Search found 609 matches

by Bob Yoesle
Mon Jan 18, 2021 6:35 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Re: Sony IMX253 mono cameras

Thanks Mark!
by Bob Yoesle
Sun Jan 17, 2021 6:11 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Re: Sony IMX253 mono cameras

Hi Mark, My pier(s) have 120 v AC at the pier, and the 12 v DC power supply is connected to this (lower arrow). This power supply (referenced in the above post) then feeds a 3 receptacle 12 v outlet near the mount (upper arrow), to which I can feed a 12 volt load, such as the telescope mount and cam...
by Bob Yoesle
Sun Jan 17, 2021 5:15 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Re: Sony IMX253 mono cameras

Thanks Stu, Franco, & Mark! So it looks like we have something else in common Mark: Virgo's & rack.jpg Analog playback is a legacy Well Tempered Classic Turntable (bought new in the 80's.) Still have a ton of vinyl in my collection going back over 5 decades! Analog phono/preamp is the Audible Il...
by Bob Yoesle
Sun Jan 17, 2021 2:29 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Re: Sony IMX253 mono cameras

Well, I finally had some sunshine through thin enough clouds to do some full disc imaging with the IMX253 1.1 inch CMOS FLIR Grasshopper 3 camera and my old laptop with improved RAM, SSD, and USB 3.0 expansion card. Seeing was about average even though the Sun was low in altitude: Grasshopper 3 FD t...
by Bob Yoesle
Sun Jan 10, 2021 6:21 pm
Forum: Solar Scope Modifications
Topic: Repairing a CaK PST
Replies: 40
Views: 672

Re: Repairing a CaK PST

Hi Stu, I'm pretty sure the first filter (pointing at the Sun) blocks most wavelengths except for those close to 393 nm (this one appears blue) and the eyepiece filter passes all wavelengths except for those below about 393 nm (this one appears yellow as it is absorbing blue and passing green/red li...
by Bob Yoesle
Fri Jan 08, 2021 2:26 pm
Forum: Solar Scope Modifications
Topic: "Magic" distance of Lunt LS50PT etalon from focal plane?
Replies: 17
Views: 3692

Re: "Magic" distance of Lunt LS50PT etalon from focal plane?

There is no "magic distance." There is a very real correct distance. This distance for the negative collimator is for it to lie towards the objective the exact focal length of the collimator lens from the objective's focal plane. With a negative lens, the focal length is more difficult to determine ...
by Bob Yoesle
Tue Jan 05, 2021 3:32 pm
Forum: Solar Scope Modifications
Topic: Repairing a CaK PST
Replies: 40
Views: 672

Re: Repairing a CaK PST

Hi Alexandra, Looks like you're back in business. I haven't yet had a chance to to try it, but the Baader K line filter has two elements; one tilted and the other not. You might try to disassemble the filter and use only the tilted element. From the little I have seen of this it will not significant...
by Bob Yoesle
Sat Jan 02, 2021 6:40 pm
Forum: Solar Scope Modifications
Topic: Repairing a CaK PST
Replies: 40
Views: 672

Re: Repairing a CaK PST

Hi Alexandra, They do look pretty much the same, so I don't know why exactly one would be better than the other - other than perhaps 656 nm is less susceptible to tilt aberrations than 394 nm. It also could be there is a variable amount of misalignment as the pentaprism moves through its range of tr...
by Bob Yoesle
Fri Jan 01, 2021 7:02 pm
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 315

Re: Evaluating the PST etalon with a neon bulb

Hi Ken,

Thanks for all the links and additional information, and the very nice analysis of the etalons!

I would indeed be interested in obtaining a suitable slit mechanism, PM me when you have the time.

Happy New Year :-)
by Bob Yoesle
Fri Jan 01, 2021 6:46 pm
Forum: Solar Scope Modifications
Topic: Repairing a CaK PST
Replies: 40
Views: 672

Re: Repairing a CaK PST

Hi Mark and Alexandra, I might be missing something, but have some concerns. "Thanks Mark, however, what about the eyepiece bit, surely that filter has a function and needs to be added?" If I'm not mistaken, the eyepiece holder objective-side filter is an ITF for IR blocking, and has obviously "rust...
by Bob Yoesle
Thu Dec 31, 2020 4:41 pm
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 315

Re: Evaluating the PST etalon with a neon bulb

Hi Ken, "but not sure at the moment as to how the results could be used by the "average Joe" to give him/her guidance in determining whether on not to buy a $10,000 air spaced etalon......" My thoughts are that right now the typical FWHM specification generically applied to etalons for solar filter ...
by Bob Yoesle
Thu Dec 31, 2020 3:30 am
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 315

Re: Evaluating the PST etalon with a neon bulb

Hi Ken, That's a very good question. These procedures are more qualitative than quantitative. Right now I don't have the equipment that can derive the FWHM. It appears one would need a system such as the one linked below in order to determine the FWHM: https://www.holmarc.com/fabry_perot_interferome...
by Bob Yoesle
Thu Dec 31, 2020 12:16 am
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 315

Re: Evaluating the PST etalon with a neon bulb

As Christian notes, a better methodology would be to use a Hydrogen lamp with a diffuser. See: https://solarchatforum.com/viewtopic.php?f=10&t=15443&start=50#p174440 As seen below, a well performing air-spaced etalon will have a small central ring surrounded by additional tightly focused interferenc...
by Bob Yoesle
Sun Dec 27, 2020 9:03 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Re: Sony IMX253 mono cameras

Thanks Rainer for the SSD recommendations. So here's what I have for the computer mods: Upgrade from 6 to the maximum of 8 GB of 1066/1333 Crucial RAM. Replace 300 GB HDD with 1 TB MX500 Crucial SSD. Install StarTech 2-port USB 3.0 ExpressCard 54. Total expense: $175 USD. Nix on the GPU and processo...
by Bob Yoesle
Sun Dec 27, 2020 8:51 pm
Forum: Solar Scope Modifications
Topic: Repairing a CaK PST
Replies: 40
Views: 672

Re: Repairing a CaK PST

Hi Alexandra. That appears to another case of peripheral filter deterioration in a secondary filter. Did you use the CaK for visual, imaging, or both? I'd be leery of using the scope visually with any DIY filter system replacements. You can salvage the crucial "yellow" filter which isolates the CaK ...
by Bob Yoesle
Sat Dec 26, 2020 8:59 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Re: Sony IMX253 mono cameras

Thanks for that caution advisory Great Attractor :-) Well it looks like I have a pretty well regarded and very well-built laptop - the Dell Latitude E6420 circa 2011. I did a little internet searching and it appears it can be relatively easily upgraded with up to 8 GB of RAM, a (internal) 500 GB SSD...
by Bob Yoesle
Sat Dec 26, 2020 4:22 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Re: Sony IMX253 mono cameras

Thanks for the input gentlemen! In the meantime I've decided to pull the trigger. https://www.flir.com/products/grasshopper3-usb3/?model=GS3-U3-123S6M-C For $275.00 USD "as new barely used" (versus new OEM $3250.00) with a 30 day return option, it's seems a pretty good a deal, and if doesn't work ou...
by Bob Yoesle
Thu Dec 24, 2020 3:47 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Re: Sony IMX253 mono cameras

Thank you all for your input - and Merry Christmas! :D I'm still finding it a difficult decision. Some of these 2 year old cameras are showing up used for very reasonable prices - $200 - $300 USD versus their new cost of $2000 to $3000 USD. I'm mostly interested in this particular sensor because the...
by Bob Yoesle
Wed Dec 23, 2020 5:01 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Sony IMX253 mono cameras
Replies: 28
Views: 567

Sony IMX253 mono cameras

I'm pretty behind the times when it comes to the newer sensors and the latest laptops. Has anyone used one of these for solar? It's the CMOS Pregius IMX253 1.i inch 12 MP with 3.45 um pixels? https://www.phase1vision.com/userfiles/product_files/imx253_255llr_lqr_flyer.pdf Thinking of going to this s...
by Bob Yoesle
Tue Nov 24, 2020 5:37 pm
Forum: Solar Scope Modifications
Topic: G band instead of Ca-k filter
Replies: 48
Views: 1443

Re: G band instead of Ca-k filter

Resolution is wavelength dependent. So a shorter wavelength with the same aperture has the potential to have higher resolution if the optics and seeing conditions allow. For imaging of course you would need to match pixel size to the higher resolution to realize the benefit. For example, the differe...
by Bob Yoesle
Tue Nov 24, 2020 4:11 am
Forum: Solar Scope Modifications
Topic: G band instead of Ca-k filter
Replies: 48
Views: 1443

Re: G band instead of Ca-k filter

An f10 achromatic refractor is your best bet for significantly better spherochromatic aberration at 430 nm: https://www.telescope-optics.net/achromats.htm A shorter f ratio APO or semi-APO (except Tak TAO 130/150 ;-) will generally not perform as well: https://www.telescope-optics.net/semiapo_and_ap...
by Bob Yoesle
Mon Nov 23, 2020 2:54 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Advice requested on Quantum filter purchase
Replies: 49
Views: 2019

Re: Advice requested on Quantum filter purchase

Hi Alan, Looks to me like you have two issues: 1. A DERF keeps the filter cooler from the start. Your first image is closest to on band where the filter was nearer to ambient temp. As the filter heats up more, it is shifted further into the red wing and goes off band. The second set of images withou...
by Bob Yoesle
Thu Nov 19, 2020 2:02 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Coronagraph
Replies: 9
Views: 410

Re: Coronagraph

Since you're talking H alpha filters, it seems you're talking about a solar prominence telescope (e.g. the chromosphere), not a coronagraph. There's a huge difference. https://en.wikipedia.org/wiki/Coronagraph You may want to review this couple of threads on Cloudy Nights: https://www.cloudynights.c...
by Bob Yoesle
Mon Nov 09, 2020 3:38 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Advice requested on Quantum filter purchase
Replies: 49
Views: 2019

Re: Advice requested on Quantum filter purchase

I've emailed DayStar to request a test report for my replacement PE etalon. This whole topic brings up an important issue for consumer narrow band solar filters. At least DayStar produces a report for some of their filters. I note however in both the reports reported above there is no measurement fo...
by Bob Yoesle
Sun Nov 08, 2020 6:07 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Advice requested on Quantum filter purchase
Replies: 49
Views: 2019

Re: Advice requested on Quantum filter purchase

Thanks for that information Rainer. I'll give DayStar a call and see if I can get the test report that is generated for all PE grade filters:

http://www.daystarfilters.com/QuantumPE.shtml