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How long for an exposure with oiii filter

Craig123

By Craig123
in Getting Started With Imaging

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Craig123

Craig123

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Hi all

I have tried abit of narrowband with ha filters on my Atik 314 mono on the Veil using 20 minute exposures and decided to buy an 0iii. filter today. Would I stick to this exposure for the different filter. When I do a fairly short 5 min sub with ha I can see the nebula OK if I have everything right. Would Oiii be fainter or should I expect similar. Lastly is it all bin1 for narrowband.?

Many thanks

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Adam J

Adam J

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6 minutes ago, Craig123 said:

Hi all

I have tried abit of narrowband with ha filters on my Atik 314 mono on the Veil using 20 minute exposures and decided to buy an 0iii. filter today. Would I stick to this exposure for the different filter. When I do a fairly short 5 min sub with ha I can see the nebula OK if I have everything right. Would Oiii be fainter or should I expect similar. Lastly is it all bin1 for narrowband.?

Many thanks

You will be fine with 20 min subs no need to bin more than likely as your pixels are quite big anyhow.

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Craig123

Craig123

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7 minutes ago, Davey-T said:

I think the Veil O111 is quite bright so 20 minutes is fine.

Binning depends on your scope getting a reasonable arc sec's / pixel resolution.

Dave

Thanks Dalvey.. I'm not sure how to work that out yet but will go with 20 mins bin x1

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Adam J

Adam J

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10 minutes ago, Craig123 said:

Fingers crossed.. If I get a few hours in one night this week what ratio would be good for Ha and oiii for data. 

Its target dependent but for the Vail I would just match the Ha integration as its bright in OIII.

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MarsG76

MarsG76

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it depends of what you want to image. some nebulae are brighter in OIII than others and so the time exposure per sub will change object to object.

To determine the exposure length, I do a test shot first.

 

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Craig123

Craig123

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1 hour ago, Davey-T said:

Just to clarify if I bin 4X4 using Atik 314L on the 10"SCT it gets me about the same resolution as you using bin 1X1 with the ED80.

Dave

One day I will understand the details a little better Dave

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Craig123

Craig123

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2 hours ago, Davey-T said:

Just to clarify if I bin 4X4 using Atik 314L on the 10"SCT it gets me about the same resolution as you using bin 1X1 with the ED80.

Dave

Dave.. I am a beginner at astro using a ccd and tracking etc. The last session went badly wrong after polar alignment with star trials on subs. I was frazzled so packed away feeling not so good about it lol. The only thing I can think was that I rotated scope the wrong way during polar alignment with sharp cap. Iam right in thinking this would screw everything up. It's bugging me so thought I would ask. Cheers

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Davey-T

Davey-T

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Never used Sharp cap but I have spent / wasted many nights fighting guiding so much so that I resorted to buying a mount that runs unguided :grin:

I also tried to plan my imaging sessions to avoid meridian flips as they chuck everything upside down and back to front and cause more hassle than they're worth if you're just starting out.

Perfect PA is overrated and not worth spending ages getting it spot on, guiding " should " cope with just a bit of field rotation that can be taken care of in stacking.

If you're imaging I don't see any point obsessing over 3 star alignments either which only serve to improve the GoTo.

So after PA'ing I selected a target rising in the east, aligned on one star near the imaging target, calibrated PHD in that area and start imaging.

Dave

 

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Craig123

Craig123

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21 minutes ago, Davey-T said:

Never used Sharp cap but I have spent / wasted many nights fighting guiding so much so that I resorted to buying a mount that runs unguided :grin:

I also tried to plan my imaging sessions to avoid meridian flips as they chuck everything upside down and back to front and cause more hassle than they're worth if you're just starting out.

Perfect PA is overrated and not worth spending ages getting it spot on, guiding " should " cope with just a bit of field rotation that can be taken care of in stacking.

If you're imaging I don't see any point obsessing over 3 star alignments either which only serve to improve the GoTo.

So after PA'ing I selected a target rising in the east, aligned on one star near the imaging target, calibrated PHD in that area and start imaging.

Dave

 

Thanks for that Dave. Much appreciated. Its not just me who has things going wrong.. so frustrating after getting something I was happy with then 3 sessions of mishaps. The battle continues. ?

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mikeonnet

mikeonnet

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The biggest battle regarding AP is of course the clouds & weather. I think we have all had frustrating sessions and many wasted hours BUT when you do nail that DSO you have captured all by yourself, it is so pleasing & rewarding that this by far outweighs the disastrous sessions and keeps me wanting more.

I recently purchased a ZWO mono camera with a HA filter, and to this date, I have managed to take.......... Nothing......... because of the weather. I have also still got to find out how long my exposures need to be with LRGB & HA compared to the DSLR i used.

You could try running different imaging plans as in run 20x subs @ 3 mins and another plan @ 5mins etc and see the difference. I could never get past 3 - 4 minute subs on the DSLR due to the light pollution but I'm hoping the HA will make a difference when I get a chance.

Anyway, Good luck and enjoy.....

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Craig123

Craig123

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14 hours ago, mikeonnet said:

The biggest battle regarding AP is of course the clouds & weather. I think we have all had frustrating sessions and many wasted hours BUT when you do nail that DSO you have captured all by yourself, it is so pleasing & rewarding that this by far outweighs the disastrous sessions and keeps me wanting more.

I recently purchased a ZWO mono camera with a HA filter, and to this date, I have managed to take.......... Nothing......... because of the weather. I have also still got to find out how long my exposures need to be with LRGB & HA compared to the DSLR i used.

You could try running different imaging plans as in run 20x subs @ 3 mins and another plan @ 5mins etc and see the difference. I could never get past 3 - 4 minute subs on the DSLR due to the light pollution but I'm hoping the HA will make a difference when I get a chance.

Anyway, Good luck and enjoy.....

Yeah thanks Mike. 

Last time I got a good run using an ha filter and was getting decent 20 minute subs. 

Then a few things went amiss and I was back a few steps again wondering what had happened. So near but so far... and of course just as I had spent an hour or two getting  close again the cloud comes in at 12.30.I hope to be out later as its forecast clear. 

20 mins (or longer) seems to be a standard time for narrowband filters and I will stick with that as the clouds are never far off from here. Good luck with your set up. 

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swag72

swag72

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I use the same exposure time on Ha, OIII and SII filters. Of course it's target dependent and it's not possible to generalise, but more often than not OIII is the faintest filter of them all and often in 30 minute subs I can see nothing..... but it stacks up to something that makes a difference ? 

Regarding numbers of exposures,  I try to use the same number of Ha, OIII and SII subs as a minimum, but if I've got the inclination I'll add more OIII and SII.

Hope that helps ☺

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Craig123

Craig123

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43 minutes ago, swag72 said:

I use the same exposure time on Ha, OIII and SII filters. Of course it's target dependent and it's not possible to generalise, but more often than not OIII is the faintest filter of them all and often in 30 minute subs I can see nothing..... but it stacks up to something that makes a difference ? 

Regarding numbers of exposures,  I try to use the same number of Ha, OIII and SII subs as a minimum, but if I've got the inclination I'll add more OIII and SII.

Hope that helps ☺

Yes. Very much so. Thanks Sara.

Is there a resource you use for what targets are suitable for various filters. 

I'm hoping to get  my 0iii delivered today which means pulling an rg or b out of the wheel. Since moon is about that was the plan but how do I know if rgb will get better rests on a target than say ha and 0iii.Im working on the Veil Btw.

Enjoyed the dragon nebula... Its this sort of thing that keeps me lugging stuff out in to the garden ?. Thanks

 

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swag72

swag72

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I don't check if any targets are suitable for OIII......if I want to do a narrowband image i just go for it anyway ?

Looking around the net is the only way I've ever found to see if stuff will work well in Hubble palette..... but sometimes it's fun to just throw caution to the wind and try something new ?

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Craig123

Craig123

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14 hours ago, ollypenrice said:

Bear in mind that Sara works out how much exposure time she needs and mulitplies it by ten then doubles it. A bit like my pal Tom O'Donghue!

?lly

Well from my limited experience in the UK its seems best to imagine a time and then half it for the clouds but I got 3 hrs of ha last night. Not oiii as I accidentally got a visual filter yesterday fro flo.  I got the Bhatiinov working though  as per your last suggestion Olly. 

Thanks

 

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