Search found 557 matches

by Bob Yoesle
Thu Jan 03, 2019 2:50 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Solarscope SF 70 filter DS
Replies: 8
Views: 1427

Re: Solarscope SF 70 filter DS

Very Nice - detailed and contrasty - especially for SS.
by Bob Yoesle
Thu Jan 03, 2019 2:02 pm
Forum: Solar Scope Modifications
Topic: PST Etalon with a Quark, Log & Results
Replies: 115
Views: 10939

Re: PST Etalon with a Quark, Log & Results

Looks like you nailed it Mark! Your greyscale is perfect:

https://www.flickr.com/photos/brierleyh ... otostream/
by Bob Yoesle
Wed Jan 02, 2019 7:28 pm
Forum: Solar Scope Modifications
Topic: PST Etalon with a Quark, Log & Results
Replies: 115
Views: 10939

Re: PST Etalon with a Quark, Log & Results

Hi Marty, "... and if that kills the double limb, I'd be happy with that for the time being until I can figure out something better that is affordable." What do you consider affordable?! "Better" H alpha performance (especially double stacked) and "affordable" is kind of working at odds with each ot...
by Bob Yoesle
Wed Jan 02, 2019 3:44 pm
Forum: Solar Scope Modifications
Topic: PST Etalon with a Quark, Log & Results
Replies: 115
Views: 10939

Re: PST Etalon with a Quark, Log & Results

Very nice implementation George! After the Quark, you are over f/30 and don't need the lenses. RE: PST etalon. Remember, an air spaced etalon is a different beast than a solid spaced etalon, and suffers from the decreased refractive index of air compared to a solid spaced etalon, and field and instr...
by Bob Yoesle
Mon Dec 24, 2018 7:28 pm
Forum: Solar Scope Modifications
Topic: Calcium K blocking filter
Replies: 17
Views: 2169

Re: Calcium K blocking filter

Hi George, If I were you, I'd just add the PST to the Lunt as described, and get a pre-filter attached to the front of the Lunt module for larger aperture use: https://www.edmundoptics.com/p/394nm-cwl-50mm-dia-hard-coated-od-4-10nm-bandpass-filter/19839/ or https://www.edmundoptics.com/p/390nm-cwl-5...
by Bob Yoesle
Mon Dec 24, 2018 3:28 pm
Forum: Solar Scope Modifications
Topic: PST Etalon with a Quark, Log & Results
Replies: 115
Views: 10939

Re: PST Etalon with a Quark, Log & Results

I'm on 3G speeds with my air card (I live in the boonies), so even if I shaved it down, it would take a long time to upload some where. But I'd be willing to try something if you have any ideas on how to best shave it down without culling good data. HI Marty, Don't really have any suggestion other ...
by Bob Yoesle
Mon Dec 24, 2018 3:22 pm
Forum: Solar Scope Modifications
Topic: Calcium K blocking filter
Replies: 17
Views: 2169

Re: Calcium K blocking filter

Hi George, I think the Baader B-CCD is an all dielectric reflection filter on a clear BK7 or similar substrate, not an absorption filter. My CaK system has and continues to evolve. And I have only done this for CaK imaging use. Many years ago I and a few others started with a Baader Blue CCD filter ...
by Bob Yoesle
Sun Dec 23, 2018 7:59 pm
Forum: Solar Scope Modifications
Topic: PST Etalon with a Quark, Log & Results
Replies: 115
Views: 10939

Re: PST Etalon with a Quark, Log & Results

Hi Marty, Much improved! Yeah, you still have a little double limb. Could be a PST etalon tuning issue. And to my eye still a little soft towards and at the limb - but still much better ;-) How big is the above double stack video file? Perhaps if you can uploaded it to Dropbox, I could download it a...
by Bob Yoesle
Sun Dec 23, 2018 7:34 am
Forum: Solar Scope Modifications
Topic: PST Etalon with a Quark, Log & Results
Replies: 115
Views: 10939

Re: PST Etalon with a Quark, Log & Results

I agree Mark. I use minimal gamma in my capture process, generally underexpose, and bring out almost everything in post-capture processing. Marty PM'd me about this possibly being a double limb issue, but it doesn't look like it to me. The last image looks pretty good at the center of the disc, but ...
by Bob Yoesle
Mon Dec 03, 2018 5:40 pm
Forum: Solar Scope Modifications
Topic: Dismantling and modification of a PST CaK
Replies: 29
Views: 4364

Re: Dismantling and modification of a PST CaK

"Painted the inside of the OTA with Berger Antireflexfarbe."

Unfortunately, can't be delivered to the States. Anyone know of a similar product available in North America?
by Bob Yoesle
Mon Dec 03, 2018 5:01 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Internal vs. external Etalon placement question.
Replies: 2
Views: 943

Re: Internal vs. external Etalon placement question.

Ditto to what Mark has said ;-) Here's a little more detail as to why: All etalons are sensitive to the angle of light passing through them, and theoretically perform best with only parallel light passing at a 90 degree angle ("normal") to the reflective elements. The Sun, being an extended object i...
by Bob Yoesle
Wed Nov 21, 2018 4:02 pm
Forum: Solar Scope Modifications
Topic: optical contact experiments? Anybody?
Replies: 4
Views: 1151

Re: optical contact experiments? Anybody?

"If an airspaced etalon is just two pieces of partially reflective glass contacted between mica spacers..." Not quite Apollo! Polishing to lambda/100 flatness across 25 mm is not too difficult using relatively standard production techniques, achieving this over the full area of a larger filter becom...
by Bob Yoesle
Mon Nov 19, 2018 3:16 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Rust on either Lunt or Coronado
Replies: 7
Views: 1459

As shown in Ken's pics, and as in the above Cloudy Nights link, the Lunt issue now appears to be "glass disease:" https://en.wikipedia.org/wiki/Glass_disease See the Stage 1 and Sage 2 descriptions. It is known the Lunt uses BG glass (verses an ITF), which is a simple soda lime glass. It seems the K...
by Bob Yoesle
Thu Nov 15, 2018 8:36 pm
Forum: This is SolarChat !!
Topic: Old Coronado BF30
Replies: 27
Views: 2495

Re: Old Coronado BF30

Hi Bart, No doubt a killer deal, as the filter itself is probably worth 10 times the price advertised. I have 3 BF 30's and they all have different brightness levels. Sometimes darker is better... Your proposed ancillary filters should work well, as the DERF will block UV and near IR, the 35 nm H al...
by Bob Yoesle
Thu Nov 15, 2018 4:44 pm
Forum: This is SolarChat !!
Topic: Old Coronado BF30
Replies: 27
Views: 2495

Re: Old Coronado BF30

I checked out this filter as well... The Isle of Man blocking filters were designed for an etalon with a higher finesse and narrower FSR than the later Coronado or Solar Scope etalons. As opposed to today's Coronado and Solar Scope BF's with about a 6-8 A FWHM, the one in question probably has a 2-3...
by Bob Yoesle
Mon Nov 12, 2018 12:48 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 3444

Re: Mg II in UltraViolet

" Here are the simulations for a re-spaced classic C8 :
http://astrosurf.com/viladrich/astro/in ... -Plate.htm "

Thanks so much for this Christian!
by Bob Yoesle
Mon Nov 12, 2018 12:41 pm
Forum: Solar Scope Modifications
Topic: Lunt CaK B1200 + PST #1 yellow
Replies: 6
Views: 1380

Re: Lunt CaK B1200 + PST #1 yellow

Hi George, I don't know if you saw these, but here's my recent results using a $350 Chameleon CCD camera. I already knew from a few years ago that double stacking CaK filters provides a contrast improvement. Triple stacking CaK filters is useful for bringing out details near to the solar limb. The s...
by Bob Yoesle
Sat Nov 10, 2018 2:35 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 3444

Re: Mg II in UltraViolet

Without the optical prescriptions of the lens system, it is impossible to know. The respaced SCT corrector probably does a better job of coma reduction, while I believe a separate system would be required for chromatic spherical aberration correction at 393 nm. For CaK work, the PST filters will be ...
by Bob Yoesle
Sat Nov 10, 2018 12:27 am
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 3444

Re: Mg II in UltraViolet

Hi Christian, It's the standard (not the Edge-HD) C8. Any chance you could "cook up" a spherical aberration corrector using COTS fused silica len(es) from Edmund, Thor Labs, etc? That seems like it would be an ideal CaK imaging platform and relatively less expensive compared to a custom CaK refracto...
by Bob Yoesle
Fri Nov 09, 2018 4:50 am
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 3444

Re: Mg II in UltraViolet

Hi Christian,

Thanks you very much - that would be wonderful :-) I have seen your C14 re-spaced write up and have purchased a carbon fiber tube towards the implementation...
by Bob Yoesle
Thu Nov 08, 2018 4:47 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 3444

Re: Mg II in UltraViolet

Hi Valery, Do you have a transmission plot for the C8 DERF? I also would like to know the physical dimensions, and if it is possible to put a central hole in the filter. I'm considering a re-spaced SCT mod and would prefer to mount the secondary mirror to the DERF if it could be made to replace the ...
by Bob Yoesle
Wed Nov 07, 2018 5:13 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 3444

Re: Mg II in UltraViolet

Thanks for that Peter ;-) OK, so now we add a sounding rocket to the equipment list: https://www.youtube.com/watch?v=sQw_C5KLhFM Alternatively, one could always move to Antarctica: Solar-Spectrum-GballEditz.png https://www.youtube.com/watch?v=fzN0LbZXX1s&feature=youtu.be But you'll probably also nee...
by Bob Yoesle
Wed Nov 07, 2018 4:15 pm
Forum: This is SolarChat !!
Topic: Mg II in UltraViolet
Replies: 31
Views: 3444

Re: Mg II in UltraViolet

An interesting research paper - thanks for sharing it Valery. "If one will go this way, he should not save money on a too small telescope. 100mm is a minimal size I would say. Minimal SA is a must for such a telescope. A must have also a SSM. The main price driving factor is an etalon with a 0,5A ba...
by Bob Yoesle
Wed Nov 07, 2018 2:49 pm
Forum: Solar Scope Modifications
Topic: Pst Cak filter secret -
Replies: 10
Views: 2048

Re: Pst Cak filter secret -

Hmmm - this is a notch filter (not bandpass), hence the NF prefix. What would it be useful for in a CaK solar filter?
NF405-13_Transmission_780.gif
NF405-13_Transmission_780.gif (17.05 KiB) Viewed 1424 times
by Bob Yoesle
Tue Nov 06, 2018 5:42 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: LS60 upgrade options
Replies: 12
Views: 2110

Re: LS60 upgrade options

Hi Dano, If at all possible, for whatever you decide to buy, make sure you can return it if you are not pleased with the performance. Even the very most highly regarded manufacturers can have a lemon slip through, and with commercial production pressures, overall quality has seemed to slip from what...