Coronado PST Solar telescope review and eyepiece comparison

[mikeknowle]

With all the cloudy night-skies we've been having lately, I decided to borrow my societies newly-purchased Coronado PST for my first ever solar observing session, cloud-permitting.

As it happened, the morning cloud-cover was about 70% and getting worse, so with a short window of opportunity, I just mounted it on a normal camera pan/tilt tripod and pointed it in the general direction. Set-up time 90 secs.

Wow! As I panned towards the Sun, the first thing I saw in the eye-piece was an amazing prominence! What a wonderful first experience, even before I'd found the Sun's disk itself! That image will stay with me forever (I've since learnt it was a type of prominence called an unconnected arch).

Then, looking at the Sun itself, I noticed two clumps of sunspots, with both umbra and penumbra clearly seen. Having seen literally thousands of pictures of them, it was brilliant to actually see them with my own eyes at last.

All this was seen within the first minute of observing, which just goes to show how easy it is to setup and use this little scope.

Whilst the focus knob was easy to use, I didn't really find the need to adjust it that much.

Although the scope comes with a mini solar-disc finder that you look down onto, I kept finding myself glancing up towards the Sun to check alignment as I would at night time - not advisable obviously but so hard to stop! In full sunlight, its hard to see this window, and although there is a shadow-plate accessory you can buy, I didn't have that so found wearing my cricket hat served just as well.

Then out of curiously, I thought I'd see what the view looked like with one of my own e/p's, instead of the standard supplied 'K20'. I used one of my favorite/regulars - my Meade Super Plossl 32mm (I think K20 means Kellner 20mm, but I'm not sure about that).

Despite the disc image being of similar size, the amount of detail was quite greater. Now I could see 4 more prominences, as well as 2 more groups of sunspots. As this was within 3 minutes swapping e/p's I doubt the increase had anything to do with any heightened observing skill!

A bit of cloud cover interrupted my session, and it was then that I noticed how much heavier the Meade e/p was compared to the K20, so I thought when the Sun comes back out, I'd try the best e/p I had to hand - a Teleview 13mm Ethos 100degree.

The view was absolutely stunning - 9 prominences and over 20 sunspots! Further, I could make out granulation detail on the Sun's surface. As I had to wait an hour for the cloud to clear, the Sun was that bit higher in the sky and so that may well have contributed to the improved image.

I noticed it was easier to see fine detail by gently tapping the tripod - as the image shook, the fine outer penumbra structures and surface granularity became clearer. I guess that's the opposite of adverted vision in some way - activating the eye's rods and cones.

Anyway, although I was rushing due to the impending cloud, I managed to sketch what I saw (see attached).

Ideas for next steps:

> The tripod pan/tilt was clumsy, and it was hard to track - next time I will mount it on a goto

> I'll repeat my little e/p experiment more scientifically to see how much better one is than the other

> I'll get my USB camera and start playing with video capture - initially just one-shot. but ultimately to try to capture sunspot rotation over a few days (if weather ever allows that) or weeks.

Summary: For the price, the scope is really amazing and so simple to use out of the box. I realise it is a bit of a luxury item, costing the same as a Skywatcher Skyliner 200P FlexTube AUTO.....but had I not got access to my societies one, I would definately consider buying myself one.

PST first light review.pdf

[S.A.M]

The PST is a good starter scope for solar viewing and as you said it does not take very long to set up and start viewing. Once you have the bug for solar viewing you might want bigger, unfortunately solar viewing gets expensive when you increase the aperature. If you want to do imaging with the PST you will need an extension tube about 65mm long, this will bring the focusing into range of your camera.

Yes, solar viewing can become a bug that you want more of as the Sun is all ways changing its face.

Now all you need is some clear days, happy viewing.

Peter

[Merlin66]

A good review..

The sense of excitement comes through. I find the K20 (Yes, it is a Kellner) is pretty useless and a 10.4mm TV plossl gives great views.

As you look more - you'll see more

Welcome to the bright side!!!

[mikeknowle]

A good review..

The sense of excitement comes through. I find the K20 (Yes, it is a Kellner) is pretty useless and a 10.4mm TV plossl gives great views.

As you look more - you'll see more

Welcome to the bright side!!!

"The bright side", Haha - it feels wierd using a scope during the day, without 12 layers of clothes on....

....and the neighbours thinking I'm some sort of ejit that doesn't know the stars come out at night-time:eek:

[geoff_k]

I think the PST is great. It took a while when I first got mine to actually see things but you 'waste' a lot of time looking at the Sun through it as more and more detail becomes apparent. It is ever-changing and quite fascinating.

Agreed that the K20 supplied is not great and I normally use a 12.5mm plossl which is just about right.

Given the sort of night weather we have been having, the PST is a godsend.

Trying out imaging but that is another story ....

Geoff

[mikeknowle]

...hooked it up to an RF-out mini-cam and can now watch the image live on the TV.

smokin'....

[Adz]

Great insight for someone like me Mike, I would love to buy one of these some day.

I presume when you look at the sun through it with eyepieces, it is just like a telescope? By that I mean that switching eyepieces lets you view the full disc all the way down to an extremely high magnification?

[Merlin66]

Yes, is the simple answer, but in reality I never seem to be able to get much above x90 with a "basic" PST.

[brianb]

I never seem to be able to get much above x90 with a "basic" PST.

Well that's 2.25x per mm of aperture, and 1.2x per mm is a good "rule of thumb" as to the maximum useful magnification!

The PST is very tolerant of eyepieces - chromatic aberration cannot exist in a monochromatic solar scope, and the f/10 working focal ratio is tolerant of just about any design on the market. A simple eyepiece (few lenses, few surfaces) usually works better than a complex one as the contrast is higher; a wide field of view is not required, the 5mm blocking filter in the PST restricts the field width to not much more than the diameter of the solar disk.

[mikeknowle]

Well I went right up with a 3x barlow on top. Weeeee...

indeed, Adz, it seems very tolerant.

Super little scope.

[astroimpulse]

Great read and an excellent purchase for those cloud trapped at night.

[Gina]

I have one of these on my wish list Maybe by spring or summer funds will have recovered enough. I have several "dark side" things on my list to get first.

[Hypernova]

That is brilliant review, thanks for sharing

I remember having great view through a couple of PSTs at SGL6, the detail on the sun was amazing and the ability to fine tune the etalon to get either surface detail or prominences worked brilliantly. Eventually I wish to get one myself but I suppose that is a long way off at the moment. Still I wonder how much in-focus is provided as I'd like to have go with my 14mm Speers-Waler UWA eyepiece, it needs to racked in quite far on my dob.

[Daveman1]

Nice review - the bit about the eyepieces is particularly interesting! I noticed that the PST now comes in a "Double Stack" version. Has anybody had a chance to try one of these?

Dave

[Merlin66]

Yes, they work very well and give a far tighter Ha bandwidth (around 0.4A) which enhances the views of the surface detail.

[Adz]

I recently aquired a nagler 6-3 zoom. The eyepiece at 6mm is pushing the magnification and high as you can go. But it provides great views of the sun, very very impressed. Much better than the 6mm BGO as the fov and eye relief are larger.

[andre2]

Hi is a baarder Zoom hyperion 4 and the 2.25x barlow a Nice addition for the PST? ( i have heard Some things aboud zoom and Barlow combinations atamazon.com pst review. And it seems to really works!) but i dond know for sure, thanks!!!

[spaceboy]

My thinking is that the MK IV zoom is all you need and the x2.25 barlow would be over kill. I have a PST but have yet to try it with my MK IV. I have though tried it with my Lunt60Tha and it works well but again the 8mm setting (x62) is as far as I'd want to push it on an average day. Not sure how good the seeing is in Holland but it is very rare I get above x42 most days in the UK. Even in my 100mm PST mod most days only allow for x66. All said and done though there are those rare days where even in the 60mm lunt I have pushed x100 (5mm)

[andre2]

Thank! When i order the PST, i think i beginning with a cheeper eyepiece or zoom, ( 15 mm made 4000 plossl  or /and sky watcher  zoom 8-24 mm €84!) instead of going for highe power , if i beleave that i can crank up the power ,espesially to see more proms at the edge - witch i think is amazing -MABY i will take a chance / risk another time.