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ASI1600MMC Beta test

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#1101 tolgagumus

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Posted 28 May 2016 - 10:57 AM

Tolga,

I love your images. Your setup is very similar to mine. I have something to compare to and strive for. That is great. That would have been shot towards the moon not away from the glow.

Thank you Emilio. Moon was 45° away
 

#1102 tolgagumus

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Posted 28 May 2016 - 10:58 AM

Emilio, the only thing I can comment on is that to neutralize my background on the ARP104 data I needed the following ratios

1.55:1.13:1 R:G:B

versus your

1.22:1.08:1 R:G:B for color calibration.

Looking at the relative QE data, I don't really see that this should be the case. I know from experience in planetary that my red filter needs the shortest exposure so shouldn't be passing less light. I'm a bit confused.


I shoot equal and use linear fit to red
 

#1103 bigeastro

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Posted 28 May 2016 - 11:01 AM

Jon,

From looking at Tolga's equipment list.  I think we do have different filters.  I am using the latest version of the Baader LRGB set.  However there is a trend in that it appears that the sensor is not as sensitive to red.


 

#1104 bigeastro

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Posted 28 May 2016 - 11:02 AM

Darn,

That was 13 who was comparing.  Sorry


 

#1105 Thirteen

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Posted 28 May 2016 - 11:11 AM

Emilio, the only thing I can comment on is that to neutralize my background on the ARP104 data I needed the following ratios

1.55:1.13:1 R:G:B

versus your

1.22:1.08:1 R:G:B for color calibration.

Looking at the relative QE data, I don't really see that this should be the case. I know from experience in planetary that my red filter needs the shortest exposure so shouldn't be passing less light. I'm a bit confused.

I shoot equal and use linear fit to red

If I do that it seems to clip out the bottom of green and blue so I linear fit to blue. But the balance was not right even after calibration.
 

#1106 Thirteen

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Posted 28 May 2016 - 11:45 AM

I'm using ZWO LRGB
 

#1107 Jon Rista

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Posted 28 May 2016 - 11:57 AM

Since you guys are all using different filters, I would not expect the ratios to be the same for each of you. I would figure on each type of filter set having it's own set of ratios when paired with the ASI1600, and those ratios would likely be different than with the same set of filters paired with a different sensor. I am using AstroDon's myself, and I have little doubt my ratios will be different than any of yours. 

 

The red insensitivity is curious. According to the relative Q.E. chart:

 

https://astronomy-im...SI1600MM-QE.jpg

 

The reds shouldn't really be less sensitive than the blues, as both fall above the 60% relative to peak range (red stops around 700-750nm, NIR is beyond that). The sensor peaks in the blue-greens, around 520-530nm. It peaks again around 560nm, although not as high. The blues up to 400nm seem to have more area under the curve than the reds down to 700nm, but the difference doesn't appear to be huge. I think a 1.2x ratio for red seems reasonable...1.55x seems a little extreme. The fact that green is 1.13 and 1.08 respectively is curious...given that the sensor's Q.E. peaks twice in the greens. 

 

I'm sure the response and bandpass of the filters is playing a role here. I wonder if the ZWO reds are just passing less red? 

 

EDIT:

 

Here is the ZWO LRGB transmission chart:

 

http://www.highpoint..._lrgb_curve.jpg

 

Looks like the ZWO filters also try to leave a gap in between red and green to block some LP. The green bandpass is narrower, so that probably explains why Jason needs 1.08x green to normalize SNR. The red and blue both appear to be fairly broad bandpasses, though...and red transmits at 90% or more. Very curious why it would require 1.55x the exposure. 

 

EDIT 2:

 

Here is a Baader LRGB transmission chart. I do not know what the most recent generation from Baader is...there are a number labeled 2008. Anyway:

 

http://www.alpineast...-Filter_set.jpg

 

These filters are closer to 100% transmission, and seem to span the spectrum pretty well. Green is narrower, however, than blue or red. 


Edited by Jon Rista, 28 May 2016 - 12:03 PM.

 

#1108 tolgagumus

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Posted 28 May 2016 - 12:07 PM

Astrodons are made specifically for KAF and KAI kodak sensors. I am not familiar any other filter to match any other sensor. I would have been surprised if the times matched. That's why people do G2V calibration 


 

#1109 Jon Rista

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Posted 28 May 2016 - 12:30 PM

I created a chart comparing the Q.E. curves of the KAF-8300 and the ASI1600. When scaled properly to each other, it appears the ASI is a bit more sensitive in the blues, and a bit less sensitive in the reds. Up through 650nm there isn't much difference in the red sensitivities...beyond 650nm (so, mainly SII) the ASI sensitivity drops a bit more. Looks like SII sensitivity is right around 43%, while Ha is around 48%. OIII and Hb sensitivity should be higher with the ASI, while SII sensitivity would be around 47% with the KAF-8300. 

 

m9x4Jzv.jpg

 

 


 

#1110 Jon Rista

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Posted 28 May 2016 - 02:20 PM

Woot! My PP adapter is "Out for delivery" right now. I guess I'm getting it today. Would be totally awesome if I do, as I might have a couple hours of clear sky tonight. At the very least, I could get some lights and flats and test vignetting. 


 

#1111 Jon Rista

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Posted 28 May 2016 - 02:34 PM

I have been doing some caliper measurements of the camera and all my imaging train parts. For those interested, here are the various backfocus depths:

 

ASI1600 Male M42 Flange: 4mm

ASI1600 Female to Female M42 Adapter: 10.99mm (11mm spec)

ASI1600 1.25" Adapter: 29.15mm

ASI1600 M42 to M48 Adapter: 18.5mm

 

EFW2 Filter Wheel Back to Thread Flange: 10mm

EFW2 Filter Wheel Back to Case Back: 7mm

(Effective Minimum ASI1600 Sensor to filter distance: 13.5mm)

(Measured ASI1600 Sensor to Filter distance: 14.5mm)

EFW2 Body Thickness: 21.95mm (22mm spec)

EFW2 M54 to M42 Scope Adapter: 1.5mm (Specs state 1.3mm, but it is definitely 1.5mm)

 

TSEOS-T2s Backfocus Depth: 10.1mm (10mm spec)

TSEOS-T2s Thread Depth: 3.9mm (4mm spec; May be important, depending on how much depth you have in your FW before the threads hit the filters)


Edited by Jon Rista, 28 May 2016 - 02:41 PM.

 

#1112 Shawnxc

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Posted 28 May 2016 - 02:43 PM

 

This indeed a nice high resolution picture, congrats Emilio. You may have posted earlier, what was the total integration time to get this?

edit-- never mind, saw the info on Astrobin

I am trying out different integration times.  As you can see this one is 30 seconds for each frame.  I used 1x1 for the L and took 15 subs.  I took 10 each of the R G and B.  I used my newly calculated ratios to compensate for the Camera's apparent weakness in collecting Red and Green.  I am very interested on the white color balance.  I like to be as close to the correct white color as possible.  The target was fairly high in the sky for me so I don't think I have to compensate much for the altitude of the target.  It also seems like the traditional binning of 2x2 for the RGB frames makes for a richer color image.  I have an experiment going on with M3 where I produced an image with all 1x1 bin and I have to go back and get the data for 2x2 for the RGB so I can compare how it combines.

 

The color seems to be retained pretty well also, what gain setting you were using? noticed any star clipping?


 

#1113 JoseBorrero

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Posted 28 May 2016 - 02:54 PM

not bad for a 12bit chip!    still a 12bit  :p


 

#1114 CCDer

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Posted 28 May 2016 - 03:44 PM

not bad for a 12bit chip!    still a 12bit  :p

So if computer monitors only offer 8 bits per color channel, how can you tell the difference in a finished image that used 12 bits per color channel vs 14/16, unless you mishandled the data? :)


 

#1115 tolgagumus

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Posted 28 May 2016 - 04:27 PM

get.jpg

 

Technical card
Imaging telescope or lens: GSO RC 10
Imaging camera: ZWO ASI1600MMC
Mount: Software Bisque Paramount MX
Focal reducer: Astro-Physics 27TVPH .75 reducer/corrector
Software: Adobe Photoshop CS6,  PixInsight 1.8
Resolution: 2136x1538
Dates: May 27, 2016
Frames: Custom Scientific RGB (1.25"): 131x60" -20C bin 2x2
Integration: 2.2 hours
Avg. Moon age: 19.60 days
Avg. Moon phase: 75.79%
Mean SQM: 18.00
RA center: 250.425 degrees
DEC center: 36.459 degrees
Pixel scale: 0.973 arcsec/pixel
Orientation: -87.988 degrees
Field radius: 0.356 degrees


 

#1116 Jon Rista

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Posted 28 May 2016 - 04:31 PM

ASI1600 with PP EFW2 adapter:

 

ASIPP.jpg

 

And the fully assembled camera-side train:

 

ASITrain.jpg

 

And the full imaging train (from TSRCFlat2 to the camera):

 

ASITrainFull.jpg


Edited by Jon Rista, 28 May 2016 - 04:34 PM.

 

#1117 FirstC8

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Posted 28 May 2016 - 04:46 PM

Looks to me this is the closest you can have from filter to chip?
 

#1118 rockstarbill

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Posted 28 May 2016 - 04:47 PM

Nice Jon! Looks like its coming along well. I am still lurking here in this thread for a future purchase and the wheel you have there looks to be the one I would want to get as well, so once you have that adapter tested, I would love to know how you configured it on the PP site, in the event I would need to do the same..?


 

#1119 Jon Rista

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Posted 28 May 2016 - 05:18 PM

Looks to me this is the closest you can have from filter to chip?

 

Just about. Now that I have the PP adapter in hand, I do indeed think it should be possible to create one that has 0mm extension. Right now, the filter is going to be 15.5mm from the sensor, but that could probably be reduced to 14.5mm. I'll find out tonight how the vignetting looks with the 600mm lens at f/4. 


 

#1120 Jon Rista

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Posted 28 May 2016 - 05:19 PM

Nice Jon! Looks like its coming along well. I am still lurking here in this thread for a future purchase and the wheel you have there looks to be the one I would want to get as well, so once you have that adapter tested, I would love to know how you configured it on the PP site, in the event I would need to do the same..?

 

I chose Atik (left) and Other Brands (right) and hit next, then chose EFW2 without adapter (left) and ASI1600 (right). I then plugged in 1mm for the extension (Adapter Effective Length) and hit build. 


 

#1121 Thirteen

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Posted 28 May 2016 - 06:26 PM

Ok, all we need is someone to make a EF lens mount with an OAG port and we are set!


 

#1122 bigeastro

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Posted 28 May 2016 - 06:36 PM

In case anyone wants to run a G2V calibration, the first set of coordinates are the coordinates of the G2V star I used to white calibrate.  I wanted to make sure I did not saturate the chip.  I exposed for 10 sec each filter.  The star was fairly dim.  It was in  a perfect position for calibrating starting about 9 to 10 pm or so Eastern Time.  The second one is also in a great location nearby.  I used the first.

 

 

HIP ID      RA (J2000) DEC (J2000) V Mag  Parallax  PM (RA) PM (DEC)   Sp. Type

63698      13:03:14.89 +28:36:25.2   10.32     5.83       -88.45      -5.76            G2V

62967      12:54:11.29 +29:29:35.5   10.70     0.00         0.00        0.00            G2V

 

ShawnXC,

 

I am pretty ignorant.  I am not quite sure what you mean about clipping the stars.  I did try to not clip either the dark or the light side of the histogram.  I did clip the dark side just a tiny bit if I recall correctly.  There seems to be some noise in the image that needed to go.  Everything I have been imaging has been at unity gain toggle setting which sets the gain at 139 and offset at 21.


 

#1123 Shawnxc

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Posted 28 May 2016 - 06:42 PM

 

I am pretty ignorant.  I am not quite sure what you mean about clipping the stars.  I did try to not clip either the dark or the light side of the histogram.  I did clip the dark side just a tiny bit if I recall correctly.  There seems to be some noise in the image that needed to go.  Everything I have been imaging has been at unity gain toggle setting which sets the gain at 139 and offset at 21.

well, it works that is what really matters. who cares about the numbers ;). Beautiful image with great colors. Good to know unity gain works with this type of objects.  


Edited by Shawnxc, 28 May 2016 - 06:42 PM.

 

#1124 Joe G

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Posted 28 May 2016 - 07:38 PM

Tolga and Emilio, those are great images.  I think my camera arrives from HPS Tuesday.  Can't wait.


 

#1125 CCDer

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Posted 28 May 2016 - 09:45 PM

I never thought about spending imaging time on clusters before. You guys are opening my eyes to them. Thanks. Maybe I'll get my color version from HP this week as well. Even better the skies might clear some so I can use it!


 


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