I give up - I need to Guide. Pls advise.

[Spacehead]

Ok guys - I am working on this as hard as I can right now - tonnes of tips here to go for and I am taking ****every single one of them on board**** as best I can understand.

Hopefully I will get back with good news.  I apologise for the digression, my OP still stands really - I DO think guiding will help me in other areas such as longer subs for getting the Ha.

ATM - I am running a quick stack with 70 lights and 5 flats (I only have 5 - should have done more) - but today I'll create a load of flats, I will be using the following setup.
I can spend a few hours on this, this "temperature" thing - I am not sure what is meant there yet.
I only understand ISO and Exposure time as yet really.



In addition to a range of ISOs and Exposure times, I am going to go EXPLICITLY with the following tutorial for median brightness - it's where my own method above is derived from.  I hope im on the right track
https://photographingspace.com/how-to-create-dslr-and-ccd-flat-frames-for-astrophotography/







 

[alexbb]

Definitely guiding is the way to go and then dithering. My advice about this is to try with a laptop and PHD and first try with ST4 guiding, only after you succeed you should try with EQASCOM and pulse guiding. This is to keep things simple and take it one step at a time.

About the temperature thing: the warmer the sensor gets, the noisier the result is. Hot pixels and amp glow will have about the same values at the same temperature and the subtracted darks will correct better.

For instance, if the lights are taken at a low temperature, the image will have an amount of noise. If darks are taken at a high temperature, a dark will have more noise and, therefore, higher pixel values and not proportional. Worse, there will be more hot pixels which are saturated as the temperature increase. If you subtract these hot pixels which are not present or have a lower value in the lights, you'll get dark(er) pixels instead in the calibrated frame. Combined with the drift, what do you believe the effect is?

[Oddsocks]

.

 

 

[alexbb]

I would recommend to use the autosave.tiff or save the unaltered image and process this instead. If you apply the stretch in DSS and the histogram peak is to the left of the rising curve, you will reduce a lot of your signal. Then if you want to stretch it in another processing tool, you will have some coarse data to work with and it will be more difficult.

[ollypenrice]

17 hours ago, Spacehead said:

I don't think uneven illumination (vignetting) in this case moves with the scope at all.  The vignette remains constant in the center of all frames - (or in my case slightly off left center) - and the stars move across it - positioning themselves as per the drift.   Irrespective of the position of the scope.
 

 

If the vignette remains constant in the middle of each frame  (you're right, it does) and the scope then moves, a different part of the sky will be vignetted.

Flats are applied to each sub before combining because the vignette and the sky as captured in that sub must be one and the same. When the scope takes the next sub the stars will have moved slightly, the vignette will have moved with it, so that discrete image must be corrected. And so on.

16 hours ago, Spacehead said:

Yeah I am getting that (to an extent) - but am I wrong in saying that flat application to a frame can only be done AFTER the frame is aligned to its final position within the constructed final image?

 

If the stacking software moves image 2 to align it with image 1 it most move image 2's flat to the same position and apply it to image 2. The logical thing for the software to do is apply the flat to image 2 and only then move the flattened image 2 to its now position aligned on image 1.

Olly

[Spacehead]

Holy cr** I have been given some serious advice here - I can't thank you guys enough for your time and effort in helping me out.
I am on it - and will get back to you as soon as I get some good flats together - I am on a learning curve so please bear with!!!
Thanks again!!!!!

[Spacehead]

I can't thank you all enough for putting up with me flapping like a pelican with no head!

I have taken on board EVERYTHING you have all said - i've worked hard today checking and double checking every single post / hint / advice and the progress has astounded me.

I know I am moving forward now - and am proud to say the following (even though I know I am a complete noob) :-
Lights - 65 - 1 Min Subs - Tracked
Darks - 15
Flats  - 26
ISO 800
Skywatcher 200p, Canon EOS 1300d (Modded).

THANKYOU GUYS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

My journey has begun at long last

[Oddsocks]

.

[wxsatuser]

That's a big step and made all the difference.

As Oddsocks points out, use RAW, it's no harder to process in DSS, they may look grey but William posted how to deal with that.

[Spacehead]

Guys - these are the RAW (CR2) files for the lights, darks and flats.

My next step now is to equate the functionality available to me in PaintShop Pro X8 with what is available in the vastly more widely used Photoshop - which at this point I can't afford to subscribe to unfortunately - but I'm working on that.
To be honest I think X8 is going to have much of what Photoshop has (I hope) - just I haven't had much practice yet.  (And the excitement got to me - with all that redness captured I just HAD to report back here!!!!)

I have uploaded the stacked image which I used in Painshop Pro X8 - would anyone be kind enough to show me how good it would be with Photoshop - whats in it - what can photoshop bring out?  This way I can compare (I will be going back to it today to try and process it properly) what I am capable of doing with this example set, against what people of more experience can do with Photoshop - I think that would further motivate me - not that I need it - I have totally got the "bug" now.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
http://www.serlimited-uk.co.uk/space/pel1stack.TIF

 

[happy-kat]

With your camera you will need DSS 3.3.4 other wise using raw your image will be tall and thin.

Output as fits from DSS if you want a truely uncompressed file. (Though PaintshopPro can't open fits).

PaintshopPro can run the two useful plugins of gradient exterminator and hastalevista green. Budgetastro.net has some use full tutorials on processing and I had found I could pretty much follow then using PaintshopPro.

[Spacehead]

Thanks Happy-kat - there is quite a lot of the vignette left in the image, am I correct in thinking this is what gradient exterminator is for?
I cant find a download for it anywhere.

[Oddsocks]

.

[Spacehead]

let me check oddsocks - i thought I had that nailed.

 

[Spacehead]

Oddsocks - its the final stacked image - very faint still until processed - but its a TIFF, so it was created using the DSS save picture to file.  Can you try it?

[Oddsocks]

.

[Spacehead]

I have just checked the histogram in it - it has the DSS border around it creating the small lump on the left.
Also - for ref - here is a sample of an original which went into the stack - really quite different (and CR2 naturally)
http://www.serlimited-uk.co.uk/space/IMG_0870.CR2

 

 

[Oddsocks]

.

 

[Spacehead]

It doesnt make sense - you can see what I got out of it with PaintShop X8 in the cropped out bit I showed above when I got all excited!

[Spacehead]

If I upload the lot - would you stack and process for me - for me to check out what I should be looking to achieve?

 

[Oddsocks]

.

[Oddsocks]

.

[Oddsocks]

.

 

[happy-kat]

I have used it in x8 I now have x9 (19.99 offer so got latest version) and yet to add my plugins. The only thing it didn't do is keep the licence key so I had to add it on each use.

[Oddsocks]

.