And Yet another C2022 E3 (ZTF)

[tomato]

This is just 20 minutes from last night, 20x30 secs on the Esprit150/QHY268OSC and 20x 30 secs on the Esprit150/QHY268Mono. The framing is not good, I didn’t realise how long the ion tail is, calibrated and stacked (stars and comet) in APP, StarXterminator and Pixel math used in PI to create a stacked comet and non trailed stars. It is moving really fast now across the sky, there was noticeable movement on a single 30 sec sub. If you look closely the ghosts of the trailed stars are visible, so maybe I need to play with the Pixelmath parameters.

[geeklee]

That looks great @tomato

Was it tricky bringing the mono and OSC together on this?

12 hours ago, tomato said:

there was noticeable movement on a single 30 sec sub.

I was thinking 60s was a sweet spot but 30s does look better.  I tried 120s too and the nucleus became a very clear line to my eye, although 60s is getting that way.

[tomato]

3 hours ago, geeklee said:

That looks great @tomato

Was it tricky bringing the mono and OSC together on this?

I was thinking 60s was a sweet spot but 30s does look better.  I tried 120s too and the nucleus became a very clear line to my eye, although 60s is getting that way.

Hi Lee,

It was indeed. I tried combining the Lum and OSC comet registered stacks, but APP was not happy, it seemed to decide that the images had over 650 million pixels, so massively downsampled them and then just got stuck in a loop when it tried to register them. In the end I converted the Lum frames to RGB colourspace and integrated them all together in APP, that was successful.

With it now at closest approach I think even 30 secs is pushing it at my imaging scale, if I get another chance I'll go with 10 or even 5 secs but lots of them. Maybe it needs planetary techniques but there isn't much in the way of features to register the frames.

I've just realised that this comet is supposed to be green (are they they only objects in the Cosmos that can be this colour?) so here is another version with the green put back in!

 

[powerlord]

hi, how do you stack the comet in APP ? standard settings stack based on stars, and I end up with a mushed comet.

cheers

stu

[geeklee]

43 minutes ago, powerlord said:

how do you stack the comet in APP ? standard settings stack based on stars

Under the "4) Register" tab, change mode to:

You'll then get prompted during registration about time shot metadata and then asked to select the comet nucleus in certain frames (like the first two and then the last, for example).

Edited February 1, 2023 by geeklee

[powerlord]

ah thanks - so I did that - and I've got a stack with the comet and star trails.

And by doing a normal stack I got the stars.

How did you then remove the star trails from the comet stack ? Is it just an affinity/photoshop job using frequency/levels to strip out the star lines or is there a better way ?

cheers

stu

 

[tomato]

I used StarXTerminator to subtract the fixed stars from the smeared comet and the registered comet from the star trails. The first was 100% ok as the tool treated the comet like a galaxy, the second missed a couple of the trailed stars and seemed to leave a faint ‘ghost’ of the trails which became discernible after further processing. 
Other folks have done this in Photoshop, but I’ll let a layers expert chip in on that one.

[Scooot]

6 hours ago, tomato said:

Hi Lee,

It was indeed. I tried combining the Lum and OSC comet registered stacks, but APP was not happy, it seemed to decide that the images had over 650 million pixels, so massively downsampled them and then just got stuck in a loop when it tried to register them. In the end I converted the Lum frames to RGB colourspace and integrated them all together in APP, that was successful.

With it now at closest approach I think even 30 secs is pushing it at my imaging scale, if I get another chance I'll go with 10 or even 5 secs but lots of them. Maybe it needs planetary techniques but there isn't much in the way of features to register the frames.

I've just realised that this comet is supposed to be green (are they they only objects in the Cosmos that can be this colour?) so here is another version with the green put back in!

 

Lovely image.

I just used Sky Safari and fast forwarded a minute to see how much the Comet’s RA and Dec changed. Dec changed the most on the night I imaged (8.6” over a minute) and as my imaging scale is 2.06 arc per pixel I estimated 20 seconds would be ok. Got to process them now, about 500 before I thin the numbers down.  

Edited February 1, 2023 by Scooot

[geeklee]

22 minutes ago, tomato said:

I used StarXTerminator to subtract the fixed stars from the smeared comet and the registered comet from the star trails. The first was 100% ok as the tool treated the comet like a galaxy, the second missed a couple of the trailed stars and seemed to leave a faint ‘ghost’ of the trails which became discernible after further processing. 

I went a little bit of a round about way.  I used StarXTerminator to save all the calibrated, debayered frames as starless.  Then used PI's updated CometAlignment process.  The exported frames from this were then integrated in PI with mainly defaults (the CometAlignment process documentation has a basic workflow and tips).  A little smearing still if pushed too hard. Got:

I did the same as you for the stars though - brought the APP image stacked normally into PI and then extracted the stars.  

Edited February 1, 2023 by geeklee