PST / 102GT Mod

[olddogg60]

Hi all,
I followed my friend Solarhound (Mike) over here where mod'ed PST can be discussed. Mike put up pictures of his 102 XLT mod'ed. My scope is similar using a Celestron 102 GT that I had picked up for $60. I also used the Lunt 100mm ERF which I mounted by modifying the retaining ring for the objective lens. With the ring removed I made up and installed two O-Rings, one fit inside the other as a base/separator for the ERF. To allow the retaining ring to thread all the way in and seat properly, I ground off most all of the un-threaded portion of the ring leaving enough so that pressure was allied to the ERF to hold it against the O-Rings.
The PST Etalon was adapted to the original focuser for now and I used a Coronado BF 15 blocking filter adapted with a twist lock adapter and a 2" to 1.25" reducer modified to work in the twist lock adapter.
I have attach two images the I have taken with my scope using a DMK 21 camera.
Best regards,
Bill

[JohnM]

Nice way of doing it. I have that same scope, I sure do hate that ugly plastic front end
I've decided that when I get enough saved for a DERF I'll go with an internal mounting.
I believe a 90mm will fit right up against the first baffle.
I took 2 1/2 inches off the rear of the tube so I could just bolt up a 2 speed cratford I had handy using factory adapters for the 3.8" ID tube.

Hmm, I'm surprised yo could get your etalon correctly positioned using the stock R&P focuser.

[marktownley]

Welcome to the forum. Great mod with the ERF and objective cell, cunning idea. Excellent pickies!

[olddogg60]

Nice way of doing it. I have that same scope, I sure do hate that ugly plastic front end
I've decided that when I get enough saved for a DERF I'll go with an internal mounting.
I believe a 90mm will fit right up against the first baffle.
I took 2 1/2 inches off the rear of the tube so I could just bolt up a 2 speed cratford I had handy using factory adapters for the 3.8" ID tube.

Hmm, I'm surprised yo could get your etalon correctly positioned using the stock R&P focuser.

Thanks all. I'm certainly happy with the mod so far.
I forgot to add the I could focus in some configurations of the camera (Could reach focus with my Powermate.) and EP's but I did cut 2" off of the tube for more focal range. 1" would have been sufficient as it turns out. I will be upgrading the focuser soon.

[Solarhound]

Well done Olddogg

[swisswalter]

Hi Bill

great mod, have fun and welcome to that woderful site

[olddogg60]

I forgot to add the solar finder that I'm using. It is a little coarse but it gets the solar disk in the EP. I figure that is was a good way to use a red dot finder. :cheer:




Edit: The focuser will be replaced as soon as my new Crawford two speed arrives.

[olddogg60]

Just an update on my Stage 2 mod. I had replaced the original focuser with a GSO Crawford 2 speed focuser but the Etalon was still located so that it moved when focusing. I have since relocated the Etalon to a permanent location by reinstalling the original focuser. This would allow for adjusting the Etalon position but I believe that I'm in the correct position as is with the focuser run in. I had originally cut 2" from the OTA. Now with the Etalon located in the forward position, I have mounted a GSO SCT Crawford 2 speed focuser using a 1.5" twist lock adapter to replace the 2" adapter that I originally used. This setup looks to allow me to have plenty of travel in or out. I'm waiting fro a 'nice' winter day to give this new setup a try. B)




Here is an image taken with the previous arrangement and I am hoping to improve on this. My preference is, 'The closer, the better.'. :cheer:

[Solarhound]

Well done Bill , love that filament image !!

[olddogg60]

Thanks Mike. I can see a little blue through the haze today. That's progress. B) My new DMK 41 is in dire need of another test run. :cheer:
http://solartelescopeviewingimaging.blogspot.com/

[swisswalter]

Hi Bill


a wonderful first shot on that filament

[marktownley]

A great result indeed!

[olddogg60]

Thank you for the kind comments. The filament image was taken before this last rearrangement. Before the sweet spot was a problem which I'm sure is to be expected with the Etalon out of the magic spot. I'm hoping for better results now and I have a new DMK 41 to try out. I have had one chance to use the 41 with bad seeing but the results were very encouraging. The filament image was taken with a DMK 21.
Here is one of the first images taken with the 41. (Cropped some due to the sweet spot issue.)

[swisswalter]

Hi Bill

wild, very wild shot

[olddogg60]

Thank you Walter. I have high hopes for my reconfigured scope using the DMK 41.