Astrophotography

Yup. Looks like a bloomin’ spillover! Like I said, that was the brightest star in the image, but when I processed it did not seem oversaturated. At least I was able to get it inside the curves in Lightroom. 

Jeff,

I am responding without having seen the image, but pixels of CCD's often
"bloom" into adjacent pixels when heavily loaded with light. CCD's for
astrophotography have "antiblooming gates" to reduce this effect. CCD's
for scientific research have "non-antiblooming gates" for better
linearity. I strongly suspect that is what you are seeing. I also
strongly suspect that you, of all people, would appreciate the double
negative in this terminology!

As I said, I haven't seen the image, so others may have a better
explanation.

Dean


On 04/26/2018 10:24 AM, Astrophotography wrote:
>
>
>
> These images were not binned and I cooled the camera to -35C.
>
> This camera is 2048x2048 pixels which are 13.5 micron yielding a plate scale of 0.51 arc seconds per pixel on the 24 inch scope. The FOV is 17.31 arc minutes square.
>
> Willie
>
>
>> On Apr 26, 2018, at 9:55 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>>
>>
>>
>>
>> Yes! All light frames and calibration frames were using the 24 inch scope, ACE & MaxIM DL.
>>
>> Willie
>>
>>
>>
>>> On Apr 26, 2018, at 9:36 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>>>
>>>
>>>
>>>
>>> Willie,
>>> Were the exposures on the Club scope?
>>> There is one anomaly in the image. The bright star bottom center, HD 168521, has a downward spike that only appears on the Luminance exposure. It is not unlike the spike that appears if the scope is bumped during an exposure, but only shows on that star. That singularity may be because HD 168521 is by far the brightest in the image.
>>> I bring this up because if you used the observatory scope a “bump” is unlikely and it may be an indication of something else.
>>> For whatever it is worth, the images were pretty clean with only a minimal number of warm pixels and not too noisy for the limited number of stacked exposures. I processed the image using Nebulosity 4 and eliminated the warm pixels using the Adaptive Median Nose Reduction feature in that app. I then fine-tuned the color and contrast using Lightroom 5.
>>> Jeff
>>>
>>> On Apr 23, 2018, at 8:34 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>>> I am providing 4 files for anyone who would like to process them. I would like to see what these produce but dont have the chance to try them myself. These are 60s x 3 LRGB using the loaner PIXIS camera from Princeton Instruments, binned 1x1.
>>>
>>> Conditions were pretty good early this morning, but the last few images were near twilight. I calibrated the images with bias, darks & flats, aligned them and median combined them for these 4 masters.
>>>
>>> The files can be found at this link.
>>>
>>> https://app.box.com/s/k30p0wr6h6xgh1h83f74o9fbzqk9dsj5
>>>
>>> Willie
>>>
>>>
>>>
>>>>> --------------------------------------------------------------------------------------<<
>>> You have received this message as a member of: Central Texas Astronomical Society
>>> Change preferences (including opt-out): https://CTAS.clubexpress.com/content.aspx?page_id=13&club_id=901132
>>>
>>>
>>
>>
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>
>
>>> --------------------------------------------------------------------------------------<<
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Jeff and Dave. This camera really does not have antiblooming so that saturated that star in under two minutes.
Aubrey On Apr 26, 2018 1:19 PM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>
>
>
>
> Jeff : I think that camera maybe  does not have anti-blooming feature.
>
> Dave
>
>
> ---------- Original Message ----------
> From: "Astrophotography" <astrophotography@centexastronomy.org>
> To: "jde209@netzero.net" <jde209@netzero.net>
> Subject: re: M92 with the PIXIS loaner <<$195526129359$>>
> Date: Thu, 26 Apr 2018 09:36:15 -0500
>
>
>
>
> Willie,
> Were the exposures on the Club scope?
> There is one anomaly in the image. The bright star bottom center, HD 168521, has a downward spike that only appears on the Luminance exposure. It is not unlike the spike that appears if the scope is bumped during an exposure, but only shows on that star. That singularity may be because HD 168521 is by far the brightest in the image.
> I bring this up because if you used the observatory scope a “bump” is unlikely and it may be an indication of something else.
> For whatever it is worth, the images were pretty clean with only a minimal number of warm pixels and not too noisy for the limited number of stacked exposures. I processed the image using Nebulosity 4 and eliminated the warm pixels using the Adaptive Median Nose Reduction feature in that app. I then fine-tuned the color and contrast using Lightroom 5.
> Jeff
>
> On Apr 23, 2018, at 8:34 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
> I am providing 4 files for anyone who would like to process them. I would like to see what these produce but dont have the chance to try them myself. These are 60s x 3 LRGB using the loaner PIXIS camera from Princeton Instruments, binned 1x1.
>
> Conditions were pretty good early this morning, but the last few images were near twilight. I calibrated the images with bias, darks & flats, aligned them and median combined them for these 4 masters.
>
> The files can be found at this link.
>
> https://app.box.com/s/k30p0wr6h6xgh1h83f74o9fbzqk9dsj5
>
> Willie
>
>
>
>
>
>
>

Jeff : I think that camera maybe does not have anti-blooming feature.

Dave


---------- Original Message ----------
From: "Astrophotography" <astrophotography@centexastronomy.org>
To: "jde209@netzero.net" <jde209@netzero.net>
Subject: re: M92 with the PIXIS loaner <<$195526129359$>>
Date: Thu, 26 Apr 2018 09:36:15 -0500




Willie,
Were the exposures on the Club scope?
There is one anomaly in the image. The bright star bottom center, HD 168521, has a downward spike that only appears on the Luminance exposure. It is not unlike the spike that appears if the scope is bumped during an exposure, but only shows on that star. That singularity may be because HD 168521 is by far the brightest in the image.
I bring this up because if you used the observatory scope a “bump” is unlikely and it may be an indication of something else.
For whatever it is worth, the images were pretty clean with only a minimal number of warm pixels and not too noisy for the limited number of stacked exposures. I processed the image using Nebulosity 4 and eliminated the warm pixels using the Adaptive Median Nose Reduction feature in that app. I then fine-tuned the color and contrast using Lightroom 5.
Jeff

On Apr 23, 2018, at 8:34 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
I am providing 4 files for anyone who would like to process them. I would like to see what these produce but dont have the chance to try them myself. These are 60s x 3 LRGB using the loaner PIXIS camera from Princeton Instruments, binned 1x1.

Conditions were pretty good early this morning, but the last few images were near twilight. I calibrated the images with bias, darks & flats, aligned them and median combined them for these 4 masters.

The files can be found at this link.

https://app.box.com/s/k30p0wr6h6xgh1h83f74o9fbzqk9dsj5

Willie

These images were not binned and I cooled the camera to -35C.

This camera is 2048x2048 pixels which are 13.5 micron yielding a plate scale of 0.51 arc seconds per pixel on the 24 inch scope. The FOV is 17.31 arc minutes square.

Willie


> On Apr 26, 2018, at 9:55 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>
>
>
>
> Yes! All light frames and calibration frames were using the 24 inch scope, ACE & MaxIM DL.
>
> Willie
>
>
>
>> On Apr 26, 2018, at 9:36 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>>
>>
>>
>>
>> Willie,
>> Were the exposures on the Club scope?
>> There is one anomaly in the image. The bright star bottom center, HD 168521, has a downward spike that only appears on the Luminance exposure. It is not unlike the spike that appears if the scope is bumped during an exposure, but only shows on that star. That singularity may be because HD 168521 is by far the brightest in the image.
>> I bring this up because if you used the observatory scope a “bump” is unlikely and it may be an indication of something else.
>> For whatever it is worth, the images were pretty clean with only a minimal number of warm pixels and not too noisy for the limited number of stacked exposures. I processed the image using Nebulosity 4 and eliminated the warm pixels using the Adaptive Median Nose Reduction feature in that app. I then fine-tuned the color and contrast using Lightroom 5.
>> Jeff
>>
>> On Apr 23, 2018, at 8:34 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>> I am providing 4 files for anyone who would like to process them. I would like to see what these produce but dont have the chance to try them myself. These are 60s x 3 LRGB using the loaner PIXIS camera from Princeton Instruments, binned 1x1.
>>
>> Conditions were pretty good early this morning, but the last few images were near twilight. I calibrated the images with bias, darks & flats, aligned them and median combined them for these 4 masters.
>>
>> The files can be found at this link.
>>
>> https://app.box.com/s/k30p0wr6h6xgh1h83f74o9fbzqk9dsj5
>>
>> Willie
>>
>>
>>
>>>> --------------------------------------------------------------------------------------<<
>> You have received this message as a member of: Central Texas Astronomical Society
>> Change preferences (including opt-out): https://CTAS.clubexpress.com/content.aspx?page_id=13&club_id=901132
>>
>>
>
>
>
>>> --------------------------------------------------------------------------------------<<
> You have received this message as a member of: Central Texas Astronomical Society
> Change preferences (including opt-out): https://CTAS.clubexpress.com/content.aspx?page_id=13&club_id=901132
>
>

Yes! All light frames and calibration frames were using the 24 inch scope, ACE & MaxIM DL.

Willie



> On Apr 26, 2018, at 9:36 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>
>
>
>
> Willie,
> Were the exposures on the Club scope?
> There is one anomaly in the image. The bright star bottom center, HD 168521, has a downward spike that only appears on the Luminance exposure. It is not unlike the spike that appears if the scope is bumped during an exposure, but only shows on that star. That singularity may be because HD 168521 is by far the brightest in the image.
> I bring this up because if you used the observatory scope a “bump” is unlikely and it may be an indication of something else.
> For whatever it is worth, the images were pretty clean with only a minimal number of warm pixels and not too noisy for the limited number of stacked exposures. I processed the image using Nebulosity 4 and eliminated the warm pixels using the Adaptive Median Nose Reduction feature in that app. I then fine-tuned the color and contrast using Lightroom 5.
> Jeff
>
> On Apr 23, 2018, at 8:34 AM, Astrophotography <astrophotography@centexastronomy.org> wrote:
> I am providing 4 files for anyone who would like to process them. I would like to see what these produce but dont have the chance to try them myself. These are 60s x 3 LRGB using the loaner PIXIS camera from Princeton Instruments, binned 1x1.
>
> Conditions were pretty good early this morning, but the last few images were near twilight. I calibrated the images with bias, darks & flats, aligned them and median combined them for these 4 masters.
>
> The files can be found at this link.
>
> https://app.box.com/s/k30p0wr6h6xgh1h83f74o9fbzqk9dsj5
>
> Willie
>
>
>
>>> --------------------------------------------------------------------------------------<<
> You have received this message as a member of: Central Texas Astronomical Society
> Change preferences (including opt-out): https://CTAS.clubexpress.com/content.aspx?page_id=13&club_id=901132
>
>

Willie,

Thanks, Jeff. Looks pretty good to me for such little data.

Willie


> On Apr 25, 2018, at 10:47 PM, Astrophotography <astrophotography@centexastronomy.org> wrote:
>
>
>
>
> Willie,
> Here is my feeble attempt at post processing your PIXIS image of M-17.
> Jeff
> On Mon, Apr 23, 2018 at 8:34 AM Astrophotography <astrophotography@centexastronomy.org> wrote:
> I am providing 4 files for anyone who would like to process them. I would like to see what these produce but dont have the chance to try them myself. These are 60s x 3 LRGB using the loaner PIXIS camera from Princeton Instruments, binned 1x1.
>
> Conditions were pretty good early this morning, but the last few images were near twilight. I calibrated the images with bias, darks & flats, aligned them and median combined them for these 4 masters.
>
> The files can be found at this link.
>
> https://app.box.com/s/k30p0wr6h6xgh1h83f74o9fbzqk9dsj5
>
> Willie
>
> Attachment(s):
> File: M17 LRGB-1.jpg (575.4 KB) -- Address: http://s3.amazonaws.com/ClubExpressClubFiles/901132/attach/1955081_1_M17_LRGB-1.jpg
>
>
>
>>> --------------------------------------------------------------------------------------<<
> You have received this message as a member of: Central Texas Astronomical Society
> Change preferences (including opt-out): https://CTAS.clubexpress.com/content.aspx?page_id=13&club_id=901132
>
>

I am providing 4 files for anyone who would like to process them. I would like to see what these produce but dont have the chance to try them myself. These are 60s x 3 LRGB using the loaner PIXIS camera from Princeton Instruments, binned 1x1.

Conditions were pretty good early this morning, but the last few images were near twilight. I calibrated the images with bias, darks & flats, aligned them and median combined them for these 4 masters.

The files can be found at this link.

https://app.box.com/s/k30p0wr6h6xgh1h83f74o9fbzqk9dsj5

Willie