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Transit of Mercury in the Spicule Layer. Phil took this great image with his Quantum 6 Scope, Solar Spectrum etalon and PGR Camera.

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PST control box replacement various versions

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Astrophil
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PST control box replacement various versions

Post by Astrophil » Sun Jun 30, 2019 2:12 am

The weather here in Florida has been lousy for solar recently and the Sun is so quiet. Naturally, it was a good time to take something apart and fix it. This time it was the PST. The control box, while brilliantly designed, has been a source of frustration for me at times so I decided to try a more conventional approach.

I had previously purchased a PST to T2 adapter and have quite an assortment of extension tubes, eyepiece holders, diagonals, and stuff. The only additional part that was needed was an adapter to connect the PST's eyepiece and filters to the optical train. Having access to a 3D printer, I made an adapter threaded on one end to capture the PST eyepiece/filters and the other end was simply 1.25" OD to attach to a focusing EP holder. Extension tubes can be added or removed to accommodate various optical requirements.

This arrangement adds a few inches to the length of the system but eliminates 700 grams, the weight of the control box. Of course without the control box and it's 1/4 20 tapped holes, an alternative mounting system is needed. My solution can be seen in the images below. It's light weight and works well so far.

I have only tested visually using a diagonal with a 19 mm Panoptic without the extension tubes and with a PGR camera to verify focus. A few proms were seen but no images were captured. I will post images taken with this setup here when the weather cooperates.

Phil

PST mod front.jpg
PST mod front.jpg (338.31 KiB) Viewed 970 times
PST mod .jpg
PST mod .jpg (298.04 KiB) Viewed 970 times
PST mod camera end.jpg
PST mod camera end.jpg (391.04 KiB) Viewed 970 times
Last edited by Astrophil on Wed Jul 10, 2019 1:06 am, edited 1 time in total.

Starry Jack
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Re: PST control box replacement

Post by Starry Jack » Sun Jun 30, 2019 2:43 am

Nice. I did a similar Stage 2 mod with th3 5mm BF using a plethora of extension tubes from 20 years of collecting. The the other fun things I did was use the sawed off gold tube in two places. I love your 3D printing solution. Eag3r to see how you're performs.

E90F9994-D718-4017-AD15-E16499187AEE.jpeg
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E90F9994-D718-4017-AD15-E16499187AEE.jpeg
E90F9994-D718-4017-AD15-E16499187AEE.jpeg (2.09 MiB) Viewed 968 times
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B60216D2-F195-48E6-91D0-D34576534364.jpeg
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Explore Scientific 152mm f6.5 achromat
Aeries D-ERF
Quark Chromosphere f27 native, (f14 when focal reduced)
Mallincam .5x focal reducer (large format)
ZWO174 (IMX249 chip 5um)
Huge Sense of Adventure Viewing Creation

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Re: PST control box replacement

Post by marktownley » Sun Jun 30, 2019 6:10 am

Great solutions both!
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Re: PST control box replacement

Post by Astrophil » Tue Jul 02, 2019 10:31 pm

Here are a couple images taken to test the modified PST. This arrangement works well but I don't see much of an improvement in image quality over the stock setup. I will be adding a non rotating helical focuser soon. That should help with the ease of use.

Phil

Jack, How did your mod perform?


.
20190702_101937_PST_c.jpg
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20190702_093450_PST_inv.jpg
20190702_093450_PST_inv.jpg (361.78 KiB) Viewed 925 times

Starry Jack
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Re: PST control box replacement

Post by Starry Jack » Wed Jul 03, 2019 1:11 am

Something is wrong with my rig. I'd Love to have your quality. i never got that in either Stage 1 or 2.
Explore Scientific 152mm f6.5 achromat
Aeries D-ERF
Quark Chromosphere f27 native, (f14 when focal reduced)
Mallincam .5x focal reducer (large format)
ZWO174 (IMX249 chip 5um)
Huge Sense of Adventure Viewing Creation

Starry Jack
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Re: PST control box replacement

Post by Starry Jack » Wed Jul 03, 2019 2:56 pm

Phil,
It's hard for me to tell but is this a straight stock PST or a double stack? And it looks like you are using the original front ERF and lens rather than doing a mate to a donor scope?

Also what is the distance from the rear of the etalon to the blocking filter itself (the actual BF not just the holder)? Your rig performs better than

Thanks.
Explore Scientific 152mm f6.5 achromat
Aeries D-ERF
Quark Chromosphere f27 native, (f14 when focal reduced)
Mallincam .5x focal reducer (large format)
ZWO174 (IMX249 chip 5um)
Huge Sense of Adventure Viewing Creation

Astrophil
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Re: PST control box replacement

Post by Astrophil » Wed Jul 03, 2019 8:10 pm

Before another imaging test I decided to take a quick look using some WO binoviewers. Not much to see today but the setup worked and focus was achived using a 1.5x barlow in front of the binoviewers. Image below.

Dodging clouds, I captured an image using the straight through setup pictured in the original post. I'm still finding it difficult to tune the double stacked PST.

Phil

Jack, The scope is a newer PST (blue objective lens, ITF and blocking filters in the eyepiece holder) with a SME-40 etalon screwed into the front end.
The distance from the etalon to the BF varies in this setup depending on focus adjustments. Today it's about 150mm.


.
PST_bino.jpg
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20190703_100104_PST_DS_acm.jpg
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20190703_100104_PST_DS_cc.jpg
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Astrophil
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Re: PST control box replacement

Post by Astrophil » Sun Jul 07, 2019 2:25 am

The focusing eyepiece holder was replaced with a non rotating helical focuser. This made focusing much easier but not necessarily any sharper.

This PST is double stacked with a SME-40 etalon on the front end. With all components readily accessible I decided to remove the main PST etalon and reconfigured it for a single stack using the front etalon only. It was a breeze to tune and worked quite well although contrast was less than double stacking. Maybe I'll even throw a Quark Combo into the mix someday.

What I like the most about this mod is that now the scope looks like a real solar telescope. Albeit a tiny one.

The images below show the current setup, a double stack image from July 5th, and lastly a single stack one on July 6th.

Phil
PST mod Camera end 2.jpg
PST mod Camera end 2.jpg (451.43 KiB) Viewed 850 times
20190705_091033_PST_afcc.jpg
20190705_091033_PST_afcc.jpg (471.54 KiB) Viewed 850 times
20190706_112754_PST_SME40.jpg
20190706_112754_PST_SME40.jpg (258.24 KiB) Viewed 850 times

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Re: PST control box replacement

Post by Starry Jack » Sun Jul 07, 2019 3:27 am

Outstanding. Thank you for the ruler photo.
Explore Scientific 152mm f6.5 achromat
Aeries D-ERF
Quark Chromosphere f27 native, (f14 when focal reduced)
Mallincam .5x focal reducer (large format)
ZWO174 (IMX249 chip 5um)
Huge Sense of Adventure Viewing Creation

Astrophil
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Im an EXPERT!
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Joined: Thu Dec 20, 2018 2:00 am

Re: PST control box replacement

Post by Astrophil » Wed Jul 10, 2019 1:04 am

Another cloudy, rainy day and a perfect opportunity to reconfigure the PST. Starting from where I left off I added a Quark Combo. This setup has a SME-40 etalon on the front of the PST, various adapters and extension tubes, a 2.5x Powermate, and a Quark Combo. No control box or the main PST etalon. It looks like it should work but I don't know how well yet. After a brief check through clouds and haze all I could do was verify focus. Then the rain set in.

I will post some images taken with this setup when the skies clear. In the meantime, any comments or suggestions from anyone who has tried a setup like this would be welcome.

Correction. The photo shows both a 15mm and a focal reducer. One of them needs to be removed in order to focus.

Phil
SME40_Quark_Combo_2.jpg
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SME40_Quark_Combo.jpg
SME40_Quark_Combo.jpg (366.33 KiB) Viewed 817 times

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Re: PST control box replacement various versions

Post by Astrophil » Tue Jul 16, 2019 1:35 am

I imaged today through haze but no clouds to test the current setup using the SME-40 etalon and a Quark Combo, as seen in the previous post. The extension tubes were shortened by 15mm and the Powermate extended slightly to reach focus. A circular polarizer was added to the front of the Quark and a 35 nm Ha filter added to the front of the Powermate to reduce reflections. These additions increased exposure times to about 20ms depending on gain and gamma. A 0.5x focal reducer was close coupled to the camera resulting in about a .75x reduction.

Once the Quark was up to temperature, tuning the SME-40 was straight forward and easier than when using it in combination with the PST etalon. I attempted to maximize contrast while keeping a uniform illumination of the disk. The placement of the disk in the field of view was critical to get good contrast around the limb without distortion. The uneven field illumination of the Quark was unavoidable and no flats were taken.

The performance of this setup is as expected. Increased contrast compared to either the Quark or SME-40 used alone was achieved. I suspect the performance is similar to a double stacked PST. It was fun to play around with various setups but I will be replacing the Quark with the PST etalon but without the control box.

Here are the images taken July 15. Not much on the surface and the proms were hard to capture through the haze. They have not been rotated to the correct orientation.

Phil
20190715_102519_SME40_Qcombo_1.jpg
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20190715_102711_SME40_Qcombo_inv.jpg
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20190715_103118_SME40_Qcombo.jpg
20190715_103118_SME40_Qcombo.jpg (209.34 KiB) Viewed 748 times

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Re: PST control box replacement various versions

Post by marktownley » Tue Jul 16, 2019 5:15 am

Came out very well Phil!
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http://brierleyhillsolar.blogspot.co.uk/
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Re: PST control box replacement various versions

Post by Astrophil » Wed Jul 17, 2019 3:29 am

Thanks Mark.

I took one final image with the SME-40 + Quark Combo trying to get the most detail out of this little 40mm scope that I could today. It's way over sharpened and not quite on band but it shows the feasibility of the setup.

Phil


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20190716_152715_SME40_Qcombo.jpg
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Re: PST control box replacement various versions

Post by marktownley » Wed Jul 17, 2019 5:31 am

It has great potential for full disks Phil.
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http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

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