Search found 3113 matches

by Merlin66
Mon Jul 16, 2018 12:32 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Even when there's little going on....
Replies: 6
Views: 98

Re: Even when there's little going on....

Once again you demonstrate the excellent capabilities of the SHG system. Well done!
by Merlin66
Sun Jul 15, 2018 6:12 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Recent Digital SHG
Replies: 12
Views: 200

Re: Recent Digital SHG

Yes, definitely a very good SGH image!!
I'd appreciate seeing an image of your set-up.......
by Merlin66
Sat Jul 14, 2018 8:15 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Recent Digital SHG
Replies: 12
Views: 200

Re: Recent Digital SHG

More detail on the SHG system, please!!!
by Merlin66
Fri Jul 13, 2018 3:14 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

No sun, but bright cloud (!!)
The illustration below shows the SM60 etalon bands and the CaK II absorption lines.

Not good news...
The FWHM of the bands is 7A in this region...finesse 18.7A and the tilt adjustment gives 1.2A towards the blue.

Any comment/ feedback?
SM60ED80_CaK II.JPG
SM60ED80_CaK II.JPG (109.41 KiB) Viewed 143 times
by Merlin66
Tue Jul 10, 2018 5:39 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

Quick update - the weather has been absolutely terrible - clouds, clouds and wind, rain...repeat.... I did manage to set up the Spectra-L200 with a 1200 l/mm grating, resolution around 0.7A and get the CaK II lines focused in the NIR. Needed a red sort filter to suppress the 2nd order spectrum. Just...
by Merlin66
Tue Jul 03, 2018 8:56 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Coronado SolarmaxII 60 problem
Replies: 6
Views: 300

Re: Coronado SolarmaxII 60 problem

I think we need feedback from current SMII users.....
by Merlin66
Tue Jul 03, 2018 6:56 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: strong prom in Ha and even in Hb
Replies: 5
Views: 214

Re: strong prom in Ha and even in Hb

John,
Very good mate!
You're doing well.
by Merlin66
Tue Jul 03, 2018 1:56 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Coronado SolarmaxII 60 problem
Replies: 6
Views: 300

Re: Coronado SolarmaxII 60 problem

Aahhh, OK, I now realise the problem!
I would have thought the retaining ring that the nylon tipped grub screw sits it would have been more robustly held in the glass plate....

I found these on my files...an early SM60 "failure" - looks like a small retaining collar?
by Merlin66
Tue Jul 03, 2018 1:49 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

Guys, Unless you can analyse the etalon comb/ CWL's in the "new" target wavelength - it's just a guess..... I'm going to set up the spectrograph (R=10000) which should give at least 0.1A resolution and record the PST "comb" at the NIR CaII lines...if all goes well then I can try other lines...... If...
by Merlin66
Sun Jul 01, 2018 11:38 pm
Forum: Solar Scope Modifications
Topic: Baader Telecentric - Lower flux in blue/CaK?
Replies: 4
Views: 749

Re: Baader Telecentric - Lower flux in blue/CaK?

What exposure times are you comparing it to??
Which camera?
by Merlin66
Sun Jul 01, 2018 11:37 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Coronado SolarmaxII 60 problem
Replies: 6
Views: 300

Re: Coronado SolarmaxII 60 problem

Maier Photonics supply a drop in replacement for the ITF. I don't honestly know, I use an original SM60... but I'd think the central pressure screw is adjusted to give an on-band CWL (or really just to the red wing) and then given a spot of Loctite to hold it. Then by turning the turner ring the pre...
by Merlin66
Sun Jul 01, 2018 4:27 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

Valery,
I’ll see what I can do.
An exposure of the NIR same camera, same exposure, with and without the etalon will be influenced by the etalon comb......let me think about it.
by Merlin66
Sun Jul 01, 2018 12:51 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

Looking more closely at the Liege solar atlas, it appears we have the double CaII lines in the NIR - 8542A and 8662A.
I've done a rough calibration on the PST spectrum to show these lines.......
Liege_PST etalon_NIR_Ca II.JPG
Liege_PST etalon_NIR_Ca II.JPG (188.97 KiB) Viewed 386 times
by Merlin66
Sat Jun 30, 2018 6:48 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

I've seen the etalon bands all the way down to the UV, but never paid attention to the NIR, I expect to see them all the way. How close is one band to the required CWL I think will be the issue. (OK, found an old spectrum of a PST etalon - low resolution and not focused for the NIR but the wavelengt...
by Merlin66
Sat Jun 30, 2018 2:57 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

Valery,
The attached screen from BASS2000 shows both lines.....
CaII_NIR.JPG
CaII_NIR.JPG (67.41 KiB) Viewed 456 times
by Merlin66
Sat Jun 30, 2018 1:24 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

Looking at the solar spectrum map....
There seems to be an interesting CaII line at 8498.1A as well as the large shallow CaII 8542.2A.
If I ever see the Sun again I'll see how the etalons perform out in the NIR.
by Merlin66
Fri Jun 29, 2018 12:40 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

Christian,
I have access to a SM60 external etalon and a PST etalon and a hi-res Littrow spectrograph (R=10000).
I have previously looked at the transmission peaks but not in detail or at the nominated wavelength.
Let me see what I can do.
Ken
by Merlin66
Thu Jun 28, 2018 12:53 am
Forum: Solar Scope Modifications
Topic: Can i use my EDGEHD800 for Ha?
Replies: 10
Views: 612

Re: Can i use my EDGEHD800 for Ha?

Re PST mod with an Edge SCT....I'm not sure the built in corrector and the available back focus would allow you to achieve the necessary -200mm . The mod would there entail more work and cost besides the upfront ERF!
There may be members with practical experience ........
by Merlin66
Thu Jun 28, 2018 12:21 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: NEW direction in the solar narrowband imaging.
Replies: 53
Views: 1466

Re: NEW direction in the solar narrowband imaging.

A good SHG with large aperture and a good pixel/ chip sized camera would probably give you the results you're looking for. The attached spreadsheet shows with a 900mm spectrograph and an 1200 grating an R>50000 could be achieved. Theoretical bandwidth at 8542A around 0.09A; seeing at 2 arcsec would ...
by Merlin66
Sun Jun 24, 2018 6:34 am
Forum: This is SolarChat !!
Topic: Today's SUN (20180623) with good seeing (WL, Ca-K & H-alpha)
Replies: 10
Views: 299

Re: Today's SUN (20180623) with good seeing (WL, Ca-K & H-alpha)

Pedro,
Your full disk CaK gives me a benchmark for the current Omega filter trials.
Thanks for sharing.
by Merlin66
Sat Jun 23, 2018 9:00 am
Forum: Solar Scope Modifications
Topic: Finally testing new CaK filter stack
Replies: 18
Views: 366

Re: Finally testing new CaK filter stack

Mark,
Thanks for the suggestion.
I’ll try it the next opportunity.
by Merlin66
Sat Jun 23, 2018 8:13 am
Forum: Solar Scope Modifications
Topic: Finally testing new CaK filter stack
Replies: 18
Views: 366

Re: Finally testing new CaK filter stack

Thanks Mark, appreciate.
The conditions were far from ideal.
I hope to get better weather and a better camera soon.
by Merlin66
Fri Jun 22, 2018 9:09 am
Forum: Solar Scope Modifications
Topic: Finally testing new CaK filter stack
Replies: 18
Views: 366

Re: Finally testing new CaK filter stack

I probably agree, but at a total price of a few hundred dollars it's much cheaper than the commercial options.....
by Merlin66
Fri Jun 22, 2018 6:29 am
Forum: Solar Scope Modifications
Topic: Finally testing new CaK filter stack
Replies: 18
Views: 366

Re: Finally testing new CaK filter stack

I bought an ASI 183MM earlier this year to compliment the shorter focal length ED80 and "improve resolution" for solar imaging. Cutting a looooong story very short, ZWO finally admitted "technical problems when the ASI 183 is used for narrow band solar imaging" and accepted a return. I'm now looking...
by Merlin66
Fri Jun 22, 2018 6:09 am
Forum: Solar Scope Modifications
Topic: Finally testing new CaK filter stack
Replies: 18
Views: 366

Re: Finally testing new CaK filter stack

A touch of colour and re-aligned axis.....
CaK_220618a.png
CaK_220618a.png (1.63 MiB) Viewed 350 times
CaK_112110_crop.png
CaK_112110_crop.png (461.2 KiB) Viewed 350 times