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Caldwell 14 - Double Cluster in Perseus


Padraic M
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7 hours ago, ApophisAstros said:

Nice  , how do you do the Flats?

Roger

I'm taking flats using an A4 tracing pad through a folded t-shirt. Nina Flats Wizard, 30 flats and 30 dark flats each filter stacked in APP. 

 

I've set it up to select an exposure time of around 0.5 sec.

 

Red master flat worked out fine. Green and Blue integrated lights both had dust circles that I tried to desaturate in the final RGB mix.

 

These are the Nina settings. Camera is the ASI1600MM Pro at -20c. Looking for an ADU between 26214 and 39322. Maybe this is too high?

 

image.png.3e62b2899fbcb2bec5630b95a1ec9967.png

 

This was last Thursday night, with a 90% moon.

 

Master flats below.

Red:

image.thumb.png.661f572e4d5f1b9ce7ddc30043ed45c7.png

 

Green:

image.thumb.png.736c06f91f934aa44c01cdc63f24eed8.png

 

Blue:

image.thumb.png.04d5a6a36ac576fa20de6a76d072ae83.png

 

And these are the integrated, calibrated mono lights

 

Red: 

image.thumb.png.4824e9674d81a34c32e9ce15f942879e.png

 

Green:

image.thumb.png.f1e29a5f1f9dad7d133350b993c926d3.png

 

Blue:

image.thumb.png.ce03930b7ecac2b5cbf63cfdd00f85d9.png

 

 

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6 hours ago, Padraic M said:

These are the Nina settings. Camera is the ASI1600MM Pro at -20c. Looking for an ADU between 26214 and 39322. Maybe this is too high?

I think your ADU is a little too high Padraic. With my 1600, I aim to get the histogram a 1/3 away from the left. It always works for me, never have a problem with flats.

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Right, so I retook darks and dark flats at 33% ADU +/-10%. No massive difference, but I think that there may have been too much movement in the OTA at this point since the lights were taken. I'll try again in the next imaging session. Also of course, this wasn't helped with an almost full moon, and quite a bit of LP in the images.

 

Here's the new stack with the new flats. I can still make out the bunnies, but I've been able to keep more of the star colour in the stretch. There's a slight red sheen in the background here that I don't see when I view locally.

 

446222811_1C14-3x45c.thumb.jpg.27f6176b4dc1b0203e1f6c837ed40908.jpg

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1 hour ago, Padraic M said:

Right, so I retook darks and dark flats at 33% ADU +/-10%. No massive difference, but I think that there may have been too much movement in the OTA at this point since the lights were taken. I'll try again in the next imaging session. Also of course, this wasn't helped with an almost full moon, and quite a bit of LP in the images.

 

Here's the new stack with the new flats. I can still make out the bunnies, but I've been able to keep more of the star colour in the stretch. There's a slight red sheen in the background here that I don't see when I view locally.

I use a flat panel to take my flats, but omit the Tee shirt. I use the flats wizard in SGP. I set the ADU to 20000, and let it calculate the exposure time for each flat. My exposure times are as follows.

 

Red - 1.25s

Green - 0.51s

Blue - 0.42s

 

I don't see any red sheen here. I took the image into Pixinsight and your background is quite balanced in all 3 channels.

Edited by AstronomyUkraine
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On 12/18/2021 at 7:00 PM, Padraic M said:

I'm taking flats using an A4 tracing pad through a folded t-shirt. Nina Flats Wizard, 30 flats and 30 dark flats each filter stacked in APP. 

 

I've set it up to select an exposure time of around 0.5 sec.

 

Red master flat worked out fine. Green and Blue integrated lights both had dust circles that I tried to desaturate in the final RGB mix.

 

These are the Nina settings. Camera is the ASI1600MM Pro at -20c. Looking for an ADU between 26214 and 39322. Maybe this is too high?

 

image.png.3e62b2899fbcb2bec5630b95a1ec9967.png

 

This was last Thursday night, with a 90% moon.

 

Master flats below.

Red:

image.thumb.png.661f572e4d5f1b9ce7ddc30043ed45c7.png

 

Green:

image.thumb.png.736c06f91f934aa44c01cdc63f24eed8.png

 

Blue:

image.thumb.png.04d5a6a36ac576fa20de6a76d072ae83.png

 

And these are the integrated, calibrated mono lights

 

Red: 

image.thumb.png.4824e9674d81a34c32e9ce15f942879e.png

 

Green:

image.thumb.png.f1e29a5f1f9dad7d133350b993c926d3.png

 

Blue:

image.thumb.png.ce03930b7ecac2b5cbf63cfdd00f85d9.png

 

 

I would use a flat panel as the weave material in a T-shirt is showing as lines on your flat,

Roger

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