Jump to content

Narrowband

PST stage 2 parts list help needed.


Recommended Posts

Would this http://www.365astronomy.com/2-Non-rotating-Helical-Micro-Focuser-with-M48-thread-and-0.1mm-Scale.html with the 2" nose piece removed to reveal M48 thread for attachment of https://www.firstlightoptics.com/adapters/william-optics-sct-adapter-for-2-diagonals.html to the etlon (with a bit of PTFE tape to help secure in place). The opposite end of the helical focuser having a http://www.365astronomy.com/Visual-Back-T2-to-1.25-with-additional-T2-male-thread-SHORT-version.html for a revelation diagonal to fit with blocking filter screwed in ????? My estimate makes this 97mm total length with the focuser giving up to 40 mm travel and what ever the diagonal adds to the length. SCT or even T thread extensions are available in different lengths to be added to either end should I need to extend the focal distance any.

If anyone is aware of stand alone M50 PST etlon adapters for stage 2 mods that would be of great help save trying to fudge it with the sct thread / ptfe tape?

Link to comment
Share on other sites

28 minutes ago, spaceboy said:

I'm not 100% sure but this looks like it might be a better option over the sct vb pst-50.jpg ???

Thanks Sean

From a quick search it looks like this is just a nose piece IE: for Stage 1 (scope side) and is no use for stage 2 (diagonal side) :( 

 

20 minutes ago, nightfisher said:

What frac is your pst based on?

The usual TAL100RS mod mate.

Link to comment
Share on other sites

8 hours ago, Merlin66 said:

The proposed set-up should work OK.

AOK Swiss manufacture a M50 to 2" rear adaptor for the PST mod.....

http://www.aokswiss.ch/index_sonne.html

Thanks Merlin. Several searches of the net have led me to this site already but neither IE or chrome is giving me an option to translate the page to be able to navigate to the desired part. Do you know if they ship to the UK?

 

24 minutes ago, nightfisher said:

Did you get the 100rs on ABS that was going cheap?

I've seen the one your referring to a couple times on ukb&s mate but I was a little hesitant given the description of the optics and the distance for me to give them a once over.

 

Link to comment
Share on other sites

9 hours ago, Merlin66 said:

The proposed set-up should work OK.

AOK Swiss manufacture a M50 to 2" rear adaptor for the PST mod.....

http://www.aokswiss.ch/index_sonne.html

I must assume it is this one http://www.aokswiss.ch/d/zub/adapter/pst-2''.html but it appears it is only threaded one end and push fit the other ?? Ideally I'd have preferred threading a helical focuser direct to the adapter rather than introducing further adapters to enable a push fit connection. Both to save on further cost of adapters along with introducing a weak link in the chain.

Link to comment
Share on other sites

Here's my first stage two bits. The silver ring behind the etalon is effectively a spacer, the knurled ring is part of the helical focuser and then there's a 2" eyepiece holder.

Might give some ideas. if I get a chance later I'll split my current version apart and take some more pics.

Image result for moonshane pst mod

For my binoviewers set up I had to shorten the light path behind the etalon and now it looks more like this

20161005_162209.jpg

Thought I'd post these in case it helps.

Link to comment
Share on other sites

2 hours ago, Moonshane said:

Here's my first stage two bits. The silver ring behind the etalon is effectively a spacer, the knurled ring is part of the helical focuser and then there's a 2" eyepiece holder.

Might give some ideas. if I get a chance later I'll split my current version apart and take some more pics.

Image result for moonshane pst mod

For my binoviewers set up I had to shorten the light path behind the etalon and now it looks more like this

20161005_162209.jpg

Thought I'd post these in case it helps.

Thanks mate. Do you know if there is any special requirement regards the focuser as this is obviously going to be the expensive part (not that any of the adapters are particularly cheap). I'd rather not cut corners on the focuser as it would kind of defeat the whole point of disregarding the PST POS focuser. That said if there is no need to push the boat out I'd rather not as I don't have a huge budget.

Link to comment
Share on other sites

I know stage 2 mods have already been set in stone so there's probably no other configurations suitable but I thought I'd just throwing this out there anyway.

Would it be possible to thread a PST BF / eyepiece holder into a 1.25" barrel using a custom coupler (or 1.25" filter with the filter removed and male thread chopped off) to effectively make an eyepiece /extension of sorts. My thinking then is use a 2" sct fit diagonal. The SCT side obviously connecting direct to the back of the PST etalon with some ptfe tape and grub screws to hold secure. The 2" EP holder of the diagonal is then unscrewed to reveal the diagonal body thread (no idea what thread that would be?) You then fix a helical focuser to this thread some how (maybe straight fit or adapter custom made).

So the configuration would go from the back of the donor scope as such. 2" to etalon nose piece adapter - PST etalon - 2" sct fit diagonal - possible adapter or direct fit 2" helical focuser - 2" - 1.25" eyepiece reducer - 1.25" nose piece / PST BF / Eyepiece holder - eyepiece.

Maybe with the use of the 2" diagonal the optical length would be increased while keeping everything fairly compact and neat as you wouldn't have to make up the length with spacers and adapters here there and everywhere.

I realise this isn't a PST mod but this gave me the idea 126789618_3tAlydMV.thumb.jpg.06e8691d31aed0bda50034547342cb06.jpg I'm sure you'll agree it looks a lot neater plus my guess this would also feel more comfortable focusing as you tend to cup around the eyepiece anyway when solar observing.

 

Link to comment
Share on other sites

 

I have converted my PST stage two to T2 fittings all round where possible. I have a M57 male thread on the back end and bought an M57-T2 male adapter to fit on this. The I either connect this male T2 directly to the Baader T2 diagonal (no nosepiece required) if using Bvs without a GPC or extension to get to the right length if using GPCs. I did find though that I could add the extension after the BF rather than between the etalon and the BF. I am still experimenting with the benefits of the differing layouts and hope to check out all the permutations this weekend at the DIYPSP.

Some of the discussion was here

 

Link to comment
Share on other sites

I'd had a browse of your BV topic previously. It's very interesting how the BV's have enabled you to see the full solar disc while retaining the BF5 filter. It is worth noting though that I have read some safety caution towards the distance between the BF and the etalon in that it should not be increased or reduced ?? I personally can't see how it would make the slightest difference to the safety in actual use ?? I agree that for it to work optimal the focal distances need to be adhered to but from a safety point of view the ERF in the front of the etalon surely stops anything unwanted getting into the mix.

TBH I have no need for full disc views as my lunt provides that. My only need for the stage 2 would be to do away with the focuser, prism and weight of hanging the PST black box off the back. At the moment it's looking like this could well turn in to more expense than actual gain. :confused3:

I agree that there are advantages of sticking to one common thread type if possible as it's a joke how many different types are used across astronomy gear.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.