Issue with my Coronado PST: shift towards green

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c12marin
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Issue with my Coronado PST: shift towards green

#1

Post by c12marin »


Hi folks:

I'm having trouble imaging with a Coronado PST and a DLSR APS-C. The thing is the telescope allows more light to enter than it should and also there is a shift towards green in the left upper quadrant. A friend of mine told me that filters are likely to be misplaced (PSTs are said to be very sensitive to the position of their filters) :confusion-helpsign:

Has anyone run into the same problem?

Thanks in advance.
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Solar disk with my PST.jpeg
Christian García-Mascaraque Marín

GEMs: Vixen Saturn FS2; Losmandy G11 OnStep; Celestron CGEM-DX; SkyWatcher EQ8-R Pro. Minimounts: SkyWatcher Merlin + Meade 884 tripod.
Dioptric doublets: Celestron CR-150 HD & 100ED-R; TS Optics AP 70/420 ED CF + 0.79x 2" ED in a dual rig; Dörr Danubia Space & Field 80 f6.
Catoptrics: Orion Optics UK VX12 300 f4 1/10λ PV with an Antares Optics 3.5" 1/18λ PV, tube in carbon fiber. Catadioptrics: Celestron C11-A (OO UK Hilux coating).
Dedicated CCD cameras: QHYCCD QHY-9 mono (Kodak KAF-8300). APS-Cs: Nikon d5300, stock (Sony IMX193); Canon 600D, IR+ (EOS 60/600D).
Accessories: Baader Fluorite Flatfield Converter; TeleVue Powermate 2.5x. Eyepieces: Baader Hyperion 8 & 13, 36 Hyperion Aspheric.
Photosphere: Baader Cool-Ceramic safety HP, 2", P-version. Chromosphere: Coronado PST HBW<0.5Å; DayStar Quark, chromosphere.
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Re: Issue with my Coronado PST: shift towards green

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Post by Solsearcher »


If you are talking about a PST in original un altered form the filters can not be "misplaced" I do not understand what you mean by your PST is letting in too much light . Are you talking about a PST mod ? If you are be very sure that you fully understand what you are doing and DO NOT try using PST filters without a proper ERF (energy rejection filter)
One more thing a DSLR color camera will work but is a poor choice for solar imaging .
Solar scopes (Coronado Ha) 60mm double stack , 90mm double stack , 150mm single stack .
W/L scope Williams Optic Megrez 110mm / Lunt herschel wedge .
Night scope Celestron 9.25 XLT
Mounts HEQ6 , HEQ5 , Losmandy G8
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Lady Fraktor Slovakia
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Re: Issue with my Coronado PST: shift towards green

#3

Post by Lady Fraktor »


I see Solsearcher has got here first and I must agree I do not understand about the telescope letting in to much light.
The PST is quite a solid piece of equipment but if you suspect any movement of the etalon or other internal parts you should have it inspected by a qualified person.
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
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Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
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Re: Issue with my Coronado PST: shift towards green

#4

Post by Tillibobs »


I'll add to the above.
The Coronado is an excellent instrument for viewing the Sun but was not designed with Photography in mind.
Most folks use a cmos or similar type of camera, taking upward of 1,000 images in a short space of time, stacking them etc. You would have difficulty in getting a camera to focus properly but this can be overcome by screwing the lens from a 2x Barlow onto the camera. We also use a mono camera.
Keith.
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Re: Issue with my Coronado PST: shift towards green

#5

Post by Solsearcher »


Hello Christian
There are people here who can help you , we just need more information about your scope . Your description about too much light would indicate there is an issue with the scope . I did not mean to sound discouraging , our goal is help you . When you say the scope allows more light than it should this should not happen if the scope is working correctly . If your scope is un altered and works fine visually (do not try it unless you are sure) then you are saying that the scope is letting in too much light for your camera and this can be corrected .
When you say the filters could be "misplaced" , did you mean not tuned correctly ? The reason I ask is that when PST's are "modded" the "placement" or location of the etalon is critical . I just need to know more about the scope you are working with , PST's are a popular scope to mod and your original description made me think you might be talking about a modded scope .
Solar scopes (Coronado Ha) 60mm double stack , 90mm double stack , 150mm single stack .
W/L scope Williams Optic Megrez 110mm / Lunt herschel wedge .
Night scope Celestron 9.25 XLT
Mounts HEQ6 , HEQ5 , Losmandy G8
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