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#1 SloMoe

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Posted 12 August 2020 - 08:13 AM

Morning all, I've considered getting a scope that I could see more of whats happening on the Sun, will need to learn a little terminology for discussions but for now I'm getting started.

 

The Coronado PST seems pretty popular, I've read that they deteriorate or the filters show a rusting when they are past their prime.

 

I've been doing some basic observation with a Hershel Wedge but I think I want to see more of the activity than I can with the Wedge.

 

Is there a thread or forum here that deals with that scope so I can learn more about it and what to look for?

 

Thanks


Edited by SloMoe, 12 August 2020 - 09:04 AM.


#2 tjschultz2011

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Posted 12 August 2020 - 08:44 AM

I'm sure someone can point you towards a couple of review postings on the PST but I've had one before and enjoyed it a lot. I sold it to raise funds for DSO imaging but it did make me decide that I want to get an even nicer solar scope at some point in the future. I never had any problems with quality on mine but it wasn't that old either. 



#3 SloMoe

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Posted 12 August 2020 - 09:35 AM

Well, as per norm while waiting for replies I've been reading about the rusting issue, recommended replacement ITF filters,

Maier seems to be the replacement of choice, not a bad price, 

 

Not sure the seller will let me pull the side plate off to inspect it but I'll ask via email and maybe save a trip, 

 

The prism likes to slide off axis, and that needs to be checked also, can be done at the same time as the ITF inspection.

 

So seems the obvious question of size, from 40mm to 90mm, is the same rule of thumb about aperture true with the PST or is it a TFOV thing.


Edited by SloMoe, 12 August 2020 - 09:40 AM.


#4 MalVeauX

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Posted 12 August 2020 - 09:53 AM

Heya,

 

If your goal is just getting toe into HA visual observation, a used PST is a good way to go. It's simple and will work. Lots of compromise.

 

That said, I would suggest that if your budget can handle it and you don't mind waiting, Lunt's new 40mm is going to offer a lot of advantages and less compromise and also be supported by Lunt.

 

With solar, you get what you pay for, and it goes up fast.

 

Very best,


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#5 SloMoe

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Posted 12 August 2020 - 10:04 AM

Thanks MalVeauX, looks like from my basic googling that the PST is sort of the ST80 of solar scopes, jumps right up to over a grand for most of the equipment,

 

oh well, just a pipe dream, you know, searching local CL, saw a PST at half price and think of starting in solar exploration, still thinking it's a good starting scope for it, 

When do you think Lunt will market the scope you mentioned?

an idea of what they will sell for?

 

Went to their site, about the same as a new Coronado 40mm.


Edited by SloMoe, 12 August 2020 - 10:08 AM.


#6 MalVeauX

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Posted 12 August 2020 - 10:11 AM

Heya,

 

Honestly a PST for $300 as long as its in good working order is a great way to do visual HA solar astronomy.

 

Anything new will cost $700~800 at least.

 

But if you're truly interested in this, I would target the Lunt 40 or Lunt 50 ideally, if you want new stuff.

 

If you're ok with used, there's nothing wrong with the PST at $300 as long as everything is in good working order (the ITF, etc).

 

Very best,



#7 SloMoe

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Posted 12 August 2020 - 10:12 AM

It's a pre-order price, no need to have a bunch of these sitting on a shelf to be sold, I see their side of it.

 

Price isn't out of my budget range to start off with.

 

I'll call them today if they answer the phone, dang Covid,,,,,,,,,,,



#8 MalVeauX

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Posted 12 August 2020 - 10:16 AM

It's a pre-order price, no need to have a bunch of these sitting on a shelf to be sold, I see their side of it.

 

Price isn't out of my budget range to start off with.

 

I'll call them today if they answer the phone, dang Covid,,,,,,,,,,,

It will eventually offer a double stack module too.

 

For total cost, I would get the Lunt over a PST.

 

But if you don't plan on double stacking and you only want to spend $300, the PST will do that (you can always sell it if you're not into it).

 

Very best,



#9 SloMoe

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Posted 12 August 2020 - 10:18 AM

I'm thinking that the one I see on CL is from a guy that does a lot of astro gear selling, more selling than using.

 

First time I talked with him a few years ago about another celestial scope he seemed sort of over priced used.

 

This scope may very well have both issues, but I'll wait to hear back from him, 

 

The Lunt 50 sounds like something more in the line of proper first scope for solar viewing, I know well the learning curve for astronomy's different area's.

 

And it's best not to try for inexpensive success when the reality is like you mention, get what you pay for.


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#10 MalVeauX

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Posted 12 August 2020 - 10:33 AM

That is true,

 

If you think this will be something you want to enjoy daily for the next few years, and you really like the idea of seeing our star in HA, I would put a little more into it and push for that Lunt 40 (and double stack it later) or the Lunt 50 (and double stack it later) as a starting point for visual. And if budget allowed, I'd go for the 60mm Lunt (modular, ED refractor) but I realize that costs $2k.

 

Very best,



#11 SloMoe

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Posted 12 August 2020 - 10:47 AM

What about Daystar Solar Scout 60mm Hydrogen Alpha Solar Scope, how do they compare to Lunt?



#12 MalVeauX

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Posted 12 August 2020 - 11:01 AM

What about Daystar Solar Scout 60mm Hydrogen Alpha Solar Scope, how do they compare to Lunt?

Personally I would not bother with any Daystar "scope" option, at all. It's a Quark jammed into a tiny achromatic doublet and requires electricity and takes time between each tuning point and if the electronics fry, you have a very expensive white light scope and you can't even take the Quark out. If you want a daystar Quark by all means get the standard Quark, it will work on any refractor pretty much and is versatile in that way, that one is worth while if you want to do larger apertures fast, that's the benefit of the Quark, but those `scout' scopes I would avoid completely. I'd go for a Lunt over a Scout any day for any purpose.

 

Very best,



#13 SloMoe

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Posted 12 August 2020 - 11:07 AM

Thanks, I see the standard Quark at around $1,100, would that also be a double stack, or considered single stack?



#14 MalVeauX

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Posted 12 August 2020 - 11:10 AM

Thanks, I see the standard Quark at around $1,100, would that also be a double stack, or considered single stack?

With the Daystar options, its all single stack (despite some very false advertising on their 60mm scout "DS" which is absolutely not a double stack nor does it remotely perform like a double stack at all, very poor advertising on their part frankly). But a Quark will let you get an 80mm, 102mm, 120mm, etc, instantly because you can use any old achromatic refractor that you already have, or ED refractor you already have for this and instantly have high resolution large aperture views. Great with binoviewers too. But always a single stack.

 

Versus if you go with a smaller instrument, dedicated, like a Lunt 40/50/60 you can eventually double stack for the enormous contrast increase and these are ideal for full disc viewing and show plenty of detail. No electronics to fail (not saying they fail, but it's just something to consider).

 

The best thing is to try as many options as you can, like at a club or something. I realize that's difficult right now (to impossible) depending on location and the COVID situation. But it would help greatly to get a little time behind one of these to know what you prefer. Preference is a big part of this. There's no magic bullet for everyone.

 

Visually, my own preference, is to favor a smaller double stack over any large aperture single stack. The contrast difference is significant. And for visual I prefer a quick view without much fuss. Rather than setting up a big scope, need tracking, etc, just for a single stack view. Again, its all preference and personal.

 

Very best,


Edited by MalVeauX, 12 August 2020 - 11:14 AM.


#15 SloMoe

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Posted 12 August 2020 - 11:15 AM

I always was sort of fascinated by the idea of an electronic filter of the Quark, 

 

So I'd like to know more about double stacking, can you give me some idea of what that is?



#16 MalVeauX

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Posted 12 August 2020 - 11:26 AM

I always was sort of fascinated by the idea of an electronic filter of the Quark, 

 

So I'd like to know more about double stacking, can you give me some idea of what that is?

Double stacking is two etalons (HA comb filters) and a single blocking filter working together to get rid of any parasitic continuum light from the photosphere. The photosphere is incredibly bright, much brighter than the chromosphere, so when you try to view HA, you have to block out the photosphere to do that, and it requires very, very narrow filtration to get there. The photosphere is underneath the chromosphere, and its brighter, so if you think about how challenging it is to block the light of something under the structures you're trying to see, that are dimmer, you're presented with a challenge. So if we can block the photosphere's light and only see a single wavelength of light, we can start to see just that, and see the chromosphere's fiery hell scapes. With a single stack, some parasitic continuum bleeds through, so you will see less contrast on the disc surface due to the brighter photosphere coming through, but the limb will be unaffected so prominences will be bright and fine, but you will see a double limb effect, as you see both the layer of the chromosphere (dimmer) over the brighter lower photosphere, at the same time (which is a super interesting concept if you think about it). There's less contrast on the disc with a single stack because of the brighter photosphere bleeding through. Double stacking without another HA etalon is a means to then further filter things down, basically it trims the wing profiles of the transmission curve so that the off-band light is blocked even more, and the peak of transmission in HA then is sharper, narrower (ie, greater finesse). The bandpass number is irreverent to the results (ie, the sub-angstrom value, like 0.7A or 0.5A, etc). So blocking the off-band wavelengths of light that form the wings of the transmission profile, it will block that last bit of unwanted photosphere light and so then the disc is higher contrast because it no longer has photosphere light bleeding through, and when tuned together, no longer has a double limb, the effect is a disc that is the same brightness at the limb with the proms as it is on the disc itself with its features and way higher contrast on the disc features (filaments, plages, etc) and much easier to see individual spicules, mottling, etc. This cannot be done with a single etalon filter (even a $16,000 0.3A Daystar Quantum will show a double limb!).

 

Once you view through a double stack, you will hardly be able to view a single stack again. Just a preference though. There are those that prefer a brighter single stack view. Single stacks are great for the limb structures like prominences. But if you like the disc structures too, a double stack just makes such a profound difference. A double stack is dimmer, the sharp peak transmission is lowered as each etalon grinds away 45% of the transmission each time. So viewing is just like viewing night time (dark adapt, wear a shroud, block ambient light, etc) and so some just prefer a brighter view, but again, the contrast difference is huge.

 

For me, I have 150mm and 200mm solar scopes. I used my Quark in them for high res, large aperture single stack views. But, my preference for visual HA strongly favors the high contrast of a double stack. I vastly prefer my small 60mm double stack for visual HA over my much larger single stacks.

 

150mm & 200mm single stacks with Quark & Binos:

 

BinoViewing_HA_C8Edge.jpg

 

Solar_150mm_Visual_Quark_Bino.jpg

 

120mm Quark & Binos:

 

120F5_Quark_Bino_web.jpg

 

40mm (ST80) Quark & Binos:

 

60mm_HA_Binoview_Visual_01282019.jpg

 

60mm double stack with Binos (my preference for fast visual):

 

SM60DS_ED80_Binos_05302020.jpg

 

Very best,


Edited by MalVeauX, 12 August 2020 - 11:40 AM.

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#17 SloMoe

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Posted 12 August 2020 - 11:49 AM

I just talked with Faye at Lunt, nice people, she sort of explained pressure tuning, is that better than mechanical tuning?

As good as?

 

What's the gain for visual with pressure tuning?

 

btw, nice scopes,,,,,,,,


Edited by SloMoe, 12 August 2020 - 11:50 AM.


#18 SloMoe

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Posted 12 August 2020 - 11:52 AM

And again back to a Coronado PST double stack set up, much difference between the Lunt double stacked?

visual that is,,,,, 



#19 MalVeauX

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Posted 12 August 2020 - 12:09 PM

I just talked with Faye at Lunt, nice people, she sort of explained pressure tuning, is that better than mechanical tuning?

As good as?

 

What's the gain for visual with pressure tuning?

Pressure tuning is better than tilt tuning because of the shape of the sweet spot that results and uniformity as well as the plates stay parralell.

 

And again back to a Coronado PST double stack set up, much difference between the Lunt double stacked?

visual that is,,,,, 

We will not know how different until Lunt drops their 40mm scope on the market soon. I would guess it will be better in general. Lunt makes great scopes. The PST is originally Lunt's design, later sold and went with Coronado to Meade when Meade about it. Lunt's son layer opened what we know as Lunt's company today and now they're remaking the 40mm as the Lunt 40mm. I would bet it is likely better and well made. Also, the support. Lunt will support their product. I cannot say that for Meade (so if your ITF is rusted, it'll probably be on you to fix it, other than an outright return). Meade is sued and filed bankruptcy, so I'm not sure how the support will be for any product from Meade. May be all smoke, but it's worth knowing before shelling out your money.

 

I had a double stack PST for a while, still have two of them. They're good little scopes as long as you get a decent quality one with a good sweet spot and it all stays aligned and the ITF isn't rusty. They're a good value used. I wouldn't buy them new personally at this point though.

 

DS_PST_Install2_04062019.jpg

 

Very best,



#20 Stargazer3236

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Posted 12 August 2020 - 12:54 PM

Marty, I noticed the ERF on your Edge 8HD. Would the ERF work with my Nexstar 8SE OTA? What does that bit of glass retail for?



#21 MalVeauX

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Posted 12 August 2020 - 01:51 PM

Marty, I noticed the ERF on your Edge 8HD. Would the ERF work with my Nexstar 8SE OTA? What does that bit of glass retail for?

Heya,

 

The D-ERF works on any optic as long as it's mounted properly, but this particular D-ERF is really only good for SCT/Mak/Refractor and not so much for newtonians due to how the secondary position is relative to the radiation from the sun. It blocks enough to allow the use of a mirror system like the SCT it was designed for, but it's not a complete blocking; I use a secondary D-ERF after it in the imaging train, a 50mm (2") one to complete the blocking. My C8 Edge and a normal C8 found on a Nexstar is the same size, so it fits the same. The glass is of course expensive (optically flat glass with dielectric coatings to reflect thermal energy with unwanted wavelengths), and the holder cell was custom made for it specifically and to match the C8 Edge I use. Overall it cost twice what the C8 Edge costs on its own to get the 214mm D-ERF with its holding cell. But it opens doors to instruments like SCT to be easier to use for this. Frankly a long focus refractor is better to use and you could use a smaller D-ERF internally to do the same job. But a large refractor is much bigger, heavier, physically longer, and requires way more mount to handle so that offsets the cost savings of the D-ERF; that said, I generally don't recommend going down this pathway unless you know for sure your seeing conditions can support the image scale and aperture. Realistically a 6 inch refractor is already high resolution for solar if seeing is not the limit and it's much less expensive to enjoy a big refractor of 6" aperture compared to trying to get a mirror design to work with a big D-ERF just for those 2" or more apertures where the reality of seeing limits will always have them limited to whatever the seeing is (you can get a 8", 11", 12", etc, and not see any resolution better than 5" or 6" if seeing is limited to that, it will just big a finer image scale but the true resolution will always be at the limit of whatever the seeing is). So again, unless you have excellent seeing, this is not something I suggest.

 

Note, the D-ERF and holding cell is 7lbs +/- on its own. It takes my C8 to 21lbs total, plus another 3~4 lbs for the focusers and imaging train, for a cool 25lbs. It's not something to put on a Nexstar mount at all. You'd have to move into a very robust mount if you want to not have fits focusing it and it changes how it balances obviously with that big heavy glass on there).

 

Realistically, a 6" refractor can be used with just a 50mm (2") sub-aperture internal D-ERF and it will handle it fine. I do this often with the images you've seen via my 6" refractor with a simple Baader Red CCD-IR Block filter to prove this concept with my seeing metrics to show that it's not limited by the tube's internal thermal characteristics at all; over and over, repeated over and over, to establish that the idea of needing a full aperture D-ERF on a refractor is myth. A full aperture D-ERF is absolutely required on a mirror based optic, like SCT/Mak/Newt. But refractors transmit all thermal energy, they do not absorb or reflect like a mirror does, where even 1~2% matters quite a bit. And the resolution and cost of an unobstructed 6" refractor with an inexpensive yet effective internal sub-aperture D-ERF is simply way more cost effective and can clearly image high resolution for significantly less cost so that nearly anyone can get into that, compared to shelling out to make a mirror based optic handle the thermal load (like a full aperture D-ERF on an SCT). The only reason to use an SCT for this purpose is because you can get a ton of aperture, in a compact scope, making it easier to mount and carry (an average person can move a 8" or 11" SCT no problem, they're less than 30lbs). But that's the simplest way to get larger aperture inexpensively without needing a far more substantial mount to handle it (otherwise a refractor would be superior and long focal-length newts are much superior, but they're massive instruments and require big mounts and are too heavy for one person to safely move often likely).

 

So again, unless you have excellent day time seeing conditions often I would not bother trying to get into a larger instrument for solar beyond a 6 inch refractor. If you're already topping out resolution with a 8" SCT/Newt in white light on the photosphere at critical sampling, then sure, go for it. But if you're not already doing that, then I wouldn't go beyond a 6 inch refractor until you know for sure your seeing will ever support such resolution. Just being as realistic about it as possible since I've done that and I have routinely sub-arc-second seeing conditions (per my SSM metrics I post every time) and that still doesn't always support a full 8 inch aperture's resolution.

 

Granted this is way, way, way beyond the "scope" of a PST starting thread... maybe we should move on to a different thread so we don't swamp this one; apologies to the thread starter!

 

Very best,


Edited by MalVeauX, 12 August 2020 - 02:07 PM.


#22 cptbobrfh

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Posted 12 August 2020 - 02:35 PM

And again back to a Coronado PST double stack set up, much difference between the Lunt double stacked?

visual that is,,,,, 

My 2 cents: 

 

I have a Lunt 50mm H-Alpha scope,with Feather Touch Focuser,Lunt Zoom eyepiece,and a Lunt LS50C Double stack module.

IMHO,this is the best entry level scope. We are already in the 2nd half of the year,and I believe getting used to H-alpha details visually in this scope is a great STARTING POINT.

 

With that being said,NEXT YEAR,get the Daystar Quark Chromosphere AND a Lunt 102mm ED F/8 refractor.

 

With the Lunt 50mm,you can hone your visual observing skills,for full disc views,and then step up to high resolution,zoomed in views with the Quark. I have this setup and highly recommend it!

 

I would stay away from the PST,whether you double stack it or not,and the Daystar 60mm DS scope for entry level.I HAVE HAD BOTH AND SOLD THEM BOTH.You will pay more for the Lunt 50mm DS,but you will get SO MUCH MORE ENJOYMENT!

 

Best,

 

Bob


Edited by cptbobrfh, 12 August 2020 - 02:56 PM.


#23 SloMoe

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Posted 12 August 2020 - 03:48 PM

Thanks for all the input here, this isn't something to just jump right into.

 

Bob, what do you think that kit you mentioned with the 102 cost?



#24 SloMoe

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Posted 12 August 2020 - 06:21 PM

I found out how much Bob, when the price is a little more for more then when to stop and what was I ever thinking of getting into solar viewing,,,,,,,,,,,

 

Knowing what I do know about celestial I should have known better,,,,,,,,

 

I have an Orion ST-90, fl 500mm f/5.6, si if I cut an apiture cap to bring the f ration up to f/10 or so, 

Mine is the older ST-90, and I have upgraded the focuser to a GSO 2 speed.

I think it's still in collimation, and right now I have cut the dust cover for 40mm aperture 

 

So if I go for a Quark to use, how would this compare to the Lunt 50 single stack and/or double stack.



#25 hopskipson

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Posted 12 August 2020 - 06:52 PM

I found out how much Bob, when the price is a little more for more then when to stop and what was I ever thinking of getting into solar viewing,,,,,,,,,,,

 

Knowing what I do know about celestial I should have known better,,,,,,,,

 

I have an Orion ST-90, fl 500mm f/5.6, si if I cut an apiture cap to bring the f ration up to f/10 or so, 

Mine is the older ST-90, and I have upgraded the focuser to a GSO 2 speed.

I think it's still in collimation, and right now I have cut the dust cover for 40mm aperture 

 

So if I go for a Quark to use, how would this compare to the Lunt 50 single stack and/or double stack.

I used the ST80 wit a GSO 2-speed and the Quark for a while before moving to an ES102.  The 80 was a great performer with and without the aperture mask.  Without the mask, the proms were very bright.  I eventually made a 60 mm mask and that worked well too.  It's also lightweight and very portable!




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