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Danon

First mono camera

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2 minutes ago, tooth_dr said:

Can you save that as a JPEG and attach locally please!

Sure. In jpeg edges looks a little bit shiny like amp glow. On fits in maxim there is no such things. 

dark_1800(samyang 135mm -20) (9).jpg

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One of mine to compare could just be spurious causes and differ from one dark to another.

Dave

KAF8300-dark.thumb.png.99a17c53e1fdf33ab54eca5bda95ff2b.png

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Really thanks everyone for reply. That topic was bothering since a month, and no one from my country give me any anwser. But now... I even more don't know what to choose :D As beginner I go to site telescopius and look ad Heart nebula. If fov didin't get whole nebula I'm little bit sad. For 460EX with 420mm whole wide field of Heart nebula needs to be a 4-pane mosaic! But 2 pane is still good. Due to that I have now 2-3 clear nights per month, I'm little afraid when I complete all these popular large nebulas :(  That's why I looks at kaf 8300 so much, but QE and readout noise of sony chip is really tempting. 

Edited by Danon

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Well one scope / camera combination won't get good pictures of every target up there but there are more targets than clear nights so should take you a while to run out and making mosaics is fine with a bit of practice.

Dave

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Well, that's true. I must consider everything now, which one give best results 

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1 hour ago, Danon said:

Really thanks everyone for reply. That topic was bothering since a month, and no one from my country give me any anwser. But now... I even more don't know what to choose :D As beginner I go to site telescopius and look ad Heart nebula. If fov didin't get whole nebula I'm little bit sad. For 460EX with 420mm whole wide field of Heart nebula needs to be a 4-pane mosaic! But 2 pane is still good. Due to that I have now 2-3 clear nights per month, I'm little afraid when I complete all these popular large nebulas :(  That's why I looks at kaf 8300 so much, but QE and readout noise of sony chip is really tempting. 

Theory suggests the 460EX is twice as fast as the KAF8300, but with only half the area. Thats fine when you have a large subject and you can either do a two panel with the KAF8300 or 4 with the Sony in approximately the same time the Heart like you say is a good example but more planning required.

But if its a smaller fainter target (soap bubble for example) or anything that fits the Sony FOV in a single frame it will just be faster and higher resolution than the KAF8300 and on an identical scope the KAF8300 has no come back to that. Also worth noting that the gap in sensitivity is even larger for SII than for Ha due to the fall off in QE of the KAF8300 at longer wavelengths. Finally you can afford to bin 2x2 the Sony for faint OIII and SII where as the larger pixels of the KAF8300 will result in a large pixel scale if you bin them 2x2. 

Adam

Edited by Adam J

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77% QE and 5e- is twice faster than 56% and 7e-? 🤔

I copied this from CN

"The KAF-8300 has 5.4µm pixels, while the ICX-694 has 4.54µm pixel size. In terms of area, the KAF has a 41.5% advantage.

The ICX-694 has 77% Q.E., while the KAF has 56% Q.E., and the advantage goes to the Sony at 37.5%.

Read noise is similar between the two, ~7e- for the ICX, ~9.3e- for the KAF. I don't think the ~2e- difference here is going to be particularly significant, although the Sony sensor's lower read noise may be enough of a margin to matter for your particular applications.

Quantum efficiency is a simple measure of the ratio of incident photons at the photodiode that release an electron (photon to charge conversion ratio). Area is not a factor here. Given that, in terms of total sensitivity, the larger pixels of the KAF actually result in a 4% sensitivity advantage over the Sony. " 

Edited by Danon

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1 hour ago, Danon said:

77% QE and 5e- is twice faster than 56% and 7e-? 🤔

No faith,

5/7 = 0.71

56/77 = 0.72

0.72 * 0.71 = 0.516

At the same image scale (as pixel size is also a factor) and accepting that read noise is dominant in narrow-band imaging.

OR

77/5 = 15.4

56/7 = 8

1 / (15.4 / 8 ) = 0.519

Rounding errors hey.

So what does that actually mean for you?

Well it means that if you want to achieve about 2 arc seconds per pixel (a good starting point) at a reasonable FOV the two following combinations will work.

1) The KAF8300 with the SW ED 80DS-Pro will give 2.18 arcsec / pixel at 2.04 x 1.52 degrees.

You can go with the KAF8300 and the 65Q becuase that will leave you at 3.12 arc-seconds per pixel...maybe a little more than what I would consider optimal. 

2) The 65Q with the Atik460EX will give 2.62 arc-seconds / pixel and will give you 2 degrees / 1.6 degrees so virtually identical or actually a little larger FOV than case 1) above. But it will be almost exactly twice as fast as the above option image scales are very close.

Cant use it with the ED80 because the FOV is too small.

image.png.c44e9cd0b40b256ded645fb9d7601239.png

 

But the really interesting stuff happens if you go a little faster with a scope, perhaps something like a WO ZS73 at F6 or even a GT71 at F4.7. In both cases the pixel size of the ATIK460EX will still work at those focal lengths but the KAF8300 is increasingly sub optimal.

Maintaining FOV an Esprit 80 will give you F5 and so will be something like 4 x faster than the KAF8300 and SW ED80DS-Pro combination.

Adam

 

 

 

 

 

 

 

 

Edited by Adam J

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6 hours ago, Davey-T said:

Apart from the general stuff of CMOS versus CCD, amp glow, 12bit etc I feel the file size is the main drawback requiring a lot of storage.

8300 files around1600 kb versus ASI1600 around 5000kb ? maybe, can't remember, which soon adds up when taking short exposures whereas one 30 minute 8300 sub is still only 16,274kb

Dave

At 5 minute per ASI1600 sub that's only twice the storage space.

And storage is cheap I bought two 1TB USB3 WD hard drives for £42 each today.

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19 minutes ago, Stub Mandrel said:

At 5 minute per ASI1600 sub that's only twice the storage space.

Think you've missed of a 0 :grin:

Dave

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20 minutes ago, Stub Mandrel said:

At 5 minute per ASI1600 sub that's only twice the storage space.

And storage is cheap I bought two 1TB USB3 WD hard drives for £42 each today.

Yes that is how I would it. I use unity gain although I have seen some still using gain 200 at that exposure length.

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15 hours ago, Davey-T said:

Think you've missed of a 0 :grin:

Dave

? using the figures given...

5,000 x 6 = 30,000kb vs 1x16,000kb.

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1 hour ago, Stub Mandrel said:

? using the figures given...

5,000 x 6 = 30,000kb vs 1x16,000kb.

From reading up the FITS file is 32000kb for the 1600.

So 32000 x 6 = 192000 versus 16000, or about 12 times more storage space.

 

I read the above from Davey last night, and thought it didnt seem right, since 2x storage space wouldnt be a big deal, but obviously 12x is.

Edited by tooth_dr

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21 minutes ago, tooth_dr said:

From reading up the FITS file is 32000kb for the 1600.

So 32000 x 6 = 192000 versus 16000, or about 12 times more storage space.

 

I read the above from Davey last night, and thought it didnt seem right, since 2x storage space wouldnt be a big deal, but obviously 12x is.

Hah! 'tis @Davey-T who missed an "0" off - hoist by  his own petard!

Methinks the two sensor are so different other considerations are more important - such as sensor size.

 

 

Edited by Stub Mandrel
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4 minutes ago, Stub Mandrel said:

Hah! 'tis @Davey-T who missed an "0" off - hoist by  his own petard!

Methinks the two sensor are so different other considerations are more important - such as sensor size.

 

 

They give a similar FOV.  This was my consideration when I ended up with the 8300.

image.png.9e5855bead7069962e8bdc4590138bf4.png

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25 minutes ago, Stub Mandrel said:

Hah! 'tis @Davey-T who missed an "0" off - hoist by  his own petard!

Methinks the two sensor are so different other considerations are more important - such as sensor size.

 

 

Do you think anyone will notice if I edit it 😂

Still 12 x is a lot of storage on the other hand the 1600 pro can do 30 minutes but it also has other reported  cons like reflections from the sensor window and saturated bright stars.

Done some browsing around out of interest and discovered that the mounting ring off my Canon 300 f/4 fits nicely on the ZWO 1600, not that I'm thinking of buying one :rolleyes:

Dave

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54 minutes ago, tooth_dr said:

They give a similar FOV.  This was my consideration when I ended up with the 8300.

So ... bin the ASI 2x2 🙂

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@Adam J Thanks a lot! I read a lot for two days, and if I use 80/500 with 0.8x corrector I will get 400mm F5 photon machine with a little bit less fov than 510mm + kaf8300 :) That could be great. Do you think that SW Equinox is good choice? It will be 2.34"/pix on 460ex vs 2.18"pix on Atik. This is big change of resolution on final image? But another question.. If you have this 80/400 f5 and would be in my place, but with your knowledge, you would pick Asi1600 or Atik460EX? I read that Asi is annoying with these amp glow, small pixel, and number of frames. My PC that I do my stack I quite good but still I dont know what would be serving me for quite a long time 

Edited by Danon

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8 hours ago, Danon said:

@Adam J Thanks a lot! I read a lot for two days, and if I use 80/500 with 0.8x corrector I will get 400mm F5 photon machine with a little bit less fov than 510mm + kaf8300 :) That could be great. Do you think that SW Equinox is good choice? It will be 2.34"/pix on 460ex vs 2.18"pix on Atik. This is big change of resolution on final image? But another question.. If you have this 80/400 f5 and would be in my place, but with your knowledge, you would pick Asi1600 or Atik460EX? I read that Asi is annoying with these amp glow, small pixel, and number of frames. My PC that I do my stack I quite good but still I dont know what would be serving me for quite a long time 

Not sure that its a good idea to use something like the SW Equinox (which is a doublet) with a 0.8 reducer, I think that would be pushing the optics a little hard and you will see some some chromatic abberation. Lots of 80/480 triplets such as the Altair Starwave 80EDT or the WOGT81-III etc and go down to 384mm with a 0.8 reducer and a little under F5.

ASI1600mm pro or Atik460EX was the decision i struggled to make, I dont think there is a correct answer in fact. What I can say is that wither one is capable of producing stunning images and so your not going to experience any disappointment or regret in either case. 2.34"/pix vs 2.18"/pix is insignificant you will not notice any difference. So that leaves just a few factors on which you make a choice.

1) How do you feel about the micro lens diffraction effect on a ASI1600mm pro?

Ill be honest with you I have found myself actively avoiding some targets due to it. The Ghost of Gamma Cas being one example that I considered imaging then decided not to because I knew I would end up with unsightly reflections and diffraction effects from the ASI1600mm pro and would never be happy with the image. Two more are the Horse head and the Butterfly nebula, serious targets that I dont want to image because i know ill get a big boxed shaped refraction effect around them.  

2) The ASI1600mm pro is larger than the 460EX so is the extra size worth it to you in exchange for the diffraction effects and reflections.

3) I dont think i would personally buy a new 460EX vs a new ASI1600mm pro because that is a huge difference in price, but they come up often second hand and hence cheaper than a ASI, they are well built so buying used is low risk.

4) Despite what some here will argue I have had some issues taking good flats with a ASI1600mm pro, you end us with multiple dark flats because each channel needs a flat and they are all different exposures. Its a pain to me at least.

5) I think that the file size thing is overblown but using APP it can mean that when using things like dynamic distortion correction the stacking time will be very significant (24 hours in one case for me).

6) You need to dither a ASI1600mm pro to get the best results and that can lose you between 30seconds and 60 seconds per frame if you are dithering for every frame at 300s exposures that not an insignificant hit to efficiency.

7) I think that the ASI1600mm pro is slightly more sensitive than the 460EX but for my friends results vs my camera on similar setups I dont think its so significant such as to be the driving factor behind your choice. Also in many situations the ability to fully hardware bin 2x2 for OIII and SII is not an insignificant advantage as it results in a large increase in sensitivity for the 460EX.  

8 ) With a ASI1600mm pro you will be doing 5 mins subs for narrow band vs 10min subs for the 460EX. Personally I think that if you can guide for 5 mins you can guide for 10 mins so I dont see that as a significant issue, also note that this does not mean that the ASI1600mm pro is twice as fast as the 460EX that is not how it works.

So bottom line, if you take all the above into account I think it boils down to: slightly less effort, smaller FOV and hardware binning for the 460EX Vs Slightly more effort, larger FOV, situational but nasty diffraction effects and slightly more sensitivity for the ASI1600mm pro. Armed with that information its down to individual preference.

Hope that helps you make your choice. For me, I picked the ASI1600mm pro because of the FOV of my 130PDS at 650mm demanding a larger sensor. But if i was working at around 400mm I would have picked the 460EX. Others will disagree for sure, but as I say there is not correct answer only personal choice both are great cameras.

Adam

 

 

 

 

 

Edited by Adam J
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6 hours ago, Danon said:

@Adam J Thanks a lot! I read a lot for two days, and if I use 80/500 with 0.8x corrector I will get 400mm F5 photon machine with a little bit less fov than 510mm + kaf8300 :) That could be great. Do you think that SW Equinox is good choice? It will be 2.34"/pix on 460ex vs 2.18"pix on Atik. This is big change of resolution on final image? But another question.. If you have this 80/400 f5 and would be in my place, but with your knowledge, you would pick Asi1600 or Atik460EX? I read that Asi is annoying with these amp glow, small pixel, and number of frames. My PC that I do my stack I quite good but still I dont know what would be serving me for quite a long time 

There's a lot of technical bits in all the responses but honestly I wouldn't worry too much about it all.  You will having to learn so much to start with that in itself will be a challenge.  You can make excellent images from most setups (realistically your mount is the most important part).

You really want something that is relatively forgiving at this stage.  That means a short focal length and larger pixels as it will mean tracking errors, polar alignment errors etc show up more slowly.  Then you need to consider how you are going to guide the telescope.  That's another smaller guide camera and either a small finder telescope or an off axis guider.  Also with a mono camera you need filters and a filter wheel.

The most important thing though is what you want to image.  Galaxies/planetary nebulae tend to be small (except a few) which means smaller pixels, longer focal length telescope.  Emission nebulae tend to be larger and need shorter focal length, larger pixel camera which would be just fine.  The 8300 class cameras are just fine for imaging, they are a good workhorse.  Their advantage is that CCDs tend to calibrate easier but are noisier (generally) but the Sony (460 etc) ones are relatively low noise.  CMOS needs a bit more consideration on the calibration frames because of amp glow and walking floor noise, plus they tend to have smaller pixels needing better guiding.  However CMOS tend to work better with shorter but many frames that puts less onus on guiding compared to CCD which tends to need more and longer images.  

So each option has its strengths and weaknesses, however from a beginners perspective they are all a challenge whichever way you look at it.  Honestly from a beginners perspective I'd go with a CCD simply because there are tens of years of experience on these cameras and you will always find help.  CMOS are still relatively new to the field and I still think people are working out how to get the best out of them.  Therefore guidance might be a bit less on how to resolve certain issues.

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20 hours ago, Adam J said:

Hope that helps you make your choice. For me, I picked the ASI1600mm pro because of the FOV of my 130PDS at 650mm demanding a larger sensor. But if i was working at around 400mm I would have picked the 460EX. Others will disagree for sure, but as I say there is not correct answer only personal choice both are great cameras.

Adam

I really appreciate that you did. All of You from this thread :) Asi give me nice fov and detail but something inside me tell me that I need that CCD. Finaly I will be looking after 460EX with maybe some 80mm with F5. Best scope I think would be Espirt80 with flattener 1x. The 400mm is what I need when I look on telescopius frame samples on nebulas. Every nebula fits in 2 pane mosaic or smaller on one pane. Only that scale makes me sad. On Canon now I have 2"/pix. Do you think that Drizzle 2x will give me anything ? Im too focused on detail I think... But first I need to calculate if I have/want to spent such amount of money for scope and camera

@Whirlwind I have a short experience with practice from febuary, and 70% time was reading astrosites and what is important with all specification.  Weather was't good. From march I've taken about 5-8 photos which maybe 3-4 is 3h+. Rest of them are "Im curious how it will look like".  I always need to know what Im doing, thats why I search always how everything works. Every step from photons that gets into scope to understand how to scretch. Now I just don't want spent and change equipment and buy something that will be serve me well. Acording to weather speed is now important do me. 

Edited by Danon

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14 minutes ago, Danon said:

@Whirlwind I have a short experience with practice from febuary, and 70% time was reading astrosites and what is important with all specification.  Weather was't good. From march I've taken about 5-8 photos which maybe 3-4 is 3h+. Rest of them are "Im curious how it will look like".  I always need to know what Im doing, thats why I search always how everything works. Every step from photons that gets into scope to understand how to scretch. Now I just don't want spent and change equipment and buy something that will be serve me well. Acording to weather speed is now important do me. 

Realistically if you want speed then the largest aperture is the way to go as it will collect more photons per pixel (for the same camera).  You could get something like the RASA 8" with a ASI1600 which would really help maximise your imaging if you are limited by a few days per month.  You would just need a filter drawer (or choose a colour CMOS).

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40 minutes ago, Danon said:

I really appreciate that you did. All of You from this thread :) Asi give me nice fov and detail but something inside me tell me that I need that CCD. Finaly I will be looking after 460EX with maybe some 80mm with F5. Best scope I think would be Espirt80 with flattener 1x. The 400mm is what I need when I look on telescopius frame samples on nebulas. Every nebula fits in 2 pane mosaic or smaller on one pane. Only that scale makes me sad. On Canon now I have 2"/pix. Do you think that Drizzle 2x will give me anything ? Im too focused on detail I think... But first I need to calculate if I have/want to spent such amount of money for scope and camera

@Whirlwind I have a short experience with practice from febuary, and 70% time was reading astrosites and what is important with all specification.  Weather was't good. From march I've taken about 5-8 photos which maybe 3-4 is 3h+. Rest of them are "Im curious how it will look like".  I always need to know what Im doing, thats why I search always how everything works. Every step from photons that gets into scope to understand how to scretch. Now I just don't want spent and change equipment and buy something that will be serve me well. Acording to weather speed is now important do me. 

There is a RGB matrix in front of your Canon (RGGB) its giving you less resolution than you think because of that, while as the mono will resolve more detail because it lacks the RGB filters even in comparison to a color camera of equal pixel size. So I promise you that a 460EX will outperform your canon in terms of resolved detail with ease you wont want to drizzle!

The key thing to understand in this is that on a color camera only 25% of pixels are Red, 50% green and 25% are Blue.

Not to mention the fact that the amount of noise reduction you need to use with a DSLR is much higher and all noise reduction techniques in effect exchange resolution for signal to noise in any case. SO using less noise reduction gives you more resolved detail.

Edited by Adam J
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11 minutes ago, Whirlwind said:

Realistically if you want speed then the largest aperture is the way to go as it will collect more photons per pixel (for the same camera).  You could get something like the RASA 8" with a ASI1600 which would really help maximise your imaging if you are limited by a few days per month.  You would just need a filter drawer (or choose a colour CMOS).

Not so, the number of photons arriving per pixel is purely determined by the f-ratio of the scope. A larger aperture at the same f-ratio will only give you more photons per arc-second^2 it will not give you more per pixel and that is what matters for signal to noise ratio. That happens because at fixed F-ratio as you increase aperture you increase focal length and as a result you reduce the image scale in terms of less arc seconds per pixel and so everything remains equal but you have less field of view and more ""magnification"" although the idea of magnification in terms of imaging is a false concept in itself.

Adam

Edited by Adam J
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I would go with the ASI1600 or the QHY163, going for a 15 year old sensor like KAF8300 doesn't really make sense today.

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