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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:
By Richard Shaw
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?
I have the following for sale, originally bought for a full PST mod that was never done:
Coronado PST - £430. Boxed.
Vixen A80M - £150. Includes tubes rings, dovetail and focuser but no box, finder or diagonal. SOLD.
90 mm D-ERF - £200. SOLD.
Filter holder - £8. Homemade and bought off a SGL member. Fits the 90mm D-ERF and has a internal diameter of 105mm the other end. SOLD
Solar Finder - £15. SOLD.
WO Dielectric Diagonal D-DIG2 - £35. Boxed. Bought to be used on the Vixen before the scope was modded. SOLD.
All are in excellent condition and do not include postage. Collection preferred for the scopes.
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?