M13 in first imaging session

[Galactic Wanderer]

This was my first imaging session with my newly bought telescope and I'm very happy. I took about 50 images of M13 at ISO 100 and each 25secs. Next morning I stacked in deep sky stacker and processed in GIMP.

I'm quite happy since it is my first imaging session

hercules cluster.xcf

[wimvb]

Nice image, but you might want to EXPORT the image in GIMP to either jpeg or png. I don't think many people here can see it otherwise.

Did you use calibration frames (darks, bias, flats)?

[laudropb]

Sorry image will not open on my IPad.

[Galactic Wanderer]

1 hour ago, wimvb said:

Nice image, but you might want to EXPORT the image in GIMP to either jpeg or png. I don't think many people here can see it otherwise.

Did you use calibration frames (darks, bias, flats)?

Sorry, I did export it to GIMP and I will change it to a jpg.

I only used darks. Not quit sure how to do bias and flats yet

[Galactic Wanderer]

Sorry, there is the jpeg version.

[Galactic Wanderer]

5 hours ago, laudropb said:

Sorry image will not open on my IPad.

The image is now above.

[pyrasanth]

Welcome to the world of imaging- you wont come up for air for years!

I looked at your image & the most important is that M13 is slightly out of focus- this has made the ball of stars fuzzy & its a very common mistake but harder to sort. I don't image with DSLR cameras so perhaps better to seek advice about this from other experienced DSLR users. Image scale is important so try & choose objects that will show detail by more filling the camera frame. I've seen some fabulous pictures of tiny objects on big DSLR sensors & whilst they are brilliant the main subject is the size of a pea when it needs to be as big as an apple to see any detail!

The histogram of your image was seen as a tight band dead center in the dynamic range. This gives you plenty of room to stretch such an image to make improvements to contrast or background so no problems there.

The picture you have taken needs flat fielding as the illumination is uneven. You might wish to explore this on your next adventure as there is plenty of help with regard to this on this & other internet sources. I have flat fielded your image with software & you can see a big improvement as below. Unless there is a compelling reason for a big wide starfield around an object that is more toward the top you may wish to consider cropping the image but that is personal choice. I think the most important of the 2 issues to get sorted fast is focus as it will ruin all subsequent sessions. Gradients can be dealt with in post processing at any time.

I hope this is of help.

 Enjoy the journey!

 

[wimvb]

The easiest and best way to fix focus issues is to get a so called Bahtinov mask. This gadget is dirt cheap and one of the best investment you can make in astrophotography.

I's basically a plastic disc with a pattern of slits. When light from a star falls through the disc, it creates a diffraction pattern in your eyepiece or on the camera sensor. When the pattern is symmetrical you have achieved perfect focus.

Just don't forget to remove it before starting to do your exposures. :-)

[Galactic Wanderer]

Thanks for your repiles, Ill make sure to do this next imaging session!

[Galactic Wanderer]

On ‎5‎/‎8‎/‎2016 at 21:46, wimvb said:

The easiest and best way to fix focus issues is to get a so called Bahtinov mask. This gadget is dirt cheap and one of the best investment you can make in astrophotography.

I's basically a plastic disc with a pattern of slits. When light from a star falls through the disc, it creates a diffraction pattern in your eyepiece or on the camera sensor. When the pattern is symmetrical you have achieved perfect focus.

Just don't forget to remove it before starting to do your exposures. :-)

Thanks for the suggestion. I have just ordered one!

[wimvb]

Glad could be of help (spending some money )

[Galactic Wanderer]

 

18 hours ago, wimvb said:

Glad could be of help (spending some money )

Hey wimvb,

I ordered the bahtinov mask and it arrived today. I bought it from here:

 https://www.amazon.co.uk/gp/product/B01B8U29QI/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

This was for my 150mm (6 inch) opening. Unfortunately I don't think it fits. Here are some pics as well:

 

IMG_1532 [13959].lnk

[wimvb]

Sorry, can't open your linked image.

As for the mask, fit is not crucial. The mask I have is simply a plastic disk with two screws in it. I just hang it over the scope without securing it in place.

I think that if you remove one of the three screws in your mask, you can do the same.

[Galactic Wanderer]

Ok thanks!

[Galactic Wanderer]

sorry here it is again

 

[wimvb]

That certainly looks too small for the scope. If you can't return it for a larger one, you can try fitting a plastic ring around it.