Coronado PST shows no detail. Hope can fix but if not, it was a joy to have while it lasted

[Rusted]

1 hour ago, Tej said:

1kg of 3D printing material is about £25.  How much would be needed for 3D printing a Boa Constrictor?

 

But anyway, happing buying the tool and looks useful to have for other applications in the home.

 

There is a Baby Boa and a medium Boa.  @Rusted , which one do you have? Thanks

 

Medium:

https://www.amazon.co.uk/gp/product/B017W7WE2K/ref=ox_sc_act_title_1?smid=A3P5ROKL5A1OLE&psc=1

 

The Medium. They have improved the design to contain the full width of the rubber strap.
Normally it wouldn't matter but I needed a pipe to get enough leverage to break the PST red locking stuff.
The pipe helpfully contained the strap and handle and provided more leverage.
The PST body was held down with G-cramps. It was a hell of a struggle despite my decades of practical experience.
 

[Tej]

Ok thanks, everyone, I've ordered the medium constrictor.  I'll report back on my progress!

 

[Tej]

OK, so I received the Boa Constrictor tool.  I used my Nexstar 8SE mount to as my clamp for the PST.  I used the Boa Constrictor to try unscrew the holder...but there was no budging.  So I plugged in a hair dryer and heated up the holder for 8 minutes. I used the Boa constrictor again and without much force, the holder unscrewed!  Yay!  Thank you @Rusted and @Montana for your excellent solution.  It totally worked.

 

So I am over the first hurdle.  What have I got?  Certainly does look like a bad filter indeed!  Even worse than what @Craney showed.   What amuses me is that the filter looks like a solar image with lovely groups of sunspots!  So I guess I need to replace this specific filter which just to confirm is the ITF, right?

So my next question is...how do I take the old to filter out?  I see two pin holes on it...are these a means to take the filter out?  What tool do I need for this?  Thanks.

 

 

 

[Rusted]

Good to know, but that filter is even worse than mine was!

I used a pair of [screw adjusting] engineering dividers to unscrew the top plate.
Screw adjusting means a perfect fit for maximum torque.

It would be silly to invest heavily in new tools just for that job but cheaper tools are readily available these days.

[Tej]

2 hours ago, Rusted said:

Good to know, but that filter is even worse than mine was!

I used a pair of [screw adjusting] engineering dividers to unscrew the top plate.
Screw adjusting means a perfect fit for maximum torque.

It would be silly to invest heavily in new tools just for that job but cheaper tools are readily available these days.

Ha, well the wrench looks to be a very useful  tool to have so no regrets there.  But I just bought this tool to unscrew the filter ring cover for £10.99 which I doubt I will ever need to use again... Unless it has other uses apart from dismantling camera lenses.  Perhaps maybe needed if I decide to modify my dslr? 

https://www.amazon.co.uk/gp/aw/d/B00J5F6ZI2/ref=ox_sc_act_image_2?smid=A1FPCQKROFZVDU&psc=1

 

One more question, do I need to unscrew the holder in the middle also?  

 

Edited June 19, 2020 by Tej

[Merlin66]

If you unscrew the eyepiece end of tube, you'll see the ITF filter is visible at the bottom of the other tube.

You should also see the retaining ring which holds the ITF filter. I find it easier to work from this side.

 

[Rusted]

Here are views of the PST ITF holding plate with new Maier filter in place.
Only the glass filter is supplied. You have to re-use the housing.

[Merlin66]

Undoing the retaining ring, shown in the first illustration above, is the easier way of changing the ITF filter. Just watch when re-fitting, it has a slight tilt....

 

[Tej]

On 21/06/2020 at 02:28, Merlin66 said:

Undoing the retaining ring, shown in the first illustration above, is the easier way of changing the ITF filter. Just watch when re-fitting, it has a slight tilt....

 

Thanks @Merlin66 @Rusted.  I received the tool.  Although I am still waiting for the new ITF filter to arrive, I wanted to test the tool and unscrew the filter ring component.  I find it quite dangerous using the tool as it slipped quite easily and poked the filter surface!  Have to be very careful if I need to use it to screw the holder back in to get it tight (unless screwing it by hand is enough?)

 

Next question is what tool you use to unscrew the filter out of it's housing?  I see the two notches as per the top photo in Rusted's last post.

Edited June 25, 2020 by Tej

[Merlin66]

Just take your time....use the flat tips to unscrew the retainer.

 

[Rusted]

I use a steel rule as a screwdriver.
Or any other piece of metal stiff enough for the job which can bridge between the slots.
A coin would be too curved and might scratch the filter glass.

[Merlin66]

Yeah,

A six inch steel rule works well.

[Pete Presland]

Fascinating to catch up on this thread, it will be interesting to see the results of the new filter.

[Tej]

I just realised the same tool that I used to unscrew the filter holder has two types of ends, one pair are bradawl type which is what I used to unscrew the filter holder but the other ends are flat tips!  So I unscrewed the inner ring with it. 

Just a reminder, this is the tool I bought.

https://www.amazon.co.uk/gp/aw/d/B00J5F6ZI2/ref=ox_sc_act_image_2?smid=A1FPCQKROFZVDU&psc=1

 So I think that is all the prep I need.  All I need now is wait for that new filter to come!

 

@Pete Presland I absolutely will post result images!  I guess I should do one with the bad filter just to show the difference but it really is bad, Don't even see any spicules, sunspots, filaments or prominences.  Just a solid disk.  But this is what I was able to get in it's glory days:

 

Edited June 27, 2020 by Tej

[newbie alert]

Reading the thread I think I may have the same issues...

[Pete Presland]

8 hours ago, Tej said:

I just realised the same tool that I used to unscrew the filter holder has two types of ends, one pair are bradawl type which is what I used to unscrew the filter holder but the other ends are flat tips!  So I unscrewed the inner ring with it. 

Just a reminder, this is the tool I bought.

https://www.amazon.co.uk/gp/aw/d/B00J5F6ZI2/ref=ox_sc_act_image_2?smid=A1FPCQKROFZVDU&psc=1

 So I think that is all the prep I need.  All I need now is wait for that new filter to come!

 

@Pete Presland I absolutely will post result images!  I guess I should do one with the bad filter just to show the difference but it really is bad, Don't even see any spicules, sunspots, filaments or prominences.  Just a solid disk.  But this is what I was able to get in it's glory days:

 

I would even if you decide not to post it. Love seeing a before and image, makes a good record for the future.

[Tej]

Just thought I show a picture of the disassembly so far for anyone else following this journey for their own attempt in replacing the filter.  I definitely recommend getting the tool in the picture as both bradawl point and flat head ends help to unscrew the filter container (bradawl ends) and the ring (flat head ends).

[Tej]

Update:  I received the new filter (656 ITF Bandpass), which I had purchased from Maierphotonics in the US for $75+$14.50 shipping.   I then paid a further £22 Customs Duty, so all in all, total cost was £93.  There is an alternative to purchase from Beloptik in Germany which sells for 149 EUR (£135) + shipping.   I simply went for the cheaper option.

I've now replaced the filter, very easily, having done the prep as per previous posts.  Now to test!  And wouldn't you just know it...rain and cloudy forecast for the rest of the week!

So it's just a matter of waiting for the Sun to come out before I report the results.