17 replies to this topic

[Bandit03]

My first attempt at M81 i think its ok for only 2 hours. ive been trying to get a little color in the arms but i cant seem to get it right ive tried selctive color boost without success. do i need way more intergration time first? any ideas would be greatly appreciated thanks

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[cjarvis64]

What equipment did you use to get this? Also, what were your sub-exposure times and camera settings? I find that longer exposure times help to get more detail, given that you are auto-guiding.

[jpoulette]

Nice - great job for 2 hours of data. May I ask about your set-up and exposure times ?

 

Jim

[jlinsobe]

What processing software are you using?

 

. 

[bobzeq25]

Basics about color.  The bald facts, there's a lot of stuff that comes along with that, I have no time to write the encyclopedia.  <smile>

 

You lose color if you overexpose subs.

 

Stretching inevitably dilutes color.  You need to process well to fix that.

 

Dimmer stuff tends to have less color.  I do color in order to get colorful stars, generally take what I can get elsewhere.

 

May be relevant, may be not.  So-called "light pollution filters" tend to distort color.  On emission nebulae filters work.  On other targets like galaxies - not so much.

[matt_astro_tx]

Your galazy is looking a little brown which leads me to believe you used photometric color calibration?  Running a manual color calibration will allow you to pull the color out.

[xiando]

as Bob noted, over exposure reduces or eliminates color. Still, there's a bit more in your image you could pull out with a bit of elbow grease.

 

I snapshotted the central area of your image and did a quick , adhoc curves filter on it in Paint dot net. I think you can see the red tonation of the stars has been reduced, and the arms have been made more prominent.

 

So I'd suggest that you work on your stretching and post processing techniques. And use a larger qty of  shorter exposures in your stacked data sets to preserve color. What shorter means...? subjective I suppose, (aperture, sky conditions, etc) but the exposure length should be set such that a single light does not fill the RGB  color bins entirely. Or you accept the color loss for a fainter target and longer exposure.

 

 

OH, ps> you *could shoot the same area again later with short exposure to fully capture the star color, then blend (or mask) that into the original via photoshop or other...

Edited by xiando, 31 January 2023 - 11:13 AM.

[Bandit03]

thanks for the replies everyone i was using a Esprit100 and a zwo2600mc pro, 240mm guide scope with a zwo174mm mini i shot 40, 3 min subs Nina indicated that i only had 85 pixels completely saturated, so I don't think I was over exposed but then again, I do not have a benchmark to compare. it may look a little brown due to my attempts to pull out more color. also, I post process using Photoshop.

Edited by Bandit03, 31 January 2023 - 11:15 AM.

[AstroVagabond]

thanks for the replies everyone i was using a Esprit100 and a zwo2600mc pro, 240mm guide scope with a zwo174mm mini i shot 40, 3 min subs Nina indicated that i only had 85 pixels completely saturated, so I don't think I was over exposed but then again, I do not have a benchmark to compare. it may look a little brown due to my attempts to pull out more color. also, I post process using Photoshop.

Under what Bortle sky did you collect this data? Good start.

[Bandit03]

the Data was collected under Bortle 6/7 skies using an Optolong l-Pro LP filter

[bobzeq25]

the Data was collected under Bortle 6/7 skies using an Optolong l-Pro LP filter

You set the subexposure well, took enough subs (though more is always better, particularly in light polluted skies).

 

The LP filter is a bad idea on a galaxy.  The reason.

 

Filters work well on emission nebulae, not because the filters are so great, but because the light from the emission nebulae comes in 1-3 very narrow bands.  _Perfect_ for sorting out with a filter.

 

For other targets, like galaxies, that strategy does not work well.  The light from the covers the whole spectrum.  Any filter will take out precious signal, and you really don't want to do that.

 

What works is gradient reduction.  It lessens the effect of light pollution while not removing signal from the target.  There's an addon for Photoshop, but it's not the best tool, and PS is not the best tool for doing astrophotography.  It's a terrestrial photoediting program, and an astro specific processing program is significantly better.  I recommend Astro Pixel Processor.  Excellent gradient reduction tool, and other advantages.  Not the smallest one is that it's an integrated software package the replaces bot DSS and PS.  Some people like to touch up APP images in PS, nothing wrong with that.

 

Here's an Andromeda I did with a simple DSLR.  My skies are Red Zone, Bortle 7, mag per arc sec squared low 18s.  No (not so) magic light pollution filter was used.  Astro specific processing program and gradient reduction were used, those were the key things. 

 

Click on the picture for a better version, with more information.  Do you like the color?  The dim detail?

 

Edited by bobzeq25, 31 January 2023 - 02:35 PM.

[Spaceman 56]

 ive been trying to get a little color in the arms but i cant seem to get it right ive tried selctive color boost without success. do i need way more intergration time first? 

I think the image is reasonably good.   your doing well Bandit. 

 

the raw colours seem to be there to my eyes. its certainly not Grey visually.

 

the rest is Photoshop and post processing. pulling all those tiny colours out, and making them bigger. 

 

post a stacked results file, thats not a Tiff, and someone will amaze you with their processing of your data.

 

Spaceman 56

Edited by Spaceman 56, 31 January 2023 - 03:23 PM.

[idclimber]

Listen to Bob and skip the filter. You will of course also need to adjust the exposure, perhaps as low as 60 seconds. The filter is only killing your signal and color. 

[Bandit03]

thanks for the replies everyone so my takeaway is ditch the lp filter when shooting Galaxies got it. shorter exposures and a bunch of them next clear night ill give it a try ........ISS i think your photo of M31 is awesome i would be very happy with that result. Spaceman thanks I'm trying to get the hang of this stuff there is so much to learn   

[idclimber]

thanks for the replies everyone so my takeaway is ditch the lp filter when shooting Galaxies got it. shorter exposures and a bunch of them next clear night ill give it a try ........ISS i think your photo of M31 is awesome i would be very happy with that result. Spaceman thanks I'm trying to get the hang of this stuff there is so much to learn   

The filter you do want is a UV/IR filter. This will minimize blooming in the brighter stars. I am not sure if that is built in to the 2600mc or not. I use a mono version of that camera. 

 

Alternatively if you are imaging emission nebula you can add a dual narrowband filter like the L-Extreme. 

 

What you have is designed for reducing mercury and sodium lights, which were replaced by broad spectrum LEDs. As such these filters are no longer effective if they ever were. At least for AP. 

 

You are dong exposure correctly by monitoring clipping. 

 

ISS is the orbit Bob is at given his 30,000 post count. Mine is still Soyez because I have other things to do besides post here.   The user name is just above that post ranking. This is a common mistake so no worries, we are used to it. 

Edited by idclimber, 31 January 2023 - 04:49 PM.

[pedxing]

The 2600MC has the UV/IR cut filter built in.

[Robert7980]

Looks great to me… best thing you can do is try for longer sessions.. With only 2 hours you have a really great image, but there’s just not going to be enough data in it yet to really bring out everything… You could probably set the white balance to change the colors, or make it more accurate, but getting a lot of detailed color just requires more time, detail happens pretty fast, it’s the colors and contrast that take a lot of integration time to capture…. I’d be happy with that though, especially for a 1st attempt… 

[Bandit03]

thank you for the replies when I get some clear skies I'm going to try again with no filter and will post my results thanks again for all the info it really helps when your just starting out.