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JGM1971

The "No EQ" DSO Challenge!

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I've just had a quick process of my M101 from last night. There's something odd going on here; this is heavy stretch after after cropping and wiping, and I have this odd effect mainly visible in the top left, but it does extend to around the galaxy. It doesn't matter how hard I crop (and this is already quite a crop) I can't get rid of it.

58d7bba9307a3_M101147stackfirststretch-1.thumb.JPG.0df59e65997d14d596871020aadb3b4e.JPG

There's nothing like it on the flats, and of course I didn't take any darks, which might have revealed if there was any amp glow. But that said, I've never seen anything like this before so I would be surprised if amp glow is now rearing its head. Any ideas? I suppose it might be an effect of high cloud, such as a vapour trail, but there was quite a breeze yesterday so I wouldn't have thought it would hang around in one place too long. I don't recall anything like it on M64 I did the day before.

Anyway, I've pressed on with the processing just to see what I could get out, and this is the result. The black point is set quite hight but the artefact is still just about visible.

58d7bd30aba2b_M101147stackST2colLR1.thumb.jpg.ee680013416a89f06e773468e40d1687.jpg

Not too sad. There is some chromatic aberration visible on some of the bright stars - whether it's down to my optics or ice in the high atmosphere I wouldn't care to say. The galaxy towards the bottom right is NGC 5474, and near the middle of the LHS is NGC 5477. I had hoped to reveal NGC 5422 off beyond the top but it was right in the crop area needed as a result of field rotation.

Ian

Edited by The Admiral
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2 hours ago, Shaun_Astro said:

Need to have ten posts before I can have a signature apparently; I'll find some threads to spam :)

It doesn't really help when it comes to a particular image, most signatures have a selection of mounts, telescopes and all sorts even you have two telescopes so either one might have been used. It's just helpful to know what created an image.

Ian that's great processing it's come out well and CA if there is any is very polite compared to the stuff I'm getting. 

Edited by happy-kat
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Thanks Happy-Kat.

I agree with you about what equipment is used. So often one sees a pic in forum and there's nothing about what it took to get the image, other than a list of subs, times and whether it's L, R, G, B, or Ha, or whatever. I'm sometime guilty of that mind, like in my above image :wink2:.

Ian

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46 minutes ago, Stub Mandrel said:

Well on the plus side you have some lovely colour in the galaxy.

Thank you Neil, and thanks to StarTools!

Ian

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1 hour ago, The Admiral said:

There's nothing like it on the flats

If it's not in the flats then it may be dew. Is it in every sub or just some? It doesn't look like amp glow which show stretch from a side or corner rather than curve unless you had both glow and dew!

It's a shame as it's the only think spoiling the galaxy which is showing some nice red areas in the arms. 

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Thanks Ken. I'm quite pleased I've also captured some detail in NGC 5474, which apparently is a rare dwarf spiral galaxy, in the M101 group. One can make out the spiral nature of the galaxy and the star forming regions, just!

The pic I showed is of the stacked fits, after wiping and hard stretching. There's nothing obvious in the subs, but then without dealing with the backgrounds in all of them individually, I don't really expect to be able to. I might check a selection when I have a moment. It wasn't a dewy evening, and a quick glance at the OG when I was doing the flats at the end of the session revealed no misting up. It's very much the sort of effect one might get with ST if one doesn't crop all of the stacking artefacts away before wiping. But as I say, I cropped quite a bit off so I can't believe I left any stacking artefacts. It was also an easterly target so field rotation shouldn't have been excessive (though the mount was wandering a bit).

Ian

EDIT. I think I may have a way around it! I'll report later when I've had a chance to implement.

Edited by The Admiral

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Right, I've had another (well, several actually!) go and whilst not getting to the bottom of it, I have at least managed to suppress it by using a higher aggressiveness in wipe-vignetting. This has also allowed me to extend the frame size to include NGC 5422. Because this is in the stacking artefact zone I've ended up needing to clone some of the background back in, in that extreme corner. I think this must now be the definitive image!

So, in summary, I collected a total of 205 x 30s subs at ISO1600 (battery ran out on the final batch :icon_eek:) on 25th March 2017, from which I selected 147 to stack in AstroArt. I used 60 flats and a generic bias from 200 frames. Processing was performed in StarTools and final polishing in both Lightroom and PWPro.

The usual equipment:  Fuji X-T1 through an Altair 102mm f/7 Super ED with a TS Photoline 2" 0.79x reducer/flattener. Mounted on a Nexstar 6/8SE Alt-Az mount, now with added StarSense! (even if the operator of it doesn't have any :icon_biggrin:).

Ian

58d80ef79e767_M101147stackST5colLR1cln.thumb.jpg.fe4866d96d878f3d899004de7ab57caf.jpg

Edited by The Admiral
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This is last night's process of comet 41p, no interesting bed fellows this time and I had to do a very generous crop because the comet advanced into the gutter. May have slightly over egged the colours directly on the comet. No more comet now until it appears out the back, with the clocks changed it will be too high for being out the front.

DSS is clipping the data it produces as on loading the fits file converted to tiff and opened in PSP looking at levels it's clipped straight away equally saving the stacked output from DSS to tiff is also clipped straightaway. I am not sure why DSS is now clipping the data I produce so I will compare a stack from last year with a comet and the gutter. I do use the baader filter but I had this last year.

Virtuoso mount Canon 1100d vintage 135mm at f4 ISO 1600 49 lights 22 flats 25 bias plus 8 inch flocked lens shield and cardboard sheet on a stick to block the nearest street lamp.

 

41p v3.png

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Well caught Happy-Kat. As you say, it makes a nice change to see one of the rarer targets.

My images always have some stars which are saturated, so I can't quite understand your surprise, if I understand you correctly.

Ian

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Thank you.

When I look at levels in PSP on this new data last couple sessions to data taken say last year then the data is right up to the left edge in levels (clipped) it never used to be it's clipped to the right as well.  The single change is stacking on windows 10. Tuesday I will stack this data using XP and compare.

Edit 1: I think it is because I haven't installed the Canon utilities etc. on this W10 disc. W10 comes with the capabilities to review raw files so it didn't occur to me to install them.

Edited by happy-kat

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Hmm, OK. I'm not familiar with PSP, and I'm not sure how a change of operating system could bring that about. I do wonder though if data is ever that consistent. Light pollution alone would not be the same.

Ian

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Would you mind posting the stacked file? I had a similar issue last night on my M51. Big dark spot in the middle.

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Did you take flats Herzy, and if so, before or after the session? Did they show any abnormalities?

I've just done a bit more checking. I stacked the flats and examined the RGB separately; no sign of anything unusual. I scanned through the individual subs and whilst there was nothing major that might have given rise to the artefact, I did notice that the background 'red fuzz' appeared quite blotchy and gave the appearance of drift between subs, so I'm wondering if this was the result of thin high cloud drifting in the wind.

Ian

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26 minutes ago, The Admiral said:

so I'm wondering if this was the result of thin high cloud drifting in the wind.

I find that almost impossible to remove post process so I don't include any subs with cloud. I wonder is StarTools treats cloud gradients like artefacts and has a wobbly too?

High cloud is my bane. It pretty much prevents me imaging. Frustrating, as I the camera pierces them. I just can't remove them from the stacked result. 

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12 hours ago, Herzy said:

Would you mind posting the stacked file? I had a similar issue last night on my M51. Big dark spot in the middle.

That means you have the very bottom Luminance slider too far to the right, it causes the curve to droop and causes hollow stars.

 

Just for references, I have no problems using DSS with W10.

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Doing a bit more sleuthing, at the time of my imaging on 25th we had an ENE breeze at ground level, and as we were then under the influence of high pressure I would postulate that any high clouds would have been subjected to a more northerly breeze. As M101 was itself more or less ENE this would mean that the cloud would have been drifting from left to right across the frame, which is more or less what I observe. So if anything this reinforces the assumption, though quite why it should appear in the way it did I don't know. One can only assume that the wipe algorithm was confused by the varying pattern of light and dark.

Ian

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With starsense can you control the scope remotely still like with pc stellarium or mobile app? 

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I've had an experiment with bias files and the result was very promising and can be sen here, I redid my comet process.

Link

Edited by happy-kat

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18 hours ago, jimbo747 said:

With starsense can you control the scope remotely still like with pc stellarium or mobile app? 

I believe you can but I haven't tried it yet (only just got my Starsense for SW kit).

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On 29/03/2017 at 17:03, DorsetBlue said:

I believe you can but I haven't tried it yet (only just got my Starsense for SW kit).

Well if you happen to find out, please let me know (mines a SLT mount but imagine should work the same). Don't know whether to get the wireless adapter instead, or both... Stellarium no longer playing with my mount so it's sat outside unused for 6 months.

 

Cheers

 

James

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On 01/04/2017 at 16:54, jimbo747 said:

Well if you happen to find out, please let me know (mines a SLT mount but imagine should work the same). Don't know whether to get the wireless adapter instead, or both... Stellarium no longer playing with my mount so it's sat outside unused for 6 months.

 

Cheers

 

James

Need less cloud first lol. My SS had the new USB port connections, so I have a USB-Serial converter built into the handset.  This apparently simplifies the connection greatly (it did for the Firmware update) but we will see.  The SS is currently connected to a bitsa (i.e. Astroboot special) SW AltAz BTW.

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Seething. Raging even. 

Last night I decided to properly sort my scope out, focused the mak with barlow and 224mc ready for some jupiter shots, attached the IR and UV cut to my 1100d, perfect focus at 10-12 degrees, spot on alightment, set scope to park, connected via my remote intel nuc in my mini observatory ready for tonight.

 

Moon looks good, jupiter now above houses, will see orion, lovely calm night, best one this year. Turn on mount, get laptop and a glass of wine and boot up teamviewer... no connection. Try another laptop and same...

 

Just read as of 10 minutes ago teamviewer down for 8 hours of maintenance!!! Just my nonefamilyfriendlyword-ing luck!!!

Remote desktop not setup. None of the software setup on my laptop and I'd have to do another alignment which is a pain to do without line of sight (took an hour last night). I just wanted to use the 224mc and modified dslr for the first time, and the Gods are laughing at me. 

 

If something happens tomorrow night, theres a free keter max storage box, raspberry pi with linear actuator, SLT mount, 127 mak, 1100d, asi 224mc, intel NUC and a load of filters, web cameras and storage cases available for collection from derbyshire FOC.

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That's real tough luck Jimbo. 

Enjoy your wine at least, there will be more clear sky's for you and you know it's worth the wait. 

These things are sent to try us.

Can you not  manually track and video Jupiter. You only need 30 seconds or so to get a good stack in Registax or Autostakkert. 

Chin up. ☺

Nige

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