Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_dslr_mirrorlesss_winners.thumb.jpg.9deb4a8db27e7485a7bb99d98667c94e.jpg

Recommended Posts

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)?

Share this post


Link to post
Share on other sites
Posted (edited)

Seeing as it’s likely out of warranty it can’t hurt to take a look.

The PST uses a 5-sided prism to bounce the light up to the eyepiece. One face should be parallel with the front on the scope, one with the eyepiece. When you’re turning the focuser you’re just screwing the prism holder back and forth within the black box.

The holder isn’t a great design. The prism is “pinched”, if you will, at the slides (like a litter picking claw might pinch some rubbish). It’s not a great way of securing something so it’s not unknown for the prism to slip a little which puts the whole optical alignment out of kilter.

Have a go at unbolting the hex bolts on the side of the black box and see what you find. They might be a bit stiff - I think mine were loctited. It could just be a case of manually adjusting the the prism so it’s facing the correct way in its cradle.

Good luck.

Edited by hunterknox
Add extra detail

Share this post


Link to post
Share on other sites

Are you using it with a eyepeice or a camera? The pst was made to use with a ep, so there's a few problems accociated with using with a camera..easiest way is by using a barlow

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By hazza001
      Evening all,
      I've wanted a solar scope for the longest time so I recently took the plunge and bought the Daystar Solar Scout SS60, It arrived maybe a week or so ago and its been cloudy nearly every day since (always the way with new astro gear!!!) 
      Well the clouds parted for a while yesterday so I fired it up and took a few "snaps"
      I was using my Nikon D3300 with a 2X barlow. at first all I saw was a red ball.... not too interesting then I fiddled around with the settings and got this... (I have editied slightly by bumping up the contrast but that was it!)

      I still have alot to learn but its getting there I managed to capture some detail texture(?) in the surface and some prominence detail
      I then tried taking a video then stack and prosess in registax which didnt turn out so great

      I got the Proms, but the disk is very washed out, I struggled here because the camera recorded in MOV. file which I had to convert to an avi. before registax would even look at it.
      Not as good as the first one (I think it was more luck than anything else!!) plus I had my iso setting a bit high, the video had lots of noise and I didn't take a reference frame (might of helped?) Alot of faf for not much reward 😂
       
      From the first few hours I've had with the scope I really enjoy using it, the only thing I struggled with was achiving focus as I only had the disk to focus on which was supprisingly tricky.
      I'm hoping for a bit more practice before the 11th 😁
       
      Let me know what you think and if you have any tips or tricks I'm all ears
       
      Harry
       
       
    • By astrorg
      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:

       
       
       

       
       
    • By Waynescave
      Hi guys
      Can anyone identify which control box this is? Is it focusmaster? And does it run off robofocus driver in Indi lib as I cannot get a successful connection (in indi within ekos) 
      I bought a robofocus motor with this control box second hand. 
      I have faith with seller that hardware works as should. 
      I've tried other cables and USB ports too. The software (k stars) I use does do port search when connecting equipment.. 
       
      Any help appreciated 
      Wayne

    • By Andrew Larmour
      Hi all, 
       
      Absolute newby here - my first foray into astronomy. I bought a Saxon 1400mm 6" refractor secondhand complete with a EQ mount for a bargain price and I'm keen to get it working properly for both planetary and deep space observations.

      I invested in a few extras such as a laser collimator and a 3x barlow. I think I have a handle on how it all works including the EQ mount.  I took the scope out for a test over Easter - which just happened to coincide with a ISS transit of the full moon. Rippa, I thought, that would be great to capture on my first night of observations. The problem I have is the complete inability to focus the scope to anything like sharp enough.
      I have some photos I took with the scope attached: 
      The scene with the normal camera lens for my daylight practice session
      A shot of a distant house with the telescope (using a Nikon D7000 on a t-mount adaptor)
      The same house with the barlow attached
      A shot of the moon- no barlow - as sharp as I could get it - certainly no way to see the silhouette of the ISS with the scope this out of focus
      When I was collumating the scope, I noticed a that the reflection on the primary mirror was not a single spot but rather a line

      ... which means that the laser on the collimator target is a line rather than a dot

      I confirmed that this is not a problem with the shape of the laser beam coming from the collimator by showing the shape on my hand at a distance of 14m

      I'm not sure if the distortion of the laser is the fault of the secondary mirror or the lens(es) in the bottom of the eyepiece mount. I'm also not sure if this distortion is what is causing the inability to focus the scope, but I suspect that both issues are symptoms of the same problem.
      I'd appreciate any ideas on what to do next to resolve the focus issue. 
       
       
    • By SacRiker
      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. 
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.