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JGM1971

The "No EQ" DSO Challenge!

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It was clear last night and surprisingly mild so went out the front and the best view between the street lights was Peliades but it is wide field as was using the 40mm pancake lens on the 1100d sat on the Virtuoso mount. For once set the time lapse running on DSLR Controller and checked focus every 10 or 20 images. I couldn't use a full set of calibration files as the orientation of them was wrong in my library. 123 lights 30 seconds (a couple 45 seconds) and 29 dark flats well over n hour of data the most I have processed and what a difference the noise is totally minimal and processing was so much easier. The clouds did roll in with thin wispy patches so I kept going and stacked the lot with plane trails galore. Kappa Sigmas Clipping appears to have sorted that out.

Below is the first pass process in DSS and StarTools, yey have nebulousity around the Peliades.

664579566_Autosave.ftsv1.thumb.jpg.8b11d358b306fe99ebb3659809587b03.jpg

Next process will deal with the little chromatic aberration and odd star issues like Aldebaran, I'm also checking to see if the nebulosity is in general all around or not. The image does process with a consistent dark background with out the possible nebulosity.

Edited by happy-kat
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I did a stack with out the worst of the clouds and that was not as easy to process as the stack with everything so I ditched that process. This is a process without the final life module seen in the previous version. Binning didn't improve the process (it does appear to when there is less data) so this was cropped only.

1044260412_Autosave001.ftsv8.thumb.jpg.5fef2c3d97ac1b6f898f8aabb6d849f8.jpg

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Hello all. I had a crack at sharpcap  steve.  I took these two images on the wo 72mm megrez on the evo mount. With a asi294 mc.  They were live stacked but not really  got to grips properly  with the stretching on the fly in that yet so I did a bit of post processing  with gimp.  The horse was 28 minutes worth of 30 second exposures. The rossete  was a lot less but I cant remember  for certain as it was a while back. I'm thinking I'm going to be doing both eaa and ap  depending on the night ect.  This is the second computer I've tried startools with now and neither have been enough to run it properly so it looks like I'll be sticking with gimp  for now. There were no darks or lights added with these as I've only just figured that out. Next time though. Oh I used a 0.8 reducer too. Cheers.

Stack_38frames_1521s-01.jpeg

PSX_20181119_111215.jpg

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I've had a few cracks at m33 now. It's a [removed word]. I'm going to keep trying this was about 30 minutes of 25 secs  on a 9.25 act live stacked with the 294 on the evo mount again.  Messed with in gimp. 

PSX_20181127_180912.jpg

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4 hours ago, happy-kat said:

Those are great images and love the colours too.

Thanks . All credit to the camera. It feels like cheating a bit but I'm ok with that.  It'll  be good to see what it can do once I get familiar  with sharpcap  and get out of my orange zone  backyard. 

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The bottom half of Orion with the Belt and Sword, from a stack of six separate frame stacks with various ISOs from 100 to 3200 (which I roughly normalised before the final 6 image stack) from various evenings over the last month.

Pics is a 1800 wide scale of the resultant frame.

The detail of the M42/M43 nebulae is my best so far, with some structure showing. "The Running Man" and the Edge nebulae are both clearly visable. The Horsehead Nebula's position is just visable.

There is some small misalignments in the top left and bottom right of the composite image from the lens geometric distortion as the various sets have come from different starting positions. There are also visable green background "swirls" which are from the intermixing of the lens' edge light dropoffs for the different sets. The emphasis for this stack is very much on the Nebulae detail.

Stars in the original are down to magnitude 14 (according to Stellarium). Rigel is the very bright star at magnitude 0.15 in the bottom right hand corner.

Static "hand-held" in the window frame: Nikon D800 with pre-Ai Nikkor 105mm f/2.5 at f/2.8; ISO at 100, 400 & 3200; stack of c.550 frames at 2.0 seconds each. IDAS LPS-D1 filter.

Taken in West London, in a Bortle 8+ zone (for a visibility scale if I look very hard in "best" conditions I can just about see Cursa / Beta (67) Eridani, which is about magnitude 2.8).

orion-c550-frame-image-stack-1b-scale1800.thumb.jpg.ea35d0faf0bde5eb975566fd72085160.jpg

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You certainly got some nebulosity there, I think my pc would curl up if I tried to stack c550 frames. Well done.

Does that mean you also have comet wirtenan 46p from your window?

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Why not put that in challenge #20 as you've got the constellation of the belt.

Maybe you could grab two more tiles to get the right hand side of the belt in.

Edited by happy-kat

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8 minutes ago, happy-kat said:

You certainly got some nebulosity there, I think my pc would curl up if I tried to stack c550 frames. Well done.

Does that mean you also have comet wirtenan 46p from your window?

Thanks 🙂

The biggest stack I have done in one go was just over 200 frames. These are from a D800 so each frame is 7360x4912 pixels, about 200MB each as 16 bit TIFFs. It took over six hours on my i7-2600K CPU computer (which is a slow-coach at the best of times).

Unfortunantly I don't have any of the comet: http://www.cometwatch.co.uk/comet-46p-wirtanen/

Most days I don't get visabilty as there are usually clouds.

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Your widow looks East facing so the comet was a possibility to image, it's heading towards Capella now.

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1 minute ago, happy-kat said:

Your widow looks East facing so the comet was a possibility to image, it's heading towards Capella now.

Sorry, my window looks pretty much due South (I was staying up late to get the Orion shots).

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47 minutes ago, happy-kat said:

Why not put that in challenge #20 as you've got the constellation of the belt.

Maybe you could grab two more tiles to get the right hand side of the belt in.

Um... mine isn't quite there yet:

... also I am using a 105mm lens, so I normally only get parts of constellations. I could try my Nikkor 60mm f/2.8 Micro which is probably my best lens optically but I don't have a Light Polution filter in that size (which may or may not be too aweful but I lose at least a stops worth of light differential).

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Why not get the two extra tiles to finish off the belt. It's for all to have a go and share what's possible from all different approaches.

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Example Cloud from last night to show the amount of local light pollution. Average RGB levels are at aproximalty 50% brightness.

Nikkor 105mm f/2.5 @ f/2.8 , 2.0 seconds, ISO800. Scaled to 1200 pixels.

susan-parker-light-frame-cloud-cover-nikkor-preAi-105mm2f5-iso800-2seconds-f2_8.jpg

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Posted (edited)

28-60 second exposures,  15 dark, 15 flat.  Nexstar evolution  mount, wo72 mm megrez. 0.8 reducer/flattened. Asi 294mc and a baader moon and sky glow filter.  Stacked in sharpcap  , post processed in gimp and the android photoshop.  I've had this mount up to 115 seconds without any trailing that I notice , a better eye might. When weather permits I'm going to try longer, just to see when things start looking wrong. I dont know if was really good conditions and I just coincidentally  got all the settings right on the cam but it appeared that filter really helped. I have tried it on a few nebula  and it seemed good but seemed to work against me on andromeda.  Not had a chance on any other galaxys  yet but I'm reading mixed opinions on galaxy's and these filters? Thoughts on that please. North  america nebula. Orange  zone.

PSX_20181217_214437.jpg

Edited by Manners2020
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33 minutes ago, Manners2020 said:

I dont know if was really good conditions and I just coincidentally  got all the settings right on the cam but it appeared that filter really helped.

I think it’s because NAN would be in the west and at a mid altitude. Almost the perfect location to avoid field rotation. The Evo mount can easily track up to 120 seconds at that focal length so just pick your targets to make best use :)

you have a strong image though I think you still have a gradient. It looks brightest in the centre so my first thought was whether your flats were working but I think it’s probably just stubborn light pollution. I don’t know if there are any gradient removal tools in Gimp or Android PS, but it might help lift the Nebula.

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I'm going go pick your brains a bit if you dont mind. So I'm thinking if star trailing was going to occur at this fl  it already would have, so now with the field rotation. The longer I expose the more I will have to crop because the fanning effect from stacking will be increased?

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6 minutes ago, Manners2020 said:

The longer I expose the more I will have to crop because the fanning effect from stacking will be increased?

In fact I have seen that cropping also zooms in the remainging image, and so magnifies inner star trails to the point the whole image is mostly unusable. So you may be better off keeping exposure limited to a smaller value and take+process more subs.

14 minutes ago, Manners2020 said:

Mud alt = less rotation,  max exposure?

It's actually a combination of altitude and azimuth, but yes globally more alt = faster alt-az-relative rotation = less exposure. Rotation starts at a given speed low on horizon then raises to a common maximum speed (lowest possible exposures) at zenith. Azimuths East and West give the lowest rotation speed on horizon, while South and North are higher.

There's a PDF with graphs depending on your latitude somewhere in the thread... PS: I don't have it at hand, but it should be pinned somewhere as the question comes in frequently.

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