127mm Meade Triplet Mod

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AndiesHandyHandies
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127mm Meade Triplet Mod

Post by AndiesHandyHandies » Tue May 21, 2019 10:10 pm

Hi

I had second try with this PST Stage 1 mod.

After the first try I took the 2X ED barlow apart and Black2ed the holder.
Also the insides of the 4 2" etension tubes holding a front 2" filter, Baader 35nm.

This reduced the scattered light.

I have a 90mm F6.7 I bought a couple of Astro-Boot 1.25" 1.5X screw on Barlows (Put onto by Mark T). To get it to F10. They turned out to be different powers which may be useful.

I wanted a filter holder I could put in an extension stack to vary the power.

Luckily I found a Blue Fireball Technologies T2 Male and 1.25" Filter to T2 Female adapter.

This conveniently fitted between the PST AOK T2 adapter and the T2 to 48mm adapter to the 2X ED Barlow. Improved the scatter.

I tried to buy a couple of cheap Moonlight filters to use to hold my two 25mm Omega Bob 1.5A filters, so they could be used in different setups, simply screw in. They turned out to have nice steel holders but 23mm filters, Not the cheap plastic ones with 25mm filters as in my Vixen VMC110 PST adapter. However taking out the glass in one and screwing it into the T2 to 1.25" adapter was just right as a stop in front of Bobs 40nm 25mm ERF filter in the Collimator lens housing of the PST.

The problem was with back reflections off the Baader 2" 35nm on the front of the extension, which I used to reflect as much unwanted light away as possible before the PST etalon.

Using the scope without the Baader was OK. The Bobs 40nm ERF looks similar to the Daystar Combo front blocker, reflected hue, and it worked OK on its own at 127mm. And it does not have the back reflection problems of the Baader. Unlike the Baader it has full long IR blocking.

I had lent my Baader 2" UV-IR filter to Rod for his Bobs filter project and recently had it back. So I replaced the Baader 35nm with the UV-IR. This solved the back reflection problem. It must have a visible Anti-reflection coating on the back unlike the 35nm I presume. So BoBs ERF is relecting the out of band visible only.

Unfortunately Bob does not offer 2" version Rod said.

The seeing was not as good as my first try last week so could not see if the new set works as well.

Andrew

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marktownley
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Re: 127mm Meade Triplet Mod

Post by marktownley » Wed May 22, 2019 5:55 am

Sounds like you've been busy. Interesting to know about the variability in the astroboot barlows, like you say lends itself to more potential.
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AndiesHandyHandies
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Re: 127mm Meade Triplet Mod

Post by AndiesHandyHandies » Wed May 22, 2019 10:23 pm

Hi

First light with the PST Mod:

The Sun looked like the first solar picture in Pedros Post after any equipment images.

viewtopic.php?f=4&t=26149

And with the Bobs filter 1 placed on the Beloptic KG3 under the eyepiece the surface looked similar to the first orange sun with a full box of yellow sun to the right. Bobs filter 1 is slightly above the H-alpha line to the longer end, I lost half of the proms which would be motion away from us I presume.

Andrew.

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Re: 127mm Meade Triplet Mod

Post by AndiesHandyHandies » Thu May 30, 2019 7:06 am

Hi

The focusser tube extends 7ish cm beyond the extension tube stack with UV-IR at the front.
In my collection of filter step rings there was a 49 to 43 which screwed on the front seems about right to mask reflections.

I gave a second coat of Black2 to the bodge stop in front of the PST.

It was cloudy but clear gaps without contrail clouds. Slightly windy.

Rod said the background was good, better than his Zeiss. I have a bit of red with the Sun just out of the field.
Because the dew cap slides back its a bit shiny inside, Rod said people do not use dew caps for solar.

Rod converted a very cheap pair of Zeiss 45deg research grade microscope bino-viewers to 1.25" for me.
Rod reckoned he could see more Sun with them than the eyepiece. They have a collimator arrangement.
With those perched in the PST he said he could see more surface detail than on the Zeiss.

Unfortunately a tree intervened before I could have a look.

Andrew

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Re: 127mm Meade Triplet Mod

Post by AndiesHandyHandies » Sun Jun 16, 2019 8:08 pm

Hi

I have lent all my solar bits and telescopes to Rod to play with.

From his investigations with the ED 2x Barlow I was observing through the bare PST Etalon at F30.

So it seems to perform well in that configuration.

Look forward to a stage2 mod with 25.4mm Bobs H-alpha 1.5A Comb Blocker filter or Bobs 2 H-alpha 1.5A filters double stacked with the PST.

Andrew.

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