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  #41  
Old 05-11-2011, 05:54 PM
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rcheshire (Rowland)
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Yes. Still thinking it over. I've had a look at Sony's Super HAD and Super HAD CCDII technology. Would be good to hear what users think of their Sony chip gear. The CCDII looks promising for video cams.
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  #42  
Old 05-11-2011, 07:34 PM
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Bassnut (Fred)
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It's funny, thinking of a new cam, I read adds/specs, customer feed back, agonize over hot new features, mega cooling,mega pixels, back thinned hi qe, fast downloads,support, RBI, brand difference, it's a head spin.

So I take a step back and look at my rather limited (sbig only) brand experience,compare it to other brand user posts, what I really want in features in practical terms,and, although it's not a priority ,value for money.

I see peters experience with the u47 and very few image posts generally with back thinned CCDs, they seem very attractive qe wise, but I've also read there are many difficultys with them and are very expensive, so I keep coming back to a 6303 chip, which despite it age is still the chip of choice for NF NB

So brand. Yes FLI has better cooling and faster downloads, but at what cost, and does it really, really matter (for me).

I don't give rats if download is 2 or 4 secs, or whatever the diff between usb1 and 2 is, and from experience, with accurate darks, I don't much care about the max cooling temp either, I don't have to battle RBI so -10 or 15 Or 20 is fine by me.

So, value for money. Well, I need a 7 pos filter wheel so:

Fli 6303 proline with 7 pos filter wheel total us$10490' SBIG STL 6303 with 8 pos filter wheel $6795 total. (OPT as reference). Mmm, big diff.

Ok, fli has better cooling and faster download, not that I care much, but SBIG has internal guide, AO interface, plug for a very sensitive cooled guide cam.

Support. I don't know about FLI , but when I sent an st10 for an upgrade, it was a smooth reasonably priced experience, and a guide cam in for repair got, I kid you not, a daily report on progress by the repair tech and a full explanation of the problem and what was done.

So, I'm thinking, do I go with what I know is a bullet proof , tried and tested product, albeit a bit behind in unessential specs, but with excellent support and oddly much cheaper with a wider range of interfaces and accessories ( eg AO). or another newer very attractive more expensive brand that may well give the same image result for far more money and less options?
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  #43  
Old 05-11-2011, 08:05 PM
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bert (Brett)
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Hi Rowland,

You managed to get an interesting thread going....

I have an st4000xcm and I love it. I have used it on a variety of scope and focal lengths. I have it currently mounted on an Astro Physics 130 f6 refractor, but I have used it on a vc200 at 1800 and 1260fl, a vixen fl102 refractor at918fl and a william optics triplet refractor at 480mm. My buddy had it mounted on his rc at 2800fl as well for a while, All worked well.

One advantage of this camera is because it is one shot colour, you can use adaptive optics with the internal guide chip. No OAG needed. I get a -35 delta cooling, dessicant needs charging once a year (this time when I charged it I filled the chamber with argon as well).

It is by no means sensitive, better than some osc cameras, worse than others. A lot worse than most mono cameras though. There is noise, but it is not too intrusive.

It has not missed a beat since in the 2 years I have had it. And I have done a lot of imaging with it, as my observatory is automated enough to do data collection all night unattended.

Check my posts here on iis to see some of the imaging I have done with it.

Brett
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  #44  
Old 06-11-2011, 06:06 AM
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rcheshire (Rowland)
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It seems that SBIG gets a good wrap on a number of fronts including price. Customer service wasn't a consideration when first starting this thread - so let's add that to the list of requirements for an OSC.

Given that there is not a huge variance in sensor technology for OSC's in the price range under consideration and it really comes down to 8mp vs 4mp or even 2mp - resolution vs charge capacity (if I understand correctly) - and to what degree that matters given the manner in which the camera will be used. The considerations in no special order for DSLR replacement are;

Charge capacity (QE)
Electronics (noise)
Cooling (noise) - accurate temperature control.
Simplicity (ease of use)
Easy to adapt to camera lenses
Software compatibility
Customer service
Price

Bonus items are;

In-built guiding chip, preferably using the main optics with no requirement for a separate guide scope.

From what I can see SBIG meets those requirements reasonably well.

Any other considerations that I've missed.

But a list like that may not satisfy purist / specialist requirements.

Alternatively (for my purposes, which are basic), spectrum enhance my 5D MKII and rely on its low noise characteristics as a relatively lower cost alternative. And implement some ideas I have for a sealed, dry air cooling system that retains access to the camera controls.
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  #45  
Old 06-11-2011, 01:30 PM
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Quote:
Originally Posted by Bassnut View Post
It's funny, thinking of a new cam, I read adds/specs, customer feed back, agonize over hot new features, mega cooling,mega pixels, back thinned hi qe, fast downloads,support, RBI, brand difference, it's a head spin.

So I take a step back and look at my rather limited (sbig only) brand experience,compare it to other brand user posts, what I really want in features in practical terms,and, although it's not a priority ,value for money.

I see peters experience with the u47 and very few image posts generally with back thinned CCDs, they seem very attractive qe wise, but I've also read there are many difficultys with them and are very expensive, so I keep coming back to a 6303 chip, which despite it age is still the chip of choice for NF NB

So brand. Yes FLI has better cooling and faster downloads, but at what cost, and does it really, really matter (for me).

I don't give rats if download is 2 or 4 secs, or whatever the diff between usb1 and 2 is, and from experience, with accurate darks, I don't much care about the max cooling temp either, I don't have to battle RBI so -10 or 15 Or 20 is fine by me.

So, value for money. Well, I need a 7 pos filter wheel so:

Fli 6303 proline with 7 pos filter wheel total us$10490' SBIG STL 6303 with 8 pos filter wheel $6795 total. (OPT as reference). Mmm, big diff.

Ok, fli has better cooling and faster download, not that I care much, but SBIG has internal guide, AO interface, plug for a very sensitive cooled guide cam.

Support. I don't know about FLI , but when I sent an st10 for an upgrade, it was a smooth reasonably priced experience, and a guide cam in for repair got, I kid you not, a daily report on progress by the repair tech and a full explanation of the problem and what was done.

So, I'm thinking, do I go with what I know is a bullet proof , tried and tested product, albeit a bit behind in unessential specs, but with excellent support and oddly much cheaper with a wider range of interfaces and accessories ( eg AO). or another newer very attractive more expensive brand that may well give the same image result for far more money and less options?

Good post Fred. Yes you raise an interesting point.

SBIG does represent good value at the moment and they definitely do have the accessories and integration.

I thought about a 6303 chip for my CDK17 for a while. A number of posts complained about the blooming. I then realised that basically its more pixel size I needed to match to the optics and the best QE. The 16803 chip is not that different in QE to the 6303 and they are both 9 micron plus it has the advantage of antiblooming. If I crop my 16803 I can get the same image scale of the 6303 (which is what I was mostly looking at).

Your needs are a bit different as you are predominantly narrowband and I am predominantly LRGB with Ha occassionally and NB occassionally.

You should grab that STL6303 before the sale ends - $2000 off is a huge saving.

By the way a fairer comparison would be Microline 6303 to STL6303 (FLI is still more expensive though).

I like my Proline but when I get another FLI Camera I would be choosing Microline as the weight difference is significant yet the difference with the Proline boils down only really to an extra 3 or 4C cooling power and a USB and Power hub built in in the Proline (plus a better shutter which you can also specify in the Microline).

The difference between the FLI and the SBIG in my opinion is that the FLI is the absolute best in all areas but the SBIG gets the job done too. The FLI makes almost everything easier (except for AO units) and foolproof like imaging with a good Tak or AP scope and it all just works everytime. You also tend to get used to whatever brand you have been using. I am now used to FLI. I was used to my STL and it served me well for some time.

Greg.
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  #46  
Old 06-11-2011, 01:55 PM
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Charge capacity (QE)
Electronics (noise)
Cooling (noise) - accurate temperature control.
Simplicity (ease of use)
Easy to adapt to camera lenses
Software compatibility
Customer service
Price

Bonus items are;

In-built guiding chip, preferably using the main optics with no requirement for a separate guide scope.

Hi Rowland,

You've got a few concepts not right there. QE stands for Quantum Efficiency which means how sensitive the camera is. In other words what % of photons hitting the chip actually get converted to an electron by a pixel that can be measured by the electronics. QE of 60% is good. One shot colour are usually around 23 to 40% depending on chip and what colour (different sensitivities for different colours, green is usually more sensitive). Most mono CCD cameras are 50-60% QE. Anything over 60% is exceptional. 60% is plenty though. 50% is fine as well. 23% is limiting you to brighter objects with faster scopes with larger aperture.

Charge capacity is called well depth. It is not really a measure of sensitivity. It is how many electrons can a pixel hold. It is measured in numbers of electrons. 20,000 electron well capacity is about as low as it goes, 110,000 is about as high as usual chips go. It is not 4022 is medium/low but workable. Small well depth means you may have to shoot shorter subexposures on faster telescopes than long well depth. It means bright stars will end up overexposed and white - no colour- fairly easily and is something you have to keep an eye on.
40,000 well depth or more is what you want. 100,000 is great. You'll get colourful bright stars even with 15-20 minute exposures.

Cooling (noise) is not about how accurate you can regulate it (I think almost all regulated cooled cameras now are accurately regulated) its about how powerful the cooling is. Highly regulated weak cooling still leaves lots of noise and artifacts in the chip. Most CCD chips have noise reduced by half with every extra 6 degrees C cooling. So running a typical chip at -20C versus -35C you are talking about 1/5th less noise in the -35C no matter how well regulated the temp is. Regulated temperature is important and all the major brands do that as far as I am aware. I think Starlight Express did not always do it but Apogee FLI and as far as I know QSI and others do this quite well. It is true accurate controlled temperature is valuable so your darks match your light exposures and do a clean dark subtract.
Weak cooling means you now HAVE to have super well done darks. I often use only 3-6 darks for a master with powerful cooling. Weak cooling would take 16-32. Again not that big of a deal perhap but almost all defects in a chip are reduced by powerful cooling. Some vertical lines in chips do not dark subtract out easily no matter how accurate your darks are. That then gives you a problem processing the images with these little background vertical lines showing up.

Also with better electronics there is FAR less noise in the first place to subract making them more reliable images.

My 8300 chip is as clean as anything at -35C yet I noticed when it was warm it actually has a slight vertical line in it. I don't know what temp it is when that disappears but I think its past -20C. I usually run it at -35 or -40C. So if your camera maxed at -20C that line would still be visible and you would be relying on your darks to remove it. That may or may not work.

Adapters to lenses are available for any camera. Precise Parts will make an adapter for anything so that is not really a difference between brands. I have had lens adapters for my SBIG, Apogee and FLI cameras.

Compatibility with software. As far as I know they are all compatible with the major software. CCDsoft does need a camera plug in to work with non-SBIG cameras. But Maxim DL I don't think does.

I thought I would clarify those points.

SBIG self guiding is handy for sure but it is useless for Ha or Narrowband so you end up needing an off axis guider or guide scope anyway. Self guiding is a brilliant idea but its weakness is the guide camera looks through the filters. Guide exposures are usually a few seconds or less. But to get a guide star through a Ha filter may require 30seconds to a minute to see one. I don't know of a mount that will handle 30 to 60 secod guide exposures and get round stars at long focal length. Not even a Paramount ME would do that. If you only do colour and no Ha (and there goes all your nebula shots) then its not a problem.

So you see there is no simple work around these laws of Physics we are up against when imaging.

Greg.
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  #47  
Old 06-11-2011, 03:03 PM
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Thanks Greg. I remember now - appreciate correction on those points.

Amending the list without actually typing it out there are some items to reconsider. The picture is clearer for sure, but after all I'm not sure that the limited opportunities for AP that present themselves warrant the expense. I have a much better understanding of the technology, which has educated me fairly well as what to expect. Time to consider - decision making time I think.
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  #48  
Old 06-11-2011, 05:25 PM
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Bassnut (Fred)
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Hey Greg (sorry for the hijack Roland). At 656nm (Ha) the16803 is 45%Qe and the 6303 is 65%. ok there's not much in it for lrgb as you say,But for me that makes the 6303 more attractive for NB, it's the difference ( roughly) between a 16 and 20" aperture for the same image result.

The 16801 on the other hand peaks at 68% Qe (nabg version) at Ha, which is very interesting, but much more expensive. I can't find any astroimager user pics, mmm, wonder why ?.

Another thing, the 16803s dark noise is 0.08e at -35c, but the 6303 is 0.0005e at -45c, several orders of mag lower, yet I often hear the 6303 is a noisy chip? Thats got me stumped, unless the cooling on the SBIG is the problem, in which case the FLI then becomes far more attractive with deeper cooling, what do you think?.
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Old 06-11-2011, 06:03 PM
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Be my guest. It's a very interesting and educational discussion.
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  #50  
Old 06-11-2011, 07:26 PM
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Quote:
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Hey Greg (sorry for the hijack Roland). At 656nm (Ha) the16803 is 45%Qe and the 6303 is 65%. ok there's not much in it for lrgb as you say,But for me that makes the 6303 more attractive for NB, it's the difference ( roughly) between a 16 and 20" aperture for the same image result.

The 16801 on the other hand peaks at 68% Qe (nabg version) at Ha, which is very interesting, but much more expensive. I can't find any astroimager user pics, mmm, wonder why ?.

Another thing, the 16803s dark noise is 0.08e at -35c, but the 6303 is 0.0005e at -45c, several orders of mag lower, yet I often hear the 6303 is a noisy chip? Thats got me stumped, unless the cooling on the SBIG is the problem, in which case the FLI then becomes far more attractive with deeper cooling, what do you think?.
I haven't seen any 16801 images either. I see what you mean, another 20% QE in Ha is pretty attractive but its less QE at 550nm (52% verus 60%). That would be relevant for LRGB so yes the camera is best used for NB. Also the chip direction Kodak seems to have taken it would seem this sort of performance will be a thing of the past from them. They are going the small pixel platform more megapixel type direction and have settled into 50% QE as being high.

I just looked at the Kodak Spec sheet. They are not the same criteria from one sheet to the next (I don't know why they do that). But it shows readout noise at 15 electrons for the 6303 and 9 electrons for the 16803. I am not sure that is the correct measure for what you are asking.

Best ask Steve Crouch about noise performance in the field in an STL body as he is the only one I see using one here. I don't see noise in his images. So like any camera you just match the darks poperly and you'll be fine.

I think it would be a nice change from the ST10 which is a legend of a camera but the 6303 is more real estate.

Greg.
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  #51  
Old 06-11-2011, 07:29 PM
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I use both the 4022 chip and the 6303e. Not much difference in noise, the 4022 does show vertical lines more in bias, but they dark subtract well.

The 6303 is on another planet with its well depth and crazy sensitivity. They are completely different to process because of the dynamic range of the 6303.

Brett

edit: the 4022 is in a st4k osc, the 6303 is wrapped in an stl body.

The stl cooling is faster than the st series, and has a better cooling delta.
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  #52  
Old 06-11-2011, 10:18 PM
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....

SBIG self guiding is handy for sure but it is useless for Ha or Narrowband so you end up needing an off axis guider or guide scope anyway......
Greg.
Beg to differ.

I often use the internal guide chip for NB.... it just needs a bit of planning (via a sync to TheSky with an instrument rotator, guide stars are pretty easy to find.)

Better still is using SBIG's Adaptive Optics a remote guide head with the AstroDon MOAG....you can get some incredibly tight stars with AO guided narrow band.

.... In short SBIG's system integration is in my opinion, the best available.

I must admit STX secondary systems have been slow to come to market, but am confident differential guiding etc. will pave the way for some very impressive images in the not too distant future.
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  #53  
Old 07-11-2011, 06:40 PM
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Beg to differ.

I often use the internal guide chip for NB.... it just needs a bit of planning (via a sync to TheSky with an instrument rotator, guide stars are pretty easy to find.)

Better still is using SBIG's Adaptive Optics a remote guide head with the AstroDon MOAG....you can get some incredibly tight stars with AO guided narrow band.

.... In short SBIG's system integration is in my opinion, the best available.

I must admit STX secondary systems have been slow to come to market, but am confident differential guiding etc. will pave the way for some very impressive images in the not too distant future.

I must admit I'd love it if my FLI had self guiding sometimes. It is extremely convenient. I did like the fact the STL was so self contained.

I'd like to see more of those features in the STX. But aren't they not needed though if you are using a MMOAG and are useful if you are using a guide scope? (which you sometimes use even if you have a MMOAG like me - CDK reducer does not allow enough backfocus for a MMOAG).

Greg.
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