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Equipment Discussions >> Video and Electronically Assisted Astronomy

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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: First Miloslick and Mallincam use new [Re: Dwight J]
      #5617223 - 01/11/13 12:47 PM

And to add to what Dwight said ...

Mallincams have changed over time, the older models did indeed have a bit more amp glow (at the same integration/exposure level) than newer models.
One thing that complicates things when discussing the amount of amp glow potentially seen is that later model Mallincams have extended integration/exposure levels (which can increase amp glow) but they also have improved cooling capabilities (which reduces amp glow). So it really depends on settings and how the camera is being used.
Sensor selection also affects the amount of amp glow seen ... the optional EXView HAD sensors are even more sensitive and therefore show a bit more amp glow.


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: First Miloslick and Mallincam use new [Re: mclewis1]
      #5617236 - 01/11/13 12:55 PM

Quote:

And to add to what Dwight said ...

Mallincams have changed over time, the older models did indeed have a bit more amp glow (at the same integration/exposure level) than newer models.
One thing that complicates things when discussing the amount of amp glow potentially seen is that later model Mallincams have extended integration/exposure levels (which can increase amp glow) but they also have improved cooling capabilities (which reduces amp glow). So it really depends on settings and how the camera is being used.
Sensor selection also affects the amount of amp glow seen ... the optional EXView HAD sensors are even more sensitive and therefore show a bit more amp glow.




No improvements, exview schmexview sensors, cooling (other than to 0K -that is zero Kelvin- , definitely not "mild") can reduce ALL noise from ALL pixels to exactly 0. Which is what the above images are showing , exactly 0 with very clipped blacks in the histogram .


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Dwight J
scholastic sledgehammer
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Reged: 05/14/09

Loc: Lethbridge, Alberta, Canada
Re: First Miloslick and Mallincam use new [Re: mattflastro]
      #5617318 - 01/11/13 01:52 PM

Check the images I have posted in the image gallery. The ones here in this thread had a lot of vignetting that I used the software to remove and thusly clipped the black level as I described in the first post in the thread. What I liked about the Miloslick software is that I could get rid of it and put up an image without it showing.

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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: First Miloslick and Mallincam use new [Re: Dwight J]
      #5617332 - 01/11/13 02:01 PM

Quote:

Check the images I have posted in the image gallery. The ones here in this thread had a lot of vignetting that I used the software to remove and thusly clipped the black level as I described in the first post in the thread. What I liked about the Miloslick software is that I could get rid of it and put up an image without it showing.




Thanks, will check .


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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: First Miloslick and Mallincam use new [Re: mattflastro]
      #5617420 - 01/11/13 03:02 PM

Matt,

Nothing in my comments had anything to do with the histogram or black levels. Check the posting times, I never saw your earlier post about clipped levels, I was just adding to what Dwight said earlier about Mallincam amp glow .

It is however pretty interesting to see a histogram like that. It's certainly not representative of the raw un processed image from any video camera through a frame grabber.


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: First Miloslick and Mallincam use new [Re: mclewis1]
      #5618133 - 01/11/13 10:28 PM

Quote:

Matt,

Nothing in my comments had anything to do with the histogram or black levels. Check the posting times, I never saw your earlier post about clipped levels, I was just adding to what Dwight said earlier about Mallincam amp glow .

It is however pretty interesting to see a histogram like that. It's certainly not representative of the raw un processed image from any video camera through a frame grabber.



I apologize for that posting, I was in a hurry this morning and missed the subtleties. I should learn to refrain from posting when I'm in a hurry .
What I meant was exactly what you said, the way that histogram looks is certainly suggesting some device in the signal chain clipped the blacks, be it the camera hardware, frame grabber hardware or software , or the Miloslick settings, and I was/am very curious as to what caused it. I am in the process of educating myself as much as possible before making some possible purchasing decisions and trying to find out how the various parts perform is a given for me.


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: First Miloslick and Mallincam use new [Re: Dwight J]
      #5618159 - 01/11/13 10:42 PM

Quote:

Check the images I have posted in the image gallery. The ones here in this thread had a lot of vignetting that I used the software to remove and thusly clipped the black level as I described in the first post in the thread. What I liked about the Miloslick software is that I could get rid of it and put up an image without it showing.




I checked your images in the image gallery , very nice images and the black background looks normal, no clipping . I saw some amp glow but very faint , also very little image noise , nothing to worry about. Thanks .


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Dwight J
scholastic sledgehammer
*****

Reged: 05/14/09

Loc: Lethbridge, Alberta, Canada
Re: First Miloslick and Mallincam use new [Re: mattflastro]
      #5618182 - 01/11/13 10:55 PM

Thanks Matt. To be sure, in warmer weather extra steps need to be taken to dissipate heat from the camera and Mallincam sells heat sinks , fans, and even the 2" adapter acts like a heat sink. Where I live nights are usually cool and cold in winter - -14C right now so amp glow is much reduced without anything other than the on camera cooling. Miiloslick can mask any glow that occurs or a dark frame can be subtracted on the fly and that removes the hot pixels too. I will post some more images using my original focal reducer and frame stacking with dark subtraction after Saturday night.

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ahopp
sage


Reged: 05/24/12

Re: First Miloslick and Mallincam use [Re: Dwight J]
      #5618611 - 01/12/13 08:47 AM

How do i get to the image gallery for Dwight to see these images referenced? When I go to Dwight's gallaery on Cloudy Nights it is empty.

Tony


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Dwight J
scholastic sledgehammer
*****

Reged: 05/14/09

Loc: Lethbridge, Alberta, Canada
Re: First Miloslick and Mallincam use new [Re: ahopp]
      #5618993 - 01/12/13 12:36 PM

Hi Tony: I don't have a gallery. My images are posted in the images thread on the last page. I also have some in the Happy New Year thread and Merry Christmas thread.

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nytecam
Postmaster


Reged: 08/20/05

Loc: London UK
Re: First Miloslick and Mallincam use new [Re: mattflastro]
      #5619484 - 01/12/13 05:23 PM

Quote:

Forgive my naive question as a non-Mallincam owner, does the Mallincam HAVE amp glow ? Everywhere I read about it I could only see praise and superlatives, not a word of amp glow. Now here comes a piece of software that eliminates it that must not be spoken???


Once asked the maker of hi-end astro CCD cams why no videocams for DSO work and he said "amp glow - why 'stack' video frames via sens-up, each with its amp glow, when a single CCD cam exposure of equal [or longer duration] has no amp glow 'cos the amplifier is switched off during the exposure" !

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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: First Miloslick and Mallincam use new [Re: nytecam]
      #5619728 - 01/12/13 07:47 PM

Quote:

Once asked the maker of hi-end astro CCD cams why no videocams for DSO work and he said "amp glow - why 'stack' video frames via sens-up, each with its amp glow, when a single CCD cam exposure of equal [or longer duration] has no amp glow 'cos the amplifier is switched off during the exposure" !




A part of the above statement is true, albeit incomplete . Stacking multiple frames with amp glow would yield a worse result than a single exposure with the amp switched off . The statement failed to mention the readout noise would be higher in the stacked scenario .
Now to the part of that statement which is false. Sense-up does not work by stacking frames in-camera . Sense-up is an actual single long exposure , just like a long exposure photo . It's true that sens-up does not switch off the CCD read amp during the exposure just the same some DSLR's don't (for example the Canon D300 ). But it is a single exposure .


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Dwight J
scholastic sledgehammer
*****

Reged: 05/14/09

Loc: Lethbridge, Alberta, Canada
Re: First Miloslick and Mallincam use new [Re: mattflastro]
      #5619864 - 01/12/13 09:52 PM

And, in keeping with the theme of the thread, using Miloslick I can subtract a dark frame on the fly so amp glow and hot pixels are removed. Only one dark is needed as it can be adjusted for different exposure times. I asked myself why I just didn't use a OSC CCD camera instead but then I would have to do post processing to see a color image after I subtracted a dark frame. I just need to get some clear skies but snow and clouds for the next two nights. Once I can get out I will post some examples.

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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: First Miloslick and Mallincam use new [Re: nytecam]
      #5620871 - 01/13/13 02:03 PM

Quote:

Once asked the maker of hi-end astro CCD cams why no videocams for DSO work and he said "amp glow - why 'stack' video frames via sens-up, each with its amp glow, when a single CCD cam exposure of equal [or longer duration] has no amp glow 'cos the amplifier is switched off during the exposure" !



And there is one of the reasons why Rock (the designer/maker of the Mallincam) gets so bent out of shape when folks dismiss his products vs. CCD imaging cameras or simple video/security cameras. There's a lot of additional design and specialized hardware work that goes into making his continuous exposure cameras work so well.

Edited by mclewis1 (01/13/13 02:05 PM)


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