LRGB filters recommendation

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mgutierrez
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Joined: Sat Oct 24, 2020 11:07 pm

LRGB filters recommendation

Post by mgutierrez »

Hi all,

Sorry if this forum is not the most appropriate to ask this.
I'm (still...) planning to buy a mono cam (a QHY294m pro, in particular) and the corresponding filter wheel (QHYCFW3-M US, 36mm, unmounted) and filters. I have many doubts about these ones.
I wish to still use Startools for my processing. That's why I'm posting here. I don't know if a particular LRGB filter set works better with Startools; for example, for white balancing colors.
Do you happen to have a mono cam and could recommend a particular (L?)RGB filter set to work flawlessly with ST? I'm looking for some, let's say, intermediate filters. I cannot afford astrodon nor chroma. I've read quite well about Baader, astronomik (don't know still if type 2c or deep sky are better for ST), antlia (the new pro series seem to be much better than the previous one), and zwo or optolong.
Any feedback and experiences (about filters and mono imaging with ST, in general) are really appreciated.

Regards

EDIT: forgot to mention my scope is a refractor (TS) 102ED f7
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admin
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Re: LRGB filters recommendation

Post by admin »

Hi,

Just replying to give you at least some guidance...

I think any filter set will be fine, though try to pay some attention to the L filter in particular.
See what the spectrum response is of the filters and how it cuts off the spectrum (UV/IR) of the camera you are thinking of purchasing.

Definitely try to purchase a set that that has the L-filter spectral response cut-off match the red (IR) and blue (UV) filters cut-off.

Some filters are more aggressive with the cut-off than others. Depending on your optics (chromatic aberration) it may help a little being more aggressive with the cut-off.

To make synthetic luminance generation more accurate, it helps having filters for R, G and B. that govern precisely 1/3rd of the spectrum (the spectrum response would ideally look like squares that overlap as little as possible, rather than "humps").

Hope any of this helps!
Ivo Jager
StarTools creator and astronomy enthusiast
mgutierrez
Posts: 51
Joined: Sat Oct 24, 2020 11:07 pm

Re: LRGB filters recommendation

Post by mgutierrez »

Hi Ivo,

Sorry for the late reply. I don't know why but I stopped to receive notifications on updates. I've just reviewed my profile config and hope to get the notifs again.
One of the best option I think can fit my setup are the astronomik deep sky RGB filter set, with the L3 luminance filter:
Image
Image
I also have been offered an astodon LRGB kit (E series, gen-2). I know astrodon/chroma are the very best brand, but maybe the curve does not fit as well as astronomik's; not sure:
Image
In the (near? far?) future I guess I would change my ota (not sure if a triplet or an RC), and I would like to buy something that fits my actual setup and the future. I guess I'm asking for an impossible :-)
any advice?

Miguel
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Re: LRGB filters recommendation

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The Generation-E series seems to have a good overlap. I'm curious as to why there is a notable "gap" between the green and red channel response (e.g. one would miss some part of the spectrum)... :think:

It seems to coincide somewhat with sodium lines (I guess it's to avoid light pollution?). This would definitely have some impact on coloring...
Ivo Jager
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Re: LRGB filters recommendation

Post by admin »

admin wrote: Thu Sep 16, 2021 2:55 am The Generation-E series seems to have a good overlap. I'm curious as to why there is a notable "gap" between the green and red channel response (e.g. one would miss some part of the spectrum)... :think:

It seems to coincide somewhat with sodium lines (I guess it's to avoid Na/Hg light pollution?). This would definitely have some impact on coloring...
Also definitely have a look at ZWO filter sets, which (if I remember correctly) have L filters that very closely follow the response cut-off of the R and B filters.
Ivo Jager
StarTools creator and astronomy enthusiast
mgutierrez
Posts: 51
Joined: Sat Oct 24, 2020 11:07 pm

Re: LRGB filters recommendation

Post by mgutierrez »

Hi Ivo,

Thanks for the reply.
Yes, I think the gap you mean is to exclude partially light pollution. Some LRGB filters have this gap, including the Astronomik LRGB deep sky. However, I did never hear about any problem regarding this.
ZWO filters have a lower blue cutoff, and I think that may impact on the aberration that my doublet introduces. That was one of the reasons I think astronomik would be a bit better.

regards
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