A puzzled visual astronomer

[Hemi]

Being a predominantly visual and EAA astronomer. (Well actually a predominantly armchair astronomer given the perpetual state of my skies!)

I’m always amazed by the hours and hours of integration time for all the wonderful images posted.

Probably a very silly question but are all these hours with the exact same setup?

Ie exactly the same location and optical train? Or can you integrate data from different scopes/cameras and locations? And if so, how?

I save all my sharpcap fits files for my EAA sessions, so have lots of short exposure data for many targets using different optical trains and occasionally different locations. It would be a fun exercise to put it all together if possible. Although I have zero Astro post processing experience outside of sharpcap and some planetary using AS3 and Registax.

Cheers

[Stephane]

Hi Hemi,

I am no expert, and have never tried imaging with different rigs (I only have one!). Edit: It appears though that data from different rigs can be combined.

Regards,
Stéphane

[RyanJones]

I can’t see why it couldn’t be done as long as the software algorithm could come up with a common image scale ( you can’t add 1/2 and 3/8 without first converting the 1/2 to 4/8 ). Obviously by reducing the image scale on an image taken on a high resolution camera and OTA combination to suit one lower, you lose the advantages of the higher detail setup. In that case would it be worth it ? I’m not sure ?

[Terry B]

It might depend on what you are trying to achieve. I don't know if it would be easy to improve the overall picture combining.

I did this in the past using radio data. We combined data from the ATCA and Parkes radio telescopes to improve the S/N and then analysed the resulting images. This might be more difficult with optical images.

[AdamJL]

I've heard of people combining different pictures from different scope/camera combinations. Never understood myself how it's done!

There's a guy in South Australia who does it with twin RASAs, but that's an identical image train which is what I'd do if given the chance (not necessarily the RASAs, but just having two of everything).

That said, to answer your question, my longer exposures are all with the same setup. We just have to wait for those clear nights and hope we can get something in that time.

Good thing is we can always come back to the same spot, and with platesolving and rotation, we can exactly match previous compositions. I did this last night using a different camera (same sensor) on a different night and had NINA tell me how much to rotate the camera so it matched previous shots.

[Stephane]

Adam, how does NINA provide this information? Do you need a rotator? I am very interested as I have been rotating my camera back and forth trying to manually match images.

[AdamJL]

Hi Stéphane

1. First, you "connect" a Manual Rotator, which is provided by NINA. See the Rotator.jpg below
2. Second, in the Framing panel when choosing your target, make sure you select the target from "File" at the top, then Load the image below. NINA will platesolve it. See the second image.

In this second image, it's not highlighted as I have no equipment selected, but the button that says "Slew and Centre" (it's greyed out), click that and select "Slew, Centre and Rotate".
NINA will slew to the target, platesolve, then pop up a window to tell you how much to turn your train clockwise or anticlockwise. You keep taking exposures until you get it. I was within half a degree last night and it took about 5-6 exposures.

[Stephane]

Adam, this is a game changer for me! Thank you for that. Since I don't have a rotator, I never explored the rotator tab and didn't know that a "manual rotator" can be connected. This means I can comfortably get the right rotation without having to crop so much any more when I make small errors.

[Stonius]

I've definitely heard of people combining data from different rigs. As long as you have the pixel scale data (focal length and pixel pitch) you should be able to combine any images in pixinsight, since you can get it to distort one image to match another target image, then dynamically crop all images to one final product.


Markus

[Hemi]

Thanks everyone,

With the lack of replies I thought it might have been a very dumb question…
I suppose my question was exactly that about image scale being different with different scopes and camera combinations.

Cheers

[ChrisV]

Hemi

I started visual Astro about 2016. Moved to EAA later that year (could figure out why I couldn't see colour visually - dooh). Within 3 years I was doing AP (but still doing EAA).

To me, AP was like an extension of EAA. Except - now use guiding, longer exposures (EAA was between 10-30sec), different software (not sharpcap, astrotoaster) and post processing is way more involved (which I enjoy). I use the same scopes as I did for EAA, but have a better mount (do not scoff at my CGEM!).

You can try processing your sharpcap individual images, or stacked image. I started with this, but .... You'll be wanting more.

As for combining different rigs - I don't know how or why. People with monochrome cameras used to image the colour part at a lower resolution (binning) to reduce noise? But that's before my time

All good fun Chris