Coronado PST + magic

[Kitsunegari]

127mm x 1200mm + pst etalon + 5mm blocking filter.

Good day!

 

 

.

[Pete Presland]

Some very nice detail visible there.

[Kitsunegari]

I can adjust the disc size by moving my extension tubes, and note that these full discs are taken with a 1200mm ota out of a 5mm blocking filter; a  Very unique setup here.

 

The sweet spot of the pst etalon has been completely eliminated.

 

[richard ashbee]

excellent set of photos

[Rusted]

Good detail but now you need to try applying flats during capture to remove the artificial sunspots.

[Kitsunegari]

8 hours ago, Rusted said:

Good detail but now you need to try applying flats during capture to remove the artificial sunspots.

Its just a little dust I can blow off with the rocket bulb.  Flats never work for me in firecapture, and also cause a ton of errors in autostakkert and registax when i apply them.

 

It would be nice if microsoft or google would just build the software we need already, its not like astronomy is a new field.

[Craney]

17 hours ago, Kitsunegari said:

 a  Very unique setup here. 

The sweet spot of the pst etalon has been completely eliminated.

These are very good pictures in terms of detail, and eliminating the sweet spot as well.  Sounds like an excellent set up.

Do you have any pictures of the scope and etalon. I'm very curious to see what you have done.

Cheers,

Sean.

[Rusted]

7 hours ago, Kitsunegari said:

Its just a little dust I can blow off with the rocket bulb.  Flats never work for me in firecapture, and also cause a ton of errors in autostakkert and registax when i apply them.

It would be nice if microsoft or google would just build the software we need already, its not like astronomy is a new field.

Interesting response. Thanks. Can you explain these "errors" please?

You are obviously doing something right to have obtained these very even images.
I have only just begun to use flats for my own PST etalon based 150mm/10 H-a imaging.
I swap regularly between a BF5 and a LUNT 12mm BF. Choosing the one which works best on the subject.
Though I use SharpCap, AS!3, ImPPG and PF7m, I have found flats rather "high maintenance" but beneficial.
Your own telescope build and processing experience might hold valuable information for us all.

Thanks again

[Kitsunegari]

On 09/05/2020 at 00:23, Rusted said:

Interesting response. Thanks. Can you explain these "errors" please?

You are obviously doing something right to have obtained these very even images.
I have only just begun to use flats for my own PST etalon based 150mm/10 H-a imaging.
I swap regularly between a BF5 and a LUNT 12mm BF. Choosing the one which works best on the subject.
Though I use SharpCap, AS!3, ImPPG and PF7m, I have found flats rather "high maintenance" but beneficial.
Your own telescope build and processing experience might hold valuable information for us all.

Thanks again

you would have to purchase a 90mm x  -800mm hydrogen alpha collimator to replicate my process.  There is one listed on ebay, and coincidently these are specifically made for the f/10 istar optical h-alpha doublet's.

 

Unfortunately there is no other way with standard pst optics, however this is worth the investment.  Based on your tag, you already have all the required essentials to complete the "nirvana system".

[Rusted]

$600?  😱

[Kitsunegari]

6 hours ago, Rusted said:

$600?  😱

a single piece of 90mm diameter fused silica custom optics cost is nearly $2000.00; and that is an unmounted product.  You can confirm this on your own time if you choose to find a supplier.

 

A_p_o_l_l_o has ebay fees, paypal fees, and shipping fees ;  The h-alpha optic is also mounted,    Nobody in the world can beat the price he has the auction listed at;  There was a business proposal with istar optical at the time of design but that never went through due to lack of interest in the solar market.  Everybody wants something for half the cost, or wants some cheaters short cut.    

 

Fortunately the  90mm optic is the cheater's shortcut.   Especially considering you have that istar optical halpha achromat and baader 160 d-erf..   Your current 20mm pst optic is the bottleneck limiting your system,

   The new optic opens the bottleneck that has plagued all pstmod's.

 

Also note that an unmounted 160mm baader planetarium d-erf filter was not a bargain item, ; $300.00 just to mount it from teleskope service.

 

But hey theres always the daystar quark gamble , or  a crazy expensive daystar quantum filter.

 

Good hardware is not cheap.

[Debo]

On 08/05/2020 at 22:46, Kitsunegari said:

Its just a little dust I can blow off with the rocket bulb

It's a shame you didn't 😉

Edited May 16, 2020 by Debo

[Peter Drew]

I don't recognise this PST mod "bottleneck".  Like Rusted I operate a 150mm F10 Istar PST mod.  Surely it's a case of "horses for courses"?  My interest lies with high resolution close-up visual images of solar details.  I use the standard 5mm blocking filter, 2x Barlow lens fitted to the nosepiece of a binoviewer which provides a magnification of 150x with a pair of 40mm Plossl eyepieces, the lowest power I use.  I can get about one quarter of the solar disc in view representing a 8 foot circle viewed from 4 feet with no sweetspot issues.  If I want a small scale full disc image I have a 60mm Coronado unit.      🙂

[Kitsunegari]

4 hours ago, Debo said:

It's a shame you didn't 😉

just cleaned it off for tomorrows session of the new active region, granted its not clouded out.

 

3 hours ago, Peter Drew said:

I don't recognise this PST mod "bottleneck".  Like Rusted I operate a 150mm F10 Istar PST mod.  Surely it's a case of "horses for courses"?  My interest lies with high resolution close-up visual images of solar details.  I use the standard 5mm blocking filter, 2x Barlow lens fitted to the nosepiece of a binoviewer which provides a magnification of 150x with a pair of 40mm Plossl eyepieces, the lowest power I use.  I can get about one quarter of the solar disc in view representing a 8 foot circle viewed from 4 feet with no sweetspot issues.  If I want a small scale full disc image I have a 60mm Coronado unit.      🙂

Yes, but can you put your coronado 60mm unit behind the 150mm istar currently?? 

 

You could do this with the 90mm collimator , and then modulate between full disc or high resolution just by altering the spacing.   Switching out the etalon is very valuable considering the variability between them all.  If its a poor sample you can trade it out for a better one without getting rid of the entire setup.  

 

The upgrade here is modularity, adding the ability to go from a 20mm etalon to a 90mm etalon;   is very unique piece of equipment.   I currently switch out between the coronado pst etalon(200mm plane), and a lunt ls50c etalon.(500mm plane)

 

This telescope is also not limited to full disc imaging, i was evaluating the distance to fit a full disc onto my basler 1920-155um sensor.   No barlow required.  No reducer required.     For high res work I use my basler aca720-500um which does 500 frames per second on larger pixels.

 

 

Peter: , id love to see your quarter disk images without flats, eyepieces typically will not show the sweet spot because it is vignetted by the 5mm blocking filter.  When you upgrade to larger blocking filter's;  This becomes very apparent with imaging wide fields. 

Also note that running a 2x barlow, and  pushing the focal lengh through a binoview greatly alters your F/ratio beyond 2x.   Your magnification increases by 1.5x for every 50mm you extend past the optic.

Unfortunately You do still have a sweet spot, it is  vignetted by the 5mm blocking filter; the reality is you are only using 7mm of your 20mm etalon.   If you upgrade to a larger blocking filter - you will become immediately aware of this bottleneck.

 

We are all still limited by seeing despite how good our equipment is.

 

 

 

 

 

        

 

 

 

 

Edited May 17, 2020 by Kitsunegari

[Rusted]

I find myself in some agreement with your arguments but not all of them.

I swap back and forth frequently between my original PST BF and a Lunt B1200S2 BF.
There seems to be no obvious logic to the correct choice. 
I just use the one which suits the conditions and subject matter at any particular moment.

It takes only a few seconds to swap between them as I have the PST BF in a home turned sleeve in a 2" fitting.

The B1200 sometimes offers startlingly better contrast than the PST BF on surface detail.
At other times it is completely fogged out by ZWO ASI174MM camera noise due to excess Gain.

The PST BF passes far more light than the Lunt 12mm BF.
So I [usually] use the PST BF for proms. The Lunt is simply far too greedy for Gain and noise intrudes.

At other times I cannot reduce the light throughput enough using the PST BF.
Because I am down to 0 Gain and less than 1ms exposure in SharpCap.
Typically I use 800x600 frame size = 400fps regardless of the WO 2x Barlow/GPC nosepiece being on the camera.

Peter, very sensibly, does not image. His visual rig is the envy of all who have tried it.
His vast experience at optics and instrument building puts most other humans to shame.

Edited May 17, 2020 by Rusted

[Peter Drew]

@Kitsunegari.  I hope my post didn't appear critical of your initial input.  Not in the least as my main interest in solar matters is the development of the means to observe it and any new approach is of great interest to me.  I have been solar observing the Sun in Ha long before PST's arrived on the market, when they did and I purchased one I was impressed with the views for the price at that time.  I was attracted to PST mods by the early pioneers but was wary of spoiling my unit, instead  for an upgrade I bought  a second PST and made a binocular from them.  Despite the significant improvement I eventually longed for greater image scale and resolution, not being able to afford a large dedicated commercial unit, a PST mod was the obvious way forward.  A long path involving more than a dozen mods and all manner of experimentation has bought me to my current rig, a large solar telescope usable with binoviewers providing high resolution and high magnification images on a par with the best photos.  I bought the 150mm F10 Istar objective new, the Bel-Optic Triband ERF, PST etalon, 5mm BF and Denk binoviewers were secondhand.  In total, the complete telescope cost me less than a new Lunt 60mm.  PST etalons have a bandpass between 1.00A and 0.7A depending on your luck, mine I selected from several PST's and is at the better end of the scale.  I have several BF's in 5, 10 and 15mm sizes, I have found no significant performance between them other than field of view, the larger ones do not increase the sweetspot, if anything they make it more noticeable.   Imager friends have photographed using mine and the resultant stacked and processed images are on a par with the best of others using comparable equipment.  I am strictly visual so completely satisfied with what I have, seeing, for my purpose, is the only "bottleneck".         🙂     

[Nigella Bryant]

brilliant images and pst mode.

[Peter Drew]

@Kitsunegari.  I hope my post didn't appear critical of your initial input.  Not in the least as my main interest in solar matters is the development of the means to observe it and any new approach is of great interest to me.  I have been solar observing the Sun in Ha long before PST's arrived on the market, when they did and I purchased one I was impressed with the views for the price at that time.  I was attracted to PST mods by the early pioneers but was wary of spoiling mine, as an upgrade I bought another one and made a binocular.  Despite the significant improvement, what I really wanted was a larger image scale and higher resolution.  I couldn't  afford a dedicated commercial unit so a PST mod was the only way forward.  A dozen or so mods and much experimentation brought me to where I am now with my dream setup.  I bought  a new 150mm F10 Istar objective,  my pre-owned Bel-optic Triband ERF, PST etalon, 5mm BF and Denk binoviewers  and telescope build cost me less than a 60mm Lunt.  PST etalons bandpass varies between 1.0A and 0.7A depending on your luck, mine selected from several PST's is close to the better end.  I have several 5, 10 and 15mm BF's but have found little difference in performance between them apart from field of view for imaging, the sweetspot doesn't change with the larger ones, in fact they seem to accentuate it.  I use a 2x Barlow lens fitted to the nosepiece of the binoviewers to get to the focus but also because it seems to increase the apparent field of view, the resulting amplification means that even 40mm eyepieces provide a magnification of 150x.

I have no interest in imaging myself, imager friends have tried my telescope and processed images on a par to the best achieved with similar sized equipment.  Overall I'm completely satisfied with what I have and for my purposes the seeing is the only "bottleneck".     🙂

Edited May 17, 2020 by Peter Drew

[Peter Drew]

• Edit.   Double post as the original seemed to have got scrambled, had to try and remember what I had initially posted, hence probably a few differences.     😀    

[Kitsunegari]

I am thankful to be a tester on a new prototype blocking filters. 

 

1-angstrom bandpass with a single cavity design, OD4 blocked Xray to FIR.    Going to be a fun summer if the rain ever stops!

 

The end goal is to eliminate/reduce the "double limb" and function as a cheater double stack system for imagers.    Typical blocking filters are 8 to 10 angstroms, so there should be an immediate difference on the first light while using this.

 

Its good to know there are still people in the world that are willing to stray away from the herd; and take a chance experimenting with new things, 

 

 

 

 

For comparison, here is a scan of a 3 angstrom filter, that is not single cavity.   The difference is immediately obvious.

 

There is considerable transmission loss on the out of band portion, 

both graphs overlapped are a great representation to the elimination of excess/unwanted bandpass .

 

Edited May 20, 2020 by Kitsunegari