<new product>What do you think of a 1.25 inch erf filter for quark?

[mami813]

What do you think of a 1.25 inch erf filter for quark?


https://player-one-astronomy.com/produc ... omosphere/

ERF-1.jpg (170.67 KiB) Viewed 2176 times

ERF-4-1024x956.jpg (43.34 KiB) Viewed 2176 times

ERF-6-797x1024.jpg (34.15 KiB) Viewed 2176 times

[christian viladrich]

Given the description, it looks basically as a red filter ?

[marktownley]

Given the description, it looks basically as a red filter ?

I agree!

[mami813]

Given the description, it looks basically as a red filter ?

I agree!

This is the content of Play One's answer.
Hi Mr. Kim,
This ERF filter combines the characteristics of Baader's D-ERF and R filters.
The D-ERF has a high cut-off rate, but the transmittance is not high. The R filter has a high transmittance and a low cut-off rate.
This ERF can achieve a good enough cutoff rate at 300nm-1100nm while maintaining a high transmittance, finding a balance between these two aspects.

[christian viladrich]

Hello,
Here is the transmission profile of a Baader R-CCD filter :

http://astrosurf.com/viladrich/astro/in ... -R-ALH.JPG

I measured it with a Ocean Optics HR4000 spectrometer.
As you can see, it takes 15 nm to go from min transmission to about 95% transmission, and then about 15 nm to go to 95% to min transmission.
The transmission profile is basically square.

Now, if we look at Player one "ERF", the transition between min and max transmission is about 15-20 nm. Quite similar to Baader R-CCD filter.
So I can't see the difference between Player One "ERF" filter and Baader R-CCD filter.

Regarding Baader ERF, I have not the measured profile at hand, but Baader gives a peak transmission of about 95%. So, I won't say that "the transmission is not high".
On top of that, Baader ERF blocks light up to 1400 nm, which is quite a good idea considering there is still a lot of energy in the solar spectrum up to 1400 nm. This is quite tricky to acheive this from a technological point of view. "Usual" coatings become transparent beyond about 1100 nm.
Player-one does not display transmission of its "ERF" beyond 1100 nm. They just say "Blocking depth: OD2 (300nm-1100nm)", meaning transmission of 1% between 300 nm and 1100 nm.

Finally, Player-One "ERF" FWHM is about 125 nm, while Baader D-ERF FWHM is 80 nm, which makes another difference in terms of transmitted energy.

At the end of the day, I still don't see a difference between Player-One "ERF" and Baader R-CCD filter.

This is not to dismiss Player-One work. I am just trying to undestand why they call it an ERF.

[mami813]

Hello,
Here is the transmission profile of a Baader R-CCD filter :

http://astrosurf.com/viladrich/astro/in ... -R-ALH.JPG

I measured it with a Ocean Optics HR4000 spectrometer.
As you can see, it takes 15 nm to go from min transmission to about 95% transmission, and then about 15 nm to go to 95% to min transmission.
The transmission profile is basically square.

Now, if we look at Player one "ERF", the transition between min and max transmission is about 15-20 nm. Quite similar to Baader R-CCD filter.
So I can't see the difference between Player One "ERF" filter and Baader R-CCD filter.

Regarding Baader ERF, I have not the measured profile at hand, but Baader gives a peak transmission of about 95%. So, I won't say that "the transmission is not high".
On top of that, Baader ERF blocks light up to 1400 nm, which is quite a good idea considering there is still a lot of energy in the solar spectrum up to 1400 nm. This is quite tricky to acheive this from a technological point of view. "Usual" coatings become transparent beyond about 1100 nm.
Player-one does not display transmission of its "ERF" beyond 1100 nm. They just say "Blocking depth: OD2 (300nm-1100nm)", meaning transmission of 1% between 300 nm and 1100 nm.

Finally, Player-One "ERF" FWHM is about 125 nm, while Baader D-ERF FWHM is 80 nm, which makes another difference in terms of transmitted energy.

At the end of the day, I still don't see a difference between Player-One "ERF" and Baader R-CCD filter.

This is not to dismiss Player-One work. I am just trying to undestand why they call it an ERF.

It seems like a bit of a trick.
Thank you for your reply. I learned a lot thanks to you.

[Dennis]

i also think its a marketing trick, since the baader d-erf has good transmition. Also in Solar H-Alpha light transmission is not the #1 importance.
Depending on the Aperture you are using i dont think its a good idea to place a ERF directly in front of the quark. -> closer to the focus point, more stress for the erf.

[mami813]

i also think its a marketing trick, since the baader d-erf has good transmition. Also in Solar H-Alpha light transmission is not the #1 importance.
Depending on the Aperture you are using i dont think its a good idea to place a ERF directly in front of the quark. -> closer to the focus point, more stress for the erf.

hello dennis
Thanks for sharing your comments.
Jongho