Imaging problems

[Astrolabe]

I've been a visual astronomer for years but a very new imager having only just acquired the equipment. It all looked so easy with an ASIairplus...at least  on the youtube channels. I sold my old SCT to pay for a dedicated camera an ASI071MC Pro. Ive now tried imaging M81/82 on 3 nights and the subframes all look great as they arrive at my iPad but when I finish the session and plug the thumbdrive into my computer all the images look like this. What am I doing wrong??

[iantaylor2uk]

Stacking the files (use software like DSS or similar) will reduce the noise. If you stack 100 frames the signal to noise ratio will be 10x better than a single frame. If you've taken any calibration frames (darks, flats etc) use these too. I have the same camera as you. Galaxies like M81 and Andromeda all look pretty underwhelming to me from a single frame but you should be able to pick up a lot more detail after stacking.

[Lee_P]

1 hour ago, Astrolabe said:

I've been a visual astronomer for years but a very new imager having only just acquired the equipment. It all looked so easy with an ASIairplus...at least  on the youtube channels. I sold my old SCT to pay for a dedicated camera an ASI071MC Pro. Ive now tried imaging M81/82 on 3 nights and the subframes all look great as they arrive at my iPad but when I finish the session and plug the thumbdrive into my computer all the images look like this. What am I doing wrong??

I'm almost certain that you're looking at the JPEG previews. You actually want to be using the FITS files, loading them into astronomy processing software and then stacking them.

[Astrolabe]

They are jpegs! How do I convert then to FITS?

 

[iantaylor2uk]

The fits files should have been stored by the ASI Air Pro - look on the thumb stick under the Light folder (if you used Autorun) or they could be on the memory card (depends what option you ticked when you were imaging). The fits files should in the same folder as the jpg files. 

I've dug out an old image I took of M81 from February. The first image is the stretched jpg, and the second image is the final result after stacking approx 70 frames. 

I also used an ASI Air Pro and ASI 071 MC Pro camera (I used a gain of 200, exposure length of 30 seconds, and cooled the sensor to -5C). I also took dark, flat and bias calibration frames. It is also important on this camera to use a UV/IR filter, as the camera does not have one built in. This was taken using a Tak TSA 102 refractor, with a 1x flattener, so the focal length was approx 820mm. The files were stacked in DSS, then further processed using Nebulosity 4. 

Hope this helps.

[Lee_P]

1 hour ago, Astrolabe said:

They are jpegs! How do I convert then to FITS?

 

You don't convert JPEGs to FITS - FITS are much bigger files that contain lots of data. Plus, those JPEGs that your ASIAIR produces are just tiny preview files to accompany corresponding FITS files. Their quality is very poor, as you've already clocked. 

There should be FITS files in the folder along with the JPEGs. I can send you a screenshot to explain if that doesn't make sense! 

[Astrolabe]

Thanks for all the help.
I reloaded the files. All the jpegs are there and the fits files are there too but not shown as images. When I try to access the fits files my computer says that there is no application available to open the files. My computer is an apple and I don’t have access to a windows one. When I search the App Store for an application to open the files it tells me that there is no app available. So you’re right that the fits files are on the thumb drive but I can’t access them!!

I can’t be the only ASIair user with Apple hardware. Any advice?

[iantaylor2uk]

I usually use Deep Sky Stacker but don't think there is a Mac version of this. ASI Studio also does stacking but not sure of there is a Mac version. 

[AstroNebulee]

2 hours ago, Astrolabe said:

Thanks for all the help.
I reloaded the files. All the jpegs are there and the fits files are there too but not shown as images. When I try to access the fits files my computer says that there is no application available to open the files. My computer is an apple and I don’t have access to a windows one. When I search the App Store for an application to open the files it tells me that there is no app available. So you’re right that the fits files are on the thumb drive but I can’t access them!!

I can’t be the only ASIair user with Apple hardware. Any advice?

Here's a link to the mac version of asi studio, so you can stack your fits files and also view them individually too. 

https://astronomy-imaging-camera.com/software-drivers

There's also Siril that you can stack your fits files and do some processing. 

https://siril.org/

Cheers 

Lee 

 

Edited May 21, 2022 by AstroNebulee
addition

[Astrolabe]

I really can't thank you guys enough. I downloaded the ASI software and can now open the fits images on my mac.

Just a single sub looks great. Now to start stacking.

[ollypenrice]

You'll want a software package which lets you process after stacking and calibrating. Astrophotos, even when stacked, are not 'ready to view.' The main reason for this is that most of the interesting signal is compressed into a very narrow range of brightnesses just above the level of the background sky. The process known as 'stretching' opens these up.  What can be confusing for beginners is that some screen previews automatically stretch the data in a temporary 'screen stretch,' meaning that what you see is stretched but the file on the hard drive is still linear (ie unstretched.) An unstretched astrophoto generally just has a jet black background, maybe a few hints of the brightest nebulosity and then stars. There will be a lot more than that in the data, though. Extracting it is the fun part!

Olly

Edited May 22, 2022 by ollypenrice
False click

[wimvb]

At about this point in the discussion, it seems appropriate to suggest your next investments in AP

https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html

https://www.firstlightoptics.com/books/dark-art-or-magic-bullet-steve-richards.html

Edited May 22, 2022 by wimvb

[AstroMuni]

On 21/05/2022 at 17:54, Astrolabe said:

Just a single sub looks great. Now to start stacking.

Suggest you take a look at Siril in the link provided by Astronebulee. This software does stacking and more. There are plenty of tutorials on their page as well.