Refractor size for High resolution - no compromise Halpha

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StarCitizen
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Refractor size for High resolution - no compromise Halpha

Post by StarCitizen » Wed May 09, 2018 12:45 am

I have been contemplating on getting a big refractor coupled with a quark chromosphere, and I have the chance to choose between a skywatcher 120mm F/8.3 and a Bresser AR152/ F8.

My question is will the bigger refractor be affected by the seeing more so than the 120mm? would the bigger diameter scope degrade the image more so than the 120 during days of bad seeing? Daystar mentions 150 and up are more affected by daytime solar radiation. what are your experiences?

I intend to do high resolution imaging mainly plus some observing.

What scope would you get if you had the chance and why? what are the advantages and disadvantages of both? (taking out size and bulk).

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Re: Refractor size for High resolution - no compromise Halpha

Post by Carbon60 » Wed May 09, 2018 6:52 am

I use a 150mm/f10 as the basis for my scope mod. It works well and can be used on most occasions, being quite forgiving even in moderate seeing conditions. Going larger is the issue. Check out my Flickr pages for examples.

I'm sure you'll get great images from either scope, so it's probably more about price and ease of handling (bulk and weight).

Stu.
Lunt LS60THa B1200 PTFT
150mm H-alpha Solar telescope with Lunt35 mod
DMK41, Basler acA1920-155
NEQ6 Pro-mount
Fluxgate Magnetometers (1s and 150s Cadence)
More images at http://www.flickr.com/photos/solarcarbon60/

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Re: Refractor size for High resolution - no compromise Halpha

Post by StarCitizen » Wed May 09, 2018 8:23 am

Amazing work Stu, this is exactly what I'm looking for. However, I will be using such refractor with a Quark chromosphere, you're using a Lunt35 mod. I don't suppose these give the same image scale?
The Quark has a 4.2x barlow I'm afraid which pushes the image scale and focal length to around 5000mm. not sure at higher focal lengths seeing get more affected or not, and maybe focusing gets harder to achieve? at what focal length are you shooting?

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Re: Refractor size for High resolution - no compromise Halpha

Post by christian viladrich » Wed May 09, 2018 8:39 am

The bigger ... the better :-)
In most places a 150 mm will make the difference.
Have a look at my web pages with 150 mm refractor and 203 mm et 280 mm SC for Ha.
Christian Viladrich
Co-author of "Astronomie Planétaire"
http://www.astroplanetes.com/
Co-author of "Astronomie Solaire"
http://www.astronomiesolaire.com/

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Re: Refractor size for High resolution - no compromise Halpha

Post by MalVeauX » Wed May 09, 2018 2:57 pm

I'd go for the 150 F8 or even longer. Brand won't matter. What does matter is if you can painlessly change the focuser to a good strong one (even an entry GSO linear bearing crayford would do the job very well). I do it with a 120 F8, but I would definitely like to have a 152 F8 (like the Celestron C6R and it can easily have a focuser change upgrade). 150 F10 or F12 would be great too, if you can find that.

150 is as big as you can go before you need a full aperture front mounted ERF with the Quark. So get the biggest you can, 150. From there, F8 or longer is going to be better (avoid those F6.5 six inchers, go longer).

Very best,

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Re: Refractor size for High resolution - no compromise Halpha

Post by StarCitizen » Wed May 09, 2018 10:11 pm

Marty your photos are simply amazing! I'm speechless! your processing is also top notch, hats off! Christian tes photos sont super également!
This is the kind of results I'm looking for. Btw Marty your Calcium K-line photos are also super nice, what's that Skybender filter you're using? is it available for purchase?

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Re: Refractor size for High resolution - no compromise Halpha

Post by MalVeauX » Wed May 09, 2018 10:39 pm

StarCitizen wrote:
Wed May 09, 2018 10:11 pm
Marty your photos are simply amazing! I'm speechless! your processing is also top notch, hats off! Christian tes photos sont super également!
This is the kind of results I'm looking for. Btw Marty your Calcium K-line photos are also super nice, what's that Skybender filter you're using? is it available for purchase?
Thanks,

You can get results like that from basic achromats that are 120~152mm no problem, the key is the seeing. If your seeing supports a long focal length, you can do high res pretty easy in solar with lucky imaging. Processing is a whole other animal of course.

The skybender is a simple housing chamber with a cut filter inside that I can tilt (to tune). On its nose is a KG3 filter (heat absorption) and on the nose of the camera are two 393nm filters stacked. It's not nearly as good as a Lunt CaK or Daystar CaH, but it holds me over until I can get ahold of one of those (I probably want the Daystar for flexibility for now). My calcium setup is more of a white light with tighter filtration towards Iron, but it is very close to Calcium, so it at least looks like it more. I color it in post. Not sure if any are for sale anymore, but you really don't need the device, you can do it by just getting the cut filters and putting them in extensions to space it out. They're cheaper than real CA options, but they're not dirt cheap at the same time to buy the individual filters.

More info here: viewtopic.php?f=10&t=22564&start=25#p206610

Very best,

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Re: Refractor size for High resolution - no compromise Halpha

Post by TheSkyBurner » Thu May 10, 2018 1:04 pm

just typing in skybender in google only comes up with some 5g internet development, but if you add various things like skybender telescope you get a post like this

Nov 28, 2014 at 8:50pm
http://istarscopeclub.proboards.com/thr ... gement-day

Image

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Re: Refractor size for High resolution - no compromise Halpha

Post by TheSkyBurner » Thu May 10, 2018 1:07 pm

looks like it didnt get any attention

https://www.cloudynights.com/topic/4777 ... ouncement/

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Re: Refractor size for High resolution - no compromise Halpha

Post by TheSkyBurner » Thu May 10, 2018 1:08 pm

skybender was never for sale or marketed, it was given away for free to very select individuals for imaging purposes only. Any secondary filters provided with it were entirely customized by its creator and were not off the shelf unless specified. Marty your 393nm filters look like you got something nobody else did.

I was also lucky enough to get one with two ERF's installed but no secondary filters, still havent figured out how to use it yet though!

Its a shame I cant get ahold of the person anymore, he does not respond to emails.

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Re: Refractor size for High resolution - no compromise Halpha

Post by TheSkyBurner » Thu May 10, 2018 1:15 pm

whoa

http://spaceweathergallery.com/indiv_up ... d_id=98948

Ar2109 - Unfiltered Double Pass Prism
Taken by Skybender on July 3, 2014 @ Naperville, IL
Image

Image

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Re: Refractor size for High resolution - no compromise Halpha

Post by MalVeauX » Thu May 10, 2018 2:05 pm

TheSkyBurner wrote:
Thu May 10, 2018 1:08 pm
skybender was never for sale or marketed, it was given away for free to very select individuals for imaging purposes only. Any secondary filters provided with it were entirely customized by its creator and were not off the shelf unless specified. Marty your 393nm filters look like you got something nobody else did.

I was also lucky enough to get one with two ERF's installed but no secondary filters, still havent figured out how to use it yet though!

Its a shame I cant get ahold of the person anymore, he does not respond to emails.
Yea, I might have gotten the last one before Apollo went off-web indefinitely. I got a pair of 393nm filters and a 370~395 cut filter (I use this one internally to tilt), and a pair of 532nm filters. I replaced the IR cut filters with KG3 filters. Apollo doesn't respond to email or anything either anymore and is either banned or self-removed from any of the websites at this point.

I found out from him where he got his filters though, they're from semrock, all the filters are still available. The filters are not dirt cheap though. But cheaper than a CaK dedicated unit like Lunt.

Very best,

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Re: Refractor size for High resolution - no compromise Halpha

Post by TheSkyBurner » Thu May 10, 2018 3:15 pm

semrock does not make any 393 band filters

https://www.semrock.com/SearchResults_S ... ultsPage=1

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Re: Refractor size for High resolution - no compromise Halpha

Post by MalVeauX » Thu May 10, 2018 3:40 pm

TheSkyBurner wrote:
Thu May 10, 2018 3:15 pm
semrock does not make any 393 band filters

https://www.semrock.com/SearchResults_S ... ultsPage=1
Well rats, that's the info he gave me when I asked where to get more filters. Sorry. :?

The filters I have are not marked, the glass was put into generic 1.25" cells and then written on with a marker for labels. The only glass I have that is marked is the KG3 and IR filters as they were made by Newport (reasonable cost on those, I bought another KG3, works great, eats the heat with my 120mm with nothing in front of it and hasn't cracked yet).

Doing a quick look, Mega-9 has 393nm filters that are FWHM 15nm +/- 3nm for around $100; and Maier Photonics seems to have a 393nm filter that is FWHM 13nm +/-2 nm for around $45. But they're all little 12mm diameter filters. :(

Very best,

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