ED80: do I ever need an ERF for it?

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Florin Andrei
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ED80: do I ever need an ERF for it?

Post by Florin Andrei » Wed Dec 09, 2020 3:05 am

I have an ED80 refractor. The plan is to use it with an H-alpha Quark filter, for visual and photography. Later perhaps I will add Quark filters for Calcium and other wavelengths.

I was advised that in this configuration, an ERF may not be necessary - just use an UV/IR cut filter in front of the Quark, making sure the relevant wavelengths are actually passed by the UV/IR filter. Okay, I can do that.

But if this is all I'll ever do - use an ED80 with various Quark filters - is there any scenario where an ERF will actually be required?

When will I ever need an ERF for the ED80?


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Re: ED80: do I ever need an ERF for it?

Post by MalVeauX » Wed Dec 09, 2020 3:19 am

You do not need a full aperture D-ERF with the 80mm aperture with a Quark. You're good. A standard UV/IR block filter will handle everything needed at this aperture.

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Re: ED80: do I ever need an ERF for it?

Post by DeepSolar64 » Wed Dec 09, 2020 5:33 am

By what I have read you are good. 80mm or smaller does not need an ERF with a Quark. In time I hope to get a Sodium D-line Quark for my Astro-Tech AT72EDII refractor.


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Re: ED80: do I ever need an ERF for it?

Post by marktownley » Wed Dec 09, 2020 6:33 am

No, you won't ever need a full aperture ERF with an ED80, just a UV/IR filter used as a sub aperture ERF.


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Re: ED80: do I ever need an ERF for it?

Post by yltansg » Wed Dec 09, 2020 9:30 am

Florin Andrei wrote:
Wed Dec 09, 2020 3:05 am

But if this is all I'll ever do - use an ED80 with various Quark filters - is there any scenario where an ERF will actually be required?

When will I ever need an ERF for the ED80?
As mentioned by our friends, you don't need an ERF to use the Quark Chromosphere. What are you thinking of that may need to use an ERF with the ED80?

Alfred



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Re: ED80: do I ever need an ERF for it?

Post by krakatoa1883 » Wed Dec 09, 2020 11:42 am

A full aperture ERF is not needed but a good sub-aperture ERF is absolutely necessary. Forget UV/IR cut filters as they are not effective, a H-alpha filter of the type used for deep sky imaging is the minimum requirement to avoid long term degradation of the in-built BF. A 35nm Baader filter would work fine for the purpose.


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Re: ED80: do I ever need an ERF for it?

Post by Florin Andrei » Wed Dec 09, 2020 7:04 pm

yltansg wrote:
Wed Dec 09, 2020 9:30 am
As mentioned by our friends, you don't need an ERF to use the Quark Chromosphere. What are you thinking of that may need to use an ERF with the ED80?
The only immediate plan is to use the ED80 with the H-alpha Quark to observe and image the Sun; I have all the hardware I need already. I may purchase another Quark later, perhaps the calcium version. Beyond that point I don't have very clear plans (maybe get the Quarks for sodium and magnesium?). So that's why I was asking a general question. I'm new to solar, I still need to educate myself in this field - and so far I've received great help on this forum, thanks everyone!

I live in a place with good seeing at night - I know this from planetary photography and from visual estimates. If seeing turns out to be good during the day as well, I may start drawing plans for an upgrade to the C8 for solar. I know that's a completely different ball game, I know that a full aperture ERF is then absolutely necessary (and might be expensive and hard to find). I'm aware of what I need to do re: focal ratio, etc. But a lot of water needs to pass under the bridge before I even begin to think seriously about this, and even then it may still never happen - e.g. if seeing turns out to be typically bad.

I think I have a way to estimate seeing during the day - I have Baader solar film filters (full aperture) for literally all my instruments, including the C8. I could use the C8 with the Baader foil to do white light imaging, and this way try to gauge the seeing. But it will take a while, probably most of 2021. I'm fairly busy most of the time.


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Re: ED80: do I ever need an ERF for it?

Post by yltansg » Thu Dec 10, 2020 12:42 am

Hi Florin,

All the best in your learning journey !!

Alfred



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