Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

ASI224MC vs ASI662MC

  • Please log in to reply
42 replies to this topic

#1 GerryGoldman

GerryGoldman

    Explorer 1

  • -----
  • topic starter
  • Posts: 66
  • Joined: 14 Oct 2021

Posted 14 March 2023 - 07:03 PM

I think I might have goofed.

 

I was buying a bunch of stuff to go with my new EDGE HD 8 today at a local astronomy store.

 

Part of my shopping list was a planetary camera. I was going with the ASI224MC as I’m totally new to planetary and was trying to keep costs down.

 

They didn’t have stock, but as I had bought so much recently from them the owner offered me the ASI662MC for the same price.

 

Not being familiar with this particular camera and noting the slower frame rate, I declined and told him to reserve me the ASI224 when they arrive next month.

 

I just checked out the specs and it seems, on paper, as a better sensor. Was I right declining the slower rate or should I grab it if the offer still stands?



#2 Lacaille

Lacaille

    Surveyor 1

  • -----
  • Posts: 1,943
  • Joined: 27 Nov 2015
  • Loc: Canberra

Posted 14 March 2023 - 07:53 PM

Hi Gerry,

 

I have a number of ZWO cameras, including the 224MC but not the 662MC.  The 224MC remains an excellent planetary camera, though it is of an earlier generation than the 662MC.

 

The frame rate quote is always a bit confusing, because it is highly dependent on sensor dimensions and pixel count. Because of the volume of data flowing from a larger sensor, it will have a lower fps than a small sensor, if you were imaging over the whole sensor. In other words, it is a quote for what the max fps would be if you were using the whole sensor.  The sensor on the 662 is similar in size to the 224 but the pixels are smaller, so it ends up with nearly twice as many pixels as the 224.  This contributes a lot to the lower max fps of the 662. In actual practice the planet will occupy only a small part of the sensor so this max fps will not apply.

 

Now, although you will be imaging the planets generally using only a small part of the sensor (using something like "Region of Interest" in Firecapture), one of the limiting steps when you are starting out is trying to land the planet on the sensor, particularly when you start using Barlows etc with a dimmer image and a smaller field of view. This can be very frustrating, and a larger sensor can be a help. However, the 662's sensor is slightly smaller in area than the 224, so there is no big difference there. 

 

But a better option might be the 585MC - the latest and improved version of the 485MC (which I have), that has an enormous sensor (though of course it is more expensive than either) - much easier tto find the planet, and you can use the big sensor for capturing wide screen vistas of Jupiter or Saturn and their moons.

 

Here is a quick comparison:

 

224MC;  sensor size (rounded) 5 x 4 mm; 1.2 MP; $199

662MC; sensor size 6 x 3 mm; 2.1 MP; $249

585MC; sensor size 11 x 6 mm; 8.3MP; $399

 

You can do a more detailed comparison on the ZWO website here.

 

Another thing to consider:- you want to optimize your f value at around 5 times your pixel size. A size around 2.9 microns (the 585 and the 662) gives 5 x 2.9 = 14.5  which is close to the native f10 of your scope - probably close if you use an ADC.  The 224 is 3.75 microns meaning you would need to use a Barlow around 2X to optimize your sampling.

 

You probably know you will need an IR-cut or luminance filter with these cameras to improve colour balance. Make sure you check out the FAQs at the top of the section - a wealth of useful advice there.

 

But I would emphasise that there are no bad options above!  Just marginal pluses and minuses. Most of the time you won't be using the whole sensor and the max fps is a bit of a red herring. And your major quality determinant will be good seeing, good focusing, and good collimation, rather than camera!

 

Regards

 

Mark


  • Flying_Fox, ewave, John Verderame and 4 others like this

#3 GerryGoldman

GerryGoldman

    Explorer 1

  • -----
  • topic starter
  • Posts: 66
  • Joined: 14 Oct 2021

Posted 14 March 2023 - 08:43 PM

Thanks Mark for taking the time to give a very detailed answer. 
 

I do intend to use a 2X Barlow and looking at the framing on astronomy.tools, the 224 “might” be the better choice unless I’m trying to get details like Jupiter’s moons in frame. 
 

I’m still wavering…


  • Lacaille and Pirate like this

#4 RedLionNJ

RedLionNJ

    Cosmos

  • *****
  • Moderators
  • Posts: 8,501
  • Joined: 29 Dec 2009
  • Loc: Red Lion, NJ, USA

Posted 14 March 2023 - 09:43 PM

Thanks Mark for taking the time to give a very detailed answer. 
 

I do intend to use a 2X Barlow and looking at the framing on astronomy.tools, the 224 “might” be the better choice unless I’m trying to get details like Jupiter’s moons in frame. 
 

I’m still wavering…

Don't forget the moons spend quite a bit of their time close-in to Jupiter's disk - they're not always a fair distance away :)


  • gfstallin and Lacaille like this

#5 Tulloch

Tulloch

    Fly Me to the Moon

  • *****
  • Posts: 6,796
  • Joined: 02 Mar 2019
  • Loc: Melbourne, Australia

Posted 14 March 2023 - 09:52 PM

I have an ASI224MC, and often would really like to image the moons further from Jupiter/Saturn's disc. Now, I could (and have in the past) simply remove the barlow, re-position, re-focus, scale and combine the two images later etc etc, but it would be much easier to just do it once.

 

The sensor size on the 224 is really quite small. if I were starting again, I'd go with the ASI678MC...

 

Andrew


  • Lacaille and dcaponeii like this

#6 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 15 March 2023 - 02:29 PM

Now, I could (and have in the past) simply remove the barlow

That's a good idea and will allow imaging full detail on the planet without Barlow replacement.
 



#7 Tulloch

Tulloch

    Fly Me to the Moon

  • *****
  • Posts: 6,796
  • Joined: 02 Mar 2019
  • Loc: Melbourne, Australia

Posted 15 March 2023 - 03:50 PM

That's a good idea and will allow imaging full detail on the planet without Barlow replacement.
 

Wrong.


Edited by Tulloch, 15 March 2023 - 04:09 PM.

  • Lacaille likes this

#8 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 16 March 2023 - 01:36 AM

That's a good idea and will allow imaging full detail on the planet without Barlow replacement.

Wrong?



#9 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 16 March 2023 - 02:05 AM

The 224 is 3.75 microns meaning you would need to use a Barlow around 2X to optimize your sampling.

Hi Mark and Gerry,

 

no Barlow required with 3.75 µm on an f/10 scope, see here.

 

CS Jan



#10 Lacaille

Lacaille

    Surveyor 1

  • -----
  • Posts: 1,943
  • Joined: 27 Nov 2015
  • Loc: Canberra

Posted 16 March 2023 - 05:23 PM

Hi Mark and Gerry,

 

no Barlow required with 3.75 µm on an f/10 scope, see here.

 

CS Jan

Hi Jan, sorry, I followed your link but I could not see any evidence of comparative work on your website -  i.e. Barlow vs no Barlow?  Can you point me to some direct comparisons where you alternated between the two setups?

 

I do not doubt that one can achieve good results without a Barlow at around f10 with a 224MC.   However, I cannot see any evidence on your site that the results would not have been improved by increasing to around f19.   You simply present images captured at one focal length, as far as I can see. I would be happy to be convinced otherwise, but please point me to the evidence.

 

Regards

 

Mark


  • RedLionNJ, Foc and dcaponeii like this

#11 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 16 March 2023 - 07:21 PM

I could not see any evidence of comparative work on your website

Hi Mark,

 

if you don't understand the comparative work demonstrated with the top GIF animation on my website, you may have a look at our colleague's tutorial included here.

 

CS Jan



#12 Lacaille

Lacaille

    Surveyor 1

  • -----
  • Posts: 1,943
  • Joined: 27 Nov 2015
  • Loc: Canberra

Posted 16 March 2023 - 11:11 PM

Hi Jan,

 

I think I understood what you did, but I did not find it convincing.  As Grant (RedLionNJ) said:

 

'If I interpret you correctly, you're saying you took a video recording, aligned, stacked, sharpened and arrived at a result.

 

Then you took the same recording, downsized all the frames to 71% (giving about 50% of the original number of pixels), then aligned, stacked, sharpened and upscaled (for a fair comparison)

And the image of part of the moon (tsk, tsk!) alternates between the two results, showing very little difference?

 

If all of the above is interpreted correctly by me, then yes, I would say under the precise situation where the video was captured, there is no discernable difference in the final result.

But this gets us no nearer to answering "is there a difference demonstrated between capturing at f/D = 2.1 vs f/D = 5 in various types of seeing?"'

 

I think that, to overturn theory and a wealth of experience, you need actual experimental data.  One could envisage a partial solution might be a process where you swap a 2X Barlow in and out of the 224MC imaging train, alternating between with/without Barlow for a number of video replicates (say 5 of each, taken alternately over an hour or two).  Process the videos to the best possible result and compare. the results.  This would start to get us somewhere. 

 

Interesting telescope, by the way!

 

Mark



#13 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 17 March 2023 - 04:12 AM

swap a 2X Barlow in and out

Hi Mark,

 

astro videos do not contain any signature indicating the presence or absence of a Barlow lens during capture. Retroactive data reduction should therefore provide video content as would result if a Barlow with equivalent magnification power were taken out from the optical train during capture. Swapping Barlows will require readjustment of capture parameters like focus, gain, shutter time, and histogram, accordingly, while data reduction has the advantage of delivering video data recorded with identical capture parameters and, moreover, under identical seeing conditions.

 

CS Jan



#14 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 17 March 2023 - 06:43 AM

swap a 2X Barlow in and out

Hi Mark,

 

you will probably agree, when I use another identical telescope and camera setup side by side instead, the other one equipped with a 2.5x Barlow capturing simultaneously for having similar seeing conditions. The long focus setup, of course, will require about 6x longer shutter times at about 6x smaller frame rates and field of view. Maybe, you would also allow comparing telescopes of similar aperture and quality simultaneously capturing the same planet or moon detail under similar seeing conditions at separate observing sites, one with, and the other without Barlow enhancement. Eventually, you might simply like to search the internet for long-focus images of similar objects from telescopes of similar aperture and compare with my short-focus results.

 

CS Jan

 

added


Edited by Jan_Fremerey, 18 March 2023 - 03:31 AM.


#15 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 21 March 2023 - 08:07 AM

Then you took the same recording, downsized all the frames to 71% (giving about 50% of the original number of pixels), then aligned, stacked, sharpened and upscaled (for a fair comparison)

Correction: I upsize before sharpening and then exactly follow the sharpening procedure applied to the original data.



#16 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 22 March 2023 - 07:55 AM

The 224 is 3.75 microns meaning you would need to use a Barlow around 2X to optimize your sampling.

No Barlow required with 3.75 µm camera pitch at f/10. My user avatar was captured with 3.75 µm at f/11 and doesn't deteriorate even by data reduction to f/8 equivalent.
 


Edited by Jan_Fremerey, 23 March 2023 - 03:43 AM.


#17 EdDixon

EdDixon

    Viking 1

  • -----
  • Posts: 733
  • Joined: 31 Aug 2019
  • Loc: Virginia

Posted 25 March 2023 - 02:46 AM

Today I have three:  ASI224MC, ASI485MC, and ASI662MC.

 

I have had good luck so far with the 224 with a Celestron 8SE and Televue 2.5X barlow.  I've used the 485 a number of times but find it harder to work with for planetary.

 

I’ve only had the 662 a short while, so less experience there.  I do believe it may do better than the 224 as its newer tech.  I'll know more later this year and next when Saturn and Jupiter get closer.



#18 RyzenAMD

RyzenAMD

    Ranger 4

  • -----
  • Posts: 341
  • Joined: 17 Nov 2022
  • Loc: Eastern Seaboard

Posted 26 March 2023 - 12:11 AM

I also just purchased the ASI662MC camera. I haven't received it yet, but at ZWO's website, I did the side by side comparison and it seems that the 662 has no amp glow and pretty low Noise, down to 0.8e. It has the same sized sensor chip, but I like the fact that it has no amp glow.



#19 TareqPhoto

TareqPhoto

    Cosmos

  • *****
  • Posts: 9,989
  • Joined: 20 Feb 2017
  • Loc: Ajman - UAE

Posted 28 March 2023 - 12:03 PM

I bought 662MC regardless that i have 385MC the big brother of 224MC, i didn't test it yet, but i bought it for a purpose, but if you can find a new 462MC that can be better, many moved from old models such as 224 to 462, but i believe it is discontinued and will release a mono version of that.



#20 Al Paslow

Al Paslow

    Ranger 4

  • *****
  • Posts: 300
  • Joined: 07 Mar 2005
  • Loc: SW Pennsylvania

Posted 02 April 2023 - 06:26 PM

There are a few points here to consider.

 

I have the ASI 224 since it came out in perhaps in 2016. It was a game changer for me at that time coming from Point Grey USB 2 camera. I also bought the 662 late last year and it works very well.

 

But the comparisons of the 224 and the 662 camera shows an overall improvement in the newer tech.

The ASI 224 has a QE of between 75 to 85%. The ASI 662 is at 91% or more.

 

There is some control for amp glow in the 224 where as previously mentioned the 662 has no amp glow.

 

Pixel size is 3.75 microns compared to 2.9 for the 662. (Even less barlow needed for the 662 in theory.)

 

The maximum resolution for the 224 is an image of 1304x976 pixels with the 1.2M pixel 1/3-inch sensor.

 

The maximum resolution of the 662 is an image of 1920 x 1080 pixels (for bigger moon and solar images) with the 2.07M pixel 1/2.8-inch sensor.

 

Additionally, the 662 has 256DDR3 ram buffer which means less dropped frames, The 224 does not have this feature.

 

On the other side the 224 can do 150 fps, whereas the 662 is only about 100, but with a substantially larger image.

 

The full well depth is also better on the 662 which usually means less overall noise.

 

Lastly, I should say that the charts posted on the ZWO site shows the QE graph of the 662 and the Relative Response graph of the 224. It probably isn't a good idea to directly compare the two compare the two as the Relative Response graph does not include the Absolute QE value of the chip. For the 224 to be directly compared to the sensitivity graph of the ASI 662 the values of the Relative Response chart would need multiplied by the QE of the colors of the 224. This is something Sony isn't very good at sharing information, - the 224's QE isn't known even by the camera maker, ZWO.

 

For proof -  if you look a bit above the Relative responsive vs. Wavelength graph on the Product page of the 224 camera you will see what I mean. It states that the QE peak is between 75-85%. Whereas the ASI 662 camera on the product page shows a QE of 91%.

 

I'm very happy with my 662 camera for the biig lunar images, and the advancements in the camera over the 224.

Perhaps you can reconsider your decision of not buying the 662. Looks like the dealer offered you a great price on a nice camera.


  • Jan_Fremerey and acommonsoul like this

#21 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 03 April 2023 - 02:30 AM

The maximum resolution of the 662 is an image of 1920 x 1080 pixels (for bigger moon and solar images) with the 2.07M pixel 1/2.8-inch sensor.

With 2.9 µm pixel pitch you might reduce focal ratio to f/6.3 without loss of detail for even wider field of view on Moon.



#22 Tapio

Tapio

    Cosmos

  • -----
  • Posts: 9,959
  • Joined: 24 Sep 2006
  • Loc: Tampere, Finland

Posted 03 April 2023 - 03:23 AM

Higher QE and less amp glow is nice but not so relevant in planetary imaging.
  • BJS and Gary Z like this

#23 Jan_Fremerey

Jan_Fremerey

    Mariner 2

  • -----
  • Posts: 218
  • Joined: 03 Mar 2010
  • Loc: Bonn, Germany

Posted 03 April 2023 - 03:39 AM

for even wider field of view on Moon.

... much more FOV with 178.



#24 Tulloch

Tulloch

    Fly Me to the Moon

  • *****
  • Posts: 6,796
  • Joined: 02 Mar 2019
  • Loc: Melbourne, Australia

Posted 03 April 2023 - 08:09 AM

With 2.9 µm pixel pitch you might reduce focal ratio to f/6.3 without loss of detail for even wider field of view on Moon.

This is still only his opinion, and not accepted by anyone else. Best focal ratio proven by many imagers over time is 5x the pixel size of the camera.


  • John Boudreau and Gary Z like this

#25 RedLionNJ

RedLionNJ

    Cosmos

  • *****
  • Moderators
  • Posts: 8,501
  • Joined: 29 Dec 2009
  • Loc: Red Lion, NJ, USA

Posted 03 April 2023 - 08:46 AM

This is still only his opinion, and not accepted by anyone else. Best focal ratio proven by many imagers over time is 5x the pixel size of the camera.

A couple other points which are very relevant to planetary AP and not mentioned (or perhaps mis-represented?) above:

 

Shorter focal ratios are at odds with the correction afforded by the ADC.  Inexpensive ADCs introduce fewer aberrations at focal ratios of around f/20 and higher.  One expensive German brand can work at ratios as low as f/12 with no compromise to the image quality.

 

Amp glow is of absolutely no relevance when you're only capturing an ROI of three to four hundred pixels from the middle of the sensor, particularly at frame rates of 100+ fps.


  • John Verderame likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics