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Old 14-03-2019, 01:13 PM
Steve14 (Steven)
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solar imaging with a daystar quark?

I was hoping for some advice on getting a daystar quark so i can attach it to my 102mm F5 apo refractor for solar imaging. I'm worried that i may not achieve focus as it has an inbuilt 4.3x barlow. The back focus of the scope is 80.3mm.
Daystar recommend either not using a diagonal or using a focal reducer if there are issues. However, i'm unsure if this will resolve any potential problems and i don't want to buy the quark only to find out i cant use it. Is there a way to figure it if it will come into focus based on the telescope and filter specs?


PS i'm aware that i have to use an UV/IT cut filter for telescope apertures larger than 80mm...
Thanks for any assistance.
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Old 14-03-2019, 07:23 PM
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Steve Massey at myastroshop will be able to answer that.
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Old 14-03-2019, 07:56 PM
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Ukastronomer (Jeremy)
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Quote:
Originally Posted by Steve14 View Post
I was hoping for some advice on getting a daystar quark so i can attach it to my 102mm F5 apo refractor for solar imaging. I'm worried that i may not achieve focus as it has an inbuilt 4.3x barlow. The back focus of the scope is 80.3mm.
Daystar recommend either not using a diagonal or using a focal reducer if there are issues. However, i'm unsure if this will resolve any potential problems and i don't want to buy the quark only to find out i cant use it. Is there a way to figure it if it will come into focus based on the telescope and filter specs?


PS i'm aware that i have to use an UV/IT cut filter for telescope apertures larger than 80mm...
Thanks for any assistance.


You only need a blocking filter before the diagonal and do not need any front mounted one on scopes up to and including 120mm as long as it is not an oil spaced doublet/triplet

I have no problems with focus

FROM Daystar Instruments
-----------------------------------

On Wed, Feb 27, 2019 at 10:46 PM Tiffany Messerschmidt <tiffany@daystarinstruments.com> wrote:
Jeremy,

It is correct to say a front mount ERF is not needed with a 120mm refractor.



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Old 15-03-2019, 10:33 AM
Steve14 (Steven)
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Thanks for the advice. I'll go on the assumption that i have to add an IR cut filter in front of the quark. I'll forgo the diagonal as i want to image rather than do visual.
Despite this, the threads i have read give me some concerns regarding focus so unless i can get some understanding about whether it will work, im not going to risk the money..I sent an email to Myastroshop so will see what they say.
thanks again
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Old 17-03-2019, 09:59 AM
Steve14 (Steven)
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just an added query here. As i look into the quark, it looks like I may have to add an ERF to the front of my OTA as it is a sextuplet - so three elements in the focusser end. i cant put a IR cut filter in front of those elements. Even though the elements are air spaced, i'm worried that i will overheat the glass elements. As an ERF is way too much, i thought it would be cheaper to get a cheap 80mm doublet. What do you think?
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Old 17-03-2019, 10:29 AM
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Merlin66 (Ken)
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Steve,
Exactly which OTA do you have???
I could understand a triplet objective, or a Petzval design with a rear element.....
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Old 17-03-2019, 12:03 PM
Steve14 (Steven)
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Its a Sky Rover ULT 102 ED Glass Sextuplet Fully Flat Field APO Astrograph Refractor
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Old 17-03-2019, 07:08 PM
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Isn't that just a triplet
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Old 17-03-2019, 07:52 PM
Steve14 (Steven)
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As i understand it, it' a triplet at each end of the scope which gives a flat field. Certainly there is a lens at the rear of the scope in the draw tube so that is what worries me about too much heat.
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Old Today, 08:05 AM
Steve14 (Steven)
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For anyone that's interested, i've been doing more research. Basically the quark will work fine with an ordinary achromat refractor as the quark removes all chromatic aberrations. I'd suggest a small aperture size of say 80mm in order to get a full disk view. Using a cheap achromat refractor with a quark appears to be the best way forward for doing solar unless you want to get a dedicated solar telescope like a Lunt which is very expensive. APOs are not necessary and probably best avoided unless an ERF is used. This is especially true if the aperture of the refractor is greater than 150mm and you are imaging a long time. Also, avoid using refractors where the elements are oil spaced. While my 102mm ED sextuplet will possibly be OK, i'm not going to risk it. Feel free to correct me if i have anything wrong.
Happy viewing.
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