My first M51 Whirlpool galaxy

[matthasboldlygone]

Couple of days ago I managed to get nearly an hour of images, but realised later I had missed the target completely and just got some random stars. Last night I got out despite the clouds, Polaris cloud covered so dodgy polar alignment, and could only do a 1 star alignment. But did manage to get it in frame a got 10 x 30 second exposures before the clouds covered everything. Stacked / aligned manually in Photoshop and I can just make out a hazy swirl. 😁

Bresser AR 102/600
Bresser HD Deep Sky Camera
HEQ5 Pro mount + Rowan
Captured in ToupLite
Processed manually in Photoshop

One small step... 👣

[Paul M]

Very brave stacking in PS!   I use it for post processing but do stacking in Deep Sky Stacker. I suspect that with 10 x 30 secs to stack there is actually a bit more in you data than you've pulled out so far.

DSS not only stacks the images it does some pre-processing too, giving a better quality stack than stacking alone. That just leaves a bit of stretching in PS.

[matthasboldlygone]

1 hour ago, Paul M said:

Very brave stacking in PS!   I use it for post processing but do stacking in Deep Sky Stacker. I suspect that with 10 x 30 secs to stack there is actually a bit more in you data than you've pulled out so far.

DSS not only stacks the images it does some pre-processing too, giving a better quality stack than stacking alone. That just leaves a bit of stretching in PS.

Spending the afternoon looking at some software, on a Mac so a bit limited without lots of fiddling. Trying Siril atm, don't seem to be getting much out of it, but will keep trying. 👍

[JonCarleton]

I use Siril, but I didn't like it at first.  There's a learning curve, but one you figure out what it wants, it works very well.

[bottletopburly]

On 25/07/2020 at 15:30, matthasboldlygone said:

Spending the afternoon looking at some software, on a Mac so a bit limited without lots of fiddling. Trying Siril atm, don't seem to be getting much out of it, but will keep trying. 👍

Try using the scripts in Siril ,very easy , just use the script that suits your imaging .

Edited July 27, 2020 by bottletopburly

[matthasboldlygone]

13 hours ago, JonCarleton said:

I use Siril, but I didn't like it at first.  There's a learning curve, but one you figure out what it wants, it works very well.

 

6 hours ago, bottletopburly said:

Try using the scripts in Siril ,very easy , just use the script that suits your imaging .

I'll keep trying with it, but just getting black images. I think my fuzzy JPG 'data' just isn't good enough for it. It managed a good alignment of the images. 

Will have another look at the scripts and read up on the settings. 

Polishing a turd is never a good idea 😁

[JonCarleton]

2 hours ago, matthasboldlygone said:

I'll keep trying with it, but just getting black images. I think my fuzzy JPG 'data' just isn't good enough for it. It managed a good alignment of the images. 

When you do the initial load of the images and convert to FITS, two viewers pop up, a composite RGB and a monochrome view from which you can select red, green or blue.  What do your images look like in the FITS viewers?

As an alternative, you could zip together some of your images and upload them here to let someone else take a whack at the stack.  Also, .JPG/.JPEG is not a great format for images.  Use FITS, TIFF or something else for your capture.  You lose a lot with .jpg compression....it is ok for the final image, and great for posting on the web, but not much good for other uses.  Or, at least, not as good as some other options.

Edited July 27, 2020 by JonCarleton

[matthasboldlygone]

11 minutes ago, JonCarleton said:

When you do the initial load of the images and convert to FITS, two viewers pop up, a composite RGB and a monochrome view from which you can select red, green or blue.  What do your images look like in the FITS viewers?

As an alternative, you could zip together some of your images and upload them here to let someone else take a whack at the stack.  Also, .JPG/.JPEG is not a great format for images.  Use FITS, TIFF or something else for your capture.  You lose a lot with .jpg compression....it is ok for the final image, and great for posting on the web, but not much good for other uses.  Or, at least, not as good as some other options.

They look ok in the FITS viewer. If you have a spare 5 minutes please feel free to play with my data to see if anything can be dragged out of it.

Matt-M51.zip

👍

[JonCarleton]

A few things I noticed:  The focus was a bit out, and the tracking was slipping, frame to frame and there was a lot of noise at varying levels frame to frame, including some light from a source at the lower left of each frame.   These are things that make it a bit more difficult and can be corrected with effort and practice.  Several frames had to be excluded in the selection process, including one frame with a satellite trace across the frame.  Sometimes satellite traces will "stack out, " but sometimes not.  I generally exclude them.

This was my Siril recipe (note that I had to exclude about 1/3 of the frames to get a good stack):

File Conversion Tab
    Change directory
    Add images
    Sequence name: M51 [Convert]
Sequence Tab
    Sequence export (check Normalize images)
    FITS (default)
    [Export sequence]
Pre-processing Tab
    Skip
Registration Tab
    Global Star Alignment (deep sky)
    Algorithm: Bicubic
    Check Match stars in selection
    Check Simplified Drizzle x2
    [Go register]
    I noticed that the sequence created by the registration had some wacky results
    due to excessive drift in your tracking.  I had to go back and exclude those
    images and re-register.
Plot Tab
    Skip
Stacking Tab
    Stacking Methods: Average stacking with rejection
    Normalizaton: Additive with scaling
    Uncheck Force recomputing
    Check Normilize to 16-bit
    Rejection: Linear Fit Clipping
    change [all] to [selected] (too few images to eleminate any now)
    [Start stacking]

The thing that would have made the most difference in this photo would have been the addition of some dark frames and bias frames to get rid of the noise.  Many more frames would have been good too.  Someone with greater skills than I certainly can do a much better job than this, but in the end, the greatest improvements will be (in order): Focus, Darks & Bias, Tracking and More Images.

Much better than My first attempt at M51, however.

    

 

Edited July 28, 2020 by JonCarleton

[matthasboldlygone]

2 hours ago, JonCarleton said:

A few things I noticed:  The focus was a bit out, and the tracking was slipping, frame to frame and there was a lot of noise at varying levels frame to frame, including some light from a source at the lower left of each frame.   These are things that make it a bit more difficult and can be corrected with effort and practice.  Several frames had to be excluded in the selection process, including one frame with a satellite trace across the frame.  Sometimes satellite traces will "stack out, " but sometimes not.  I generally exclude them.

That's great. I'll try out your recipe and lots of tips to try next time. Hoping for some clear sky tomorrow. Really useful, big thanks for putting the time in to help. 

👍

[matthasboldlygone]

Got some new images to play with tonight, thanks @JonCarleton for the tips, things are looking much better after just a quick stack and fiddle. 

[matthasboldlygone]

Another night, managed to get 50 x 2 minutes, going in the right direction

[matthasboldlygone]

Pre-processed all the images to get rid of the blue background, tried some different stacking options. So many versions of it they all start to look the same. Think this is probably the best I'll get from the images. Tonights mission is to get another 2 hours and stack them all together..

[JonCarleton]

Looking good!  You have come a long way in a very short time.  You will find that some of the options in Siril work better for some types of images and other options for other types.  It is a very powerful tool, but it takes some messing about with to get your legs under you.  Then too, most of the image software is like that.  I'm trying to wrap my head around StarTools myself....been using GIMP, and it is OK, but there are things I do in multiple steps that other programs make a single-step.

Good job getting rid of the noise!