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JGM1971

The "No EQ" DSO Challenge!

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Perhaps I'm being a bit thick, but why did you need the laptop out with your scope?

Ian

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Posted (edited)

To take photos...? And control the mount...?

I've tried trailing a big long USB cable into the house but it's just very fiddlesome and not reliable. I figured it made more sense having the laptop where the rig is, so I can get everything aligned and plate solved nicely, then go into the house and monitor proceedings inside, on my PC, using Chrome Remote Desktop via wifi. As the laptop takes the photos, it uploads them to OneDrive, so I can see what's coming through at the other end on my PC. If I need to fix something, I can dash out and sort it out at the laptop end.

I guess I could use an intervalometer for the camera and the Synscan controller for the mount, and not involve a laptop at all. But I do like to control everything through APT, and I think platesolving is a miraculous thing. And I just like mucking about with technical things, is all. I'm even going to try and get my old netbook to control everything tonight, just because it'll be interesting to see if it can handle it.

Edited by BrendanC
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Posted (edited)

I thought I’d put something back into this thread 😀

Not my best, but I’ve reprocessed my M42 shot from January. 

NexStar 5SE, Canon 100D, 97x 30s lights, 50x 30s darks.

It’s only a JPEG, the TIFF was too large to upload.

Josh 😀

 

03221C93-D02E-48A3-BE71-A9FFE01E8959.png

Edited by JoshHopk
Grammar
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Posted (edited)

I use my Nexstar 5SE on its original alt-az mount for this shot of the Sombrero Galaxy with a stock Canon 650d. It consists of 5 minutes of data using 15 second subs at ISO 3200 with 10 dark, flat and bias frames.

M104 Sombrero Galaxy.png

Edited by Nerf_Caching
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Posted (edited)

My first photo of Messier 101 taken with a 20" SW Stargate 500p dobsonian and Nikon D810 with ES coma corrector under fairly bright town 20.2 SQM skies.

Excuse the terrible vignetting on the edges! Working on that. 👀

220 x 8 second subs at ISO 2500 for a tick over 29 minutes total integration. 

No darks/flats or bias shots.  The images were stacked in DSS using recommended settings, then edited in Lightroom 5.

Will learn how to stretch photos and add darks at some point 👍

 

 

101 thrid edits-1_filtered.jpg

Edited by Ships and Stars
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33 minutes ago, BrendanC said:

That's really good. :)

Thanks Brendan, still a lot of work to do on it. Really needs dark frames adding but pretty happy with it. 

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54 minutes ago, Ships and Stars said:

My first photo of Messier 101 taken with a 20" SW Stargate 500p dobsonian and Nikon D810 with ES coma corrector under fairly bright town 20.2 SQM skies.

Very good indeed but the colour balance could use adjusting, it's very blue with a slight green tinge in the background.

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32 minutes ago, Knight of Clear Skies said:

Very good indeed but the colour balance could use adjusting, it's very blue with a slight green tinge in the background.

Thanks, I'll have a look. I set RGB all equal using eyedropper tool, don't see any green on my monitor, but didn't want to make background sky totally black, like a bit of grey for a more natural look.

I don't know much about sRGB vs Adobe RGB etc so that could explain things. 

I do notice the uploaded images here seem to discard some edits, hence the extra vignetting which I tried to crop without cutting the ends of the spiral arms.

Both M101 and M51 are naturally blue without filters, guess I'd need to shoot three or four sets of subs using filters to achieve a different colour, as in the'Hubble palette'. I actually reduced saturation a bit on this.

I'll have to practice some more. Will take dark frames and learn to stretch and edit in DSS 👍

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That's a light bucket hoover very nice

I would take bias and flats and dark flats over actual darks, the latter with a dslr can be prone to adding noise

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21 minutes ago, happy-kat said:

That's a light bucket hoover very nice

I would take bias and flats and dark flats over actual darks, the latter with a dslr can be prone to adding noise

Thanks, was just reading on DSS help about the bias exposures, etc, really need to add those!

The 20" dob is indeed a photon hoover, even with short exposures it goes pretty deep, and that's under town LP. Hoping to try this at my dark site in the autumn.

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18 hours ago, Ships and Stars said:

Thanks, I'll have a look. I set RGB all equal using eyedropper tool, don't see any green on my monitor, but didn't want to make background sky totally black, like a bit of grey for a more natural look.

I don't know much about sRGB vs Adobe RGB etc so that could explain things. 

I do notice the uploaded images here seem to discard some edits, hence the extra vignetting which I tried to crop without cutting the ends of the spiral arms.

Both M101 and M51 are naturally blue without filters, guess I'd need to shoot three or four sets of subs using filters to achieve a different colour, as in the'Hubble palette'. I actually reduced saturation a bit on this.

I'll have to practice some more. Will take dark frames and learn to stretch and edit in DSS 👍

I note you're only using DSS and Lightroom to process your images which could explain the  blue colour cast. Whilst M101 does have blue arms, the giveaway to know the colours in the image are not balanced is that both the background, which should be a neutral grey, is much bluer and slightly more green suggesting red needs a boost and blue dialled back. Also, the centre of the galaxy should be a yellow hue. Your stars are fairly saturated so they aren't going to help you balance the colours unfortunately.

Colour balance needs to be done early in processing. You'd need to separate the RGB channels and work them individually before they are stretched. And each will require it's own stretch. That way you can boost the red channel which looks to be weakest and tone back the blue. This is probably be beyond DSS and Lightroom so you may need to use a third package to do the bulk of the heavy lifting and use Lightroom to do the finishing touches (vibrance, sharpness, clarity, etc).

Did you image under heavy light pollution or under moonlight? They may have introduced the colour cast so you may also want to remove any gradients in the image before stretching.

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7 minutes ago, Filroden said:

I note you're only using DSS and Lightroom to process your images which could explain the  blue colour cast. Whilst M101 does have blue arms, the giveaway to know the colours in the image are not balanced is that both the background, which should be a neutral grey, is much bluer and slightly more green suggesting red needs a boost and blue dialled back. Also, the centre of the galaxy should be a yellow hue. Your stars are fairly saturated so they aren't going to help you balance the colours unfortunately.

Colour balance needs to be done early in processing. You'd need to separate the RGB channels and work them individually before they are stretched. And each will require it's own stretch. That way you can boost the red channel which looks to be weakest and tone back the blue. This is probably be beyond DSS and Lightroom so you may need to use a third package to do the bulk of the heavy lifting and use Lightroom to do the finishing touches (vibrance, sharpness, clarity, etc).

Did you image under heavy light pollution or under moonlight? They may have introduced the colour cast so you may also want to remove any gradients in the image before stretching.

Thanks Filroden, I wanted to ask what the 'natural' colour of M101 was.

I have GIMP I could use for working with RGB channels I suppose. I haven't done any editing in DSS, just stacking, so need to learn how to boost the red etc, I'll have plenty of time for that this summer because we lose astro darkness from early May to late August

How would you avoid overexposing the stars? Drop to a lower ISO presumably?

I also shot M82 at ISO 400 and was astonished to find it actually worked, very little noise, so may drop down to ISO 200 based on recommendations from others.

It's great fun when it all works right.

Thanks for the tips, I need to do some reading and tutorials this summer 👍

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The light histogram should be driving your ISO choice based on the exposure length being used. The peak you want to be clear of the left edge when you review an image on your camera but not as far as in the middle as you are aiming only for the left edge of the peak to be totally clear shop you aren't clipping the side of the histogram.

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3 hours ago, Ships and Stars said:

How would you avoid overexposing the stars? Drop to a lower ISO presumably?

I doubt you can avoid it. If you want coloured stars you may be better developing two versions of the same image - one with a very light stretch just to get whhat colour you can in the stars (the galaxy will probably be lost in the background) and one to process the galaxy then join the two images so the stars from one join the galaxy from the other.

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26 minutes ago, Filroden said:

I doubt you can avoid it. If you want coloured stars you may be better developing two versions of the same image - one with a very light stretch just to get whhat colour you can in the stars (the galaxy will probably be lost in the background) and one to process the galaxy then join the two images so the stars from one join the galaxy from the other.

Thank you! Might invest in Photoshop if GIMP isn't up to the task. 

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Posted (edited)
8 minutes ago, Ships and Stars said:

Thank you! Might invest in Photoshop if GIMP isn't up to the task. 

GIMP should have all the same core processing abilities as Photoshop though they may have different terminologies. Where Photoshop will possible shine is in the available (paid for) extensions which can make astro-processing easier. Before investing, you may want to trial more dedicated astro-processing software such as Startools, PixInsight, Astroart, etc. These have more astro-oriented processes such as gradient removal and colour correction built in. Each has its strengths and weaknesses, and a lot of which package you eventually use will be subjective based on which workflow you prefer.

Some of them also offer better calibration and integration tools than DSS.

There are plenty of web and YouTube tutorials for each of them and I think they all offer trials.

Edit: I should add, these packages have different ways to do colour calibration. E.g. PixInsight can plate solve your image and match the stars to their spectral type using an online database and then apply colour corrections to get your image as close to their "true" colour as possible.

Edited by Filroden
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On 20/04/2020 at 12:56, Ships and Stars said:

My first photo of Messier 101 taken with a 20" SW Stargate 500p dobsonian and Nikon D810 with ES coma corrector under fairly bright town 20.2 SQM skies.

Excuse the terrible vignetting on the edges! Working on that. 👀

220 x 8 second subs at ISO 2500 for a tick over 29 minutes total integration. 

No darks/flats or bias shots.  The images were stacked in DSS using recommended settings, then edited in Lightroom 5.

Will learn how to stretch photos and add darks at some point 👍

 

 

101 thrid edits-1_filtered.jpg

Wow, that truly proves aperture is king!

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Here's another B&W image I've started - 73 x 6" subs of M81 at ISO 400 for a very brief 9min 44sec integration, no darks/flats/bias yet. I'd like to increase contrast without losing detail, and will work on colour when I crack the RGB channel stretchy thingy!

Lots of programmes Filroden mentioned, thank you 👍

I'll make sure the histogram isn't buried to the left on these short exposures, quite pleasantly surprised ISO400 even works on this.

Looking clear again tonight, might be my last chance for awhile to get more data with the mighty photon hoover 🤣

M81 Bodes nebula-2_filtered.jpg

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M81 & M82

Altair 72mm Semi Apo Scope, AZGTi mount, ZWO 178MC camera.

Livestacked in sharpcap 15mins total integration.

950285670_M81_M8215mins178MC22042020JPG.jpg.3428c423940bbc40707a8b4a55801401.jpg

 

 

Forgot about this thread being dedicated to non EQ imaging.

 

Thanks for looking 🙂

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That's a lovely capture. I guess that's your camera giving that closer image given your relatively short telescope.

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On 21/04/2020 at 15:42, Ships and Stars said:

I'd like to increase contrast without losing detail,

Astra image would work wonders on that nice image.

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M66 and needle galaxy. Live stacked in sharcap . 9 second exposures for a total of 13 minutes on each. 9.25 sct @6.3, asi294mc, Nexstar evolution mount. Darks and flats applied and edited in snapseed.

PSX_20200423_103849.jpg

PSX_20200423_103618.jpg

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Leo triplet livestacked in sharpcap. 60 ×60 second exposures, 20×darks and flats. 72mm megrez on an evolution mount with a asi294mc. Edited in sharpcap.

PSX_20200423_103723.jpg

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Couple more from last night. 

Leo Triplet

1979627537A94799A1F7ACC0F66C4D8C.jpg.1180e571f81f7bc30a60e91b9f7af060.jpg

 

NGC2903

F2F07C5C93B74E13AB8D374A2CDAC8C4.jpg.836caf276c5e7fa0204faddf10a63d6b.jpg

 

 

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