M33

[halli]

Hi

M33 processed in DSS, Pixinsight and finished in Canon DPP.  

No coma corrector used so stars at bottom right affected by Coma.  Unfortunately the galaxy wasn't framed in the middle and was cropped from towards the right bottom corner so couldn't crop out the coma!

I guess I need to splash out on a coma corrector at some point !

I am new to astrophotography so comments would be welcome

Thanks

[pyrasanth]

I had a go at M33 but I need to think about light pollution & how it is wrecking my targets. When I look at the beautiful photograph taken in Arizona it makes me nearly cry with envy but in no way a malicious or jealous way as we all have to deal with what we get from where we are located!

This was taken under light polluted skies 4 miles from Birmingham Airport under 3 sodium street lights- so not the best conditions & certainly not Arizona! 

[kirkster501]

Good job.  Great colours and HII regions you got. You might have over done the sharpening though?  I like the top one best. 

[pyrasanth]

Hi

M33 processed in DSS, Pixinsight and finished in Canon DPP.  

No coma corrector used so stars at bottom right affected by Coma.  Unfortunately the galaxy wasn't framed in the middle and was cropped from towards the right bottom corner so couldn't crop out the coma!

I guess I need to splash out on a coma corrector at some point !

I am new to astrophotography so comments would be welcome

Thanks

m33_dbe_hist_sat_final_HDR1.JPG

That's a nice image!

I'm learning the importance of image scale & the selection of targets suited to your focal length & aperture. An example is the M42 nebula which I recently shot with technically with the wrong setup as the focal length of nearly 2 meters allowed the nebula to completely fill the sensor & thus the outer beauty is lost. This is the case with your photograph but in the other direction. M33 is a small target so would be better suited with a longer focal length to give a greater image scale & thus more detaiil but the sacrifice is often loss of brightness & longer exposures. Under my poor sky conditions I get star bloat but I think you can begin to see more detail in the image at the grater focal length.

I would suggest a good target for you would be M31 as this is 3 degrees which will fill your frame very nicely  & pull a lot of the finer detail. The image you have captured is very nice & is a great first effort- well done.

[halli]

Thanks very much guys at taking the trouble to comment - appreciated.  It certainly helps me in these early stages of the hobby !  

I guess its true that DSOs vary greatly in their sizes and some fare better imaged with longer focal length instruments - I guess you used your C11 Pyrasanth ?  

What length subs did you use ?

Certainly it has captured more detail and brought out more colour.   I love the colours in your image.    My subs were 14 x 10 mins long but only used a 130 PDS which has less aperture.  I am not sue how the lengths of the subs can truly make up for less aperture  and dont understand how these relate technically.  My own instinct is that you can never make up for the increased resolving power of a large aperture by longer exposure on a smaller aperture.  

I guess FOV is an important issue with DSO imaging.   I am still in the throes of ensuing my set up is correct and ensuring the guiding is good enough for 10min plus exposures.    Overcoming dewing has been a ssignificant issue for my ST80 guidscope and also he 130 PDS recently

The proper framing of the image is important though and I certainly need to spend more time on this.  I have downloaded Astro Tortilla and need to invest some time in using it.

I too have light polluted  skies living in Reading.  Pixinsight seems to be good at taking the worst gradients out but there is always remnant noise which I guess is caused by the polluted skies as well as the camera sensor.  I am planning to find a darker site at some point but currently the back garden is more convenient to learn the trade !

I am not too bothered at the moment about imaging stuff which is too small for the 130PDS as I am still experimenting and at least I get valuable  informaton and experience from the images and it is always exciting to see what comes out of the processing big or small. !  And like you the results teach you a lot about the importance of target size vs scope focal length.  

I guess the answer is to have at least a couple of scopes one for widefield and one for planets and galaxies  -  I am certainly envious of your C11 edge for this purpose !

[Chris]

Well halli, it might not have been centred but you've done a good job processing the data considering you are new to imaging, nice one!

[D4N]

Personally I think it is a good target with that setup as the lack of coma corrector can be largely compensated for by cropping the blobby stars. M31 would suffer badly.

Is your DSLR unmodded? The image is a lot bluer than my ones of M33.

A lovely image all the same.

Sent from my iPad using Tapatalk

[halli]

Thanks for your nice comments , it helps me to confirm that at least I am on the right track !

Yes D4N the 1100D is unmodded.  

Its tricky to understand how to deal with colours - I use the colour calibration feature in PI and hope for the best.  However I guess the amount of saturation applied is a matter of taste.

[D4N]

The colour is right for an unmodded camera, you don't pick up much of the Ha but you do pick up the OIII so this tends to make the image bluer than it would be on a modded camera or an astro camera.

Sent from my iPad using Tapatalk

[pyrasanth]

Thanks very much guys at taking the trouble to comment - appreciated.  It certainly helps me in these early stages of the hobby !  

I guess its true that DSOs vary greatly in their sizes and some fare better imaged with longer focal length instruments - I guess you used your C11 Pyrasanth ?  

What length subs did you use ?

Certainly it has captured more detail and brought out more colour.   I love the colours in your image.    My subs were 14 x 10 mins long but only used a 130 PDS which has less aperture.  I am not sue how the lengths of the subs can truly make up for less aperture  and dont understand how these relate technically.  My own instinct is that you can never make up for the increased resolving power of a large aperture by longer exposure on a smaller aperture.  

I guess FOV is an important issue with DSO imaging.   I am still in the throes of ensuing my set up is correct and ensuring the guiding is good enough for 10min plus exposures.    Overcoming dewing has been a ssignificant issue for my ST80 guidscope and also he 130 PDS recently

The proper framing of the image is important though and I certainly need to spend more time on this.  I have downloaded Astro Tortilla and need to invest some time in using it.

I too have light polluted  skies living in Reading.  Pixinsight seems to be good at taking the worst gradients out but there is always remnant noise which I guess is caused by the polluted skies as well as the camera sensor.  I am planning to find a darker site at some point but currently the back garden is more convenient to learn the trade !

I am not too bothered at the moment about imaging stuff which is too small for the 130PDS as I am still experimenting and at least I get valuable  informaton and experience from the images and it is always exciting to see what comes out of the processing big or small. !  And like you the results teach you a lot about the importance of target size vs scope focal length.  

I guess the answer is to have at least a couple of scopes one for widefield and one for planets and galaxies  -  I am certainly envious of your C11 edge for this purpose !

Thanks for the kind words. The image is not brilliant as my skies are badly light polluted. The image was taken with my C11 at F7 with an Atik 460 mono CCD. A full set of Baader RGB filters were used LRGB. These filters have superb colour rendition but are fairly expensive. Each channel had 5 eight minute subs using a Celestron off Axis guider & a Lodestar X2 guider. I plan to repeat the imaging exercise on the next clear night to continue adding data to this image. I might try and add some H-A data as well.

Only you can judge if M31 is a viable target- give it a try- you might be really surprised at the result. You might get distortion but at your focal length it should not be too distracting.

I would suggest you get a copy of the book "The deep sky imaging primer" by Charles Bracken. ISBN 9781481804912. This little book will teach you more about your hobby in one good reading session than a month of reading forums. It will explain why lots of subs work & why aperture might not be as important as you think. It is all about the selection of the right target for the telescope you are imaging with- believe you me I still have not got this right. A long focal length will give you image scale but the time taken to gather the light may be substantially longer. Only a very large mirror can give you both image scale & speed of light gathering power.

Take a look at the colours on this M42 image I took. They are beautiful but the target is too big for the Atik sensor at the focal length of nearly 2 meters- so I've called it a close up to save face!

Now consider the 2 images below much smaller objects and perhaps more suited to the focal length I use

M1

M82

I will re-post the image of M33 when I get more subs and lets discuss the differences we might well see.

Happy imaging- best wishes-Mark

[halli]

Lovely colours in the images ! I guess M1 and M82 are best suited to the C11 because of their size. Certainly I think the colour composition of images is a great differentiator between average and truly outstanding.

I have imaged M31 previously - see below. I suppose it always beckons because of the lovely large spiral shape and captures the imagination as a stereotypical galactic image which is timeless.

Again I should have paid more attention to the framing and would have resulted in not running into the buffers at the galaxy edges.

I guess M31 fills the frame nicely. However you can always crop a smaller image to whatever size you want with a shorter focal length scope which perhaps makes it fairly versatile, but you haven't the resolving power of a larger aperture longer focal length scope to bring out the detail for the smaller stuff.

There are some clear skies coming in my area tomorrow and I will probably have a crack at the Pleiades next.

I will take a look at the book you recommended - thanks for that.

Hope you get some clear skies soon and look forward to seeing your images

[Daniel-K]

if you run ACDNR i think the equivalent to HLGV ( based on PI) to get rid go the green cast you will have a nicer image  

[halli]

Thanks - yes I've heard of that process in PI I will give it a go

[wxsatuser]

Thats a reasonable M33, some more data and you will have a very nice image.