Search found 451 matches

by Bob Yoesle
Sat Oct 20, 2018 1:13 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Experimenting calcium imaging with small refractors
Replies: 22
Views: 572

Re: Experimenting calcium imaging with small refractors

"An exceptionally detailed image posted somewhere in this forum (I have been unable to locate it again, may be from Bob Yoesle) made me curious to image the Sun in Ca-H light with a 100ED f/9 refractor. In the used market I could find one that accidentally was already mine five years ago :lol: and n...
by Bob Yoesle
Thu Oct 18, 2018 6:09 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: BF30 ITF replacement
Replies: 2
Views: 36

BF30 ITF replacement

I just got a note from Oliver Smie that he can now provide his drop-in replacement for the ITF in the BF30 size: "After endless time I have also durable ITF replacement filters for the Coronado BF30 in stock, a batch of 18pcs. Filter design is the same to my smaller ones for PST, BF10... https://bel...
by Bob Yoesle
Mon Oct 15, 2018 5:20 pm
Forum: Solar Astronomy Shop and Swap
Topic: "Astronomie Solaire" - New (French) book on Solar Observation now available
Replies: 16
Views: 336

Re: "Astronomie Solaire" - New (French) book on Solar Observation now available

So, we have to get working to get this English version available ASAP ;-)
Yeah! Looking forward to it Christian :-)
by Bob Yoesle
Thu Oct 11, 2018 9:01 am
Forum: Solar Scope Modifications
Topic: Mersenne telescope design
Replies: 2
Views: 158

Re: Mersenne telescope design

I have considered this as well. There is a good discussion on the Mersenne design here: https://www.cloudynights.com/topic/392210-wide-angle-compound-telescope/ Would a Mersenne telescope in front with a h-alpha scope in the back attached achieve a higher resolution? There is significant potential f...
by Bob Yoesle
Fri Oct 05, 2018 6:30 pm
Forum: Solar Scope Modifications
Topic: ⚠️ ⚠️ Chroma 1.25” filter cell thermal fracture
Replies: 8
Views: 281

Re: ⚠️ ⚠️ Chroma 1.25” filter cell thermal fracture

Thanks for the heads up Apollo. I checked my filter and it uses a plastic retaining ring. I loosened it up when I got it and there is a slight rattle to it when gently shaken, so hopefully I'll have no issues. It is a hard coated filter on a fused silica substrate so it should be quite stable therma...
by Bob Yoesle
Thu Oct 04, 2018 5:11 am
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

I have asked Dick at Chroma Tech about the discrepancy of the data sets. So far, no answer. I did ask about the nomenclature difference; Apollo's files were labeled 393.37 0.1, the data sets Dick sent me were labeled 393.4 0.1. Dick stated it was just a labeling difference and that they indeed were ...
by Bob Yoesle
Wed Oct 03, 2018 7:10 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

Single.

Chroma Tech said they could do a double cavity filter, but not a triple. I didn't ask what the price would be.
by Bob Yoesle
Wed Oct 03, 2018 5:01 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

I don't know why there is a discrepancy, all I know is that this is the data Dick Stewart sent me. My filter also appears to need more than 1.5 degrees of tilt, but I have yet to calculate it from what I can measure in the Skybender - going to have to brush up on my trigonometry skills ;-) Dick did ...
by Bob Yoesle
Mon Oct 01, 2018 11:16 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

Hello all, Spoke to Dick Stewart at Chroma Technology about the CT 392.37 0.1bp filter's tilt performance, and he provided me the following data: 0.0 degree tilt peaks at 393.999 nm 99.69% 1.0 degree tilt peaks at 393.386 nm 99.69% 1.5 degree tilt peaks at 393.371 nm 99.70% 2.0 degree tilt peaks at ...
by Bob Yoesle
Sun Sep 30, 2018 2:41 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

Maybe the PST filter is natively narrower and the quoted 2.2a is the bandpass in the f/10 beam? Perhaps a multiple cavity filter with steeper transmission sides, which may make it less susceptible to light ray incident angle effects(?) Bob, if you have a TZ-2, you might give it a try. They are desi...
by Bob Yoesle
Sat Sep 29, 2018 3:57 am
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

Hi Bob, Thanks for your test. The incraese of contrast from the Chroma filtre, PST single stacked, PST double stacked and triple stack is clearly appearant. BTW, I have probably overlooked the information ... what F/D ratio did you used with the Chroma filter in this test ? Best regards Hi Christia...
by Bob Yoesle
Wed Sep 19, 2018 5:47 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Experimenting calcium imaging with small refractors
Replies: 22
Views: 572

Re: Experimenting calcium imaging with small refractors

Thank for posting your results Raf ;-) Great images Pedro! The only drawback of the TOA 150 is its the price and ... its aperture. I wish I have a TOA 200 ;-) Hi Christian, my thought is that this seems to be pointing perhaps to using a reflector telescope such that you already have with an appropri...
by Bob Yoesle
Wed Sep 19, 2018 5:30 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

Hi Apollo, Hoping to get out for another run for prominence imaging this coming Monday the 24th... hoping some prominences will cooperate !-) Hi Mark, Brilliant no - just results of being a bit obsessive compulsive ;-) As you know, one must reduce the variables as much as possible, and it's impossib...
by Bob Yoesle
Wed Sep 19, 2018 3:58 am
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

A little better seeing today, so here are my latest test images for the CT 393.37 (used in Skybender tilt unit) - ED100/900, FireCapture set at minimum gain (160), gamma 700, histogram max ~ 190 +/- 10. All used a Baader B CCD and KG3 sub-aperture ERF's. All are 30 sec. captures @ 18 fps, aligned an...
by Bob Yoesle
Fri Sep 14, 2018 10:30 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

Had another chance to try some imaging before the weather deteriorated. The imaging train consisted of a Orion ED100/900, Baader Blue CCD and KG3 for ERF duties, Baader K line used as a blocker, a ND 0.6 for image brightness control, and finally either the PST CaK or CT 393.37 0.1 filter. All images...
by Bob Yoesle
Fri Sep 14, 2018 9:39 pm
Forum: Solar Reference Library
Topic: Surface contrast in CaK for various filter bandpasses.
Replies: 19
Views: 596

Re: Surface contrast in CaK for various filter bandpasses.

Hi Peter,

Thanks for this very informative and interesting information.

Not sure what it would take either, but so far at least no one has made such a filter...
by Bob Yoesle
Wed Sep 12, 2018 1:38 am
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: Narrowest 393.37 ever by Apollo Lasky

Unfortunately I can no longer rely on Bob Yoesle to correctly use this filter if he is not going to install it in the Skybender. I plan to do just that in the coming week or so. I will have the Baader Blue CCD filter, KG3, Badder K line, followed by the CT393.34 0.1 correctly oriented in my Skybend...
by Bob Yoesle
Wed Sep 05, 2018 1:24 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: 393.4 bp0.1 - yes it does exist.

Hi Mark, I used a Baader Blue CCD filter, followed by a KG3, and then the Baader K line as ERF and blocking filters prior to the CT and PST filters. I will next attempt some tests with tilting the CT, and at f25 using a UO Klee barlow if/when my seeing allows. I likely will remove the Baader K line ...
by Bob Yoesle
Tue Sep 04, 2018 9:54 am
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: 393.4 bp0.1 - yes it does exist.

Hi everyone, I have a couple of new images from my first run that for some reason didn't process correctly the first time, but had better seeing/resolution. The overall results do not change however: CT 0.1 nm, exposure 0.100 ms: CT 0.1.jpg PST 0.2 nm, exposure 0.191 ms: PST 01.jpg There seems to be...
by Bob Yoesle
Mon Sep 03, 2018 4:30 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: 393.4 bp0.1 - yes it does exist.

Hi Mark, the CT filter was just behind the Baader K line - probably not ideal ;-) But I don't think it would have performed much differently without the reflection. Outside the reflected area still suffers compared to the PST double stack. Hi Stu, I will be attempting a lot more with the filter prio...
by Bob Yoesle
Mon Sep 03, 2018 3:45 am
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: 393.4 bp0.1 - yes it does exist.

That is my suspicion as well. The Badder K line has one flat component and one tilted. I'm working on tilt wedges of 2 and 4 degrees, and better spacing...
by Bob Yoesle
Mon Sep 03, 2018 1:43 am
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: 393.4 bp0.1 - yes it does exist.

My first results with the CT393.37pb0.1 are disappointing. However, a caveat is that I did not tilt any of the filters, and spurious reflections are apparent in my old system, and even more so with the Chroma Tech filter. I will therefore have to reserve a final judgement until I can do some additio...
by Bob Yoesle
Sat Sep 01, 2018 10:17 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: 393.4 bp0.1 - yes it does exist.

Hi Mark, I'm assuming the same limitations r/t collimator vs. telecentrics apply to the very narrow CaK filter as they to to H alpha. Since the filter uses a high index spacer construction, I assume this would result in better field angle performance for a collimator system compared to an air-spaced...
by Bob Yoesle
Fri Aug 31, 2018 10:00 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 206
Views: 6291

Re: 393.4 bp0.1 - yes it does exist.

Hi Mark, I checked with Dick at Chroma, and he confirmed the CT393.37bp0.1 is a single cavity and high index filter design. As Mark has pointed out, a larger f ratio is better than a shorter, and Dick also mentioned use in a collimator type system. I think Apollo deserves credit for passionately pur...