M45 The Pleiades

[Celestron]

This is 10 x 1-min , stacked and registered in DSS . Needs lots more signal added but it's a start with first light with the 70-200mm f/4L USM and XSi piggyback mounted on my SCT 8" . The more i worked these the worse the histogram got so i stopped where the histogram says it's decent for what little signal i have here . Took these 09-25-09 (friday night) . The stars have a slight cone shape . Can't figure out why . It's the way it came out of DSS . I'm new to that program . Anyway Cs'&Cs' welcome .

[Adrena1in]

Can see the beginnings of the nebulosity. Never managed to capture it myself, and always thought I wanted 3 to 5 minutes for each exposure to do so. Stars are lovely and crisp, and I love the spikes on the brighter stars...was the lens stopped down quite a bit to get those, or did you add them later?

[Celestron]

I don't have a star spike program . Settings were 1600 ISO , f/4.5 , 60-secs , @200mm , camera sharpness set to 3 . The spikes are evident in each individual frame but more evident after stacking . Other than that it could have been the lens and LP for some reason . This is one reason i don't try M45 very often cause it takes longer exposers and many more frames .

[Adrena1in]

You're stars are spot on though, so you could probably easily expose for two, three or four times longer. "Camera Sharpness set to 3"...what does that mean?

[VIGER]

Getting there, keep on trucking

[Celestron]

You're stars are spot on though, so you could probably easily expose for two, three or four times longer. "Camera Sharpness set to 3"...what does that mean?

Camera Menu "Picture Style Settings" you can adjust saturation -contrast-sharpness .... , I have the sharpness set to 3 . I was keeping it down to 1-min because of LP but next time i'll set the f/stop to 6.3 or so and try for longer exposers . When Piggyback riding i use a cross hair EP and center a star and manually guide for exposer time . My mount has tracking motors but not a go-to so i don't have a Guider control :( .

[SteveInNZ]

Camera Menu "Picture Style Settings" you can adjust saturation -contrast-sharpness .... , I have the sharpness set to 3

Does that infer that you are using the camera jpegs for your stacking ? Those parameters don't apply to the RAW file.
If so, try using RAW. Otherwise you're stacking with gamma adjusted, non-linear data biased towards the bright stuff. ie. the wrong way for astrophotos.
You don't want the camera to be doing anything to your data before stacking. Think of how sharpening works by brightening pixels on one side of the dark/light boundary and darkening on the other. If you stack sharpened images, you're increasing the contrast of the introduced change, rather than just the real data.

Good to see I'm not the only one using a cross-hair eyepiece and twiddling with knobs.
So many people have forgotten how uncomfortable a 10 minute exposure can be.
Well done.


Steve.

[Celestron]

Thanks Steve ! Yes your correct , i shoot alway in jpeg cause of the processing . It always seems harder for me to process and PS7 and DSS and Canon software is all i have to edit with . Don't have Maximum DL or a like . Guess next time i'll just have to shoot RAW and do my best .

[SteveInNZ]

The new version of DSS will accept Canon RAW files directly. I set my camera to take both RAW and JPG. I can't think of a reason not to.

Steve.

[Celestron]

The new version of DSS will accept Canon RAW files directly. I set my camera to take both RAW and JPG. I can't think of a reason not to.

Steve.

Why do you have RAW & JPG , why not just RAW ?

[Nighthound]

Very nice Ron, super clean image.

I second the RAW only approach. I can honestly say I haven't purposely shot a JPEG with any of my DSLRs, day or night. I accidently did with the Mark II when I first got it (hit the button on back) and after looking at those files it only confirmed that RAW was the only way to shoot. They were daylight shots but the shadows for the most part were flooded and lacking detail. I couldn't adjust them to my satisfaction. In RAW the shadows are much easier to adjust because there's more detail there. I would think in astro work much more data on the low end would be present as well, although I haven't tested the difference I'd be shocked if that didn't hold true.

I sure miss astroimaging, come on winter!

[SteveInNZ]

I can't see the point of using raw for everyday snaps that will go on the wife's facebook page at VGA resolution, just as I wouldn't use camera jpegs for astro imaging. There's one setting that guarantees I'll never forget to switch from one to the other.
Imagine how embarrassing that would be. ;)

Steve.

[Adrena1in]

Funnily enough, even though I've never managed to get better results using RAW files for astro-imaging, for the first time ever the other day I noticed a difference with regular images. Had been away on holiday for a few days and was going through my pics on my work PC in Google Picasa Viewer. One by one I'd look at each picture, first in JPG format and then in RAW. Each time there would be a one or so second delay when opening the RAW, and it would adjust itself slightly on my screen. Dark bits would get a little lighter to reveal more detail, bright skies would dim slightly to reveal more cloud. It's the first time since gettng a DSLR a few years ago that I've actually thought, "Hey, yeah, I can see why people say RAWs are the way to go."

Definitely going to pursue the trend once I get back into astro-imaging.

[jmx]

I'm not sure whats going on, but 10x1 minute again should have plenty of nebulosity. The processing is your weak spot I think, just like in M31. You're doing all the stuff before the processing perfectly from what I can tell, but you need to shoot raw and you need to do processing differently.

I've never done long exposures of anything, and I've never really spent much more than an hour on any target (and even then I throw away sometimes half the frames due to bad tracking, so its only 30 minutes) and I get tons of nebulosity usually.

[chris.bailey]

I always struggle with M45 as it tends to site right where my skyglow is the worst. Its now coming up in the sky for me and it is so lovely when done right its a prime first target for me this year. I collected about 3 hours on it last year and still didnt get that fine hairlike nebulosity that you see in some images.

[Nighthound]

I'm not sure whats going on, but 10x1 minute again should have plenty of nebulosity. The processing is your weak spot I think, just like in M31. You're doing all the stuff before the processing perfectly from what I can tell, but you need to shoot raw and you need to do processing differently.

10 minutes of exposure on an object consisting of mainly reflection nebulosity is really a modest amount of time. M45 is what I would consider to be a fairly bright reflection rich object but requires at least an hour to begin to resolve the fainter regions. Here's 1 hour and 45 minutes @ f/4. Ideally I would go for twice this amount of time to feel I was getting close to optimum quality for a DSLR. Once the 3 hour barrier is broken, it's amazing what becomes visible:
http://i3.photobucket.com/albums/y67/Nighthd/POTN%20Gallery/m4508strtchxx2.jpg

[Madweasel]

Wow Steve, that's the best M45 shot I've ever seen anywhere! Good work.

I agree better processing is required on the OP. I've used the 70-200/4 with only a few minutes' worth of exposure and got more nebulosity than that, and I'm still improving too.

[jmx]

10 minutes of exposure on an object consisting of mainly reflection nebulosity is really a modest amount of time.


Sure, but its more than enough to get some data on this target, the results may just look real noisy. There's clearly a lack of processing going on, and I think once he sorts that out he's going to be very impressed with the data he's actually captured.

BTW, your shot is great!

[Nighthound]

Thanks very much Mark and jmx.