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DBK 21AU618.AS vs Mallincam

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#26 Moromete

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Posted 02 April 2013 - 01:51 PM

Oh boy, I think we have here a DBK21AU618 with TEC cooling! http://www.teleskop-...strolumina-A...

#27 mpgxsvcd

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Posted 02 April 2013 - 02:49 PM

It seems like there will never be an end to this whole “My camera is better than yours” argument. Quite frankly no one single person has tested them all under identical conditions so no one really knows what works best in every situation.

Everyone has an idea of what works well for their needs. However, you can’t possibly know what everyone’s needs are.

One person may prefer resolution. One person may prefer shorter exposures. One person may have a tight budget. Another person may prefer less wires. Another person may need better cooling. And yet another person may need all of those things with none of them being of greatest importance.

The bottom line is that you need to gather as much information about what works for other people in similar situations to yours. Then you can make an educated guess as to what options you should try.

We all have solutions that produce excellent results under certain circumstances. However, I guarantee each of us could find faults in the solutions of others if we wanted to. I hope that is not what this forum will always come down to though.

#28 Moromete

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Posted 02 April 2013 - 03:00 PM

I think you got it wrong. Nobody said here “My camera is better than yours”. Secondly, we are trying to gather as much information about what works for other people in similar situations to ours, as you correctly said. It's all about information sharing.

#29 mpgxsvcd

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Posted 02 April 2013 - 03:18 PM

I think you got it wrong. Nobody said here “My camera is better than yours”. Secondly, we are trying to gather as much information about what works for other people in similar situations to ours, as you correctly said. It's all about information sharing.


Chris did.

"At the current time you just cannot beat a Mallincam for it's value, built quality and sensitivity for deepsky observations." This statement is purely speculative since he hasn't tried all of the cameras against each other in the same situations.

This was basically the first response to the thread and it always seems that someone throws out their idea of what works best as fact.

#30 mpgxsvcd

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Posted 02 April 2013 - 03:23 PM

Nobody says Mallincam is not the best for live video astronomy.


Speaking for everyone I see. :shocked:

#31 Chris A

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Posted 02 April 2013 - 05:37 PM

Hi Travis

I am not going to get into a big debate over what I said, but I still believe (and have tested several cameras) what I previously said. We have a fantastic tool for 3 years now that anyone can use and it's called Night Skies Network (NSN) open to ALL!

To this day I have not seen hardly any people and I am on NSN a lot showing their results live with their particular camera. I have always believed in actions speak louder than words. Lets start seeing some broadcast of DSO's and that will provide us the best idea of what can be expected under certain conditions.

Chris A
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#32 ccs_hello

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Posted 02 April 2013 - 07:13 PM

RE: ASI120MM

It is using a Aptina (Micron) CMOS sensor.
IMO, the current technologies used in its sensor is not so fine-tuned toward low-light, low readout noise implementation called for by DSO imaging/viewing.

The situation may change in the near future since SONY and Aptina exchanged patent cross-licensing few months back for the entire patent portfolio. Basically Aptina will learn a lot from SONY while SONY will be granted with a few fundamental CMOS Image Sensor (CIS) original inventions (Photobit days, etc.)

One major thing that will affect future view of SONY CIS by astro folks due to this cross-licensing is:
SONY probably will produce more CMOS sensors with "contract detection" pixels embedded to perform the CDAF demanded by consumers. This means (1) some regular pixels will be replaced with CDAF pixels, (2) the gaps left by CDAF pixels will be "doctored", and (2) RAW is not true raw any more.

Again, this is mass-production day-light photography/movie vs. a very small group of niche applications. If you know SONY, the answer is obvious.

Clear Skies!

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#33 mclewis1

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Posted 02 April 2013 - 08:20 PM

Now that's a camera (Astrolumina ALccdIMG0H) I'd like to take a look at. Too bad the sensor is webcam sized (really small).

Software seems a little sparse but functional.

#34 ccs_hello

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Posted 02 April 2013 - 10:07 PM

Mark,

That cam seems to be QHY's IMG0H (using Exview HAD II type-1/4" VGA resolution ICX618 SONY interline progressive CCD). Note: tiny pixel pitch.
See this CN thread.

Clear Skies!

ccs_hello

#35 mclewis1

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Posted 02 April 2013 - 11:43 PM

CCS, Yes I recognized it after looking around a bit ... you'd think the "IMG0H" in the product name would have tipped me off ... lol.

What I'm really curious about is the ability to produce the camera at that price point and the potential ability to produce it with something like the 428-AKL 1/2" ExView HAD sensor. I'm not sure how much if anything would need to change in the camera. For example that big pixel sensor wouldn't require too much more storage for the buffer.

The real problem is likely the fact that the planetary imagers don't want that sensor so there wouldn't be that ready made market for it, reducing the potential numbers. I wonder what it would take for the QHY folks (or others) to see the potential for a live view camera based on something like a modified IMG0H?

#36 Moromete

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Posted 03 April 2013 - 02:12 AM

Almost all cameras, including Mallincam Xtreme, have old Sony sensors. Both Sony ICX428AKL and ICX618 are same old technology with low sensivity for today standards.

Now we need newer Sony CCD sensors (which already exist) like this http://www.sony.net/..._829aka_ala.pdf

The Sony ICX828AKA (ExView HAD II) has a sensitivity of 3200mV compared to 1400mV of ICX428AKL. Secondly, the ICX828AKA has big pixels and much higher resolution than ICX428AKL besides beeing 2.5 times more sensitive.

Considering the huge price, Mallincam should have now an ICX828AKA CCD inside now. Just my 2 cents.

Am I wrong?

#37 ccs_hello

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Posted 03 April 2013 - 06:43 AM

Moromete,

Great find! SONY Japan actually announced it as early as in Jan 2013.
For years (many years!) I thought SONY will ever upgrade its outdated/neglected ICX 408/409/428/429 to SuperHAD II or ExviewHAD II.
With ICX828 and ICX829 announcement, finally the overdued change took pace. Luckily it is still the same large pixel pitch and using complementary-color CMYG Bayer filter array.

We'll have to wait a bit longer (usually 3-6 month cycle) to see 828/829 based products showing up in the market. Type-1/2" is a bit expensive and I would guess will first be used in Mintron, Samsung, etc. and gradually trickle down to smaller security videocam mfg. Price-wise, gut feeling, probably no more than 5% higher than the current SCB4000 price.

Clear Skies!

ccs_hello

#38 bunyon

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Posted 03 April 2013 - 07:55 AM

I've owned a DMK21, a Flea3 and the ASI120MM. I'd say none are particularly well suited to live viewing faint objects. All have problems with noise at longer exposures and small chips.

However, the ASI is much better than the other two in this regard. I've done a bit of DSO imaging using the camera and seen a good bit of others. My avatar is the Eskimo Nebula recorded with the ASI, using 5s exposures and fairly low gain. It was very pleasing watching the nebula on screen while collecting all the subs.

But, again, I wouldn't advise anyone on buying one of these cameras for the express intent of using them for live viewing of faint objects. If you own one for other purposes (all three are excellent planetary, lunar and solar imagers) and don't have funds for a live viewer. Or you only want to occasionally use live viewing, then they can certainly be ably used in that fashion, assuming you arren't going after 18th magnitude galaxies.

If live viewing is going to be your primary means of observing/imaging, then it would probably be worth the extra money to do it "right". Realizing "right" varies considerably amongst us by time, money and interest.

Also, note that I've never used a Mallincam so I can't make a direct comparison. But, for the original question, long exposures with the DMK/DBK are very, very noisy.

#39 mpgxsvcd

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Posted 03 April 2013 - 08:19 AM

Hi Travis

I am not going to get into a big debate over what I said, but I still believe (and have tested several cameras) what I previously said. We have a fantastic tool for 3 years now that anyone can use and it's called Night Skies Network (NSN) open to ALL!

To this day I have not seen hardly any people and I am on NSN a lot showing their results live with their particular camera. I have always believed in actions speak louder than words. Lets start seeing some broadcast of DSO's and that will provide us the best idea of what can be expected under certain conditions.

Chris A
Astrogate


NSN is not the only place to share your experience. NSN requires that you have a computer and an internet connection where you observe. A lot of people don't have that or really just don't want to have that(A computer and cables). Like I said there are many different needs for each person. It is all live viewing though. It doesn't have to be on NSN to be considered as an option.

#40 Moromete

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Posted 03 April 2013 - 08:46 AM

Thank you Paul for sharing your experience with us. I'm worried about strong image noise too. Have you owned the DMK21 with the Sony ICX618 CCD sensor or with an older sensor?


@ccs_hello or other experts: Please judge my following judgement: In theory a Meade 3.3 reducer takes down a 41mm image circle (its clear aperture in fact) to a 13,53mm image circle. If I put a GSO 0.5x reducer after Meade 3.3 one, than I'll shrink the 13,53mm image circle in half to 6,76mm (which is not good for Mallincam's 12mm diagonal due to strong vignetting but perfect for a 1/3" Sony CCD with 6mm diagonal like SuperHAD II -ICX810 or ExView HAD II - ICX672). This means that a C11 can work at F/1,65 with a CCTV with a current 1/3" Sony CCD sensor of 6mm diagonal without vignetting (like Samsung SCB-2001).
On the other hand, with a CCTV which has a 1/4" Sony CCD sensor of only 4.5mm diagonal we can reduce a C11 to F/1.1 by using a cheap GSO 0.5x reducer after a Meade 3.3 reducer with appropriate spacing (like 2 1.25" extension tubes of ~60mm in total) to take the GSO down to x0.33 and almost without vignetting!
Take a look here at the bottom of the page http://www.teleskop-...cal-reducer-...


1) Am I wrong/crazy or correct?
2) Has anyone of you tried one of these combinations with a CCTV like Samsung SCB-2000/2001 (which has half the sensor size of SCB-4000 or Mallincam) or a DBK21AU618 or a QHY IMG0H?
3) How obvious are SCT's optical abberations with Mallincam and a Meade 3.3 reducer?


PS: I think nobody used such strong focal reduction till now because the sensors used in Mallincam and dedicated astrophotography cameras are not smaller than 12mm but generally are bigger than this.
In conclusion I think for live DSO viewing the best camera must have a new generation Sony CCD sensor of 4.5mm diagonal with high sensitivity in mV and must be used in a very fast SCT near F/1.2 to be able to gather photons faster than before and to achieve a wider FOV equal to today's Mallincam.
Oh, and this way Hyperstar becomes obsolete too for video astronomy.

#41 akjudge

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Posted 03 April 2013 - 08:49 AM

While NSN is a great site (I visit it often), it is not necessarily one "that anyone can use". I am not knocking the site. Originally, I posted on NSN with my Stellacam3 and DMK (lunar). However, Adobe Flash updates eventually made it impossible for me to connect to NSN. In spite of the fact that Jim tried hard to help me fix my problem (going back to older versions of Adobe Flash, etc.), we were unable to get me "on-line" anymore. This is not a criticism of NSN, but rather Adobe Flash and potential conflicts with other installed software. Apparently after reading posts on the NSN Yahoo group, I am not the only one unable to get on line. My point is that there probably are a fair number of other types of live-view camera owners that can't broadcast their images on NSN for technical reasons.

Jim

#42 Moromete

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Posted 03 April 2013 - 09:06 AM

Sorry, 1/2" Sony CCD sensors are 8mm in diagonal and not 12mm like I wrote previously but my judgment remains unchanged regarding focal redutcion factor.

#43 budman1961

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Posted 03 April 2013 - 10:26 AM

I purchased the DBK 21AU618.AS from OPT when they cam out, over a year ago. It is no doubt a solid camera, with fair to fiddly software.

Back then I had a Meade LX200 Classic 10, f6.3, and the DBK was a good match. I was able to capture planets like Mars, Jupiter, and Saturn, with aplomb, even though I did struggle with the software. The Moon was always a good time too. I did try the camera on brighter DSO's, M42 to be specific.

The results were nothing more than fair, I could capture the central bright area, and even some color. When I extended the time, thats where the camera lost its "shine" to me. It just wasnt sensitive enough to capture anything more than the brightest of bright objects.

I had hoped that this camera might be a real sleeper.....almost a something for nothing proposition. I mean that It was known the camera did well on Luna and Planets, but if I could eek-out DSO's, that would be a plus, and making it a keeper. After some thought, I ended up selling the camera off, I couldnt justify $450.00 for a super-planetary camera....so away it went.

I have had for some time Mallincam Hyper Plus Color, and thoroughly enjoy
it. I would compare the M42 view an the DBK camera to a 2 second integration at AGC 1 or 2 on the Mallincam.

I hope this helps!

Andy

#44 bunyon

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Posted 03 April 2013 - 10:45 AM

I had a 618 chip, Moromete. The software that came with it was a little clunky - I like FireCapture better. SharpCap is good for single images.

#45 mpgxsvcd

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Posted 03 April 2013 - 12:01 PM

Hi Travis

I am not going to get into a big debate over what I said, but I still believe (and have tested several cameras) what I previously said. We have a fantastic tool for 3 years now that anyone can use and it's called Night Skies Network (NSN) open to ALL!

To this day I have not seen hardly any people and I am on NSN a lot showing their results live with their particular camera. I have always believed in actions speak louder than words. Lets start seeing some broadcast of DSO's and that will provide us the best idea of what can be expected under certain conditions.

Chris A
Astrogate


I just bought a capture device for my computer. I will try NSN out next week from my house. If that works then I can try it with my phone's 4G hotspot where it is darker.

#46 jimthompson

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Posted 03 April 2013 - 12:11 PM

I just clued into this discussion when chasing down links on the Sony ICX828, so I apologise for hopping in late. Some of the basic assumptions regarding similarities between the DBK21AU618 and Mallincam are incorrect. The ICX618 and ICX428 are not all that similar. An easy mistake to make considering how difficult it is to understand the information on these devices that is available from Sony. I looked at this problem a while back, and wrote a paper on it. You can view the paper from my website:

http://karmalimbo.co... CCD Survey.pdf

The gyst is the following:

1. Sony quoted sensitivity values are 100% misleading. The method used to measure and reduce the data for a sensitivity value is different from one CCD model to another. This information can be found in the Sony spec sheets but it is easy to miss. Sneaky marketing dogs.
2. One shot colour CCD's are very different from monochrome. The colour matrix that is applied to achieve colour images has a profound impact on the resulting sensitivity of the detector. This information is barried in the Sony specs as well, once you figure it out.
3. RGBG colour matrix chips (eg. ICX618) suffer a significantly larger penalty from their colour matrix than CMYG matrix chips. This is a result of the net transmissivity you get from a colour filter that gives Red Green and Blue versus Cyan Magenta and Yellow.
4. When you roll up points #1 to #3 above, the full sensor band sensitivity of the ICX618 is 64% that of the ICX428. If you are using a light pollution filter the ICX618 sensitivity is affectively 52% that of the ICX428.
5. The Dark Current noise of the ICX618 is quoted by Sony to be 4 mV. This is twice that quoted for the ICX428. Even if the DBK21 had cooling equal to the Mallincam, it would still be noisier due to the very nature of the CCD.

It is too bad we are not looking for cameras to do security or general consumer type stuff. If we were we'd be riding the wave of demand that is driving the industry. Unfortunately we are amateur astronomers, and the best we can do is scrounge for scraps from an industry that has no real commercial reason to pay attention to us. There are more sensitive chips being developed, sure, but they are designed to serve the mass market who has different requirements than we do. Camera companies like Flea, Imaging Source, and others are producing some very nice cameras (I own a DBK51 that I love), but they are stuck using what is available for sensors. Good camera developers have actually tested all these different sensors and picked what was the best fit for the particular camera they are making. I know for a fact that the current configuration of the Mallincam came about in this way, after years of trial and error with numerous sensors. All we as users can do is ask questions, test, compare. Don't forget that we are still at the beginning of this field of astronomy, not the middle, the beginning.

Regarding the prospect of reducing a scope down to f/1.5...I am very doubtful this would ever be possible. I have tried many variations of stacked multiple reducers, and have never been able to achieve focus on my refractors below about f/3, and below about f/2.5 on my 8" SCT. To create such a fast scope would require custom designed optics, tube and focuser. Think about it, the focus plane for an f/1.5 8" aperture would be only 12" from the objective/primary! Even just dealing with the field curvature would be a big challenge. In my own testing I have also found that narrow band filters for light pollution or imaging perform poorly below f/2, a result of the difference in the incident light angle from center to edge of the light cone.

Regards,

Jim Thompson
AbbeyRoadObservatory

#47 mclewis1

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Posted 03 April 2013 - 12:21 PM

Jim,

Nice to see you posting ... instead of "just" lurking for all these years :poke:

:lol:

#48 jimthompson

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Posted 03 April 2013 - 12:38 PM

Heh heh, to be honest Mark I just don't have the time for all these different forum discussions. I think I need to retire or something. :question:

Cheers,

Jim T.

#49 GlennLeDrew

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Posted 03 April 2013 - 12:56 PM

Moromete,
Jim has stolen some of my thunder. :grin: The Meade f/3.3 reducer *just* comfortably covers a Mallincam's 1/2" format (8mm) diagonal. I once tried it on a mono CCD of 15mm diagonal and only the central circle was good; the outer field was horrible!

As Jim imtimated, obtaining something approaching f/1.5 performance from a focal reducer will almost certainly require a specialized design using several elements.

One saving grace of the video chip's small size; it enables to employ a reducer whose clear aperture is not larger than a 2" filter, allowing a narrow-band filter to be placed ahead of the reducer, where the light cone is not too steeply converging.

#50 Chris A

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Posted 03 April 2013 - 02:27 PM

I hate to brake the news to you Luc (think this is your name from glancing at your NSN broadcast), but these CCD sensors as of March 8th 2013 are still not available to the consumer yet. Trust me, when available Rock Mallin will be looking into these sensors as he always keeps up with the times.

Chris A
Astrogate






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