Recommendations for lx200 In HA

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Recommendations for lx200 In HA

Post by Sungrazer » Sun Jul 24, 2016 5:49 am

Hi all,

At the moment I'm running a Pst double stacked with the zwo174 or dmk21
I'd like to get in much closer on the sunspots
I have an ed80 and a 10' lx200

I'm interested in your opinions on how I should go about using the 10'. Or possibly the ed80 might be more viable.

I've looked around I can't see many set ups that look like they would work with the sc design.

I'd like to keep it under $6k 'ish'

Cheers
Karen
Last edited by Sungrazer on Sun Jul 24, 2016 1:37 pm, edited 1 time in total.
PST Double stacked usually on an EQ3, ZWO174mm, DMK21AU, QSI683wsg, MeadeLX200, ED80 on an EQ6, and some other stuff

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Re: Recommendations for lx200 In HA

Post by christian viladrich » Sun Jul 24, 2016 9:49 am

Hello Karen,
If you want to go for the 10", you need an 11" ERF. You can get one from Aries / Valery. Then you would need a telentric system. Airy lab has a telecentric system designed for the C8 Edge-HD. I am not sure whether it would be OK on the LX200. Still, depending on the seeing, the result in terms of "the images are splendid" is not garanteed.
It would be much easier to turn your 80 ed into an Ha telescope. You just need a 90 mm ERF filter and use it with your PST (see the PST mod).
You can even upgrade the 80 ed with a front Ha filter to double stack the PST mod. There for sure you will have amazing images, and the 80 ed is twice the diameter of the PST.
Christian Viladrich
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Re: Recommendations for lx200 In HA

Post by Sungrazer » Sun Jul 24, 2016 1:33 pm

Thanks for the reply

I'm too chicken to make the Pst mod :shock:

And though I have a few skills would not like to test them out with the scopes at stake... :lol:

I've had a look at airy thanks
Karen
PST Double stacked usually on an EQ3, ZWO174mm, DMK21AU, QSI683wsg, MeadeLX200, ED80 on an EQ6, and some other stuff

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Re: Recommendations for lx200 In HA

Post by Valery » Sun Jul 24, 2016 1:51 pm

Sungrazer wrote:Thanks for the reply

I'm too chicken to make the Pst mod :shock:

And though I have a few skills would not like to test them out with the scopes at stake... :lol:

I've had a look at airy thanks
Karen

Karen,

You can order a 265mm D-ERF from us and a telecentric system from Airy Lab. I believe, that if you will ship your PST telescope to
Airy Lab, you will have it back already transformed to be used in 10" LX200 telescope coupled with ARIES 265mm D-ERF.
PST etalons are among the best etalons for using with Airy Lab telecentric system.


Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Recommendations for lx200 In HA

Post by Sungrazer » Sun Jul 24, 2016 2:19 pm

Valery wrote:
Sungrazer wrote:Thanks for the reply

I'm too chicken to make the Pst mod :shock:

And though I have a few skills would not like to test them out with the scopes at stake... :lol:

I've had a look at airy thanks
Karen

Karen,

You can order a 265mm D-ERF from us and a telecentric system from Airy Lab. I believe, that if you will ship your PST telescope to
Airy Lab, you will have it back already transformed to be used in 10" LX200 telescope coupled with ARIES 265mm D-ERF.
PST etalons are among the best etalons for using with Airy Lab telecentric system.


Valery.
PST Double stacked usually on an EQ3, ZWO174mm, DMK21AU, QSI683wsg, MeadeLX200, ED80 on an EQ6, and some other stuff

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Re: Recommendations for lx200 In HA

Post by Sungrazer » Mon Jul 25, 2016 1:39 am

Thanks Valery

If I make the Pst mod stage 1 Presumably I can return the Pst back to original for use when double stacked couldn't I ??

The stage 1 is reversible isn't it??

Also where do I find details on the Aries erf please? Or could you PM me some information about it please.

Cheers Karen
PST Double stacked usually on an EQ3, ZWO174mm, DMK21AU, QSI683wsg, MeadeLX200, ED80 on an EQ6, and some other stuff

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Re: Recommendations for lx200 In HA

Post by Valery » Mon Jul 25, 2016 4:09 am

Sungrazer wrote:Thanks Valery

If I make the Pst mod stage 1 Presumably I can return the Pst back to original for use when double stacked couldn't I ??

The stage 1 is reversible isn't it??

Also where do I find details on the Aries erf please? Or could you PM me some information about it please.

Cheers Karen

Karen,

If the PST etalon will be taken for use in LX200 10", it can be easily installed back to the PST telescope. Nothing will be lost.

I will send you an e-mail soon.


Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Recommendations for lx200 In HA

Post by Sungrazer » Mon Jul 25, 2016 8:29 am

Valery wrote:
Sungrazer wrote:Thanks Valery

If I make the Pst mod stage 1 Presumably I can return the Pst back to original for use when double stacked couldn't I ??

The stage 1 is reversible isn't it??

Also where do I find details on the Aries erf please? Or could you PM me some information about it please.

Cheers Karen
Brilliant

thanks

Karen


Karen,

If the PST etalon will be taken for use in LX200 10", it can be easily installed back to the PST telescope. Nothing will be lost.

I will send you an e-mail soon.


Valery
PST Double stacked usually on an EQ3, ZWO174mm, DMK21AU, QSI683wsg, MeadeLX200, ED80 on an EQ6, and some other stuff

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Re: Recommendations for lx200 In HA

Post by Astrograph » Thu Jul 28, 2016 8:41 am

Speaking as an Airylab dealer, I would confirm with Frederic that the 2.7x telecentric will work with your Meade SCT. All correctors I sell for use with SCT's are very specific about what they are designed to work with. The Meade SCT is a 'normal' SCT like Celestrons C Range but with added coma correction. The Celestron Edge has an internal corrector which also makes it flat field. All correctors sold for the Edge range are incompatible with the C Range. Correctors made for the C Range are not compatible with 'coma free' designs like Meades. Knowing Frederic's attention to detail, his 2.7x will be optimised for the Edge only.

Having said this, if you are only using it for imaging and therefore only interested in the centre of the field of view then you can probably get away with it.

Remember with the 10" that seeing will have a much bigger effect than with your 80. You can use the Airylab Solar Scintillation Monitor to make sure you only capture images when the seeing is at its best but unless you are in an area that offers advantages for seeing then the results will be less consistent.

Personally if you have a $6K budget, I would consider a new scope that is in between the two. At the high end you could get a ready to go Airylab HaT 8" which will be more tolerant of seeing and give you extreme close ups. Or, for more wide field views a refractor that has more reach than your 80. Anything from 100-140mm would be a significant upgrade.

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Re: Recommendations for lx200 In HA

Post by Valery » Fri Jul 29, 2016 8:58 pm

Astrograph wrote:
Remember with the 10" that seeing will have a much bigger effect than with your 80. You can use the Airylab Solar Scintillation Monitor to make sure you only capture images when the seeing is at its best but unless you are in an area that offers advantages for seeing then the results will be less consistent.

Personally if you have a $6K budget, I would consider a new scope that is in between the two. At the high end you could get a ready to go Airylab HaT 8" which will be more tolerant of seeing and give you extreme close ups. Or, for more wide field views a refractor that has more reach than your 80. Anything from 100-140mm would be a significant upgrade.
As a _practical_ solar H-a imager, I can tell that:

1. When a seeing is OK for 8" telescope, it is same OK for 10" or even 11" telescope.

2. Close up with 8" telescope is FAR from extreme, and significantly less detailed than with 10" or 11". This can be easily shown with H-a photos, if necessary.

3. Aperture rules almost in 90% cases when imaging. Imaging post processing is quite effective in removing atmosphere influence. Lucky imaging - we all use this method when imaging the sun - is an image reconstruction when an image destroyed by seeing. The greater an aperture, the less diffraction image blurring, less photon noise.

4. PST etalon can be used without any telecentric system and be still quite effective. My own examples with 8" and 11" apertures can easily confirm this as well as Jean Pierre Brahic's images with PST etalon and 9" refractors. PST etalon in it's native configuration demonstrates the highest contrast and the highest spatial resolution among any another affordable etalons. With a telecentric configuration it shows MUCH less contrast and worser detalization than in it's native configuration.
I have three telecentric system and several etalons for them, but nothing comes close to a PST etalon in it's native configuration. Not say about factor of
performance/money.
Telecentric system has only one advantage - larger useful more uniform FOV. But with a really extreme close up this is not a problem even with 11" aperture.


Valery.
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Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Recommendations for lx200 In HA

Post by marktownley » Sun Jul 31, 2016 9:16 am

Hi Karen, there are plenty of images taken with the 8" Airylab HaT on my website if you want to get an idea of what you can get with it

https://brierleyhillsolar.blogspot.co.uk/

Mark
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Re: Recommendations for lx200 In HA

Post by Valery » Mon Aug 01, 2016 12:42 am

Hi Karen,

As were promised, personal message sent.


Valery
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Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Recommendations for lx200 In HA

Post by fjabet » Mon Aug 01, 2016 3:23 pm

Having a 8" and a 11" HaT, I don't agree with you Valery.
The larger the aperture, the more sensitive it is to turbulence. It is very well put when looking in Kolmogorov r0 statistic to have a good image.

One the following graph, you have the number of image to acquire to get one good, depending on the r0 value and the aperture.

Image

With a classical r0 of 50mm, which is pretty common by day, the difference between a 200 and 300mm is a factor 25 !

Bottom line, as my site isn't very good, I gave up on the 280mm and use only 8" HaT or my 208mm CN212.
But with a very good site, a 300mm can make sense. But I'm not sure this is very common and very often.

Now regarding the telecentric or not, actually what matters are the angles of the rays going through the etalon.
When using the PST at 400mm with its 40mm lens, angles are 0.5° (they are field angle being in a collimated mode).
But when using a larger aperture, the angle increases very quickly. A 8" SCT gives 2.8° !
The Jacquinot spot is then very small, and the field isn't homogeneous.

In telecentric mode, you have only the F/D angle. At F/D 27,5 as with the HaT, we are at less than 1° all over the field, and if we consider the 70,7° apterure angle rays then it is 0.5°.
And it can be reduced by increasing the F/D.
Now I have compared F/D 27,5 and F/D 33 and I didn't see much difference, we are in the tolerance of the air spaced FP of the PST.

And a telecentric setup is much easier to operate with a SCT. No need to set the back focus precisely for example.
Looking for professional reports about telescopes ?

http://www.airylab.fr/AirylabUS/index.p ... &Itemid=57

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Re: Recommendations for lx200 In HA

Post by Valery » Mon Aug 01, 2016 3:41 pm

Frederic,

Your reasoning about sensitivity to the seeing is OK when no reconstruction process is applied.
The Lucky Imaging Algorithm (LIA) with multi zones is a kinda adaptive optics (AO) post factum.
AO reconstructs wave front in a real time, while LIA doing so post factum using numerous images
divided for numerous subframes. LIA divides full FOV for individual subframes for each frame in
a movie, while AO divides full aperture for individual zones and reconstructs the wave front in a real time.

Both approaches allows to reconstruct an image blurred by atmosphere seeing. This is not the case with
a simple statistical equations when no reconstruction algorithms are applied.

According to my experience, when the seeing allows image reconstruction to a diffraction limit for 8"
aperture, it also allows to reconstruct images to the diffraction limit for a 14"(!) aperture, not say about
11" which is relatively easy vs 8".

And my place is a VERY common with 40m above sea level, in a 400.000 population city, telescope is
in a SkyShed pod at a 1,5m above ground level at a grass lawn. So, nothing special. And I do not use
a Seeing Scintillation Monitor. The SSM will emprove my results when I will start to use it.


Valery.
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Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Recommendations for lx200 In HA

Post by Valery » Mon Aug 01, 2016 3:52 pm

And about telecentric setup. Yes, it is more uniform. But it also GREATLY widens the bandpass of the etalon.
Typical good sample of a PST etalon has about 0,4A FWHM and some of them are even narrower. They deliver
fantastic contrast and for high resolution close up imaging I see no reasons to use telecentrics, especially such
relatively fast as F/27. F/27 will widens the bandpass of air-spaced etalon (PST one) from 0,3A to about 0,7A
if not wider! Hence significantly lower contrast.
I have experimented with Baader TZ2 and two TV Powermates 2x and 4x + PST etalon and Quark mica type etalon.
With solid spaced etalon from Quark all these telecentrics work with different contrast level. But they all work
poorly with PST etalon. This was a reason I have asked about how does your TC F/27 works with PST. Unfortunately
you didn't told me about this.

Minwhile my both PST etalons works fine with highest contrast and highest resolution in their native configuration
at F/10 and F/11 beams from my SCTs.

I would use your TC F/27 with PST etalon if will be convinced by the results achieved. So far I saw good to excellent
results only with DayStar 0.3A solid spaced etalon ION.


Valery.
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Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Recommendations for lx200 In HA

Post by fjabet » Mon Aug 01, 2016 3:53 pm

I agree that you can exceed the optical resolution as stated with the obsolete Rayleight definition thanks to processing. But when it is not good enough, you cap to a lower resolution. I would even say that a smaller aperture would give better results when the seeing isn't good enough.

Honestly, I still wait to see a picture with a resolution that matches an aperture above 250mm in the Ha band. Thierry Legault did one with is HaT 280, you also did one with your C11, but that is all I saw.

To my standpoint, only a few imagers and site can really use more than 8/9" aperture, and not very often.
Looking for professional reports about telescopes ?

http://www.airylab.fr/AirylabUS/index.p ... &Itemid=57

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Re: Recommendations for lx200 In HA

Post by marktownley » Tue Aug 02, 2016 11:07 am

fjabet wrote:One the following graph, you have the number of image to acquire to get one good, depending on the r0 value and the aperture.

Image

With a classical r0 of 50mm, which is pretty common by day, the difference between a 200 and 300mm is a factor 25 !
Hi Frederic! Interesting information; would you be able to explain a little more about the graph: what are the values on each of the axis? what is the r0 value? How is the r0 value derived?

Thanks!

Mark :)
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Re: Recommendations for lx200 In HA

Post by fjabet » Wed Aug 03, 2016 7:49 am

Hello Mark,

the ordinate shows the number of image you need to have one that matches the Fried criterion (that is a wavefront error of lambda/2Pi RMS, which isn't very ambitious optically speaking by the way) in lucky imaging mode.
And X axis is the Fried r0 value in cm. So that means that with a 100mm aperture, images are always within this Fried threshold (better than lambda/2Pi). With a 200mm and a 50mm r0, you have one every 3 image. And with a 300mm, it is one over 70, the curve being an exponential :)
If the look forward to match the Rayleigh L/4 PTV, that would be much much lower :)
Now for more details :

The hard way : http://atsol.fis.ucv.cl/dariop/sites/at ... er1981.pdf
A good start : http://www.ctio.noao.edu/~atokovin/tuto ... /turb.html
Another good second step : http://www.handprint.com/ASTRO/seeing1.html

A just wrote an article for a magazine, but it is in French...
Looking for professional reports about telescopes ?

http://www.airylab.fr/AirylabUS/index.p ... &Itemid=57

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Re: Recommendations for lx200 In HA

Post by marktownley » Wed Aug 03, 2016 7:13 pm

Thanks Frederic! Some bedtime reading for me there :)
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Re: Recommendations for lx200 In HA

Post by christian viladrich » Thu Aug 04, 2016 11:24 am

Just a quick input here : the Fried curves given above are valid only for narrow field imaging (stars). Wide field imaging (sun or moon) is a different business.
As correctly put forward by Fred, the criterium taken by Fried is not "diffraction limited" but "good images".
In any case, these curves give a generally grasp on the increased difficulty on getting HR images when diameter increases.
Another point is that seeing depends on wavelenght (power 1.2), which makes imging in K line more difficult than imaging in Ha.
In a nushell, this is not that easy to get good solar images with a 10" telescope.
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http://www.astroplanetes.com/
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http://www.astronomiesolaire.com/

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Re: Recommendations for lx200 In HA

Post by Valery » Thu Aug 04, 2016 5:03 pm

christian viladrich wrote:Just a quick input here : the Fried curves given above are valid only for narrow field imaging (stars). Wide field imaging (sun or moon) is a different business.
As correctly put forward by Fred, the criterium taken by Fried is not "diffraction limited" but "good images".
In any case, these curves give a generally grasp on the increased difficulty on getting HR images when diameter increases.
Another point is that seeing depends on wavelenght (power 1.2), which makes imging in K line more difficult than imaging in Ha.
In a nushell, this is not that easy to get good solar images with a 10" telescope.

Lucky imaging is the the drug for these problems and difficulties. A lot of imagers have take fully diffraction limited images of Moon, Sun and planets with telescopes from 8" to 16" apertures. 10" aperture is relatively easy for solar imaging, especially in H-a where detals have high contrast.

Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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