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Madratter
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Reged: 01/14/13

Re: KAF-8300 questions? new [Re: dan17]
      #5782423 - 04/06/13 07:01 PM Attachment (13 downloads)

I'm late to the party but thought I would post a single sub from my STF-8300m of M20 (the Trifid Nebula) from last night. This was a 10m Ha frame binned 2x2. It has been histogram stretched in PixInsight and the black point was moved up but zero pixels were clipped. No darks, flats, etc. have been applied. Basically all the warts are there to be seen. You can then decide for yourself how you feel about the noise.

Full size is here:

Full size frame of M20 on Astrobin

Edited by Madratter (04/06/13 07:23 PM)


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SL63 AMG
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Reged: 12/21/09

Loc: Williamson, Arizona
Re: KAF-8300 questions? new [Re: Zoeff]
      #5782959 - 04/07/13 12:42 AM

Quote:


Could you upload a full image instead? The noise would always be quite low if you downscale it like that. I'm curious to see what a microline KAF8300 can do compared to my Atik 383 as it's got 20 degrees more delta below ambient and supposedly better electronics.

Also, what exactly was the chip cooled to?




I have uploaded the M78 single FITS frame to my Astrobin RAW data storage area with public access. I also included a master bias and a 30m master dark all binned 1x1 and cooled to -35c which is my usual operating temperature.

You can download the data from the public pool M78_Noise_Eval


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orlyandico
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Re: KAF-8300 questions? new [Re: SL63 AMG]
      #5783051 - 04/07/13 02:39 AM

Late to this thread..

But Apogee has a 694 camera for $3281. The Apogee Ascent A694.

It comes in the Ascent casing, so only 25 degrees Celsius below ambient. But heck it's an Apogee (comparable to FLI reputation-wise). And it's a Sony chip which has 1/10 the dark current of an 8300.


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Calypte
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Reged: 03/20/07

Loc: Anza, California
Re: KAF-8300 questions? new [Re: orlyandico]
      #5783061 - 04/07/13 02:49 AM

My only experience with Sony chips is my Starlight Xpress Lodestar guider. It's loaded with hot pixels, which can only be mitigated (not totally zeroed out) with a library of dark frames and a hot pixel map. I'll never buy a camera with a Sony chip again.

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pfile
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Reged: 06/14/09

Re: KAF-8300 questions? new [Re: Calypte]
      #5783729 - 04/07/13 12:44 PM

i wonder if the chips that SX puts in the guiders are basically floor sweep? i'd assume that they use more defect-free sensors for "real" cameras...

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mmalik
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Re: KAF-8300 questions? new [Re: pfile]
      #5783787 - 04/07/13 01:13 PM

Quote:

I wonder if the chips that SX puts in the guiders are basically floor sweep?




That's exactly what my thoughts were if they just use rejects of sorts; I promptly sent back that piece of scrap heap. Thx


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orlyandico
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Re: KAF-8300 questions? new [Re: mmalik]
      #5783894 - 04/07/13 02:14 PM

well.. I have an old Meade DSI Pro with a Sony ICX098 chip. And it does have tons of stuck pixels and the dark noise is eye popping. Well this is an old, old chip in an uncooled camera.

My QHY8 is really great, very low dark noise, no stuck pixels, etc. etc. I think the tiny chips (which are probably all used for CCTV video) have much less stringent QA.


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Madratter
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Reged: 01/14/13

Re: KAF-8300 questions? new [Re: orlyandico]
      #5783961 - 04/07/13 02:45 PM

Kind of off topic here but I know there are plenty of people who are very happy with their lodestars. But I have to admit that a picture that was posted here of one scared me away. It looked horrible, column problems, the works. I also didn't like the very poor engineering for the connection. I ended up with a SBIG ST-i that I am liking a lot.

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Peter in Reno
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Reged: 07/15/08

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Re: KAF-8300 questions? new [Re: Madratter]
      #5784117 - 04/07/13 03:41 PM

Lodestar is not designed for imaging, it's designed for auto guiding. Who cares if it has some hot pixels and columns? My Lodestar has some hot pixels and columns but it's so sensitive that I never had to hunt for guide stars with OAG at 2000mm focal length. Lodestar is probably THE best autoguider.

Back to topic, have you considered a camera with low read noise like Sony ICX694? That's one sensitive camera. The read noise is so low that makes narrow band imaging very attractive. No darks needed thanks to super low thermal noise CCD. This CCD does not have pattern noise so no darks are necessary. Also, probably the coldest temperature this chip needs is about -16C and anything colder is not necessary. Kodak chips needs extremely cold temperature to keep thermal noise low in dark subs, not in Sony chips. Modern Sony chips also have extremely low hot pixels count.

My Atik 460EX mono camera with Sony ICX694 is an awesome and inexpensive camera. I have not used it much thanks to horrible weather but so far I've imaged Bubble Nebula and M82 and I've been pretty pleased with the camera. My image scale has been a whopping low of 0.46"/pixel. My images are found in "Peter's Galleries" in my signature.

When I get Celestron focal reducer for my C8 EdgeHD, I think Atik 460EX camera will be a perfect match.

Peter


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Calypte
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Reged: 03/20/07

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Re: KAF-8300 questions? new [Re: Peter in Reno]
      #5784228 - 04/07/13 04:24 PM

Quote:

Lodestar is not designed for imaging, it's designed for auto guiding. Who cares if it has some hot pixels and columns?



It matters because MaxIm tries to guide on hot pixels, so they must be mitigated. At 1600mm FL, using the OAG of the QSI 683, I found it almost impossible to find guide stars that the Lodestar and MaxIm (in combination) would accept. I have better luck at 1200mm (different scope). Sony chips are touted as the ultimate in low noise, compared to Trusense (aka Kodak). I never had hot-pixel problems with Kodak/Trusense chips. Never again!


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hytham
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Reged: 12/25/12

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Re: KAF-8300 questions? new [Re: Calypte]
      #5784499 - 04/07/13 06:35 PM

Quote:

Quote:

Lodestar is not designed for imaging, it's designed for auto guiding. Who cares if it has some hot pixels and columns?



It matters because MaxIm tries to guide on hot pixels, so they must be mitigated. At 1600mm FL, using the OAG of the QSI 683, I found it almost impossible to find guide stars that the Lodestar and MaxIm (in combination) would accept. I have better luck at 1200mm (different scope). Sony chips are touted as the ultimate in low noise, compared to Trusense (aka Kodak). I never had hot-pixel problems with Kodak/Trusense chips. Never again!




You're judging the entire line of Sony CCDs based on the experience you had with ONE chip that is installed in the SX line of guiding cameras?

That seems very logical and objective.


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Peter in Reno
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Re: KAF-8300 questions? new [Re: hytham]
      #5784555 - 04/07/13 07:08 PM

This thread is not about autoguiders.

All I can say is I great results with my Atik 460EX mono camera. This has extremely low noise. Also, it does not have pattern noise so darks are not necessary. You can take one dark frame for Bad Pixel Mapping.

Kodak KAF-8300 chip also has pretty low noise as compared to large full frame Kodak chips. I think you will be satisfied with KAF-8300. This chip has pattern noise so you must take enough darks at the same exact temperature and exposure as lights to successfully remove pattern noise from lights. I know this because I used to have a color version of KAF-8300 (QSI583csg) and I just checked one of its dark sub and noticed pattern noise.

Peter


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SL63 AMG
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Reged: 12/21/09

Loc: Williamson, Arizona
Re: KAF-8300 questions? new [Re: Calypte]
      #5784766 - 04/07/13 08:56 PM

Quote:

Quote:

Lodestar is not designed for imaging, it's designed for auto guiding. Who cares if it has some hot pixels and columns?



It matters because MaxIm tries to guide on hot pixels, so they must be mitigated.




This isn't necessarily true. If you take an exposure with your guide camera, then click on a star in the resulting image, Maxim will use THAT star to calibrate and subsequently guide.

I agree with Peter. The KAF-8300 chip is an excellent chip and with a good set of calibration frames any small issues are rejected.

Although I just bought an FLI PL16803 for my new RCOS, I will not part with my ML8300 which has served me well. I am sure I will find a use for it.


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blueman
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Reged: 07/20/07

Loc: California
Re: KAF-8300 questions? new [Re: Peter in Reno]
      #5784807 - 04/07/13 09:15 PM

Flats are needed to remove pattern noise.
Blueman
Quote:

This thread is not about autoguiders.

All I can say is I great results with my Atik 460EX mono camera. This has extremely low noise. Also, it does not have pattern noise so darks are not necessary. You can take one dark frame for Bad Pixel Mapping.

Kodak KAF-8300 chip also has pretty low noise as compared to large full frame Kodak chips. I think you will be satisfied with KAF-8300. This chip has pattern noise so you must take enough darks at the same exact temperature and exposure as lights to successfully remove pattern noise from lights. I know this because I used to have a color version of KAF-8300 (QSI583csg) and I just checked one of its dark sub and noticed pattern noise.

Peter




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SL63 AMG
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Reged: 12/21/09

Loc: Williamson, Arizona
Re: KAF-8300 questions? new [Re: blueman]
      #5784916 - 04/07/13 10:16 PM

Quote:

Flats are needed to remove pattern noise.
Blueman





My understanding is that flats are needed to correct uneven illumination across the sensor, vignetting and to correct for optical aberations such as donuts caused by dust.


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blueman
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Re: KAF-8300 questions? new [Re: SL63 AMG]
      #5785060 - 04/07/13 11:39 PM Attachment (9 downloads)

If you look at a flat you will see the pattern noise easily. This is how it is removed as far as I am concerned.
Blueman
Quote:

Quote:

Flats are needed to remove pattern noise.
Blueman





My understanding is that flats are needed to correct uneven illumination across the sensor, vignetting and to correct for optical aberations such as donuts caused by dust.




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Alph
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Reged: 11/23/06

Loc: Melmac
Re: KAF-8300 questions? new [Re: blueman]
      #5785169 - 04/08/13 01:15 AM

Quote:

If you look at a flat you will see the pattern noise easily. This is how it is removed as far as I am concerned.



Hmm? I have never seen pattern noise in a flat or a dark taken with my QSI camera. There is something wrong with your camera. A bias is the only frame where the patten noise should/could be visible to the eye. What does your bias frame look like at -10C?


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scirocco1
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Reged: 05/05/09

Loc: Cluj,Romania
Re: KAF-8300 questions? new [Re: Alph]
      #5785253 - 04/08/13 03:34 AM

383L+ @ -25C
http://www.scirocco.ro/tmp/masterflat.jpg (32x4sec)
http://www.scirocco.ro/tmp/masterbias.jpg (32x)
http://www.scirocco.ro/tmp/masterdark.jpg (16x10min)


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freestar8n
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Reged: 10/12/07

Re: KAF-8300 questions? new [Re: scirocco1]
      #5785260 - 04/08/13 03:55 AM

I'm not surprised there is some pattern noise in the flat - and it shouldn't be a problem after calibration. Even if a "pattern" isn't visible in the flat, there may still be pixel response nonuniformity, PRNU, in a randomish pattern that isn't obvious - and this could happen in a Sony CCD. Both are good reasons not to smooth or bin the flat at all - as some people recommend. And both are examples of the importance of flats, independent of the need to correct for vignetting.

Anyway - this doesn't surprise me and it doesn't seem like a problem - unless it isn't repeatable and ends up showing in the final image.

Frank


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blueman
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Re: KAF-8300 questions? new [Re: Alph]
      #5785887 - 04/08/13 12:38 PM

Alph,
This flat is a -25c flat.

There is nothing wrong with the camera. IT is the way a chip works and is made that caused the pattern to appear. There are pixels and chanels and that will show on a flat.

If your flats are done properly then patterns will show if that chip has them.

This is one of the reasons for flats and why they need to be done at the right ADU.
Blueman
Quote:

Quote:

If you look at a flat you will see the pattern noise easily. This is how it is removed as far as I am concerned.



Hmm? I have never seen pattern noise in a flat or a dark taken with my QSI camera. There is something wrong with your camera. A bias is the only frame where the patten noise should/could be visible to the eye. What does your bias frame look like at -10C?




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