Search found 24204 matches

by marktownley
Fri Sep 21, 2018 10:34 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Experimenting calcium imaging with small refractors
Replies: 17
Views: 262

Re: Experimenting calcium imaging with small refractors

I already changed the original cardboard spacers of my 150mm with thicker ones made from an aluminum foil but I didn't make any check of the resulting correction in calcium light compared to the original configuration. Mark, do you remember which thickness have you used ? I used foil that is used f...
by marktownley
Fri Sep 21, 2018 6:43 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Experimenting calcium imaging with small refractors
Replies: 17
Views: 262

Re: Experimenting calcium imaging with small refractors

You can pop the achromat lens out if its cell and increase the air space gap with cardboard strips to Decrease blue astigmatism , A bit of trial and error plus tedious guesswork involved but it works. Use a cheap scope! I did this with my Meade AR5 and improved perfomance in CaK, it's far from perf...
by marktownley
Fri Sep 21, 2018 6:39 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Experimenting calcium imaging with small refractors
Replies: 17
Views: 262

Re: Experimenting calcium imaging with small refractors

General rule is with achromats longitudinal aberrations are worse that latitudinal aberrations, and with apochromats latitudinal aberrations are worse than longitudinal aberrations. There will be some exceptions to the rule, the 115/7 being one and the TOA ortho apochromats for example. I found this...
by marktownley
Thu Sep 20, 2018 7:02 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Experimenting calcium imaging with small refractors
Replies: 17
Views: 262

Re: Experimenting calcium imaging with small refractors

I would hazard a guess that the 115mm/f7 triplet is a reasonable performer in CaK (or Ha or Na) based on this spherochromatism chart 115trip2.jpg http://shop.tecnosky.it/Articolo.asp?SessionID=7AF5C7A2-19D6-47EB-B6CA-6FBFF6001C93&GetInfo=TS115&AddScore=TS115&Score=1 The curve is about as close to th...
by marktownley
Wed Sep 19, 2018 6:40 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Experimenting calcium imaging with small refractors
Replies: 17
Views: 262

Re: Experimenting calcium imaging with small refractors

christian viladrich wrote:
Tue Sep 18, 2018 7:49 pm
The only drawback of the TOA 150 is its the price and ... its aperture. I wish I have a TOA 200 ;-)
:D :D :D
by marktownley
Wed Sep 19, 2018 6:37 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: New Skywatcher Solarquest mount
Replies: 9
Views: 246

Re: New Skywatcher Solarquest mount

Thanks Bart, I thought that might be the case.
by marktownley
Tue Sep 18, 2018 2:35 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: New Skywatcher Solarquest mount
Replies: 9
Views: 246

Re: New Skywatcher Solarquest mount

That was my thought too Pedro, I quite fancy the idea of something for quick grab and go full disks that I can just carry the scope and mount out in one go (in between the clouds!) - be interesting how you get on Pedro. You don't have clouds where you are very often so give it a try covering the sen...
by marktownley
Tue Sep 18, 2018 2:27 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Experimenting calcium imaging with small refractors
Replies: 17
Views: 262

Re: Experimenting calcium imaging with small refractors

Interesting comparison Raf. I did something similar several years ago with CaK. I get some reasonable images with my ED80 at higher magnifications I find, once I'm upto about f15-f25. Frederics website has some great measurements of spherochromatism https://airylab.com/astronomy-test-reports/ Regard...
by marktownley
Sun Sep 16, 2018 9:53 pm
Forum: This is SolarChat !!
Topic: Chromosphere September 16th
Replies: 8
Views: 164

Re: Chromosphere September 16th

Looking good Franco! Another cloudy weekend for me.
by marktownley
Sun Sep 16, 2018 8:06 pm
Forum: This is SolarChat !!
Topic: Tunable Calcium module by Apollo Lasky
Replies: 6
Views: 227

Re: Tunable Calcium module by Apollo Lasky

I want to try a few ideas with my skybender, these recent threads have been giving me some ideas ;)
by marktownley
Sun Sep 16, 2018 8:04 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: New Skywatcher Solarquest mount
Replies: 9
Views: 246

Re: New Skywatcher Solarquest mount

I wonder if it will stop tracking when the sun goes behind a cloud?
by marktownley
Sun Sep 16, 2018 7:58 pm
Forum: This is SolarChat !!
Topic: CaK from September 4th, 2018
Replies: 2
Views: 90

Re: CaK from September 4th, 2018

Good results!
by marktownley
Sun Sep 16, 2018 7:56 pm
Forum: This is SolarChat !!
Topic: Update on laptop and camera
Replies: 3
Views: 109

Re: Update on laptop and camera

I think I will be buying one very soon too.
by marktownley
Sun Sep 16, 2018 7:55 pm
Forum: This is SolarChat !!
Topic: Ca-H full disc of Sept. 13th
Replies: 6
Views: 108

Re: Ca-H full disc of Sept. 13th

Good shots Raf!
by marktownley
Sun Sep 16, 2018 7:53 pm
Forum: Solar Scope Modifications
Topic: A different PST Mod
Replies: 6
Views: 344

Re: A different PST Mod

Good scope there Pedro!
by marktownley
Sun Sep 16, 2018 7:50 pm
Forum: This is SolarChat !!
Topic: Calcium Chromosphere By apollo lasky
Replies: 6
Views: 234

Re: Calcium Chromosphere By apollo lasky

Thanks Apollo, don't you go skipping off now, things are just starting to get interesting...
by marktownley
Sun Sep 16, 2018 7:12 pm
Forum: This is SolarChat !!
Topic: New images of AR12671 GREAT SEEING!
Replies: 4
Views: 128

Re: Remembering old good times. 2017 08 20 GREAT SEEING!

Brilliant Valery! Can you describe the processing technique you use on the stacked image please?
by marktownley
Sun Sep 16, 2018 6:35 pm
Forum: This is SolarChat !!
Topic: Surface contrast in CaK for various filter bandpasses.
Replies: 18
Views: 397

Re: Surface contrast in CaK for various filter bandpasses.

Fascinating high brow solar science here Peter, i'm most impressed! This really does from an empirical way what we might realistically expect from our CaK devices.

Those dark structures are interesting though, i've regularly seen them too.
by marktownley
Sun Sep 16, 2018 12:27 pm
Forum: This is SolarChat !!
Topic: Tiny AR12721 in H-alpha and CaK: Sept10
Replies: 7
Views: 166

Re: Tiny AR12721 in H-alpha and CaK: Sept10

Very nice Peter. That 115mm Stellarvue seems a great performer at CaK wavelengths.
by marktownley
Sun Sep 16, 2018 6:47 am
Forum: This is SolarChat !!
Topic: NEW 12672 large group!!! 280mm + ARIES 295mm DERF + QUARK GREAT SEEING!
Replies: 13
Views: 543

Re: NEW 12672 large group!!! 280mm + ARIES 295mm DERF + QUARK GREAT SEEING!

That's a beauty Valery. When you start trying that SSM it will be very interesting to see what values it comes back with.
by marktownley
Sat Sep 15, 2018 5:39 pm
Forum: Solar Scope Modifications
Topic: Narrowest 393.37 ever by Apollo Lasky
Replies: 152
Views: 3944

Re: Narrowest 393.37 ever by Apollo Lasky

Very good bob and apollo, glad this is working out!