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Full spectrum camera vs h-a filter on scope


vertigo262

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EXACTLY!!!!!!!!!!!!!!!!!!! :)

so I have to view them with an external viewer to see what I have. So what is the point of the preview. In BYE, at least you could see what you had. They probably did that for loading speed, but it defeats the purpose because they don't look anything like what you have

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it seems to be ok in BYE. so I guess I will try to find a good viewer that can do simple things like stretching raw files and such so I can take a quick look in the field to see what I have without having to deal with serious photoshoping and such. something quick.

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EXACTLY!!!!!!!!!!!!!!!!!!! :)

so I have to view them with an external viewer to see what I have. So what is the point of the preview. In BYE, at least you could see what you had. They probably did that for loading speed, but it defeats the purpose because they don't look anything like what you have

It has various preview options such as 1:1, 1:1 scroll... There is the histogram stretch tool also (ccd mode only) which is very useful. But if you don't like APT then stick to BYE for now :).

Louise

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It has various preview options such as 1:1, 1:1 scroll... There is the histogram stretch tool also (ccd mode only) which is very useful. But if you don't like APT then stick to BYE for now :).

Louise

I said I like everything but the preview. 

it just doesn't make sense to show something that doesn't resemble what you have :) but that is ok, because I can use APT and Acdsee saves me. I just load the file from the directory to see it.

But I will scower the web for a utility that will do really quick stretches and such to see what I have between exposure tests 

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I said I like everything but the preview. 

it just doesn't make sense to show something that doesn't resemble what you have :) but that is ok, because I can use APT and Acdsee saves me. I just load the file from the directory to see it.

But I will scower the web for a utility that will do really quick stretches and such to see what I have between exposure tests 

What do you mean by 'doesn't resemble'? It's exactly the same apart from brightness and the histogram tool can be adjusted for that in ccd mode.

Louise

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Hi

This is a screen dump of an image preview taken using my full spectrum 1100d on an ST-80 and with a cls-ccd clip filter:

post-33532-0-81534100-1424279956_thumb.p

Just a 60s exposure of some stars

And this is a preview image taken with my qhy8l and Hutech Idas D2:

post-33532-0-37171200-1424280023_thumb.j

That was a 360s sub of M3, I think. The histogram slider lets you adjust the brightness but is only available in ccd mode.

In both cases the colour cast disappears on stacking and post-processing.

If your preview is radically different, maybe you could post a screendump?

Louise

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i will next time  i go out, but will most likely be clojdy for a couple of weeks.

in mine, the picture is noisy and bright pink. but the actual image is reddish, and not nearly as much noise.

in some were so pink i could not see much.

its not the biggest of deals. just thought was strange for apt to do

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Hi

The previews will still be there from the images you've previously taken with APT (if any!) :)

I have to admit I wish the preview display for the Canon was adjustable in the same way as the ccd version allows. The author of APT, Ivo, is always working on updates so maybe it's something he'll do.

Louise

Edit: Of course the difference between the preview and the raw is the difference between 8-bit data and 14-bit data

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Hi

They appear in APT under the Img tab and displayed on the right as in my screen captures. You locate the folder, double-click then select image and double-click on the small image and the full size image (if you have one) should appear in the main image area :) You only have the preview images if you've taken exposures in the first place and left them in the APT folder. If you move them to another folder (which you normally would i.e. to a different folder for stacking and processing) then APT can't see them anymore since they're no longer there... I always take raw+jpg. I forgot to mention before that you can select the raws you've taken and view them rather than the jpg. I forget things...

Louise

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ok, here it is. he somehow hides the preview images. It looks like his preview image compression is probably too high. so their is a significant noise difference ...

these pictures aren't too bad, but on some, when searching for objects, it was too noisy for me to see, and I had to manually load the image so I could see what I am looking for.

right now looking at them, they don't seem too far off ... but last night in the dark they seemed worse. But either way, you can see a significant noise difference, and color shift. even if I save my raw as a jpg with most image utilities, they look similar even though they loose data.

He probably just needs to not crank the compression so high on resave. here they are...

post-38374-0-41496100-1424334403_thumb.j

post-38374-0-78503100-1424334414_thumb.j

post-38374-0-39432300-1424334424_thumb.j

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Hi

There's very little difference between the APT screen shots and your quick view. I think the general consensus is that viewers convert raw to jpg anyway... I've been having a play about (just for fun!). Here are some screen captures comparing a jpg as seen on APT, a cr2 as seen on DPP, then the cr2 viewed on the DSS screen (which is adjustable) - comes out more pink and less detail. Then a stacked and very quickly processed image. It was 10 x 180s plus flats (which unfortunately didn't match!), stacked in DSS then stretched in CS2. The target was C42 though it's very faint and in the centre. Oh, taken on my full-spectrum 1100d and ST80 :) on 3rd Jan this year.

post-33532-0-66819600-1424360894_thumb.p

post-33532-0-49471700-1424360921_thumb.p

post-33532-0-60589000-1424360962_thumb.p

post-33532-0-86899200-1424361592_thumb.p

Apologies for the 'orrid gradients and artifacts! Still, from a bright pink set of subs to quite a few stars is quite satisfying.

I think I conclude that the APT preview is fine and nothing else is really any better anyway :)

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The last picture I posted, really shows the difference. But either way, no worries. I will just use Acdsee to view my exposures. because at points when looking for stars, I couldn't see anything in APT preview and figure out what I was seeing. it was too noisy from over compression. but I could see it fine using Acdsee. BYE doesn't do it, nor does it do it if I save my my raw into a jpg. 

although, I don't see why he wouldn't just load the raw into the main window, which makes more sense. because the point is to know what you have so you can decide if the exposure is good or you need to change your settings.  But, it is what it is, it's a really good program aside from that. 

actually, I had some feature ideas, but I forgot them. lol 

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Regardless of the various routes you use to get there, all of them lead to a view of a jpg. RAW/NEF files cannot be directly viewed. Trying to do more with a preview than framing and basic star shape evaluation is pointless.

The entire point of taking a large number of raw files and using the various stacking algorithms is to increase the signal. This resulting stack has a much wider dynamic range than a single exposure nor it  can possibly be displayed on our LED screens and as viewed the data appears to be highly compressed and dark, this is where the term STRECHING the data  comes from. The single raw file as displayed by JPEG ( by camera or software ) conversion is very different to the stack as the S/NR is very low. Any displayed image by the image capture software can only be used for framing and perhaps focus evaluation and not what the image would look like after stretching. The more AP specific capture software such as Maxim, Nebulosity, AA5, Artemis capture and the like do allow a temporary stretch to help evaluate the framing and focus as mentioned but any other data manipulation will have to be performed on the stack either in linear or none linear form by proper image processing software.

A.G

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most people show exactly what comes out of the camera in display and then give you options and tools to stretch or change things like gamma to better see what is and isn't. But usually things are represented the way they are at first. 

Then you can manipulate things. But to each their own :)

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Sorry to say, I mean no disrespect, but you've got it backwards. Manipulation is normally done AFTER stacking. No modification of image data should occur prior to or during stacking. You really have no idea what you've got, other than focus, framing, and star shape before then. If your previews are so bad that you cannot accomplish these preliminary steps, you probably need a lot more data per sub and/or have high LP (better site or get a high quality filter such as the Hutech IDAS LPS).

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