Scopes for solar imaging - Forums

WL and Ha and CaK.

Well, i can stop those down, and add telecentric Barlow or say Powermate, i have 2x and 5x, also i posted fast because if they are good i could try use it for DSO with Ha only or Ha/OIII without stars, because i have two 90mm triplets, one for RGB, and one for SII/Lum, so i want third scope for Ha or Ha/OIII because i have a dual band filter, but i don't ignore solar as well, i mean either one scope for solar and another for DSO, or one scope for both as i don't want to swap a lot but i can try use it for both sometimes, 150mm i only can buy as achromatic and no plan for DSO, but 90mm-100mm are for solar or for DSO whatever, or 70-80mm for solar only, i won't go less than 90mm for DSO with two 90mm triplets.

andrea tasselli

Frequent contributor

Jul 25, 2023

There is no "good" for achros unless they are VERY slow. And I'd use them only with a colored filter (e.g. R) for white light imaging. The fast achros are good for wide field viewing and guiding (maybe with a filter as well). Not sure I'd use them for any imaging except mono and that limited to G channel and possibly R. Stick to f/8 or better f/10. The TAL as well as the Vixen achros are still very good and can be found at bargain-basement prices in the used market.

andrea tasselli

Frequent contributor

Jul 25, 2023

And no CaK.

Tareq Abdulla

Topic starter

Jul 25, 2023

andrea tasselli:
There is no "good" for achros unless they are VERY slow. And I'd use them only with a colored filter (e.g. R) for white light imaging. The fast achros are good for wide field viewing and guiding (maybe with a filter as well). Not sure I'd use them for any imaging except mono and that limited to G channel and possibly R. Stick to f/8 or better f/10. The TAL as well as the Vixen achros are still very good and can be found at bargain-basement prices in the used market.

So if an Achro of F/5 stopped down to F/10 isn't good?

Or F/5 achro with 2x telecentric Barlow or even 5x to make it F/25 isn't good?

Only using a mono camera for solar.

Tareq Abdulla

Topic starter

Jul 25, 2023

andrea tasselli:
And no CaK.

What or why no CaK?

andrea tasselli

Frequent contributor

Jul 26, 2023

Tareq Abdulla:
So if an Achro of F/5 stopped down to F/10 isn't good?

Or F/5 achro with 2x telecentric Barlow or even 5x to make it F/25 isn't good?

Only using a mono camera for solar.

What good that would be? Just get a smaller, slower scope and save both money and weight and on top of that the performance it is very likely to be better anyway. Adding a barlow doesn't make the lens slower, you're just magnifying the image scale and consequently all the optical gremlins.

andrea tasselli

Frequent contributor

Jul 26, 2023

Tareq Abdulla:
What or why no CaK?

Because the violet is very very poorly corrected in a fast refractor and even worse if it is an achro doublet.

Tareq Abdulla

Topic starter

Jul 26, 2023

andrea tasselli:
Tareq Abdulla:
What or why no CaK?

Because the violet is very very poorly corrected in a fast refractor and even worse if it is an achro doublet.

What do you recommend for CaK full disk? I can't buy expensive scope for that.

Ed Dixon

Jul 26, 2023 · Edited: Jul 26, 2023

For solar imaging, other than white light versions, things tend to get pricey very quickly. Lunt makes very good dedicated solar scopes, but they are not cheap. One also needs a camera suitable for solar work.

  Another option area is to use a smaller refractor scope and a Quark eyepiece attachment. Mono cameras go well with that combo. I use a Quark along with a William Optics Z61 scope and a ZWO ASI294MM camera. This is a recent image I did with that combo:

  https://www.astrobin.com/es7j8z/

  There are other solar images in my Astrobin site with different cameras.

  Many local astro clubs have loaner scopes you can use to try things out. That’s where I started with a 40mm Coronado loaner.

Well Written Helpful Concise Supportive

andrea tasselli

Frequent contributor

Jul 26, 2023

Tareq Abdulla:
What do you recommend for CaK full disk? I can't buy expensive scope for that.

Prepare to spend a lot of $$$$ then. Or drop it. Anything you already have is good enough for WL as far as I can see.

Alan

Jul 26, 2023

If I had to drop to one scope for cak,ha I would keep my cheap 102/f11 achromat. It’s a very nice scope for all things solar

Alan

Jul 26, 2023 · Edited: Jul 26, 2023

Tareq Abdulla:
andrea tasselli:
Tareq Abdulla:
What or why no CaK?

Because the violet is very very poorly corrected in a fast refractor and even worse if it is an achro doublet.

What do you recommend for CaK full disk? I can't buy expensive scope for that.

See my post above. I also respaced my 150/1200 refractor for UV and it works great but my seeing rarely supports anything above 100 mm in CaK. I also have a 80/11.3 achromat that is well corrected in calcium. I believe the bresser 127/1200 is well corrected in CaK but unless you have excellent seeing you will mask the aperture.

Tareq Abdulla

Topic starter

Jul 26, 2023

Ed Dixon:
For solar imaging, other than white light versions, things tend to get pricey very quickly. Lunt makes very good dedicated solar scopes, but they are not cheap. One also needs a camera suitable for solar work.

  Another option area is to use a smaller refractor scope and a Quark eyepiece attachment. Mono cameras go well with that combo. I use a Quark along with a William Optics Z61 scope and a ZWO ASI294MM camera. This is a recent image I did with that combo:

  https://www.astrobin.com/es7j8z/

  There are other solar images in my Astrobin site with different cameras.

  Many local astro clubs have loaner scopes you can use to try things out. That’s where I started with a 40mm Coronado loaner.

I already have mono cameras ready for solar and planetary and DSO, so this is not a matter at al, only scopes is what i need to finish, and i wanted cheap scopes because i read people using achromatic scopes for solar into great results, and i know that achro scopes are cheap so how much cheapest i can go for that.

I tested my SW ST80 before with Antlia Wedge that has CaK filter built inside and it was nice, only full of dust that i didn't know how to remove and didn't take flat frames for that, but the result itself is nice, but now i received my Lunt CaK module then Antlia is thing of the past now, i will keep it, i also have the Quark "Combo" version and of course white light, i want to buy individual scopes for each and not one scope for all, ST80 is one so one or two more for full disk then i move to larger scope for close ups.

Tareq Abdulla

Topic starter

Jul 26, 2023

andrea tasselli:
Tareq Abdulla:
What do you recommend for CaK full disk? I can't buy expensive scope for that.

Prepare to spend a lot of $$$$ then. Or drop it. Anything you already have is good enough for WL as far as I can see.

You still didn't mention which scope to use with CaK, you just said $$$, i didn't ask about CaK itself, i asked about a scope to connect with CaK.

Tareq Abdulla

Topic starter

Jul 26, 2023

Alan:
If I had to drop to one scope for cak,ha I would keep my cheap 102/f11 achromat. It’s a very nice scope for all things solar

The question is, can you get a full disk of the sun with this scope without doing mosaic?

Tareq Abdulla

Topic starter

Jul 26, 2023

Alan:
Tareq Abdulla:
andrea tasselli:
Tareq Abdulla:
What or why no CaK?

Because the violet is very very poorly corrected in a fast refractor and even worse if it is an achro doublet.

What do you recommend for CaK full disk? I can't buy expensive scope for that.

See my post above. I also respaced my 150/1200 refractor for UV and it works great but my seeing rarely supports anything above 100 mm in CaK. I also have a 80/11.3 achromat that is well corrected in calcium. I believe the bresser 127/1200 is well corrected in CaK but unless you have excellent seeing you will mask the aperture.

I really don't worry about seeing at all, i am happy and lucky to live in a place where seeing is vary between excellent to poor and clear skies, so i can always find or have that great seeing for any kind of imaging, been years watching the sky so i know about our conditions here, every year i am able to have clear and nice seeing, so i only worry about the equipment an no limit, not about sky conditions, only light pollution is an issue but that is for DSO night imaging.

I have ST80, definitely for use, i am planning to buy something like Bresser 152/1200 or 152/760 and stop it down or any 150mm scope cheap later in future for close ups, but first i need to finish scopes for full disk without mosaic if possible for all three, Ha, CaK, and WL.

Alan

Jul 27, 2023

Tareq Abdulla:
Alan:
If I had to drop to one scope for cak,ha I would keep my cheap 102/f11 achromat. It’s a very nice scope for all things solar

The question is, can you get a full disk of the sun with this scope without doing mosaic?

Yes with zwo 1600

Tareq Abdulla

Topic starter

Jul 27, 2023

Alan:
Tareq Abdulla:
Alan:
If I had to drop to one scope for cak,ha I would keep my cheap 102/f11 achromat. It’s a very nice scope for all things solar

The question is, can you get a full disk of the sun with this scope without doing mosaic?

Yes with zwo 1600

Ok, cool, thank you very much

Tareq Abdulla

Topic starter

Jul 27, 2023

Well, for WL it is kind of easy, and for CaK i saw two imagers here on Astrobin using the exact same scope with exact same CaK filter that i also have but each with different cameras [i believe i have the same of one of them and not the other but similar], the scope is not expensive but it is not cheap being a doublet ED and slow [F/10], so i didn't think about buying this unless if i wait until say November then i can buy it then i never look back and solve two solar imaging filters.

For Ha with Quark i feel it needs a bit more care, they mentioned i must operate it at F/15 up to F/30 for best performance, so maybe i will look for a doublet scope and use my Powermate to reach F/15-F40 and see how it will perform, maybe something like 50mm/60mm aperture, another one than what i have to be only for solar, or if a bit larger like 80-100mm then i have to think about using my 0.5x reducer then in the setup.

andrea tasselli

Frequent contributor

Jul 27, 2023

The Quark (prominence) , which I had, has a 4x focal extender (telecentric) incorporated within the body of the filter and I used it with my f/7.5 APO without major issues, except the actual resulting image scale was far more than my seeing could afford.

Tareq Abdulla

Topic starter

Jul 28, 2023

andrea tasselli:
The Quark (prominence) , which I had, has a 4x focal extender (telecentric) incorporated within the body of the filter and I used it with my f/7.5 APO without major issues, except the actual resulting image scale was far more than my seeing could afford.

My Quark [Chromosphere] is the Combo version, which is without, so i must use a telecentric Barlow, i have Powermate 2x and 5x, so if i will use 5x then i should use a scope with f/5 or f/6 then to reach f/25-f30.

andrea tasselli

Frequent contributor

Jul 28, 2023

As far as I know the Powermate 5x isn't telecentric. At least mine isn't.

Well Written

Tareq Abdulla

Topic starter

Jul 28, 2023

andrea tasselli:
As far as I know the Powermate 5x isn't telecentric. At least mine isn't.

You know what, i wish if the language English can make the definitions very straight forward and clear to make it sense so we are non English people know what we read.

Powermate:
https://www.televue.com/engine/TV3b_page.asp?id=53&Tab=_back

Telecentric Barlow:
https://www.baader-planetarium.com/en/blog/the-benefits-of-telecentric-systems/

Mentioning about a positive lens or optics to redirect the light ray or beam, any kid will understand that they are both the same concept, if others say otherwise then i give up and leave to another planet.