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File: neowise5.jpg (620 KB, 7155x4233)
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REEE WHY IS ASTROPHOTOGRAPHY SO FUCKING HARD SOMEONE FIX MY IMAGE THIS IS A GODDAMN 70 FRAME STACK AND IT STILL LOOKS LIKE SHIT REEEE

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>>
>>3698012
Where’s the comet? What did you stack it with and what settings? I know DSS will actually remove objects for you depending on the settings, for example it can remove satellites.

Also In order to fix your image it should be 16-bit as usually things require a lot of contrast expansion at the very low end
>>
>>3698012
This has to be a troll post
>>
Ah yes, dots on a grey background. Fantastic image
>>
>>3698012
>SOMEONE FIX MY IMAGE
Here ya go buddy, just tweaked the contrast : )

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File: 1596184427368.jpg (676 KB, 7155x4233)
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>>3698012
>JPG
>That awful red
>Not enough exposure/light
>Wanting people to fix a lossy image

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File: neowise6.jpg (142 KB, 2000x1183)
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>>3698019
The comet is in the upper third intersection I've stacked with both DSS and Sequator. DSS seemed to produce the cleaner result.

I'm working from a 16-bit tiff, made from 70 1/2 second exposures at ISO 3200, f/2.5. The skyglow was pretty bad yesterday with the waxing gibbous. Is there any secret exposure combination that will produce better stars with less skyglow if I'm stacking? How many images should I try and stack? Clearly, a 35 second exposure wasn't enough.

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>>3698012
The amount of you falling for this is truly sad
>>
>>3698218
Well normally you’re supposed to take flats, bias, dark flats etc, and they will remove the unevenness from the image (and the read noise somewhat I suppose).

Trying to separate the stars onto a separate layer might help too
https://astrobackyard.com/starnet-astrophotography/
>>
>>3698085
lmao, do you even know how astrophotography works?
>>
>>3698224

Yeah, i fucked up by not shooting the support images. I didn't think they would make that much of a difference, but maybe I was super wrong.
>>
>>3698235
calibration frames wouldn't have saved this. if you're using a modern camera you also most likely don't need them.

>>3698224
not a big fan of astrobackyard. he spends too much time talking about himself. also I think he abuses photoshop on his photos. If you start doing selective modifications to your photo I think you failed imo.

Read up on https://clarkvision.com/articles/astrophotography.image.processing/ this guy has the most extensive guide on astrophotography out there.
>>
>>3698239
I was using a D800. I'm definitely getting some magenta sensor glow on the bottom of the frame.

And thanks for the clarkvision. I didn't know he was still updating his website. He's like the Lawful Good version of Ken Rockwell.
>>
>>3698218
Remember, Astro is a shit ton of technical shit. Anyway. Should’ve used longer exposures. Even 3 to 4 seconds or something(which is low). In what kind of bortle level sky are you? In a low level (sub 5) you should be able to do 10-20 sec exposures easily without much trailing. Also how about you post a single flat jpg so we can see what the source material looks like? Either your pics are worthless or you are shitting it up with stacking. Your doing something wrong buddy.

This is a bortle 8, single frame, 16mm F1.4 at 1.6 seconds unstacked pic but edited and cropped in Lightroom.

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>>3698326
Just randomly chucking in shit doesn’t work.

5 second exposure. Single frame edited in Lightroom mobile (so probably a shifty jpg source).

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>>3698326
> In a low level (sub 5) you should be able to do 10-20 sec exposures easily without much trailing.
are you talking about final exposure time or sub exposures?
>>
>>3698329
For each single frame, not total stacked. That varies anyway depending on Hoe many actual usable frames you get.
>>
>>3698329
Also I said trailing but I meant over exposure. In high bortle skies the light pollution will wash out your frame with a long exposure. Trailing depends on focal length but that doesn’t seem an issue atm.
>>
File: baseimage.jpg (170 KB, 1980x1321)
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>>3698326

Here's a randomly selected JPG out of the stack. I might just be truly shit at stacking.

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>>3698334
>Also I said trailing but I meant over exposure.
yeah I was about to call you out on that, bortle has nothing to do with trailing.
>>
>>3698337
wait, you're stacking jpegs? lmao, don't do that! use RAW wtf...
>>
>>3698337
Besides the low exposure time there’s a quite a bit of data in that pic. So expose longer. The stars are sharp as shit, and with more time the comets tail should be visible. Then with stacking you can enhance but stacking is a painful procedure I personally don’t enjoy.

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>>
File: neo4cropsmall.jpg (447 KB, 1920x1165)
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>>3698347
>>3698344

Thank you for inspiring me guys. I'm gonna try harder tonight. Sequator produced... interesting results.

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>>3698354
Look at how much data is in those frames. Keep at it. Don’t put up with that shit like your OP pic
>>
>>3698360
Sick. I'll try some 3 second exposures (shooting 105mm) tonight and see what I can come up with. Should I ignore overexposure and ETTR since I'm using raw?
>>
>>3698362
you're not gonna over expose your shot at 3sec. and make sure you still check your trailing. take a bunch of test shots until you're happy with the results before starting your shots for real.

also what ISO are you shooting at? for 3sec you'd want to be around 1600 to 3200.
>>
>>3698362
With a 105mm on a full frame sensor you can do max 4.7 second exposures(500 / focal length) before star trails. Just take test shots as the other anon said and check the results before you commit to a time lapse.
>>
>>3698365
I've been shooting at 3200 so far. And i'll definitely check for trailing before I commit to ten minutes of guarding my camera.

One last question: what should I do about manually repositioning my camera as the sky drifts? Leave it alone? The sequator shot shows some clear lines where I moved the camera down to keep Neowise in frame.
>>
>>3698372
If you mean lines at the side, crop.

Else I can’t help as I only have a wide lens, I have no experience shooting 105. Maybe you can try to check the time how long it takes to move out of the shot and make a rule on how many exposures you take before you reposition. And don’t make too big a change in position else it won’t stack properly. There’s bound to be an article on how to stack unguided DSOs which may be applicable to Neowise.
>>
>>3698372
when I shoot untracked I re-frame every 5min. but it depends on how big your target is.if you just want a shot of neowise if you start it centered I don't think you would need to re-frame. Also it shouldn't give you lines like that. maybe check your settings. I use Siril, and never had any problems.

What stacking algo are you using? I usually do Average stacking with Median Sigma Clipping rejection.
>>
>>3698070
>le random stranger walking in the city with lights and shadow
>le epic street photography
Nigger, at least this image is capture the fucking cosmos. Even if the aesthetics are lacking, the content is king.
>>
Any progress from last night OP?

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>>3698801
It was cloudy as fuck, so no. I'm going to try again tonight. I want to thank you guys for your help, guidance and inspiration. I know I can do better. Hopefully I'll have something to show for it tonight.
>>
>>3698806
Any better skies tonight? Last night was a cloud fest even if it looked nice till 10pm. Tonight should be better.

Don’t forget to scout a spot and make a nice composition!
>>
>>3698801
bruh... what happened to the colors...?
>>
File: PSX_20200717_112254.jpg (1.4 MB, 6000x4000)
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>>3698012
>>3698218
Stacking only helps to get a better signal/noise ratio.
It doesn't do anything against skyglow, only going away from populated areas and certain filters can do something about it.
Pic related, a .jpg straight out of camera.
Lens was an old ass 1960s Helios 44 58 mm f/2.
Only compressed to post it here...

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>>3698818
It’s a crop from a super wide angle pic without a lot of processing.
>>
>>3698825
A good processor can filter out light pollution. Yeah it won’t be as good as a stack from a low pollution location but saying you’ll never lose any glow in a good stack is bs. If you check the clarkvision link above he can filter it ou manually to a huge degree.
>>
>>3698836
That's a different process than stacking, but one can indeed reduce skyglow in post.
It is possible as the skyglow is a different colour than the stars, usualy a realy warm colour compared to the rather cold, white stars.
One can also play a little with contrast and exposure or the curves.
>>
>>3698836
You can't filter out light pollution. You are thinking about gradients.
>>
>>3698842
Not him, but you can reduce it to some degree in post.
However if the image is fucked by light pollution, it's fucked.
>>
>>3698842
>>3698841
Sequator does quite the jog for me.
>>
>>3698868
>>3698842
You can on a few conditions, great signal to noise ratio, minimisation of read noise, and a very even image, and high enough bit depth.

The exposure always sits above base fog (light pollution) as its additive.

You just need to expand the contrast of that section of the image a crazy amount. Which is why it has to be very flat and even, extreme low noise, read noise, and bit depth as everything gets amplified.
>>
File: 1594262079218.gif (2.36 MB, 512x512)
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Why are star tracking mounts like 300 fucking bucks
>>
>>3698889
precision instrument. full metal construction. if you want to be cheap and are the DIY type you can look into barn door skytrackers. I have no idea what kind of results you get out of them but they're a thing, and pretty easy to build.
>>
>>3698842
There are ways, but don’t expect miracles.
A classic one is a didymium filter (“red intensifier”). There are more spécialisée narrow band filters that have specific cutoffs, either to cut off light pollution (depending on what kind of lights cause that pollution, say sodium vapour or whatever), or to cutoff pretty much everything except the specific band of an object/constellation you’re trying to photograph.
Check astronomy and astrophotography forums. They make a decent difference but they cost a decent amount too (~$100 and above), and there’s some trial and error involved in what works and what not. The safest and cheapest choice is a didymium filter and works for the most common type of light pollution.

Of course the best way is to take a trip to a remote location with no pollution.
And hope it doesn’t get cloudy.
>>
>>3698889
Just buy a Pentax with Astrotracer
>>
>>3698889
OIS or IBIS also kind of does the job to a certain degree.
The gyroscopes in the camera pick up the earth rotating and counteract it, wich is why you usualy shouldn't use image stabilisation on a tripod.
It's certainly not perfect, but usualy sufficient for a few seconds more of exposure.
Especialy when stacking in post it can do the job, at least as long as the axis of the camera is pointing in the same direction as the optical axis of the lens, wich is not the case for Newton/Dobson telescopes.
>>
Could I take hundreds of 1 second exposures and get anything by stacking?
>>
>>3699069
>The gyroscopes in the camera pick up the earth rotating and counteract it
I'm going to need to proof on this claim. otherwise I'm going to assume this is a troll post.
>>
>>3699070
you definitely can. I've done it.
>>
>>3699088
Try to do a long exposure (5-10 seconds) on a tripod with image stabilisation, you'll see it yourself.
For best results you need 3-axis image stabilisation, 2-axis (lens based) only works when the optical axis of the camera is pointed parallel to the equatorial plane.
3-axis works as well in the north/south direction.
>but why does it work
The gyroscopes in your camera that are responsible for actuating the image stabilisation can't differentiate between earth rotation and you not holding your camera steady.
That usualy doesn't matter as you're not exposing longer than a second handheld anyway.
If used on a tripod, the camera will still pick up the ever so slight rotation of earth and the image stabilisation will compensate.
Though the accuracy may not be perfect as the gyroscopes will have some drift and IS isn't perfect to begin with.

A nice experiment is to take a pic with stars and terrestrial structures visible at the same time:
>IS off
Stars form trails.
>IS on
Terrestrial structures get motion blurr.
(wich is why you usualy shouldn't use it on a tripod)
>>
>>3699197
Pentax and Olympus automate this to give you star modes.
>>
>>3699197
I have ibis and that has never prevented star trails on long exposures for me. AFAIK only Pentax cams have this sort of trail reduction.
>>
Most of your problem is light pollution and nothing you do in post will fix that.
>>
>>3698012
nigga, subtract the background and stretch the image. it's not that hard
>>
>>3698889
They support a lot of weight.

You can use a barn door tracker with stepper motto and Arduino. And a threaded rod, bend the threaded rod into a radius curvature that’s the same radius from the hinge to the rod length.

Cheapest star tracker I got was a sightron nano.tracker when it was on special for like $100 in bic camera I think it was.
>>
>>3699088
Not as the anon thinks but Pentax Astrotracer works this way. Gyros pick up the attitude of the camera, GPS gives location on earth, compass gives global direction and all you need to do is to have an x-y offset on IBIS to calculated continuous speed plus some rotational correction.
It works like magic, but it has its limitations.
>>
>>3699218
>and all you need to do
I meant *all the camera has to do
You just point it in a direction and shoot.
>>
>>3699218
It’d be nice if all cameras could do this
>>
>>3699225
The compass calibration is ass though, and especially on the standalone (K-3 and before) Astrotracer module you have to use lithium AAA cell to power it unless you want a huge blind spot to the side of the module meaning you wouldn't be pointing towards the west side of the sky because the compass is blinded by the nickel battery.
I stockpiled a bunch of lithium AAA cells because of this.
>>
Why tf is clarkvision recommending narrower lenses? I get his reasoning but especially starting out it feels like the need for extra gear for narrow lenses is much higher(trackers and shit). Is a 16mm that shit?
>>
>>3698825
Ayyyy I used the helios to shoot neowise too! It has too much coma for my tastes though. Prefer my takumar 200
>>
>>3698889
To get an error of arcseconds, you need a gear precision of micrometers. Making parts that precise is expensive as fuck.
>>
ITT trolled hard.
>>
>>3698218
There is no replacement for time. No amount of stacking will make up for a lack of light. I imaged neowise two weeks ago when it was in the 2nd magnitude. With a 30 sec exposure at f2.8 I still felt I cut the exposure too soon. Now its probably 4th or 5th magnitude (100-1000x dimmer). Tl;Dr: try to get the most shutter time as you can, if you dont have a tracker neowise is probably out of reach now.



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