Search found 886 matches

by krakatoa1883
Tue Sep 29, 2020 11:16 am
Forum: This is SolarChat !!
Topic: AR12773 with Quark
Replies: 14
Views: 439

AR12773 with Quark

I had little time for imaging this month, apart from experimenting with my CaK setup I made few images only and always in bad seeing. Few weeks ago I purchased an ASI 178MM camera and immediately realized that it gives rise to a fixed disturbing pattern on every H-alpha image with any of my devices,...
by krakatoa1883
Mon Sep 28, 2020 6:56 pm
Forum: This is SolarChat !!
Topic: Ha 28.09.2020
Replies: 16
Views: 436

Re: Ha 28.09.2020

Great captures, Jozef! love the colour version
by krakatoa1883
Mon Sep 28, 2020 6:56 pm
Forum: SPoD Archive
Topic: Ha 28.09.2020
Replies: 12
Views: 180

Re: Ha 28.09.2020

Great captures, Jozef! love the colour version
by krakatoa1883
Thu Sep 24, 2020 4:47 pm
Forum: This is SolarChat !!
Topic: The Sun - 20th September 2020
Replies: 12
Views: 366

Re: The Sun - 20th September 2020

Fine discs, David.

AR102S is a quite short refractor but the Cak image is good, have you stopped the aperture ?
by krakatoa1883
Thu Sep 24, 2020 4:43 pm
Forum: This is SolarChat !!
Topic: Active region September 23, 2020
Replies: 15
Views: 413

Re: Active region September 23, 2020

Great capture, Franco, those tiny pores came out well!
by krakatoa1883
Thu Sep 24, 2020 4:41 pm
Forum: This is SolarChat !!
Topic: H-alpha Sun 2020-9-23
Replies: 14
Views: 435

Re: H-alpha Sun 2020-9-23

A really great view :bow

Is the refractor a standard achromat lens ?
by krakatoa1883
Sun Sep 20, 2020 12:11 pm
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 807

Re: Replacing Lunt CaK BF with something better

Hi Mark, thanks for your comments. You're right in everything you wrote, all images are undersampled and can't show differences in resolution. I wanted to see if making the scope slower makes also the filter more effective. It appears this is the case however from 115 mm to 80 mm I see only a modest...
by krakatoa1883
Thu Sep 17, 2020 6:18 pm
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 807

Re: Replacing Lunt CaK BF with something better

Seeing improved a little today, however not enough for hires testing. Anyway I made further experiments with the 115mm apo f/6.9 at various apertures and the modified CaK module. Here below my results by using of the ASI 178MM and a slight reducer (0.7x). All images with same seeing, frames, fps, an...
by krakatoa1883
Wed Sep 16, 2020 7:09 pm
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 807

Re: Replacing Lunt CaK BF with something better

Thanks Bob for your useful advice. Since I removed the original Lunt BF seeing was always poor here, this may be the reason why the disc appears soft, however I agree that further tests at various reduced apertures are needed to evaluate the effect of SCA, if relevant. Whatever the aberrations of th...
by krakatoa1883
Tue Sep 15, 2020 10:02 am
Forum: This is SolarChat !!
Topic: September 12 FD CaK H-alpha proms
Replies: 12
Views: 398

Re: September 12 FD CaK H-alpha proms

Great proms image, I like that red
by krakatoa1883
Tue Sep 15, 2020 10:02 am
Forum: SPoD Archive
Topic: September 12 FD CaK H-alpha proms
Replies: 7
Views: 219

Re: September 12 FD CaK H-alpha proms

Great proms image, I like that red
by krakatoa1883
Mon Sep 14, 2020 5:26 pm
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 807

Re: Replacing Lunt CaK BF with something better

True, however my scope is well corrected in CaK even at full aperture so I would prefer to maintain resolution if I can. However I'll do some tests to see what gives better results, full aperture or higher f/ratio.
by krakatoa1883
Mon Sep 14, 2020 11:16 am
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 807

Re: Replacing Lunt CaK BF with something better

I find the CaK filter gives better (repeatable) results when used at f10 (or greater) Totally agree, it's also my experience, however for imaging the full disc I would prefer to avoid making mosaics so I am using the scope at the native f/ratio to contain the disc within the sensor. I could increas...
by krakatoa1883
Mon Sep 14, 2020 10:20 am
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 807

Re: Replacing Lunt CaK BF with something better

Yes, just my habit to call "etalon" any device of that kind... :lol:

The scope I used for the full disc is f/6.9.

PS, thanks for offering advices on the SHG I would like to build, I am still in the very preliminary stage (i.e. book reading...).
by krakatoa1883
Mon Sep 14, 2020 8:21 am
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 807

Re: Replacing Lunt CaK BF with something better

Hi Alexandra, I am using of the Lunt etalon and Quark BF, they match fine. My calcium Quark no longer goes in tune so I am using the pieces for assemblying something else. Next step will be to remove the Lunt etalon from the original barrel for mounting it in a shorter one.
by krakatoa1883
Sun Sep 13, 2020 7:25 pm
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 807

Replacing Lunt CaK BF with something better

In this discussion I described the problem I had with the blocking filter assembly of my Lunt module, mainly coma and astigmatism due to the tilted filters. Placing a focal extender before the BF helped in obtaining a better definition however this cannot be a solution if one wants to image the full...
by krakatoa1883
Fri Sep 11, 2020 3:21 pm
Forum: This is SolarChat !!
Topic: Competition Winner- Alexandra
Replies: 37
Views: 1005

Re: Competition Winner- Alexandra

Great! congratulations...
by krakatoa1883
Tue Sep 08, 2020 3:22 pm
Forum: This is SolarChat !!
Topic: Quiet sun today September 6, 2020
Replies: 15
Views: 412

Re: Quiet sun today September 6, 2020

Great images, Franco, very crisp.
by krakatoa1883
Wed Aug 26, 2020 1:59 pm
Forum: Solar Scope Modifications
Topic: Lunt LS50THa PT deassembly- the saga continues lol
Replies: 3
Views: 779

Re: Lunt LS50THa PT deassembly- the saga continues lol

Bring up this old discussion because I have just published a short note on replacing the o-rings for Lunt LS50, this is the link: https://imagesofoursun.wordpress.com/maintenance/replacing-lunt-ls50tha-pressure-tuner-o-rings/ (for moderators, think this discussion should be moved to a different sect...
by krakatoa1883
Fri Aug 21, 2020 4:28 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: August 3, 2020 Spectroheliograms: the Fraunhofer Four
Replies: 7
Views: 508

Re: August 3, 2020 Spectroheliograms: the Fraunhofer Four

Than you very much Peter, I am starting with the book and your own articles, surely I will return with furter questions ;)
by krakatoa1883
Fri Aug 21, 2020 12:36 pm
Forum: This is SolarChat !!
Topic: Solar granulation with C14HD full aperture 2020.08.19
Replies: 14
Views: 506

Re: Solar granulation with C14HD full aperture 2020.08.19

ND 3.8 Astrosolar is still available although in the mounted version only, no longer as a loose foil. https://www.teleskop-express.de/shop/product_info.php/info/p8814_Baader-Digital-Solar-Filter-3-8-OD--aperture-240-mm--for-tubes--260-300-mm.html https://www.baader-planetarium.com/en/solar-observati...
by krakatoa1883
Fri Aug 21, 2020 12:25 pm
Forum: This is SolarChat !!
Topic: A few from today 20th Aug '20
Replies: 9
Views: 339

Re: A few from today 20th Aug '20

Great, Stu, CaK is particularly fine.
by krakatoa1883
Tue Aug 18, 2020 10:00 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: August 3, 2020 Spectroheliograms: the Fraunhofer Four
Replies: 7
Views: 508

Re: August 3, 2020 Spectroheliograms: the Fraunhofer Four

Very interesting and detailed images, Peter.

If I want to build a spectroheliograph by myself where should I start from ? Being a physicist I know the theory but I need some practical advice. Thanks