Date   

Re: First light for a new camera

Dean Jacobsen
 

On Mon, Feb 8, 2021 at 06:50 PM, Don Anderson wrote:
Up to now, it has been hard to beat the 694 for sensitivity and low noise until the most recent CMOS offerings have come out. I will be watching The developments closely
Don, when you are ready to get a new camera I think you will be pleased with the excellent choices that are available these days.
 
--
Dean Jacobsen
http://astrophoto.net/wp/
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/ 
Amateur Radio Call Sign - W6DBJ


Re: Counterweight Shaft Case

Astrobob
 

Clever common sense!

 

Sent from Mail for Windows 10

 


Re: How long for UNGUIDED imaging with non AE mounts?

Roland Christen
 

I have gone up to an hour with 1000mm FL and 5.4 micron pixel camera. Some nights and in some places in the sky it doesn't work out as well. Theoretically if you have a good path mapped, you can go all night. Practically you will probably need to refocus every 20 minutes. In the early part of the night you will also have satellite trails, so it's better to have lots of 15 minute shots that can be Median combined to eliminate them.

Rolando



-----Original Message-----
From: astro@...
To: main@ap-gto.groups.io
Sent: Mon, Feb 8, 2021 10:49 pm
Subject: [ap-gto] How long for UNGUIDED imaging with non AE mounts?

Following on from an earlier thread, does anyone have any info on the length of unguided imaging possible using a 1100GTO or similar with a focal length of up to about 700mm? Assuming the mount is very well aligned.

Thanks
Bob

--
Roland Christen
Astro-Physics


Re: Counterweight Shaft Case

weihaowang
 

Nice! 

Is this to protect the counterweight shaft during transportation?  Or to protect whatever other things that sit next to the counterweight shaft?

--

Homepage:

http://www.asiaa.sinica.edu.tw/~whwang/

Astrobin gallery:
http://www.astrobin.com/users/whwang/


Re: Counterweight Shaft Case

Woody Schlom
 

Barry,

 

I LIKE it!

 

Woody

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Barry Megdal
Sent: Monday, February 8, 2021 9:44 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Counterweight Shaft Case

 

I posted this long ago when I was using a 1200 as a “portable” mount.  Since then I have a 1600 mount in an observatory.

But I recently received the very impressive Mach 2 which I intend to transport on occasion.

 

So what type of case to use for the mount and its accessories has come up again.  Below is a picture of the case I made for the 1200 counterweight shaft (and will shorten for the Mach 2 shaft).

 

It is made from readily available 2” Schedule 80 PVC pipe parts glued together.  The counterweight shaft is an almost airtight fit inside that size pipe, and the screw-on cap is very convenient.

 

Put a small piece of foam in the bottom and it is ready to go.

 

 

  • Barry

 

 

 

Dr. Barry Megdal

 

President

Shb Instruments, Inc.

19215 Parthenia St.  Suite A

Northridge, CA 91324

www.shbinstruments.com

(818) 773-2000  (818)773-2005 fax

bmegdal@...

 

Faculty (retired)

Dept. of Electrical Engineering

Caltech

 


Counterweight Shaft Case

Barry Megdal
 

I posted this long ago when I was using a 1200 as a “portable” mount.  Since then I have a 1600 mount in an observatory.

But I recently received the very impressive Mach 2 which I intend to transport on occasion.

 

So what type of case to use for the mount and its accessories has come up again.  Below is a picture of the case I made for the 1200 counterweight shaft (and will shorten for the Mach 2 shaft).

 

It is made from readily available 2” Schedule 80 PVC pipe parts glued together.  The counterweight shaft is an almost airtight fit inside that size pipe, and the screw-on cap is very convenient.

 

Put a small piece of foam in the bottom and it is ready to go.

 

 

-        Barry

 

 

 

Dr. Barry Megdal

 

President

Shb Instruments, Inc.

19215 Parthenia St.  Suite A

Northridge, CA 91324

www.shbinstruments.com

(818) 773-2000  (818)773-2005 fax

bmegdal@...

 

Faculty (retired)

Dept. of Electrical Engineering

Caltech

 


How long for UNGUIDED imaging with non AE mounts?

Bob
 

Following on from an earlier thread, does anyone have any info on the length of unguided imaging possible using a 1100GTO or similar with a focal length of up to about 700mm? Assuming the mount is very well aligned.

Thanks
Bob


Re: RAPAS for use in the South

Bob
 

Thanks Mike and Len.

Takeaway then is order the RAPAS I think.


Re: First light for a new camera

Dean Jacobsen
 

We have some nice tools available to us these days.
--
Dean Jacobsen
http://astrophoto.net/wp/
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/ 
Amateur Radio Call Sign - W6DBJ


Re: First light for a new camera

Don Anderson
 

Great explanation on CMOS sensor performance Dale. I have been thinking about a larger format camera for a few years now. With the demise of Truesense CCD production last year, I was torn between getting a camera based on the existing CCD technology before they were no longer available or waiting for one with the rapidly improving CMOS sensor. I currently use a Sony icx694 based mono camera with my TV NP127is with a .8X reducer as well as native FL on my AP900GOTO. I shoot narrow band from my heavily polluted (Bortle 8) big city skies so a sensitive camera is a must. Up to now, it has been hard to beat the 694 for sensitivity and low noise until the most recent CMOS offerings have come out. I will be watching The developments closely
Thanks

Don Anderson


On Monday, February 8, 2021, 01:22:29 p.m. MST, Dale Ghent <daleg@...> wrote:



I have the ASI1600 with the Panasonic chip, 294 color, and IMX455-based QHY600 which is the same sensor as the ASI6200.

The Panasonic chip that's in the ASI1600 and other cameras has been a fantastic chip over the years and, like you said, the microlensing effect on super bright stars has been the only major complaint about it. The 12bit nature of its ADCs can be compensated with by just making more exposures. For what it is/was, it has been a very good standard in the CMOS realm.  It was a sensor designed in the early 2010's with tech of that era, and despite that, it has decently controlled amp glow and dark current. And as a chip of that era, it is a front-illuminated design with a single gain domain. These are outdated designs now.

The IMX294/492 is back-illuminated which means more photons actually fall into the pixels, which raises the QE. The vast majority of current era designs from Sony are back-illuminated. The other thing that many current-era chips have in their corner is dual conversion gain. Dual conversion gain is where a good bit of the magic occurs in these sensors and lets them be flexible. DCG sensors came about to address the need for a sensor that can perform well in both bright and dim settings. The Low Conversion Gain (LCG) domain grants you a large full well, with the trade-off being read noise. The High Conversion Gain (HCG) domain gives you lower read noise at the cost of a shallower well. Both have DR curves that largely mirror each other. LCG is meant for exposing in bright environments where the deep well would be best suited, where the HCG domain is for dark scenes, where sensitivity and low read noise is needed. Both the IMX294/492 and IMX455, as well as others, are dual conversion gain sensors.

You can spot these types of sensors by looking at the graphs commonly posted by ZWO, QHY, and others. They have two distinct areas, like this one for the IMX455-based ASI6200MM:

https://astronomy-imaging-camera.com/wp-content/uploads/ASI6200-Performance.png

You can see the two domains clearly in the DR and Read Noise charts. LCG is on the left, starting at gain=0, and then the transition to HCG happens at what looks like gain=100. You can see that LCG and HCG start out more or less similarly, with the LCG having a larger well. Once you get to gain=100, the read noise drops, DR (mostly) recovers, and the downward progression resumes as gain increases. The difference is that at gain=0, you have a 50k e- well, and at gain=100 (the start of the HCG domain) you have what looks like a ~15k well. These charts aren't the greatest but that's my guess assuming they're on a log scale. But you can see the difference nonetheless.

So what does this mean in practice? You can shoot in two different ways:

1. At gain=0 and with long exposures
2. At gain=100 and with shorter exposures

both will yield effectively equivalent results. Which one is best to use (note: I'm purposefully avoiding the word "better" here) largely comes down to personal preferences. Personally I shoot at the start of HCG (the equivalent of gain=100 here) because that's where the sensor performs its best. The very slight hit to DR compared to gain=0 is more than made up by the larger number of exposures I can rip through.  People doing photometry or planetary with these kinds of sensors might find the LCG domain a more useful place for their purposes. In this way, you can look at LCG vs. HCG more in terms of what's best for the use case.

If you have one of these kinds of dual conversion gain sensors and are not entirely sure where the LCG->HCG transition is on the gain scale, it's easy enough to figure out for yourself. Cap off the camera and run bias exposures in loop. Look at the histogram or image stats as you steadily increase the gain. As you increase the gain, you will likely also see an increase in the measured standard deviation. At some point, the stddev will suddenly drop. The gain value in which that drop in stddev happens marks the entry into the HCG domain, as stddev is a representation of the read noise.

As for IMX294/492 vs. IMX455, the 455 (and its APS-C analog, the IMX571) are hands-down the best we have on the consumer market right now. With zero amp glow, a good middling pixel size that applies to a wide range of focal lengths, QEs in the mid-70s for Ha/Sii and mid-80s for Oiii, and 16bit ADCs, they're really cement the fact that modern and highly compelling CMOS tech has arrived and is available. There's not much left to want for the amateur. These sensors are absolute monsters on fast optics as well.


> On Feb 8, 2021, at 10:55, Terri Zittritsch <theresamarie11@...> wrote:
>
> [Edited Message Follows]
>
> Dean, thanks for posting the information.
> Can you say what you think you're getting by replacing the ASI1600MM with the ASI294MM?    I have the ASI1600 and many great images are taken with this camera.  The biggest downside that I've noticed is the micro-lensing effect you can get on bright stars.    I know the ASI294 shows deeper well depth, and better DR, but do these directly relate to better images?    I know that some poo poo-ed the ASI1600 because it only has 12 bits of depth, but that didn't keep people from producing great images.    Since you've owned both, what are the benefits that you can see in the images?
> Maybe a tough question.    I wonder if there is any micro-lensing?
>
> I've recently purchase an ASI6200MM which is on my stowaway now.. and waiting to get a first image. 
>
> Terri
>







Re: How Good Can Guiding be With Non-AE Mount

Roland Christen
 

Depends how much the mount is used. Over time the periodic error changes shape, so what was in the mount when it was manufactures is not going to be accurate now. You have a super easy way to determine what is the PE and whether turning the PE correction on will make it better. All you need is a guide program like PHD2 or MaximDL.

Simply run the mount with guide corrections turned off for 15 - 20 minutes and record the cyclical motion of the guide star (ignore drift, just look at the cycles). You will see every 6.4 minutes the start of a new cycle, with each new cycle resembling the last one. Do this with PE OFF and then repeat with PE ON. Examine the results and make your judgement of what to do.

Rolando



-----Original Message-----
From: M Hambrick <mhambrick563@...>
To: main@ap-gto.groups.io
Sent: Mon, Feb 8, 2021 6:30 pm
Subject: Re: [ap-gto] How Good Can Guiding be With Non-AE Mount

Thanks Roland

Is there a recommended time limit for how long a PE curve can be used before it should be updated ? I am still using the original PE curve that was programmed into the mount when I bought it in March, 2017.

Mike

--
Roland Christen
Astro-Physics


Re: How Good Can Guiding be With Non-AE Mount

M Hambrick
 

Thanks Roland

Is there a recommended time limit for how long a PE curve can be used before it should be updated ? I am still using the original PE curve that was programmed into the mount when I bought it in March, 2017.

Mike


Re: RAPAS for use in the South

Len Fulham
 

Bob,
I have the RAPAS and have used it in Mount Isa and S-E Qld areas (dark skies). Sig Oct is hard to identify unless you have studied the star patterns well, and is faint enough that the reticule (at min brightness) with good batteries will obscure it. I find I have to turn reticule on/off and use reticule 'after glow' to make adjustments - quite doable. Easier as the batteries get low. Not something I can do in twilight and I expect harder if there is serious light pollution but should be doable.

If you are arbitrarily panning the mount to try and find Sig Oct, I think it is impossible. You need to be 'almost' polar aligned using a daytime routine or careful adjustment with a smart phone level & compass. Once you recognise the correct star pattern in the RAPAS, then alignment is quick and accurate (provided you have calibrated your RAPAS via a proper drift alignment first).

Cheers
Len.


Re: Difference between Recalibrate and Sync

Luca Marinelli
 

There is a setting in APCC Advanced Settings called “Prevent errant recalls”. If that’s checked, a recal too far from where the mount thinks it is will be rejected. 

Luca

On Feb 8, 2021, at 6:06 PM, Nick Iversen via groups.io <inoddy@...> wrote:

I once did a Solve & Sync in Sequence Generator Pro and the mount refused to do it saying something about something being more than 5 degrees. What was happening there?


Re: Difference between Recalibrate and Sync

Nick Iversen
 

I once did a Solve & Sync in Sequence Generator Pro and the mount refused to do it saying something about something being more than 5 degrees. What was happening there?


Re: Difference between Recalibrate and Sync

Lee Dodge
 

Thanks Roland.  I understand the difference more clearly now.  Very helpful.

Lee 


Re: First light for a new camera

Bruce Donzanti
 

Nice comparative list, Luca.  I also went from the 1600MM Pro to the 294MM Pro and my 2600MM Pro arrives on Wednesday.  I am hoping it does have the characteristics, as you described, for the 6200MM Pro and if it does I'll part with the 294MM Pro.  I am anxious to compare the 2 side by side in my suburban skies. 

Bruce

On Mon, Feb 8, 2021 at 3:46 PM Luca Marinelli <photo@...> wrote:

 As I mentioned above, I have been imaging with the ASI294MM Pro since the end of December. It replaced a ASI1600MM Pro on a TS ONTC 10in f4 Newtonian astrograph.  These are the main differences between the two cameras as I see them:

ASI1600MM Pro:

Pros:

- It has been around for a long time, everyone can help you if you run into trouble

- Less expensive

- Very little amp glow even for narrowband imaging

- Data calibration is robust and straightforward


Cons:

- It has been around for a long time: it may get discontinued in the not too distant future. the ASI294MC took the place of the ASI1600MC.

- Microlensing artifacts around bright stars are obnoxious and difficult to eliminate (this is really an issue only around magnitude 2-3 stars or brighter)

- QE is modest (~50% @ Ha)

- 12bit ADC

 
ASI294MM Pro:

 Pros:

- New sensor with probably long life in front of it

- Two pixel sizes in one camera (2.3um, 4.6um)

- Extremely high QE (it's an amazingly sensitive camera, 80% @ Ha)

- very low noise and high dynamic range when high gain mode kicks in
- no microlensing artifact

- 14bit ADC instead of 12bit

 

Cons:

- More expensive than ASI1600MM

- Calibration is a bit trickier and requires some getting used to (flats have some swirly patterns that some people have had trouble with)

- Amp glow is pretty significant. It calibrates out well but again it requires flawless calibration practice to ensure high quality data is produced.

 
Low read noise combined with high sensitivity and 14bit ADC of this camera makes it compelling vs the older 1600MM. The questions Roland asked about speed compared to CCD cameras comes down to two factors:

1) QE: How sensitive is the camera? In comparison to the numbers above, the FLI ML16200 has QE of 45% @ Ha - quite a stark difference.
2) Read noise: Low read noise is meaningful in relation to noise from sky glow. That's why with CCD cameras subexposure times for narrowband imaging can be 20, 30 minute or even longer. With the ASI294MM even imaging faint targets I have found that I can achieve optimal exposure levels for narrowband imaging with 3nm filters under Bortle 5 skies in less than 8 minutes per sub. This means that I can guarantee not to lose any SNR efficiency in image integration and accumulate SNR as fast as total integration time. 

I recently completed an imaging project of an extremely faint planetary nebula (HFG1) that I started in September 2020. I collected most of the 82 hours of data with an ASI1600MM Pro but during the last month of data collection I switched to the ASI294MM. For the purpose of illustrating differences in sensitivity of the two cameras, I integrated 20x6 minute subexposures of OIII  signal from each of the two cameras. Pixel size is a bit different (3.8um vs 4.6um) and I registered all the images to the higher-resolution ASI1600MM data before image integration to try and reduce the effect of bigger pixels in the ASI294MM on image SNR. You can see the results of the experiment here:

https://astrob.in/tbilkr/B/

I am also imaging with an ASI6200MM Pro and while the sensitivity is comparable to the ASI294MM Pro (IMX455 sensor), the noise profile is even more favorable with lower read-noise, 16bit ADC, and no amp glow. The new APS-C sized IMX571 is expected to have similar characteristics.

--Luca



Re: First light for a new camera

Luca Marinelli
 

 As I mentioned above, I have been imaging with the ASI294MM Pro since the end of December. It replaced a ASI1600MM Pro on a TS ONTC 10in f4 Newtonian astrograph.  These are the main differences between the two cameras as I see them:

ASI1600MM Pro:

Pros:

- It has been around for a long time, everyone can help you if you run into trouble

- Less expensive

- Very little amp glow even for narrowband imaging

- Data calibration is robust and straightforward


Cons:

- It has been around for a long time: it may get discontinued in the not too distant future. the ASI294MC took the place of the ASI1600MC.

- Microlensing artifacts around bright stars are obnoxious and difficult to eliminate (this is really an issue only around magnitude 2-3 stars or brighter)

- QE is modest (~50% @ Ha)

- 12bit ADC

 
ASI294MM Pro:

 Pros:

- New sensor with probably long life in front of it

- Two pixel sizes in one camera (2.3um, 4.6um)

- Extremely high QE (it's an amazingly sensitive camera, 80% @ Ha)

- very low noise and high dynamic range when high gain mode kicks in
- no microlensing artifact

- 14bit ADC instead of 12bit

 

Cons:

- More expensive than ASI1600MM

- Calibration is a bit trickier and requires some getting used to (flats have some swirly patterns that some people have had trouble with)

- Amp glow is pretty significant. It calibrates out well but again it requires flawless calibration practice to ensure high quality data is produced.

 
Low read noise combined with high sensitivity and 14bit ADC of this camera makes it compelling vs the older 1600MM. The questions Roland asked about speed compared to CCD cameras comes down to two factors:

1) QE: How sensitive is the camera? In comparison to the numbers above, the FLI ML16200 has QE of 45% @ Ha - quite a stark difference.
2) Read noise: Low read noise is meaningful in relation to noise from sky glow. That's why with CCD cameras subexposure times for narrowband imaging can be 20, 30 minute or even longer. With the ASI294MM even imaging faint targets I have found that I can achieve optimal exposure levels for narrowband imaging with 3nm filters under Bortle 5 skies in less than 8 minutes per sub. This means that I can guarantee not to lose any SNR efficiency in image integration and accumulate SNR as fast as total integration time. 

I recently completed an imaging project of an extremely faint planetary nebula (HFG1) that I started in September 2020. I collected most of the 82 hours of data with an ASI1600MM Pro but during the last month of data collection I switched to the ASI294MM. For the purpose of illustrating differences in sensitivity of the two cameras, I integrated 20x6 minute subexposures of OIII  signal from each of the two cameras. Pixel size is a bit different (3.8um vs 4.6um) and I registered all the images to the higher-resolution ASI1600MM data before image integration to try and reduce the effect of bigger pixels in the ASI294MM on image SNR. You can see the results of the experiment here:

https://astrob.in/tbilkr/B/

I am also imaging with an ASI6200MM Pro and while the sensitivity is comparable to the ASI294MM Pro (IMX455 sensor), the noise profile is even more favorable with lower read-noise, 16bit ADC, and no amp glow. The new APS-C sized IMX571 is expected to have similar characteristics.

--Luca



Re: First light for a new camera

Dale Ghent
 

I have the ASI1600 with the Panasonic chip, 294 color, and IMX455-based QHY600 which is the same sensor as the ASI6200.

The Panasonic chip that's in the ASI1600 and other cameras has been a fantastic chip over the years and, like you said, the microlensing effect on super bright stars has been the only major complaint about it. The 12bit nature of its ADCs can be compensated with by just making more exposures. For what it is/was, it has been a very good standard in the CMOS realm. It was a sensor designed in the early 2010's with tech of that era, and despite that, it has decently controlled amp glow and dark current. And as a chip of that era, it is a front-illuminated design with a single gain domain. These are outdated designs now.

The IMX294/492 is back-illuminated which means more photons actually fall into the pixels, which raises the QE. The vast majority of current era designs from Sony are back-illuminated. The other thing that many current-era chips have in their corner is dual conversion gain. Dual conversion gain is where a good bit of the magic occurs in these sensors and lets them be flexible. DCG sensors came about to address the need for a sensor that can perform well in both bright and dim settings. The Low Conversion Gain (LCG) domain grants you a large full well, with the trade-off being read noise. The High Conversion Gain (HCG) domain gives you lower read noise at the cost of a shallower well. Both have DR curves that largely mirror each other. LCG is meant for exposing in bright environments where the deep well would be best suited, where the HCG domain is for dark scenes, where sensitivity and low read noise is needed. Both the IMX294/492 and IMX455, as well as others, are dual conversion gain sensors.

You can spot these types of sensors by looking at the graphs commonly posted by ZWO, QHY, and others. They have two distinct areas, like this one for the IMX455-based ASI6200MM:

https://astronomy-imaging-camera.com/wp-content/uploads/ASI6200-Performance.png

You can see the two domains clearly in the DR and Read Noise charts. LCG is on the left, starting at gain=0, and then the transition to HCG happens at what looks like gain=100. You can see that LCG and HCG start out more or less similarly, with the LCG having a larger well. Once you get to gain=100, the read noise drops, DR (mostly) recovers, and the downward progression resumes as gain increases. The difference is that at gain=0, you have a 50k e- well, and at gain=100 (the start of the HCG domain) you have what looks like a ~15k well. These charts aren't the greatest but that's my guess assuming they're on a log scale. But you can see the difference nonetheless.

So what does this mean in practice? You can shoot in two different ways:

1. At gain=0 and with long exposures
2. At gain=100 and with shorter exposures

both will yield effectively equivalent results. Which one is best to use (note: I'm purposefully avoiding the word "better" here) largely comes down to personal preferences. Personally I shoot at the start of HCG (the equivalent of gain=100 here) because that's where the sensor performs its best. The very slight hit to DR compared to gain=0 is more than made up by the larger number of exposures I can rip through. People doing photometry or planetary with these kinds of sensors might find the LCG domain a more useful place for their purposes. In this way, you can look at LCG vs. HCG more in terms of what's best for the use case.

If you have one of these kinds of dual conversion gain sensors and are not entirely sure where the LCG->HCG transition is on the gain scale, it's easy enough to figure out for yourself. Cap off the camera and run bias exposures in loop. Look at the histogram or image stats as you steadily increase the gain. As you increase the gain, you will likely also see an increase in the measured standard deviation. At some point, the stddev will suddenly drop. The gain value in which that drop in stddev happens marks the entry into the HCG domain, as stddev is a representation of the read noise.

As for IMX294/492 vs. IMX455, the 455 (and its APS-C analog, the IMX571) are hands-down the best we have on the consumer market right now. With zero amp glow, a good middling pixel size that applies to a wide range of focal lengths, QEs in the mid-70s for Ha/Sii and mid-80s for Oiii, and 16bit ADCs, they're really cement the fact that modern and highly compelling CMOS tech has arrived and is available. There's not much left to want for the amateur. These sensors are absolute monsters on fast optics as well.

On Feb 8, 2021, at 10:55, Terri Zittritsch <theresamarie11@gmail.com> wrote:

[Edited Message Follows]

Dean, thanks for posting the information.
Can you say what you think you're getting by replacing the ASI1600MM with the ASI294MM? I have the ASI1600 and many great images are taken with this camera. The biggest downside that I've noticed is the micro-lensing effect you can get on bright stars. I know the ASI294 shows deeper well depth, and better DR, but do these directly relate to better images? I know that some poo poo-ed the ASI1600 because it only has 12 bits of depth, but that didn't keep people from producing great images. Since you've owned both, what are the benefits that you can see in the images?
Maybe a tough question. I wonder if there is any micro-lensing?

I've recently purchase an ASI6200MM which is on my stowaway now.. and waiting to get a first image.

Terri


Re: How Good Can Guiding be With Non-AE Mount

Mike Dodd
 

On 2/8/2021 12:14 PM, Roland Christen via groups.io wrote:

The problem with MaximDL is that in RA the calculated arc seconds are
divided by CosineDec. So as you go higher in the sky towards the pole,
the calculated value of 1 pixel will be a large number of arc seconds
compared to what it would be at 0 Dec. I consider this a bug in the
program which affects the guide graph but not the guiding.
Thanks, Roland; I didn't know this.

--- Mike

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