CCDs have higher charge capacity which allows to catch fainter elements while still not overexposing the brighter ones (it's easier for them to get higher dynamic range).

Interesting, I dont really know what all the technical stuff means just know what I have found from my experience.

At the end of the day I cant see anyone being disapointed with either a 320e or 314l but for sure the 314l utilises a better chip and is suited to a wider variety of scope choices but then it does come at a cost, I wouldnt call the £300 difference in prices a small sum myself, you could get your filters and wheel for that price

[lukebl]

Thanks Rik for those graphs. Still not sure what they mean in terms of exposure times? And how would my current ancient IXC429AL chip compare with those ones?

As I said, I'm interested in the 320 not because it's cheaper, but because of its considerably higher resolution. If the exposure is, say, doubled, then that might have an impact on my choice.

[Whippy]

IMO, another thing to take into account is the seeing. If the sky can't support very high resolutions that night, say 0.5 - 1 arcsecs/pixel then there's nothing to be gained from imaging at that resolution. I've frequently had nights where I've had better results imaging at around 2 arcsecs/pixel with my ED80 over my ED120 where the resolution is around 1.5 arcsecs/pixel.

Tony..

[ollypenrice]

Sorry, I hadn't seen this thread (and I hope I don't rant too much!!) Yes, we did do some testing of a 320E and Jordan, JCJC, posted a good Ha Wizard with it, I think. I haven't done the kind of scientific comparison Lukebl is looking for though.

Resolution is a word that has too many meanings, in my view! It can mean pixel size. It can mean plate scale. It can mean spot diameter. It can even mean a subjective impression of the sharpness of a final picture.

Clearly if you make a 15mm chip with 150 pixels it is going to look pixelated. But, as someone whose primary concern is the final image, I see no real correlation between the pixel size of the camera and the detail carried in the final image. (I'm talking about the real world here, and cameras that actually exist.) I have imaged the Leo Triplet in my big pixel Atik 4000 next to Maurice (Toet) with his smaller pixel SBIG 8300 at simiar FLs. There is no rhyme or reason to it. I feel I have one of the galaxies sharper than Maurice and he has one sharper than me. His is a better image but he is way ahead of me on the computer.

So... 'resolution' in the sense of the subjective final result will have more to do with how much SN you get and how much data you collect in the time. If you get a lot you can sharpen more and have less noise. So I think the 314L will beat the 320E for this reason, producing more 'resolution' from less 'resolution' ... (at the same 'resolution!!!') despite the pixel size.

Look at all the Tak FSQ masterpieces taken with the 11 meg chip by wealthy Americans (and a certain Irish friend of mine!) They don't look too bad to me despite the pixel size.

Like Steve I think the 320E is insufficiently less expensive than the 314L to have a big chance of catching on, but it is a good camera, no question, and £300 is not nothing.

Olly

[lukebl]

Thanks Olly. Useful info, and I was hoping you'd respond. I think the apparently significant lower response of the 320 chip to H-a (if I'm reading the graphs correctly) would make me go for the 314L. But as I'm more interested in smaller objects, and not bothered with wide fields, I'm still tempted by the 320 with its smaller pixels which (in theory) would produce less-pixelated (i.e. higher-res) images of smaller objects. However, if I need twice the exposure, then it probably isn't worth it. Despite its lack of popularity, though, the 320E still seems a useful cam, with its own potential niche area of use.

[JCJC]

Yup, no science but a few images...

Crescent

NGC6823

The Wizard

Jordan

[lukebl]

Yup, no science but a few images...

Crescent

NGC6823

The Wizard

Jordan

Thanks, Jordan. Lovely images, but would they have been better if taken on the 314L? Decisions, decisions.