So timely for me! I just started shooting with a filter wheel and was trying to debug this very problem. I have something to try tonight. Thank you! Clear skies
Opaque filters of any standard size, mounted and unmounted, are available from virtually any astrogear supplier (they're intended for taking dark/bias frames). They're very inexpensive, around US$25. So it's easy to get them to fill any empty slots.
Oh… this could explain some of my flats. Have 1 empty slot in my ZWO filter wheel. To be safe I’ll make sure to cover the empty slot even if it does not matter for me just to make sure. Thanks
I'm not saying this is a proper solution, but it works pretty well. Gaffers Tape. I put it on my filter wheel when I was first getting filters. Cheap. Light. DARK. I had no idea why I felt that the blank filter slots needed to be blacked out, but it was a strong impression. Only have one slot open now, been taped for a long long time...
maybe somebody already suggested this to you, but you should add a wider Ha Filter to your filter wheel. Planetary nebula also emit Nitrogen Nii, which emission line lies directly next to the Ha but will be blocked by your 2,8nm filters.
That is extremely helpful - never heard that before - thanks a lot!!!!!! I will surely consider that once I buy a more narrow scope - with the 400mm the planetary nebulae are a bit out of reach!
Very interesting. Did you also find that the flats taken for the filters either side of the LUM filter were also affected? One would imagine that there is not much difference between an empty slot and an IR cut filter.
I did not see the same behaviour around the Lum. On one side I believe the optical properties of no filter or Lum filter are different, on one side as now some glass is in there but also as Lum filters do filter some light. On the other side I did have on one side of the Lum filter and empty slot and on the other the Red filter. It needs much less light to make flats of RGB filter than of narrowband filters, and this mitigates the issue massively.
@@viewintospace That makes a lot of sense. The length of the flat exposure in the case of RGB filters is making the difference. Then perhaps that also is worthwhile advice to take from this. Keep your LUM filter among the RGB rather than the classic arrangement of LRGBSHO, where Oiii may be affected by LUM.
Yes that's a solution...But not a correct one, 1 reason I like to leave 1 filter wheel open is to do some visual viewing without any filter. What the Filter wheel makers need to do a install light baffles to perfect an open filter wheel slot letting in light causing what you had happened.
Hi Sasha I have the ZWO 5 postion EFW and the ZWO LRGB filters and the ZWO Narrowband SHO (S-II, H-a & O-III) Imaging Filter Set.I want to the put LRGB in Filter Wheel but want to use the other slot for one of the Narrowband filter which one should I put in there and use a filter drawer for the other two filters in the Narrowband set.
@@viewintospaceHi Sasha I noticed that the 7 slot filter wheel from ZWO doesn't have Threaded type filters looks like I need ZWO 8 slot filter wheel instead like you have will have to get the 3D. printed cover you got.
That is a great question which I asked myself too. I assume the glass kind of directs the light in a more linear direction. Also the R which is neighboring L is less sensitive than the Narrowband filters, as less bright light is used to create the flats.
Hi Sascha, So, I have a few questions, if you don't mind, and I hope you can answer them. So, then, does this mean, that you can no longer be able to shoot without a filter, if you wanted too? Is there no other way to block out the light? Could this light leak, itself, have been sealed instead of blocking off your empty slots? Did you ever find out where this light leak was coming from? If you did, find this light leak, where was this light leak coming from? I am looking forward to your reply on my several questions. I have a new 7 filter filter wheel, for 2 inch mounted filters, coming from ZWO, shortly. I was not planning on using all 7 of the slots so I can shoot without a filter, if I wanted too. Since I am using a One Shot Colour camera, ASI2600MC Pro, I would want to use it without filters, in many cases. Anyway, thank you for the video. It was very interesting and informative, as always. I will reply back after I get my new ZWO filter wheel and try it with only 6 filters. Now I am, naturally, very curious to see if I get the same problem when I do my flats. I will check back and let you know. Maybe, since I am using "Mounted" filters it might make a difference. Or, maybe, since it is a different brand it might make a difference. Either way, I promise that I will stop back into this video and let you and the community know what I find out. Thank you, once again, for the video. Sincerely, Richard Williams Astor, Florida 32102 USA!
Hi Richard, The light leak is definitely coming through the empty filter slots, so in principle making a detour around the narrowband filters. Important points: 1. Depending on many factors (Brand, Size, Framed or not, amount of slots), this issue might occur or not. 2. It is only an issue when shooting the flats 3. It is only an issue when Narrowband filters are beside an empty slot (as it needs much stronger light to create the flats) So if you want an empty lot, simply select it besides an broadband or light pollution filter (e.g L-Pro) and not beside the Dual-Narrowbandfilter. BTW - I'm curious why you chose the 7 slot and not the 5 slot Filter wheel, as for OSC usually 3 filter plus an empty slot is about all you can use.....
That is a great question which I asked myself too. I assume the glass kind of directs the light in a more linear direction. Also the R which is neighboring L is less sensitive than the Narrowband filters, as less bright light is used to create the flats.
As stated, it depends on many factors. Depending on yours, this might not be an issue at all, it is just crucial to know that it might be an issue and to check it.
So timely for me! I just started shooting with a filter wheel and was trying to debug this very problem. I have something to try tonight. Thank you! Clear skies
Opaque filters of any standard size, mounted and unmounted, are available from virtually any astrogear supplier (they're intended for taking dark/bias frames). They're very inexpensive, around US$25. So it's easy to get them to fill any empty slots.
Great video, thanks.
3D printed black discs look great, BUT note however that some plastics can be transmissive in the IR!
Oh… this could explain some of my flats. Have 1 empty slot in my ZWO filter wheel. To be safe I’ll make sure to cover the empty slot even if it does not matter for me just to make sure. Thanks
I'm not saying this is a proper solution, but it works pretty well. Gaffers Tape. I put it on my filter wheel when I was first getting filters. Cheap. Light. DARK. I had no idea why I felt that the blank filter slots needed to be blacked out, but it was a strong impression. Only have one slot open now, been taped for a long long time...
maybe somebody already suggested this to you, but you should add a wider Ha Filter to your filter wheel. Planetary nebula also emit Nitrogen Nii, which emission line lies directly next to the Ha but will be blocked by your 2,8nm filters.
That is extremely helpful - never heard that before - thanks a lot!!!!!! I will surely consider that once I buy a more narrow scope - with the 400mm the planetary nebulae are a bit out of reach!
Would you know how wide is wide enough? 5nm is ok or wider?
@@viewintospace Nii is at 654nm and 658nm. With a 7nm you should get all of it.
@@hottokatrazi THANKS!!!
Good catch! CS!
What an incredible factoid to have under the sleeve…. 🙏🏼
Excellent info for sure.
Now a dumb question...what is this R+ filter you speak of??
Antlia includes a filter which only lets pass the (near-) IR spectrum. More here: ua-cam.com/video/6190mfW4RsI/v-deo.html
Very interesting. Did you also find that the flats taken for the filters either side of the LUM filter were also affected? One would imagine that there is not much difference between an empty slot and an IR cut filter.
I did not see the same behaviour around the Lum. On one side I believe the optical properties of no filter or Lum filter are different, on one side as now some glass is in there but also as Lum filters do filter some light. On the other side I did have on one side of the Lum filter and empty slot and on the other the Red filter. It needs much less light to make flats of RGB filter than of narrowband filters, and this mitigates the issue massively.
@@viewintospace That makes a lot of sense. The length of the flat exposure in the case of RGB filters is making the difference. Then perhaps that also is worthwhile advice to take from this. Keep your LUM filter among the RGB rather than the classic arrangement of LRGBSHO, where Oiii may be affected by LUM.
Yes that's a solution...But not a correct one, 1 reason I like to leave 1 filter wheel open is to do some visual viewing without any filter. What the Filter wheel makers need to do a install light baffles to perfect an open filter wheel slot letting in light causing what you had happened.
Hi Sasha I have the ZWO 5 postion EFW and the ZWO LRGB filters and the ZWO Narrowband SHO (S-II, H-a & O-III) Imaging Filter Set.I want to the put LRGB in Filter Wheel but want to use the other slot for one of the Narrowband filter which one should I put in there and use a filter drawer for the other two filters in the Narrowband set.
That is is dead end! Will never work! Sell the 5 slot filter wheel and buy the 7 slot from ZWO.
@@viewintospaceHi Sasha I noticed that the 7 slot filter wheel from ZWO doesn't have Threaded type filters looks like I need ZWO 8 slot filter wheel instead like you have will have to get the 3D. printed cover you got.
@@walterlewis1029 No, the EFW-7x2 has 2’’ threded filter slots - no problem
Random question. Will these filter wheels work with other cameras? I’ve been looking for a 36mm wheel that has more than 7 slots
A not so random answer.... 😉 No, unfortunately they do only work with their own camera, as the controller of the filter wheel sits in the camera.
Does this not happen adjacent to the Lum filter?
That is a great question which I asked myself too. I assume the glass kind of directs the light in a more linear direction. Also the R which is neighboring L is less sensitive than the Narrowband filters, as less bright light is used to create the flats.
Hi Sascha, So, I have a few questions, if you don't mind, and I hope you can answer them. So, then, does this mean, that you can no longer be able to shoot without a filter, if you wanted too? Is there no other way to block out the light? Could this light leak, itself, have been sealed instead of blocking off your empty slots? Did you ever find out where this light leak was coming from? If you did, find this light leak, where was this light leak coming from? I am looking forward to your reply on my several questions.
I have a new 7 filter filter wheel, for 2 inch mounted filters, coming from ZWO, shortly. I was not planning on using all 7 of the slots so I can shoot without a filter, if I wanted too. Since I am using a One Shot Colour camera, ASI2600MC Pro, I would want to use it without filters, in many cases.
Anyway, thank you for the video. It was very interesting and informative, as always. I will reply back after I get my new ZWO filter wheel and try it with only 6 filters. Now I am, naturally, very curious to see if I get the same problem when I do my flats. I will check back and let you know. Maybe, since I am using "Mounted" filters it might make a difference. Or, maybe, since it is a different brand it might make a difference. Either way, I promise that I will stop back into this video and let you and the community know what I find out.
Thank you, once again, for the video.
Sincerely, Richard Williams
Astor, Florida 32102 USA!
Hi Richard, The light leak is definitely coming through the empty filter slots, so in principle making a detour around the narrowband filters. Important points:
1. Depending on many factors (Brand, Size, Framed or not, amount of slots), this issue might occur or not.
2. It is only an issue when shooting the flats
3. It is only an issue when Narrowband filters are beside an empty slot (as it needs much stronger light to create the flats)
So if you want an empty lot, simply select it besides an broadband or light pollution filter (e.g L-Pro) and not beside the Dual-Narrowbandfilter.
BTW - I'm curious why you chose the 7 slot and not the 5 slot Filter wheel, as for OSC usually 3 filter plus an empty slot is about all you can use.....
Very interesting. Why doesn't L cause the same problem?
That is a great question which I asked myself too. I assume the glass kind of directs the light in a more linear direction. Also the R which is neighboring L is less sensitive than the Narrowband filters, as less bright light is used to create the flats.
@@viewintospace for me S is next to L and I haven't noticed before (not that it's not happening), the main difference is mine are mounted.
As stated, it depends on many factors. Depending on yours, this might not be an issue at all, it is just crucial to know that it might be an issue and to check it.