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Equipment Discussions >> Video and Electronically Assisted Astronomy

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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: DBK 21AU618.AS vs Mallincam new [Re: mclewis1]
      #5770659 - 04/01/13 11:59 AM

Mark, John said his old DBK21 does a good job on DSOs with longer exposures. I think he knows what he is speaking as a DBK21 user.

Yes, the new DBK21 with ExView sensor is 60% less sensitive than Mallincam and is only 8bit vs 12bit. But neither the price is the same. For a 60% difference Mallincam is 3-4 times more expensive which is too much for me. Nobody says Mallincam is not the best for live video astronomy.
So Mark don't be so surprised we are comparing DBK21 to Mallincam under these circumstances. Nobody said DBK21 is better or the same with Mallincam.
But don't forget that price is very important for some of us and the planetary bonus DBK21 has.

The question is how much worse is DBK21 compared to Mallincam considering the big price difference.

I know there is more noise with the new DBK21 than Mallincam due to lack of cooling especially but I wonder how much more noisy is in practice DBK21 after 1min exposures.

I just feel the new DBK21 has DSO potential for the money but I don't know how much. That's all.

Don't forget that due to smaller sensor one can use stronger focal reduction with the DBK21 than Mallincam without vignetting and DBK21 can recuperate its sensitivity handicap this way.

John could you help us with some answers regarding:
- for live viewing on my laptop of DSOs with DBK21 at exposures of say 1 min each, do I have to record movies on my HDD or that's not mandatory?
- could you show us some images or an Youtube movie of Running Man or M51 (or other faint DSOs) taken with 1 min exposure and maximum Gain to see how much noise the camera generates?


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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: DBK 21AU618.AS vs Mallincam new [Re: Moromete]
      #5770850 - 04/01/13 01:42 PM

I never suggested that the DBK can't do DSO work or that it isn't a great value as a planetary camera that can do some other work too. I was primarily focused on your comment/question about the DBK being "more appropriate for live video DSO than Mallincam ...".

I think it is very valid to question "how much better" or "how much noise" and to look into actual comparisons.

Your point about the smaller sensor being able to handle more aggressive focal reduction is a very valid point for small objects. This would be very apparent on smaller galaxies for example.

I don't think John said it would do a "good job on DSOs", he did say he was "impressed" and that it's "not at all shabby" ... but he also said he wouldn't suggest buying a DBK specifically for DSO work. But if the DBK capabilities worked out for you I think that would be great because I think we need more DSO cameras in this price range.

I'm totally in line with your desire for a reasonably sensitive, easy to use camera with a 30-60s maximum exposure capability that priced in the $500-700 range. I see this as a really under served "sweet spot" in the market. There are tons of alt az goto or small gem mounted scopes around that were purchased by folks who have very restricted budgets (for example high end Mallincams are out) but would still love to do near live viewing. This would be a very strong market for a good 30 second camera at a reasonable price.

I'm also very curious about the upcoming Starlight Xpress SX Video camera.


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Ed Wiley
scholastic sledgehammer


Reged: 05/18/05

Loc: Kansas, USA
Re: DBK 21AU618.AS vs Mallincam new [Re: Lorence]
      #5771709 - 04/01/13 09:13 PM

I'm not about to get into a debate parsing what is live view and what is AP and what is video observing. Everyone can have it their way so far as I am concerned.

Ed


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akjudge
member


Reged: 02/25/08

Loc: Western NY, USA
Re: DBK 21AU618.AS vs Mallincam new [Re: Ed Wiley]
      #5772405 - 04/02/13 09:18 AM

Interesting thread... I have a DMK that I use mainly for lunar/planetary viewing. Have not tried it on DSO's since I use my Stellacam3 for DSO's.

But getting back to the idea of a cheaper alternative to the Mallicam (great camera), has anyone tried the ASI120MM camera? Specs say it has a resolution of 1280x960 @ 35fps. Exposure range up to 1000s (16 minutes). It is USB and sells for less than $300.

Here is a link to the specs:

http://www.zwoptical.com/eng/Cameras/ASI120/index.asp

More interestingly, here is a link to actual images. While most are lunar/planetary, there are several DSO images that look very impressive (middle of the page):

https://www.google.com/search?q=ASI120MM&hl=en&tbm=isch&tbo=u&...

I am just curious whether anyone has any DSO experience with this camera (which is priced at 1/6 of the Mallicam)?

Jim


Edited by akjudge (04/02/13 09:26 AM)


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jgraham
Postmaster
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Reged: 12/02/04

Loc: Miami Valley Astronomical Soci...
Re: DBK 21AU618.AS vs Mallincam new [Re: akjudge]
      #5772937 - 04/02/13 01:17 PM

I was just going to make a comment about the ASI120MM. This looks like a very interesting camera along the same lines as the Imaging Source and Point Grey cameras. I'm waiting to hear whether a bid I placed on a scope was successful or not. If not I may have to drown my sorrows by picking up one of these.

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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: DBK 21AU618.AS vs Mallincam new [Re: jgraham]
      #5773092 - 04/02/13 02:51 PM

Oh boy, I think we have here a DBK21AU618 with TEC cooling! http://www.teleskop-express.de/shop/product_info.php/info/p5165_Astrolumina-A...

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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: DBK 21AU618.AS vs Mallincam new [Re: Moromete]
      #5773195 - 04/02/13 03:49 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.


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: DBK 21AU618.AS vs Mallincam new [Re: mpgxsvcd]
      #5773220 - 04/02/13 04:00 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.

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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: DBK 21AU618.AS vs Mallincam new [Re: Moromete]
      #5773256 - 04/02/13 04:18 PM

Quote:

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.


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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: DBK 21AU618.AS vs Mallincam new [Re: Moromete]
      #5773265 - 04/02/13 04:23 PM

Quote:

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




Speaking for everyone I see.


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Chris A
scholastic sledgehammer


Reged: 02/03/07

Loc: Toronto, Canada
Re: DBK 21AU618.AS vs Mallincam new [Re: mpgxsvcd]
      #5773650 - 04/02/13 06:37 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
Astrogate


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ccs_hello
Postmaster
*****

Reged: 07/03/04

Re: DBK 21AU618.AS vs Mallincam new [Re: jgraham]
      #5773912 - 04/02/13 08:13 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!

ccs_hello


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mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: DBK 21AU618.AS vs Mallincam new [Re: Moromete]
      #5774118 - 04/02/13 09:20 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.

Edited by mclewis1 (04/02/13 09:28 PM)


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ccs_hello
Postmaster
*****

Reged: 07/03/04

Re: DBK 21AU618.AS vs Mallincam new [Re: mclewis1]
      #5774392 - 04/02/13 11:07 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


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mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: DBK 21AU618.AS vs Mallincam new [Re: ccs_hello]
      #5774552 - 04/03/13 12:43 AM

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?

Edited by mclewis1 (04/03/13 01:09 PM)


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: DBK 21AU618.AS vs Mallincam new [Re: mclewis1]
      #5774667 - 04/03/13 03:12 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/Products/SC-HP/cx_news/vol71/pdf/icx828_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?


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ccs_hello
Postmaster
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Reged: 07/03/04

Re: DBK 21AU618.AS vs Mallincam new [Re: Moromete]
      #5774795 - 04/03/13 07:43 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


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bunyon
Post Laureate
*****

Reged: 10/23/10

Loc: Winston-Salem, NC
Re: DBK 21AU618.AS vs Mallincam new [Re: ccs_hello]
      #5774908 - 04/03/13 08:55 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.


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mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: DBK 21AU618.AS vs Mallincam new [Re: Chris A]
      #5774978 - 04/03/13 09:19 AM

Quote:

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.


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Moromete
professor emeritus


Reged: 02/15/12

Loc: Romania
Re: DBK 21AU618.AS vs Mallincam new [Re: bunyon]
      #5775068 - 04/03/13 09:46 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-express.de/shop/product_info.php/info/p676_Focal-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.


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