Search found 3585 matches

by Merlin66
Tue Sep 15, 2020 11:34 pm
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 227

Re: Replacing Lunt CaK BF with something better

Bob,
You mention resolution..
What is your typical plate scale, arcsec/pixel?
I find down here at the coast that working around 0.79 arcsec/pixel is about my limit. Using ED80 (80/600) for Ha and WL and stopped to f10 for CaK.
by Merlin66
Mon Sep 14, 2020 10:31 pm
Forum: This is SolarChat !!
Topic: Re: Sun in Ha and Ca II K, September 9th '20
Replies: 12
Views: 198

Re: Re: Sun in Ha and Ca II K, September 9th '20

Stu,
Did you get the chance to try the various filter combinations?
Ken
by Merlin66
Mon Sep 14, 2020 10:30 pm
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 227

Re: Replacing Lunt CaK BF with something better

Raf,
A compromise would be to stop the scope to at least f10 and then use a reducer just before the camera to give you full disk coverage.
(With my ASI 1600MM on the ED80 I use either a x1.6 barlow or the very good x2.25 Baader Hyperion barlow to give me a slightly larger image on the sensor)
by Merlin66
Mon Sep 14, 2020 10:49 am
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 227

Re: Replacing Lunt CaK BF with something better

Raf,
Like Mark and others, I find the CaK filter gives better (repeatable) results when used at f10 (or greater).

I respect anyone who considers building a SHG!
I'm finding that there's always a "twist" in the final design! Finding suitable sized gratings for instance.....
by Merlin66
Mon Sep 14, 2020 10:21 am
Forum: This is SolarChat !!
Topic: Spectroscopy measure of Omega/PST CaK filter
Replies: 14
Views: 152

Re: Spectroscopy measure of Omega/PST CaK filter

Andrew,
The two profiles show the bandwidth shift when the filter assembly was slightly moved.
It’s the same filter, just different tilts.
by Merlin66
Mon Sep 14, 2020 9:01 am
Forum: Solar Scope Modifications
Topic: Replacing Lunt CaK BF with something better
Replies: 17
Views: 227

Re: Replacing Lunt CaK BF with something better

RAF,
As far as I can tell, the Lunt CaK filter doesn’t involve an etalon solution, just multi-coated filter elements.
The Quark obviously (I think may have a micra solid etalon) is different.
What f ratio scope are you using??
by Merlin66
Mon Sep 14, 2020 3:30 am
Forum: This is SolarChat !!
Topic: Spectroscopy measure of Omega/PST CaK filter
Replies: 14
Views: 152

Re: Spectroscopy measure of Omega/PST CaK filter

Thanks everyone for the comments/ feedback. Using the spectrograph to measure filters/ etalons etc. removes the subjectiveness of assessing the capabilities of your filter(s). My usual spectrograph (R=10000) is locked up on the C11 for ProAm work at the moment. Bit difficult at the moment, but if I ...
by Merlin66
Sun Sep 13, 2020 11:53 pm
Forum: This is SolarChat !!
Topic: Spectroscopy measure of Omega/PST CaK filter
Replies: 14
Views: 152

Re: Spectroscopy measure of Omega/PST CaK filter

Frank,
The combination of the cut-off wavelengths and "double stacking" contributes to the reduced bandwidth.
The tilt (sag of the filter assembly) moved the central wavelength (CWL) towards the blue.
by Merlin66
Sun Sep 13, 2020 8:32 am
Forum: This is SolarChat !!
Topic: Spectroscopy measure of Omega/PST CaK filter
Replies: 14
Views: 152

Re: Spectroscopy measure of Omega/PST CaK filter

Just checked the Lunt CaK filter the 18mm is over $1000 and rated for 2.4 A (or less???)
by Merlin66
Sun Sep 13, 2020 6:36 am
Forum: This is SolarChat !!
Topic: Spectroscopy measure of Omega/PST CaK filter
Replies: 14
Views: 152

Re: Spectroscopy measure of Omega/PST CaK filter

Limited test... The only available spectrograph was a Spectra-L200 with a 1200 l/mm grating, this gave a dispersion of 0.23A Using the normal set up with the ED80 stopped down to f10. The bandwidth of the DIY filter is very close to 1.0 A Bad news: due to the filter assembly "sagging" due to the add...
by Merlin66
Sun Sep 13, 2020 3:00 am
Forum: This is SolarChat !!
Topic: Spectroscopy measure of Omega/PST CaK filter
Replies: 14
Views: 152

Re: Spectroscopy measure of Omega/PST CaK filter

Three Omega Bob filters (yes, I know some users say they are rubbish quality!), a Baader Blue CCD filter as an upfront erf and fitted with the #1 "yellow" filter from a PST Cak scope. Certainly not cheap!!! I think the Lunt CaK filter is probably more cost effective, but.....I think the DIY has a ti...
by Merlin66
Sun Sep 13, 2020 1:31 am
Forum: This is SolarChat !!
Topic: Spectroscopy measure of Omega/PST CaK filter
Replies: 14
Views: 152

Spectroscopy measure of Omega/PST CaK filter

Between cloud....
I'm in the process of measuring the bandwidth and central wavelength of the DIY CaK filter I use.
Based on the images I've uploaded previously, any bets on the outcome????
111932c_full.jpg
111932c_full.jpg (663.5 KiB) Viewed 152 times
by Merlin66
Sat Sep 12, 2020 10:57 pm
Forum: This is SolarChat !!
Topic: CaK disk, September 11th, 2020
Replies: 10
Views: 107

Re: CaK disk, September 11th, 2020

Frank,
Well done!
Very impressive outcome.
by Merlin66
Sat Sep 12, 2020 10:57 pm
Forum: SPoD Archive
Topic: CaK disk, September 11th, 2020
Replies: 6
Views: 27

Re: CaK disk, September 11th, 2020

Frank,
Well done!
Very impressive outcome.
by Merlin66
Fri Sep 11, 2020 12:52 am
Forum: This is SolarChat !!
Topic: Re: Sun in Ha and Ca II K, September 9th '20
Replies: 12
Views: 198

Re: Re: Sun in Ha and Ca II K, September 9th '20

Stu, sorry to high-jack the thread..... Alexandra, Interesting question... My CaK DIY (three Omega filters + PST Cak "yellow") always seem to give "sharper" contrast features compared to others. I'm using the ASI 1600MM and sampling at 0.79 arcsec/pixel. My seeing is pretty average to bad..... I use...
by Merlin66
Mon Sep 07, 2020 5:13 pm
Forum: This is SolarChat !!
Topic: Quiet sun today September 6, 2020
Replies: 15
Views: 170

Re: Quiet sun today September 6, 2020

Franco,
Well done mate!
Nice presentation

Ken
by Merlin66
Mon Sep 07, 2020 5:13 pm
Forum: SPoD Archive
Topic: Quiet sun today September 6, 2020
Replies: 10
Views: 36

Re: Quiet sun today September 6, 2020

Franco,
Well done mate!
Nice presentation

Ken
by Merlin66
Mon Sep 07, 2020 5:09 pm
Forum: This is SolarChat !!
Topic: First real CaK prom!
Replies: 11
Views: 140

Re: First real CaK prom!

Thanks everyone!
Your feedback is appreciated.
by Merlin66
Mon Sep 07, 2020 5:39 am
Forum: This is SolarChat !!
Topic: First real CaK prom!
Replies: 11
Views: 140

First real CaK prom!

Imaging on the 6th Sept after days of cloud and wind....
I've seen "shadows" of possible proms with my DIY CaK filter - but today there was no ambiguity!
Definitely a CaK prom.
ED80/x2.25 Baader/ ASI 1600
095926C.jpg
095926C.jpg (40.64 KiB) Viewed 140 times
100929c.jpg
100929c.jpg (22.38 KiB) Viewed 140 times
101026_imppg_r.jpg
101026_imppg_r.jpg (124.82 KiB) Viewed 135 times
by Merlin66
Tue Sep 01, 2020 8:04 am
Forum: Solar Scope Modifications
Topic: PST Mod and TEC140
Replies: 9
Views: 270

Re: PST Mod and TEC140

Alexandra,
Even with the ERF the PST mod would act as an aperture stop and bring the TEC to a100mm f10 system.
by Merlin66
Mon Aug 31, 2020 9:01 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Solarmax 60 + BF 15mm
Replies: 5
Views: 115

Re: Solarmax 60 + BF 15mm

Charon,
I have used an original SM60 mounted on an ED80 successfully for many years.
IMHO opinion it works better than the current SM60II scope.
by Merlin66
Mon Aug 31, 2020 8:58 am
Forum: Solar Scope Modifications
Topic: PST Mod C11
Replies: 10
Views: 449

Re: PST Mod C11

Mark, et al,
As recently reported the tuning of the PST etalon is by pressure, distorting the plates.
Any additional knobs on the orange ring are there to “equalize” this pressure nothing to do with tilt.
by Merlin66
Tue Aug 18, 2020 8:41 am
Forum: Solar Scope Modifications
Topic: Need Help Identifying This
Replies: 2
Views: 167

Re: Need Help Identifying This

I’d say they are dumped gold tubes from PST mods. This tube is replaced by a larger objective scope. Check the condition of the front objective, if it’s gold colored then it has the original ERF coated version which has failed, and no longer usable. These are redundant and off no real use. They can’...
by Merlin66
Thu Jul 23, 2020 4:56 am
Forum: This is SolarChat !!
Topic: AR 2767 quite impressive
Replies: 15
Views: 416

Re: AR 2767 quite impressive

Thanks everyone, I really appreciate your support.