Exposure time with Optolong l-enhance filter

[Gaurav Mk]

Hello,

I am planning to buy the Optolong L enhance 2" filter. Currently my setup is limited in terms of maximum exposure, i.e. 30s exposure max subs.

So if I am using the filter on the following DSOs like Orion nebula, Andromeda galaxy, Flame and Horse head Nebula will there be an issue considering that I am using a strong blocking filter and giving only 30s exposure?

Is it necessary to have a large exposure time when using this filter? Will I be able to get useful shots with the same 30s exposure when using the filter?

I am currently getting decent shots without any filters with 30s exposure. The following is a shot or Orion nebula(no edits) using Nikon d5300 with the moon around 60-70% illumination.

[smashing]

56 minutes ago, Gaurav Mk said:

Hello,

I am planning to buy the Optolong L enhance 2" filter. Currently my setup is limited in terms of maximum exposure, i.e. 30s exposure max subs.

So if I am using the filter on the following DSOs like Orion nebula, Andromeda galaxy, Flame and Horse head Nebula will there be an issue considering that I am using a strong blocking filter and giving only 30s exposure?

Is it necessary to have a large exposure time when using this filter? Will I be able to get useful shots with the same 30s exposure when using the filter?

I am currently getting decent shots without any filters with 30s exposure. The following is a shot or Orion nebula(no edits) using Nikon d5300 with the moon around 60-70% illumination.

What are you looking to use the filter for? Light pollution? 

Also remember that this type of filter isn't really designed for broadband targets such as galaxies 

[Gaurav Mk]

 

36 minutes ago, smashing said:

What are you looking to use the filter for? Light pollution? 

Also remember that this type of filter isn't really designed for broadband targets such as galaxies 

Yeah true. Nebulae are the primary target. I live in Bortle 3-4. My expectation is that the filter will improve the quality of image and make the nebulae pop

[smashing]

14 minutes ago, Gaurav Mk said:

 

Yeah true. Nebulae are the primary target. I live in Bortle 3-4. My expectation is that the filter will improve the quality of image and make the nebulae pop

I'm not sure it will do what you are expecting with 30 second subs although I could be wrong.

You're probably better just getting more subs to stack and saving the money towards increasing the exposures that your rig can do.

Edited December 28, 2020 by smashing

[Stuart1971]

15 minutes ago, Gaurav Mk said:

 

Yeah true. Nebulae are the primary target. I live in Bortle 3-4. My expectation is that the filter will improve the quality of image and make the nebulae pop

What scope are you using, as with 30 second subs, this filter will be of very little use to you...you will need much longer to allow the narrowband light to pass through....at least 3-5 minute.... at 30 seconds, the image will just be black with nothing to show.... 👍🏼

[PeterCPC]

+1 for longer exposures.

[Gaurav Mk]

1 hour ago, Stuart1971 said:

What scope are you using, as with 30 second subs, this filter will be of very little use to you...you will need much longer to allow the narrowband light to pass through....at least 3-5 minute.... at 30 seconds, the image will just be black with nothing to show.... 👍🏼

I am using skywatcher 200pds

[Stuart1971]

2 minutes ago, Gaurav Mk said:

I am using skywatcher 200pds

Well, as I stated you need much much longer exposures to get any benefit whatsoever from that filter, also some good PA and tracking would also be needed first, but a great start all the same....👍🏼

[Gaurav Mk]

 

1 hour ago, Stuart1971 said:

Well, as I stated you need much much longer exposures to get any benefit whatsoever from that filter, also some good PA and tracking would also be needed first, but a great start all the same....👍🏼

PA and tracking are already in my setup. I see some trailing around 1min exposure. So probably will need auto guiding too. Another limitation comes from the nikon camera, for which I lack an intervalometer in bubl mode allowing me to seamlessly capture greater than 30s exposures. 

[Gaurav Mk]

Thanks all for the guidance. I will add autoguiding and make the camera capture more than 30s exposures and then go with buying the filter

[Stuart1971]

4 hours ago, Gaurav Mk said:

 

PA and tracking are already in my setup. I see some trailing around 1min exposure. So probably will need auto guiding too. Another limitation comes from the nikon camera, for which I lack an intervalometer in bubl mode allowing me to seamlessly capture greater than 30s exposures. 

Your PA can’t be too good with trailing like that at 30 seconds....it really needs to be better, before setting up guiding...👍🏼😀

[smashing]

2 hours ago, Stuart1971 said:

Your PA can’t be too good with trailing like that at 30 seconds....it really needs to be better, before setting up guiding...👍🏼😀

For the price of the filter I think he could get something like a polemaster or ipolar which would help in that regards.

[alacant]

On 28/12/2020 at 08:38, Gaurav Mk said:

Optolong L enhance 2"

Hi

Hands on:

I posted an example here and some UHC examples last week.

I was disappointed with the example I tried. It offers the same effect as a €30 UHC, but costs €silly. 

To give an idea of light loss, an unfiltered flat frame takes 2s, the UHC and l-enhance take 8s.

My advice would be to try a UHC (or a cls) first. You can do this easily by joining your local astro club. If in the end you really do want narrow band, do it properly with the l-extreme.

I think that in the not so distant future, one-shot camera + (when the technology improves) single multi-band filter are gonna take preference over the filter wheel.

Just my €0.02

Cheers and HTH.

 

Edited December 29, 2020 by alacant

[SamAndrew]

You're not going to notice polar alignment error in 30s exposures; that's just poor tracking. What mount are you using? 

[Stuart1971]

9 hours ago, SamAndrew said:

You're not going to notice polar alignment error in 30s exposures; that's just poor tracking. What mount are you using? 

You will if it’s that far off, and at high F ratio... 👍🏼

[tooth_dr]

12 minutes ago, Stuart1971 said:

You will if it’s that far off, and at high F ratio... 👍🏼

I agree. I notice trailing in 30s even at 180mm if alignment is poor.  

[Stuart1971]

1 hour ago, tooth_dr said:

I agree. I notice trailing in 30s even at 180mm if alignment is poor.  

Yes, me too with a 50mm camera lens, over 25 seconds... 👍🏼

[david_taurus83]

23 hours ago, Gaurav Mk said:

I am using skywatcher 200pds

1000mm focal length really needs to be guided unless your using a premium mount.

[teoria_del_big_bang]

Some great advice above from some far more knowledgeable than myself.

But no filter is going to improve your images more than good tracking and longer exposures will.
The filter you are wanting does not come cheap and I think the money is far better put into improving your tracking which on top of proper alignment will allow 3 to 5 minute exposures (providing your mount is up to it - what mount are you using ?).
At Bortle 3 to 4 you should be able to get some great images of many DSO's and galaxies, especially Orion and Andromeda even without filters.

Personally I would concentrate on getting your rig well aligned, with good guiding and no flex which should allow 3 to 5 min subs, depending how stable your mount is as it is a reasonable size scope ideally needs a good stable mount.

Steve

[alacant]

22 hours ago, teoria_del_big_bang said:

no filter is going to improve your images more

+1. All a filter will ever do is remove light from your image. Never add to it.

ATM, I'd concentrate getting the mount set up to perfection. 

Cheers

Edited December 30, 2020 by alacant