Double cluster and M36

[gonzostar]

Hi

Took images of double cluster and M36 with my 8"SCT on a avx mount and a 6.3 focal reducer with a astronomk cls filter. I used a canon 450d camera.

Both picture where around 5 *1 min light frames (with darks and flats)

Having trouble with gimp processing, so if anyone feels like having a go with my data then let me know! or any advice gratefully recieved

Thanks

Dean

[MattJenko]

Do you have the originals somewhere to download?

[gonzostar]

Do you have the originals somewhere to download?

Hi i shall try and send you the TIFF file straight from DSS. Is that ok? 

Dean

[MattJenko]

I have had a go at it. There are a few things I would suggest. First is one you already know in that the framing is not quite right

The main one though is that you are out of focus. Get that nailed and a lot of the rest will follow. There is some colour in there, but it had to be really pushed to get it out. I think once good focus is achieved, this will all get easier and there is not much to add as that could do with being nailed first. There were also some pretty aggressive gradients, which you got rid of in your version by moving the blackpoint way up and clipping far too much of the image.

I also think your DSLR/reducer spacing is not right, as the stars are elongated ina circle around the center, which if I remember correctly is indicative of the sensor being too close. This again might get resolved with better focus, not sure. Something to try out.

Good start - keep going. I have a 450d as well, and it can produce some wonderful images.

[gonzostar]

First off all thankyou for your time and effort in having ago at this image.   It does look better than my version

Again i am very much in the learning process, so alot off trial and error!  To focus i am just using the screen at the back off the camera. Do you use anything else? Also could i ask what you mean by gradient backpoints?

Thanks again 

Dean

[MattJenko]

Look up bahtinov masks. You can then focus by pointing at bright stars. A gradient is when you have a gradual lightening or darkening of the background across the image and the blackpoint is where you set the left hand part of the histogram in gimp which sets the pixel value at which the image will be black in the final image.

[wxsatuser]

Think you did well getting any colour out of the cluster stars as they are mainly type O or B, blue/white in colour.

They are very young stars, approx 12million years and would no doubt easily saturate a dslr.

Most images I have seen of the DC show white stars with my own images showing just a tinge of blue.

[gonzostar]

Will look up bahtinov masks. Last of the photos i am afraid for 3 months. I have to go in for a cornea transplant  However that should help with focusing

I have data for m36 if you would like to have a go at. However the file size is 70mb (compressed) , and on here its a 50mb limit. Not sure how could get this to you experts 

Also the histogram is that the colour- curves icon on gimp/ or do you sort that out on DSS?

[gnomus]

Will look up bahtinov masks. Last of the photos i am afraid for 3 months. I have to go in for a cornea transplant  However that should help with focusing

I have data for m36 if you would like to have a go at. However the file size is 70mb (compressed) , and on here its a 50mb limit. Not sure how could get this to you experts 

Also the histogram is that the colour- curves icon on gimp/ or do you sort that out on DSS?

I think I would find focussing off of the back of a DSLR screen almost impossible, so well done for getting it as close as you did.  I'll second the Bahtinov mask idea.  It will remove much of the guesswork.  You may find it will work best if you slew to a nearby bright star to focus with the mask and then return to your object.  I usually try to find a star that would be selected as an 'alignment' star - Vega or something like that - but as close to your target as possible.   Are you controlling the camera with software (such as APT)?  You might find that that would make focussing easier.  If you are using capture software there is also an excellent thing called - Bahtinov Grabber - that will reduce the guesswork even further.

Good luck. 

[gonzostar]

I think I would find focussing off of the back of a DSLR screen almost impossible, so well done for getting it as close as you did.  I'll second the Bahtinov mask idea.  It will remove much of the guesswork.  You may find it will work best if you slew to a nearby bright star to focus with the mask and then return to your object.  I usually try to find a star that would be selected as an 'alignment' star - Vega or something like that - but as close to your target as possible.   Are you controlling the camera with software (such as APT)?  You might find that that would make focussing easier.  If you are using capture software there is also an excellent thing called - Bahtinov Grabber - that will reduce the guesswork even further.

Good luck. 

Hi thanks for your reply. No not using any focusing software. i dont have the set up to a laptop. I use the technique to you advised for focusing on to back of dslr, although it does look ok on the screen but changes during processing!  

Are these masks east to use? 

[gnomus]

Hi thanks for your reply. No not using any focusing software. i dont have the set up to a laptop. I use the technique to you advised for focusing on to back of dslr, although it does look ok on the screen but changes during processing!

Are these masks east to use?

I found the mask a little awkward at first until I twigged about the BRIGHT star. If you just use any old star you might struggle to see the spikes - especially on a DSLR screen. Other than this you will find it much easier to use the mask than to try focussing visually on the screen.

You are going to be spending hours capturing these images and even more hours processing them. All will be for nought if they are not in focus. The masks cost a few quid. My advice is just to get one of an appropriate size for each scope you have.

[gonzostar]

I found the mask a little awkward at first until I twigged about the BRIGHT star. If you just use any old star you might struggle to see the spikes - especially on a DSLR screen. Other than this you will find it much easier to use the mask than to try focussing visually on the screen.

You are going to be spending hours capturing these images and even more hours processing them. All will be for nought if they are not in focus. The masks cost a few quid. My advice is just to get one of an appropriate size for each scope you have.

Yes your right. It is annoying spending those many  house freezing then processing only to find pics are not good!  Again  its all practice. Do the fit on the end of dew shields? 

[gnomus]

Yes your right. It is annoying spending those many  house freezing then processing only to find pics are not good!  Again  its all practice. Do the fit on the end of dew shields?

The ones I have have adjustable pegs that are set so that they hold in place around the outside of the dewshield. Others come with foldable tabs, I believe.

[gonzostar]

thanks for this. Will investigate 

Dean