20/08/2020 Visual Report

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AndiesHandyHandies
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20/08/2020 Visual Report

Post by AndiesHandyHandies »

Hi,

I had a session comparing on the MAK180, a PST Mod and a ES 2xTE with Combo Prom Quark.

10.40 BST Mak180 2x ES Combo Prom Quark 32mm SP Fluffy clouds windy.

11.30 ( 1.30 SDO ) Long prom with a bright bottom leaning left with a bright top.

02.45 ( 09.15 SDO ) Butterfly prom.

03.00 ( 09.00 SDO ) Little bright spike with bright top.

04.00 ( 08.00 SDO ) Jet with a seperated bright top.

40mm Celestron Plossl - Slightly sharper

11.30 A bright base bent to the left. Middles brightish. Top bright. Spicule may be a feed under on the left.


10.55 BST PST Mod 25mm Fujiayma Ortho

11.30 Prom bright base the leans left 45deg. Possible feed half-way up. Bright pointy top.

02.45 Fat prom bi-furcated or seperated.

10.00 Little faint jet. 2 small pyramids above.


12.00 BST PST Mod 25mm Fujiayma Ortho

11.45 Seperated gas flame prom at the left. Small bright blob on the right. Lean left 70deg

12.30 BST 19mm EF

11.45 3 proms with pointy fir tree on the left. Middle jet. Right an open pyramid.


02.30 BST 2x ES Combo Prom Quark 40mm Plossl

10.00 Small pair of proms leaning to each other with thin connection visible at top.


I move the Quark to the 90mm F6.7 Triplet with 4.2x TC which I find is quiet sharp despite smaller than the MAK180

11.45 On the left a hedge and on the right a jet.

02.45 Faint hedge

10.00 Pair of proms leaning towards each other but middle of arch not visible.

The Mak180 at 2x or F20 starts to be a little faint. But a longer FL eyepiece sharpens the view.

I reverted to a small bino-viewer on the MAK180 PST Mod, Olympus copy with square body and sliding eye-seperation.
RodAstro likes better than hinging Zeiss binos as optics stay square so no odd reflections.
I find the 18mm entrance matches the 18mm prime focus quiet well and it seems to suppress PST reflections near the edges of the Sun for some reason. 25mm eyepieces work fine on the Mak180. I reckoned it could take a bit more magnification so got a pair of ZPO '18mm' equivalent eyepieces for the bino-viewers to replace the '25'mm it came with. Effectively pushing up the F no. I am going to use it on an I-optron mount as alt-az so the bino-viewers remain horizontal. I was having a problem with the PST Sweet spot not being central but the shorter extensions needed for the bino-viewers seem to have fortunately solved this problem. The Mak180 seems to have a 8mm fully illuminated field and a calculation posted by Valery gives 4mm for the PST Sweet spot so they need to be co-incidental really.

And use the Quarks on the 90mm with a longer FL eyepiece to effectively reduce the F No.

Cheers. Andrew.


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DeepSolar64
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Re: 20/08/2020 Visual Report

Post by DeepSolar64 »

Andrew,
Thanks for the wonderful description. I missed Ha today and barely had time for white light. Clouds.

James


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
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Meade Coronado SolarMax II 60 DS
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AndiesHandyHandies
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Re: 20/08/2020 Visual Report

Post by AndiesHandyHandies »

Hi

One advantage with the bino-viewers is it makes the surface a bit darker and more contrasty. Some plarisation between the PST and the bino-viewers as all 'square on'?

Andrew.


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Re: 20/08/2020 Visual Report

Post by AndiesHandyHandies »

Hi

Velery's calculation:

viewtopic.php?f=10&t=11392&p=117820&hil ... ry#p117820

I used the Sun one and appotioned the focal image size to get the sweet spot size.

Cheers. Andrew.


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Re: 20/08/2020 Visual Report

Post by Montana »

Very interesting Andy, I also have a problem with the PST sweetspot not being in the middle :(

Alexandra


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Re: 20/08/2020 Visual Report

Post by DeepSolar64 »

Montana wrote: Fri Aug 21, 2020 12:08 pm Very interesting Andy, I also have a problem with the PST sweetspot not being in the middle :(

Alexandra
Both of my Coronados are the same way. The sweet spot is often not in the middle. With mine it seems to usually be to the right side of the field.


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

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AndiesHandyHandies
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Re: 20/08/2020 Visual Report

Post by AndiesHandyHandies »

Hi both,

Christian V says the PST etalon has to be orthoganol to the optical axis and within a degree of alignment to get the full sweet spot. He reckons many are not.

I gave Montana the method I used on my 127mm Triplet refractor to line up the front of the PST by using a tilter and auto-collimation to line up the front face of the PST. The size of the sweet spot did seem to increase and was central. I do not use the 127mm at the moment as to large to 'pop out' with.

I put a tilter in front of the PST on the MAK with the intention of doing the auto-collimation. I did experiment on using the tilter to try and allign the circle of grey you get from tuning but I found I was vignetting the eyepiece! So I took it out and there is not room after the PST and get focus with the current set of adaptors. I had to move the blocker to the front of the PST, fortunately on a Blue Lightning T2 pass-through holder with filter thread in the middle and a turned down one with the blocker on tilted on the first one, and there was a T2 thread before the PST as well!, to get the bino-viewers to focus.

As I seem to have a centre sweet spot now I will leave well alone.

A similar issue may apply to other etalon types to be better on band across the field.

Cheers. Andrew.


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