Altair 294C Pro Tec

[Stu Wilson]

Hi all.

Ive taken a leap from CCD To CMOS in the Altair 294C Pro Tec

Ive only tried briefly as skies are terrible in Carlisle at moment with forever rain etc.

Anyway the few images i took of M51 a few nights ago with darks in DSS are showing an awful starburst/sunburst type of AmpGlow (On right hand sides) It shows in Darks too

Is anyone else out there using one of these cameras with any success in DSS getting rid of these artifacts?

Does anyone know what settings i should be using in DSS for images taken with this camera

And does anyone know of what gain and offset i should be using too.

Maybe ive jumped in the wrong barrell but there seems to be serious lack of info on this camera.

 

Thanks in advance.

Clear Skies

Stu

[Budgie1]

I have the ZWO camera with the same sensor and it also has the amp-glow you describe. In my case the amp-glow is removed by the darks and I've used DSS & PI for stacking. 

One thing I did find is that there's a residual of the amp-glow remaining if I used Bias frames in the stack. So now I only use darks, flats & flat darks.

I'm not sure I can help with the gain & offset settings, as I think they're different in the Altair, but on the ZWO I use gain of 120 with a UV/IR cut filter and 200 if I'm using the L-eXtreme or Askar Duo-Band filters. Offset for both I use 30, which is the default with the ASCOM driver.

Not much help, I know, but it may give you something to go on.

[Stu Wilson]

45 minutes ago, Budgie1 said:

I have the ZWO camera with the same sensor and it also has the amp-glow you describe. In my case the amp-glow is removed by the darks and I've used DSS & PI for stacking. 

One thing I did find is that there's a residual of the amp-glow remaining if I used Bias frames in the stack. So now I only use darks, flats & flat darks.

I'm not sure I can help with the gain & offset settings, as I think they're different in the Altair, but on the ZWO I use gain of 120 with a UV/IR cut filter and 200 if I'm using the L-eXtreme or Askar Duo-Band filters. Offset for both I use 30, which is the default with the ASCOM driver.

Not much help, I know, but it may give you something to go on.

Are you using APT or Sharpcap? as in Sharpcap im lead to believe its about 901 gain and in APT you divide this by 4.5 which would give 200

I have a quadband filter that will be used for nebula etc.

So if you just use darks does it cancel out all that amp-glow?

 

Cheers

 

Stu

[Stu Wilson]

1 hour ago, Budgie1 said:

I have the ZWO camera with the same sensor and it also has the amp-glow you describe. In my case the amp-glow is removed by the darks and I've used DSS & PI for stacking. 

One thing I did find is that there's a residual of the amp-glow remaining if I used Bias frames in the stack. So now I only use darks, flats & flat darks.

I'm not sure I can help with the gain & offset settings, as I think they're different in the Altair, but on the ZWO I use gain of 120 with a UV/IR cut filter and 200 if I'm using the L-eXtreme or Askar Duo-Band filters. Offset for both I use 30, which is the default with the ASCOM driver.

Not much help, I know, but it may give you something to go on.

Forgot to ask what settings do you use in DSS?

Thanks in advance

 

Stu

 

[Budgie1]

1 hour ago, Stu Wilson said:

Are you using APT or Sharpcap? as in Sharpcap im lead to believe its about 901 gain and in APT you divide this by 4.5 which would give 200

I have a quadband filter that will be used for nebula etc.

So if you just use darks does it cancel out all that amp-glow?

I use APT for imaging.

I take 30 darks for each exposure length, off scope with the cover over the camera sensor, and they cancel out the amp-glow with no issues.

The reason I use a gain of 200 with NB filters is because I, a many others, have had issues with the flats not working correctly on the ASI294MC Pro with the gain at 120. Others have found that with a gain setting of 200, the flats work fine. You may also find that long exposure flats work better with this sensor as well, anything upto 3-4 seconds.

1 hour ago, Stu Wilson said:

Forgot to ask what settings do you use in DSS?

In the Lights menu under Settings, I use Kappa Sigma Clipping.

Under RGB Channels Background Calibration > "RGB Channels Background Calibration" is ticked. On the Background Calibrations - Options window > Calibration Method is "Rational" and "RGB Channels Background Calibration Method" is "Minimum". This removed the green cast on the stacked image.

The thing to remember is that these two cameras share the same sensor but the internals and firmware will be different, so you may have to play with the settings above to get what's right for the Altair.

Edited May 31, 2022 by Budgie1

[Stu Wilson]

Ok thanks

 1st clear sky well try again.

Stu

[jacko61]

10 hours ago, Budgie1 said:

I use APT for imaging.

I take 30 darks for each exposure length, off scope with the cover over the camera sensor, and they cancel out the amp-glow with no issues.

The reason I use a gain of 200 with NB filters is because I, a many others, have had issues with the flats not working correctly on the ASI294MC Pro with the gain at 120. Others have found that with a gain setting of 200, the flats work fine. 

Do you then have to have a separate set of gain 200 darks to calibrate your gain 200 lights? 

Graeme

(sorry for the hijack)

[Budgie1]

30 minutes ago, jacko61 said:

Do you then have to have a separate set of gain 200 darks to calibrate your gain 200 lights? 

Yes, I've created a Darks Library for each gain & offset I use, and each has the full range of exposure settings I'm likely to need. 

A nice job for a rainy day, which we get a lot of up here!  

[Stu Wilson]

Yes I agree with the terrible weather.

Just want 1 night to image anything and see if my amp glow dissapears.

 

Stu

[peonic]

Does it matter that the camera temperature on the aforementioned rainy day doesn't match the temperature that the light images would be taken at?

If not, I might have just found myself a job for the afternoon

 

Chris

[Budgie1]

If you have a camera with setpoint (TEC) cooling, you can make the temperature the same. I normally set my ASI294MC Pro to -10°C for everything.

If you have one of the fan cooled Altair cameras then I'd say it would be best to do the darks at the same time as the lights, to make sure the sensor temps are the same. 

 

[peonic]

Ahh sorry. I missed that you had the Pro version.

 

Chris

[Stu Wilson]

Mines the pro tec version also so I've so far made a library of 1 2 and 3 minutes at -10

Only thing is if I find gain and offset are wrong I'll have to start again lol

So hoping for a clear sky 🙏 

 

Stu

[edarter]

12 hours ago, Budgie1 said:

I use APT for imaging.

I take 30 darks for each exposure length, off scope with the cover over the camera sensor, and they cancel out the amp-glow with no issues.

The reason I use a gain of 200 with NB filters is because I, a many others, have had issues with the flats not working correctly on the ASI294MC Pro with the gain at 120. Others have found that with a gain setting of 200, the flats work fine. You may also find that long exposure flats work better with this sensor as well, anything upto 3-4 seconds.

In the Lights menu under Settings, I use Kappa Sigma Clipping.

Under RGB Channels Background Calibration > "RGB Channels Background Calibration" is ticked. On the Background Calibrations - Options window > Calibration Method is "Rational" and "RGB Channels Background Calibration Method" is "Minimum". This removed the green cast on the stacked image.

The thing to remember is that these two cameras share the same sensor but the internals and firmware will be different, so you may have to play with the settings above to get what's right for the Altair.

Hi Martin,

Question regarding this please. I've been holding back on buying a 294mc Pro because I saw all the issues that were coming to light with NB filters etc both on this forum and CN. Though I must confess I've not looked of late. Are you saying that if you use a gain of 200 rather than 120 then all these issues with whacky patterns etc go away with calibration frames?
It was really putting me off the 294 as it seemed like the perfect fit for my requirements up to reading about the emerging issues. I know some have gone to the 533 instead but the sensor is so much smaller 

Thanks
Ed

[Budgie1]

25 minutes ago, edarter said:

Hi Martin,

Question regarding this please. I've been holding back on buying a 294mc Pro because I saw all the issues that were coming to light with NB filters etc both on this forum and CN. Though I must confess I've not looked of late. Are you saying that if you use a gain of 200 rather than 120 then all these issues with whacky patterns etc go away with calibration frames?
It was really putting me off the 294 as it seemed like the perfect fit for my requirements up to reading about the emerging issues. I know some have gone to the 533 instead but the sensor is so much smaller 

Thanks
Ed

Hi Ed, 

Some don't have an issue using NB duel band filter with the ASI294MC Pro, others do. 

After swapping to gain 200 and offset 30 when using NB filters, the flats work just fine for me.

Have a read through this thread, which explains it better than I can:

 

[Stu Wilson]

Ok update.

This is 30 x 1 mins with the correct darks just to test.

Slight work in ps but like I say wasn't trying for an amazing image. Just wanted rid of the amp glow.

And it's..........gone.

Thanks for info guys.

Next clear skies some proper imaging.

 

Stu