New and improved M42

[Daniel]

Just spent a while compositing my latest M42 image, this time i've just used a low exposure image (15s ISO 1000) and a high exposure image (30s ISO 3600) to add the non burnt out heart of the nebula from the Low exposure to the high exposure, then I've just played with the levels and reduced noise.

Still not great (you can really see the coma in this one, i have since re-collimated) but definetly getting there, now i just need to set my sights on something other than M42, so far almost everything else i've looked at has come up near blank, strangley one nebula i did see was the owl nebula, which is supposedly around mag 12, wheras other nebula with a much higher magnitude, I've been unable to see, could this be to do with my camera's sensitivity to different light?

Anyway, here it is!

[Tom C]

Nice one mate, big improvement on the first one. Are there any new subs, or just the same ones as the first one but better processing?

[Daniel]

these are brand new images, the last image I posted, I had to do using a camera mounted to the eyepiece because using prime focus i was unable to get the focal point close enough to the sensor on my camera. I managed later on to get the T ring close enough that I was able to focus using prime focus. so this is my first proper prime focus image (i had to use a barlow before)

:O)

[MarkS]

Daniel,

That's looking good - well done.  If you take multiple images and do some stacking you'll be able to bring out the fainter parts of the image.

As for bright Nebulae - the magnitude doesn't give a good indication because, roughly speaking, it measures the total amount of light given off.  If this is concentrated over a small area it willl be bright but if spread over a large area then it will be very dim.   The useful statistic is surface brightness - this give a good indication but I don't know know off-hand of any tables that give this.

A useful tip for finding dim objects is to do a single exposure of a few minutes (use the bulb setting on your camera).  Although you will end up with star trailing, the nebula will betray its presence.

Try the Andromeda Galaxy - that has some bright parts (but also some very dim edges!)

[Daniel]

Ahhhh, im guessing the horse head nebula is quite a spread out magnitude then, that's been a major pain, even at ISO 3200 for 1 minute, all i get is light polution, no trace of nebula whatsoever.

I think andromeda's definetly my next target, I got out last night to try to image it when there was a short break in the clouds, but it clouded over again before I got properly aligned

[Mac]

Nice Image, Love the difraction spikes, how about starting a thread up about using them.

[Daniel]

I thought they were a bad thing, though admitedly, they do look quite nice, I had terrible coma on that star up in the top right, though i didn't have time to set up properly last night, i did have time to check to see if the collimation i did just after this image was taken was working, so I think the next image should look a lot nicer.

Diffraction spikes happen because of the spider vanes don't they? i saw some setups where people made there own thicker to increase the effect

[mickw]

Mac - You'll get your bum smacked 

Mick

[Fay]

Daniel, an immediate great improvement, I bet that will spur you on to infinity & beyond!

[Rick]

Daniel, what 'scope are you using?

[Daniel]

Right now im using a Celestron C8n scope, Im buying a Skywatcher ED80 this week though, partly as a guidescope although I've been told I'll probably end up using the C8n to guide with once I've tried the ED80 

[Daniel]

Sorry to bring this old chestnut out of retirement, but thought I'd post yet another M42, Im kind of using it as a yardstick to see how my imaging is improving, anyway, this is my latest M42, as you'll see still a bit of coma (need to collimate again, but my laser collimaters out of batteries) and its also cropped a little awkwardly, this is because of the vignetting i've been getting using the 1.25" adapter, I'm having a 2" adapter custom made, so hopefully my next (there will be a next, sorry) will be a little larger and a little better collimated, anyway here it is!

[MarkS]

Daniel,

That's a big improvement.  Nicely processed too - with the centre not burnt out.  If you can stack lots of them you'll be able to pull out a lot more detail.

Well done.

Mark

[Fay]

Daniel, that is so very good.
I have yet to do M42 without the burnt out middle, you have achieved just that.

[Fay]

Daniel, did you just stack the images or did you cut out the middle & replace, or anything else fancy?

What camera have you got? I think mine only goes up to 1600 ISO.


If I can get my ports sorted, that will be the next thing I want to have a go at.

Fay

[Daniel]

Thanks  I cheated a little with the processing, I processed 2 images, one under exposed, one, over exposed and then, you guessed it cut out the middle of the under exposed one and stuck it over the main image. Im using a Canon 40D though I've only found out recently that ISO 3200 is actually a levels cheat applied by the camera itself, so i've stopped using it now.

I used a technique from Jerry Lodigruss's website (i have the CD on order) for pasting the images over one another, the website has a load of snippets from the CD rom http://www.astropix.com/GADC/INTRO.HTM

This image was made up of about 40 images at ISO 1600 20s and stacked in deep sky stacker

by the way, does anyone used deep sky stacker live? it's really quite good!

[Fay]

Yes a couple of us use DSS. I have the Jerry Lodrigiuz disc & I will follow his procedure as well. It seems to work well.

I have just been messing about with connections etc regarding the EOS. One minute it all  works the next it doesn't, which is a bummer after putting all that equipment up!
I will set up tonight with the intention of doing M42 wih the EOS, thanks Daniel

[Daniel]

Have you tried the Live version of DSS where you just set up an incming directory and images are aligned and stacked as they come in?

That Jerry Lodigruss CD seems really good, very easy to follow examples, can't wait for it to be delivered!

I have a lot of problems getting my EOS to work with any other capture software besides live view that came with it, which is a shame because I really wanted to try out one of the focusing programs like hocus focus, by the way, are standard webcams any good as guidescope camera's?

[Fay]

I use a modified webcam. I don't think an unmodified one is ok, as it won't pick up the stars for guiding. Someone, like Chris S or Mike, will probably answer that for you.

I have not heard of the live version, I just use the normal one.

[Rocket Pooch]

Hi,

You can use an un-modded one but only on bright starts, if you try Guidemaster it stacks on the fly and fools the software into thinking its a long exposure camera.  Or you could always mod one, quite easy, but you will need tiny fingers.

Chris

[Mike]

.....if you try Guidemaster it stacks on the fly and fools the software into thinking its a long exposure camera.....

AstroArt does the same.

[Daniel]

Awesome, that will probably be the way to go then, Im using a Celestron Neximage right now, but it's incredibly noisy, I've ordered an spc900 (after seeing Marks moon image posted recently) so hopefully it'll be a little better, especially at low shutter speeds!

[Mac]

did you shoot the picture in raw mode on your canon.

If so all the image is saved straight off of the ccd and is not processed down to a jpg.

the raw file size is 12bit, whilst the jpg will be 8bit, so there is potentially a little more information there.

If so you can cheat and use photoshop or canons own software, to readjust the image.

If you open the photo as shot, the center will be burnt out as you said, but you can then open the photo again and use photoshop to underexpose the same raw image.

That way you can get more detail out of the burnt out region.

Thats the beauty of using raw as opposed to .jpg

[Daniel]

Hi Mac, yes, I've been shooting in raw mode and stacking in Deep Sky Stacker, the original image was very underexposed, mainly because I chose to expose each image for only 20s because of the mist we've been getting lately, I brought out as much nebulosity as i could within photoshop with levels and curves, not worrying about the center burning out, then re-pasted another version of the center over the old.

Im seriously thinking about trying a HDR version of the same thing so that i have complete control over the exposure within the file, has anyone tried that yet?

[Fay]

This is what I want to do next, Daniel. I will use the mask method. I have had a little go before but had masks & layers all over the place & got a bit confused, did not know what I was pasting where!!!
Now I have become a little more familiar with processing, not good, but a bit better. I think I will understand it better.