Poor man double stack
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Poor man double stack
I'm going to use the unplated Newton 250/F5.6 in H-a, so I'm testing how to get the narrowest possible band with minimum attenuation in H-a, because there will be very little light. I tried a combination of BF, TZ2x, BF, Quark on the AR150/F15 and the results look pretty encouraging. It's not a real DSII, but it's definitely a lot better than the single BF variant. I wonder if the N250 will shed enough light on that.
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- sx1.jpg (405.33 KiB) Viewed 362 times
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- sx2.jpg (412.69 KiB) Viewed 362 times
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- sx3.jpg (429.79 KiB) Viewed 362 times
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- sx4.jpg (477.61 KiB) Viewed 362 times
I do not look at the sky with the eyes of an astronomer, but of a person looking for the beauty of nature.
- KMH
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Re: Poor man double stack
Very nice results, but I guess I don't understand what you're doing. How does using two blocking filters decrease the bandpass? Sorry if I'm missing something obvious.
Thanks!
Kevin
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Kevin
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Re: Poor man double stack
Adding a second BF before the TZ2 increases image contrast similar to DSII. Not that much, the 3D effect is not as noticeable, but it's an improvement. By what mechanism does this improve contrast if not by narrowing the band? I'm not an expert on etalons and BF, maybe someone more experienced can explain it to us. I'm just sharing my knowledge from practice. I'll leave the theory to the experts.
I do not look at the sky with the eyes of an astronomer, but of a person looking for the beauty of nature.
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Re: Poor man double stack
Nice closeups!
about your mod: the results look good, but a comparison with the single bf would be king (or is it shown on the images? if so, what image is what?).
As far as i understand double stacking or using 2 bfs will not narrow the bandpass. What leads to improvements is usually the "cutting of the skirts" of the bandpass, so that parasitic light is reduced.
I still can see a double limb on the images, this would indicate that parasitic light hasnt been reduced much.
about your mod: the results look good, but a comparison with the single bf would be king (or is it shown on the images? if so, what image is what?).
As far as i understand double stacking or using 2 bfs will not narrow the bandpass. What leads to improvements is usually the "cutting of the skirts" of the bandpass, so that parasitic light is reduced.
I still can see a double limb on the images, this would indicate that parasitic light hasnt been reduced much.
Triband C9.25
H-a: Quark Chromosphere with BF mod
WL: Antlia 500nm/ 3nm, 393 nm/ 3nm
Ca-K: homebrew (includes 2x 1.5A filters, thanks Apollo)
Player One Apollo Max + Mars MII
Barlows:
-2x Gerd Düring 2.7x
-2x TMB 1.8x
H-a: Quark Chromosphere with BF mod
WL: Antlia 500nm/ 3nm, 393 nm/ 3nm
Ca-K: homebrew (includes 2x 1.5A filters, thanks Apollo)
Player One Apollo Max + Mars MII
Barlows:
-2x Gerd Düring 2.7x
-2x TMB 1.8x
- arnedanielsen
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Re: Poor man double stack
One BF only.
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- One BF only
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I do not look at the sky with the eyes of an astronomer, but of a person looking for the beauty of nature.
- marktownley
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Re: Poor man double stack
Promising results Petr.
To get the best out of both of those blocking filters they need to be tilt tuned.
To get the best out of both of those blocking filters they need to be tilt tuned.
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
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Re: Poor man double stack
That probably won't work. I have them stored without the possibility of tilting, but I might figure it out somehow. That's a good idea, thanks.marktownley wrote: ↑Fri Jun 02, 2023 7:31 am Promising results Petr.
To get the best out of both of those blocking filters they need to be tilt tuned.
I do not look at the sky with the eyes of an astronomer, but of a person looking for the beauty of nature.
- Averton
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