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Hi Folks, I need a wee bit of advice, please. I'm getting a Coronado PST in the new year and wondering what would be best to mount it on. I'm considering a SkyWatcher PRONTO alt az or a decent fluid head on a camera tripod. Any thoughts/ suggestions? Thanks and clear skies for 2023. Rob.

Hi, been trying a few times to image with a Coronado PST and cannot get focus. With the ZWO 224MC I tried printing a "low profile nosepiece" found on the internet and that didn't work - the camera looks like it needs to go further into the eyepiece holder - some people have managed to get it to work I don't know how. So I modelled another low profile nosepiece which has a 4mm depth groove around the bottom of the nosepiece face so it can sink into the Coronado eyepiece holder 4mm more - nope still no focus. People have suggested unscrewing the lens part of a barlow out and using that with the camera nosepiece, tried a 2x Meade telenegative and a generic 5x - nope makes it worse. So today I tried a DSLR connected to a t nosepiece extension tube and ran into the same issues. I don't know how people are managing to image with this scope - I know it's not designed to be imaged with but it is something I wish to do considering others have managed it. On another note, how clear is surface detail visually on a PST, I can manage to see sunspots but no light/dark granular structure, with the focus ring dialled all the way to the left I can see prominances, sunspots with the ring dialled more to the right though most of the time its all a red blur - checked the ITF and that's clear (it's the newer type PST).

I acquired a second hand Coronado PST. The focus knob doesn't seem to have any effect on the image and, although it turns, it feels as if something inside the scope is "slipping". Is it worth opening up and taking a look to see the focus knob in action? Is there anywhere that services the PST without sending it outside the UK? Are there any nasty surprises if I open it up (springs, pressure points etc)?

Hope this is the right place to ask about the Coronado PST i recently acquired this scope and I can’t get any surface details to show on the sun, I have played with the tuning ring but apart from being able to see some flares on the rim of the sun, no surface details came through. I was using my own 8mm and 11mm Explore what I saw was just a red blob, pretty much like white light viewing with a red filter. Turning the tuning ring only changed the intensity of the light coming through is this what is expected of the PST? Or do you think I am doing something wrong or my PST may well be faulty?

Hello I have been away from this forum from possibly July - I never find a lot of time to do anything these days, same to be able to relax reading and interacting Astronomy forums. I asked here a few ideas about making a solar scope or modifying whatever I had and I was recommended to also see Solar Chat Forums and I did. Thanks to solarchatforums I have been able to do something decent and here is what I have done so far - very slowly! 1. I purchased a second hand PST and replaced its ITF with Maier one from the US and it finally had a clear image coming through + moved Etalon screw to third position - all the usual thing everybody does [after I researched it]! 2. used a new SCT screw-on short focuser [used once or twice on a LX200 R Classic] and using Teflon tape I screwed the PST Etalon to the focuser and purchased a 2" adaptor to fit on Etalon. 3. then used a Chinese 2" to 1.25 and modified the 2" side socket taking internal ring off and making 3x 120° threaded holes and 3x nylon thumb screws and used that as an adaptor to fit the original PST eyepiece holder - strangely enough at present this adaptor is also used as a tilter ... until I buy a proper camera tilter 4. then fit the above eyepiece holder into the SCT focuser with 2" to 1.252 adaptor in it and screwed the whole Gold PST tube with Etalon in it and made a BETTER PST - see image 5. I also initially tried a 2.2x DSLR camera Lens magnifier in front of PST and it decently works too - so PST will be fine for full solar disk mainly and without the 0.5 angstrom - not forcibly needed, I am probably around 0.7 as it is! 6. more importantly, I decided to make my own 90mm solar scope using the above bits and pieces. 7. with the help of Solar Chat Forums [great guys with a lot of knowledge, some are professional - i.e. they know the optics mathematical details - which helps] I purchased a cheap Bresser AR90/900 8. the ONLY usable thing there ... is the main tube, a nice and thick tube - the rest is ALL plastic!!! I dismounted all parts and saw tube shorter ... a bit too much ! - I could have saved ~6cm really as I went with original ideas, but forgot I was using a different telescope from my initial thoughts - silly me! So, I added a 6cm extension - no problems there to reach the 20cm inward needed for the PST Etalon which has ~20cm FL 9. initially I used a Tuna Fish 100g tin to adapt the SCT focuser onto my AR152 and fit Etalon inside the focuser to get near the 20cm needed- lets call it Quark unit - which it is really! It worked well, so I decided to add a second focuser to tune the Etalon ... getting back to AR90/900 ... 10. I was trying to avoid overspending, I could not afford to spend too much - then I remembered I had a unused AR102SX which in my mind I guessed ... the focuser should over AR90/900 and it did! It just fits perfectly - then drilled three holes for the holding screws et-voila' 11. I purchased a second hand 75mn Baader D-ERF and fit it INSIDE the AR90 tube at about 20cm inside from the front air-spaced doublet lenses, as there are the usual internal rings soldered in and just sit on it and I have about 70mm aperture - i.e 70mm width from the D-ERF for photons to get through. At that ~20cm distance from front lenses the beam is still very large - probably about 60-65mm - there is no heat in between - no need for air-escaping holes 12. when I have the time I will make a solar finder scope and fit it on the tube - not that is really needed - I usually use CDC to get there almost over The Sun [having an almost exact spot on the yard!] - then use my eye without eyepiece and look thourgh the PST eyepiece holder for solar shinging and centre the telescope over The Sun. Well, it works well after tuning Etalon focuser correctly and then focusing/tuning Etalon etc. - the usual. See some images - still learning imaging/processing and a lot more to learn about Solar ... a lot! I will probably need to get a Power-mate 2.5x when I can afford it! 1st mod - without the original black box - it works so much better - better focusing and sharper viewing too. This is the AR90/900 shorten tube with AR102SX focuser and adaptors to test it normally This is complete with the Quark Unit on the right side Since this image there have been some changing - do not use the revelation adaptor any more and added a 6cm 2" extension. Here are some images:

I recently acquired a PST and had my first light today...it took a bit of work but I was able to see some great stuff through the EP. However, when I tried to hook up my smartphone to the scope with a phone adaptor I was completely unsuccessful in capturing any good photos. Everything looked way out of focus and I couldn't come close to seeing any of the prominences on the phone that I saw visually. Is this due to the PST's setup? Or am I doing something wrong? I was attempting to do it with an 8mm EP.

Hi Guys My solar set up is finally complete.... The latest purchase is the double stack filter which I collected from its former owner on Monday. Incredibly, first light was yesterday. What a fantastic piece of kit!!!! Detail jumping out!! I was one happy happy camper! ??? - must be getting excited about SGLXII - sorry... Tuning the two etalons seemed to be trial and error. Much enjoyable fiddling about with some lovely views, but no method. My question is a simple one. Is there a better way to get the best out of this setup? Any hints & tips greatly appreciated. Paul

The PST arrived 2 days ago and since then I have been stationed at the lounge window for the faintest whiff of a shadow or direct sunlight. Well today, I had some blue sky and about 30 mins in which to blat a few frames off with a Canon 60D using eyepiece projection ( Baader Zoom). Not much time to record exposure times and ISO's , I just tried to get something before the clouds and a resident pine tree spoiled the party. Anyway I'll save all the technical noodlings to a later date. So here they are. Even got some prom action !! Wow, one of those special moments when a long held ambition materialises in front of your eyes. Any helpful suggestions about how to improve the images and to progress would be most helpful. I think I need a good mono-webcam to bring out more surface detail, although it is ironic that I choose a spotless day ( in the the literal sense) to test the PST. Cheers, Sean

Hi Guys I've now got all of the parts incoming for my 100mm PST Stage 1 mod. So got cracking on dismantling my trusty PST..... I just can't seem to shift the Etalon & Tuner from the gold tube! I know that others have encountered this problem. Any hints about how to get it moving? Paul

Hi Folks Ever since looking through Stu's PST Stage 1 Mod at the DIY Peak Star Party. I've been keeping an eye out for a suitable donor scope for my own project. Damn you Stu. He's (removed word) done it again! The man should have a wallet health warning hung round his neck?? Nothing has appeared on the classifieds / ABS / Auction site. So, I am thinking that I may have to go cheap and new. 100mm f10 seems to be the sweet spot. Most 90mm f10 scopes seem to come with 1.25" focuses and a plasticy feel (Neither desirable). By the time I have added the requisite 2" focuser. I may as well pay for a 100mm with the 2" focuser as standard. Much reading has thrown up two possibles: https://www.firstlightoptics.com/evostar/skywatcher-evostar-102-eq3-2.html https://www.telescopehouse.com/telescopes/bresser-messier-ar-102-1000-hex-focus-optical-tube-assembly.html The price is similar for just the OTA. Which would be better? Or, is there anything else that would work better without baking the bank? Paul

I think I first thought about doing a mod late 2012, and... suffice to say I've got distracted and done nothing about it last year. So this year, I will finally get round to the mod! To recap, I have two PSTs, one I'm keeping stock, one I'm modifying. I had all sorts of wacky ideas, but have now decided to go the tradition route and have ordered a TAL 100RS. The only other major component I need then is the D-ERF. I remember it was a common trick to get an under-sized one and insert it into the tube part way down. Here's where I'm getting confused. My previous notes suggest it was a 75mm one, but now I can only see a 70mm one on sale. Next one up is 90mm and also comes with a hefty price lift. Was it actually 75mm or is my memory failing me? I don't think I have much choice other than go for the 70mm.

My 2nd attempt at a mosaic, although I overcooked it a little but I'm not going to reprocess all the frames again in an attempt to fix it! I want more detail...

I've been quiet in the background for the past couple of months. Moving back to Oz and doing some "mandatory" renovations etc. Just getting/ making the time to get the gear unpacked. First cab off the rank is the TS102 PST Mod. This 102mm f11 scope is made by Hunming (United Optics), China and sold in the UK as the LYRA. It's a great scope, and perfect for the PST mod (as others have already found) I machined up an adaptor which just replaces the original Crayford focuser. (There's a dovetail connection on the rear of the OTA - just needs 3 x M4 nylon screws to lock it in place)The 2" PST nosepiece is held securely by 3 x M6 nylon screws. No cutting of the OTA and the adaptor can quickly be removed and replaced with the original focuser for white light observing. Takes all of 10sec!! I've also machined up a cell to take the SM60 etalon to give double stacking.... Good to be getting back into it.

Had a lovely imaging session on Suday morning in "runoffshed's" back garden with the PST and DMK41, this is my fourth outing with this equipment and the first time with a barlow added. The atmosphere was very steady with the only interuptions coming from Sybil the very curious cat and by John generously providing tea and bacon butty's, this sure beats messing around in the cold and dark The second image is an inverted close-up which to my eye looks like a distant church with a spire next to a tree on top of a hill, needless to say I'm very pleased with the results I'm getting from the little PST. Mel The Tree and the church

My first full pano of the sun. Actually, it was a 99% pano as I missed a tiny bit of the edge with all the processed frames, but the content aware fill in Photoshop did a great job. Since it didn't have any real detail in it anyway, I didn't go back to the raw files to expand the processing region right to the edge to recover that. This is also my first time using flats for solar imaging. Why didn't I do this earlier? I only tried it this time as there were rather a lot of dust spots I couldn't clean. In order to make a flat, I did the deep sky trick of putting something over the objective. Unfortunately that killed the sensitivity, so I had to jack up to 2 second exposures and maximum gain to see anything at all. Leaving it running for some minutes I got 200 frames and that stacked into a nice dark frame. Well, almost. I was now getting hot pixels too. My fix for that was using the dust and scratches filter to remove them, tuned so as not to remove the actual dust spots which I wanted to keep! The flats also got rid of the stripe optical interference pattern I got at times. Overall, this does give more detail than a single shot full disc capture. But it's not half a lot more work! I used 11 frames in order to fit it. Kit: PST with Hyperion eyepiece projection into DMK41. No idea what image scale is, but about 3 frames will get me across the sun with overlap.

I have a second (used) PST on its way to me, so before I get to the typical mods like replacing the objective, I was wondering if there was anything useful I can try with two PSTs first? The thought occurs, could I extract the etalon from the 2nd one and add it to the 1st? Double stack on the cheap. I'm not 100% sure on the threads but could it screw in series with the existing one? But would the positioning in the optical train be thrown out enough to make this unworkable? I'm not sure how much tolerance I have to work with here...

Note I have two PSTs now. One was bought new from earlier this year, serial 1076xx. The older one I bought used, the previous owner said it was about 4 years old. Serial number 1042xx. Both are blue objective style ones. The shaved eyepiece holder. Since the body was scratched I decided to sand it which gives it a brushed metal finish. The blocking filter to the right fell out while I was doing that. It pops in from the top and is held in by a ledge so it doesn't fall out. And to stop it going up, it was glued. Push from the bottom and it should come out. Originally I was going to remove 4mm, but now I hold it next to the unmodified one, I've taken off 5mm or more once the filing and sanding is taken into consideration. Top row left to right: Unmodified eyepiece section, shaved eyepiece section with blocking filter removed, lower section with ERF removed. Lower row left to right: unmodified lower section with ERF, blocking filter without holder, ERF without lower section. The ERF from the old scope, viewed from the lower side (nearest prism). Showing significant signs of damage. To remove this from the lower section, put something into the holes for grip then twist. The same ERF, but from a slightly different angle. The same ERF, but from the top side. ERF from the new PST, top side. Looks totally different. The ERF from the old PST, disassembled further. The clip on the top holds it in once you remove the black gunk. The ERF is a sandwich of three layers. As a general comment, the ERF seems different between the two models even putting aside the damage on the old one. The new one is a golden colour reflection viewed from either side. The old one is golden on the prism side surface only, and red on the top. I noticed the blocking filter section can be dropped into the top of the lower section. When the eyepiece section is screwed back in it holds it tightly. So if it isn't too far down to cause image issues that could be an alternative to gluing it back into the top section. If anyone finds these images useful and wants to use them elsewhere, feel free to do so.