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Possibly one of the last active regions of cycle 24? AR12757 ends january with decent activity for solar minimum. Taken by Marty Wise with his 8" SCT, Aries ERF and PST mod.

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Moving forward from solar cycle 24 to 25

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by Merlin66
Tue Jan 21, 2020 11:05 pm
Forum: Solar Reference Library
Topic: HR solar spectra
Replies: 3
Views: 142

Re: HR solar spectra

Christian,
Thanks for that!
It compliments the BASS 2000 spectral profile nicely.
by Merlin66
Sun Jan 19, 2020 6:58 am
Forum: This is SolarChat !!
Topic: Newton rings or reflections
Replies: 6
Views: 177

Re: Newton rings or reflections

Need to see the NR images to comment.
by Merlin66
Sun Jan 19, 2020 6:55 am
Forum: This is SolarChat !!
Topic: Tuning or bandwidth?
Replies: 18
Views: 372

Re: Tuning or bandwidth?

I am aware that there are 3A blocking/ sort filters being tested........
by Merlin66
Thu Jan 16, 2020 9:37 pm
Forum: Solar Scope Modifications
Topic: How close to F10 must a PST mod truly be?
Replies: 14
Views: 290

Re: How close to F10 must a PST mod truly be?

Marty,
To answer your first question, yes. You end up with a 75mm f10 system.
Can't answer the second question - never tried it.
by Merlin66
Sun Jan 12, 2020 10:07 am
Forum: Solar Scope Modifications
Topic: How close to F10 must a PST mod truly be?
Replies: 14
Views: 290

Re: How close to F10 must a PST mod truly be?

Andrew,
Nothing to do with the quoted magnification, just the clear aperture of the negative lens.
It will give you the focal length, you can use this to calculate the magnification from the thin lens formula.
by Merlin66
Sat Jan 11, 2020 11:10 am
Forum: Solar Scope Modifications
Topic: How close to F10 must a PST mod truly be?
Replies: 14
Views: 290

Re: How close to F10 must a PST mod truly be?

Andrew,
You can easily measure the focal length of a Barlow or any negative lens...
Measure the clear aperture, draw a circle twice this size on a piece of card, point the lens towards the sun with the card behind, when the image fills the circle, the spacing is the focal length of the lens.
by Merlin66
Fri Jan 10, 2020 9:52 pm
Forum: Solar Scope Modifications
Topic: How close to F10 must a PST mod truly be?
Replies: 14
Views: 290

Re: How close to F10 must a PST mod truly be?

Marty, The from collimating lens on the PST etalon assembly is designed to work in an f10 beam. If the incoming beam is faster than f10, say f8 (80/640) then the etalon will stop the beam down to an f10 beam - you end up with an effective 64/640 system. With systems >f10 the diameter of the collimat...
by Merlin66
Tue Jan 07, 2020 9:34 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Using a barlow/powermate on an LS50
Replies: 4
Views: 202

Re: Using a barlow/powermate on an LS50

Can't speak for the Lunt 50, but there's generally no issues using Powermates ....I regularly use the x2.5 PM (with the T thread camera adaptor)
Remember the back focus spacing of the PM doesn't affect the magnification.
by Merlin66
Mon Jan 06, 2020 7:20 am
Forum: This is SolarChat !!
Topic: AR2755 & Filaments, High Res & Wide Field | Jan 5th 2020
Replies: 9
Views: 97

Re: AR2755 & Filaments, High Res & Wide Field | Jan 5th 2020

Well done mate!!
Just need the smoke haze to reduce and we may be able to see the Sun......
by Merlin66
Sat Jan 04, 2020 11:36 pm
Forum: This is SolarChat !!
Topic: Full Disc 04 January 2020
Replies: 12
Views: 137

Re: Full Disc 04 January 2020

Rainer,
Well done!
A good record of AR2755, and nice to see the prom activity.
by Merlin66
Sat Jan 04, 2020 11:31 pm
Forum: This is SolarChat !!
Topic: Solar Activity 1st Jan 2020
Replies: 16
Views: 191

Re: Solar Activity 1st Jan 2020

Thanks everybody for the kind responses. The PM2.5 reading in our lounge for the past few days peaked at >150 (!!!!) Bordering on dangerous! Had to buy an Air Purifier to bring the internal house levels down. My wife can't go outside without her asthma giving major breathing problems. Not good for m...
by Merlin66
Fri Jan 03, 2020 11:59 pm
Forum: This is SolarChat !!
Topic: Solar Activity 1st Jan 2020
Replies: 16
Views: 191

Re: Solar Activity 1st Jan 2020

Franco,
Thanks for that, appreciated.
by Merlin66
Fri Jan 03, 2020 10:12 pm
Forum: This is SolarChat !!
Topic: Solar Activity 1st Jan 2020
Replies: 16
Views: 191

Re: Solar Activity 1st Jan 2020

Pedro, Thanks! We're actually pretty far from the current bushfires, and being down near the coast we are usually spared from the smoke etc due to the sea breezes, but this time things are far more dangerous and extensive. Up in the North East of the state, and the far East it is an absolute disaste...
by Merlin66
Fri Jan 03, 2020 9:43 pm
Forum: This is SolarChat !!
Topic: Solar Activity 1st Jan 2020
Replies: 16
Views: 191

Re: Solar Activity 1st Jan 2020

Thanks Alexandra! Not much hope of getting images of AR 2755 - smog and pink skies at the moment, and they say maybe >40 deg C.....difficult and troubling times. If the seeing ever improves, I think I can get better results from the CaK filter stack. About to strip and re- clean the ASI 1600 - I see...
by Merlin66
Fri Jan 03, 2020 12:49 am
Forum: This is SolarChat !!
Topic: Solar Activity 1st Jan 2020
Replies: 16
Views: 191

Re: Solar Activity 1st Jan 2020

Thanks, Marty, appreciated!
by Merlin66
Thu Jan 02, 2020 11:31 pm
Forum: This is SolarChat !!
Topic: Solar Activity 1st Jan 2020
Replies: 16
Views: 191

Re: Solar Activity 1st Jan 2020

Eric,
We've had terrible seeing, smoke and cloud....
Also had the family visiting from O'seas over Xmas and New Year, so difficult to sneak off to do imaging....
Hopefully 2020 will prove to be a fruitful year for solar observers.
by Merlin66
Thu Jan 02, 2020 11:02 pm
Forum: This is SolarChat !!
Topic: Solar Activity 1st Jan 2020
Replies: 16
Views: 191

Solar Activity 1st Jan 2020

New AR just coming into view (still un-numbered), AR 2753 just going... CaK shows the AR pretty well. Also saw for the first time CaK proms! Look carefully at the CaK full disk image (Clue - down the bottom!) Few faint proms also recorded. Enjoy! 095704a.jpg 095750.jpg 095924.jpg 101557a.jpg 102443....
by Merlin66
Thu Jan 02, 2020 10:26 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Usual duration BF filters(Lunt)
Replies: 2
Views: 120

Re: Usual duration BF filters(Lunt)

The pre-blocking filters on both the Coronado and Lunt BF are subject to failures...
They can fail after a few months or last for years....
The good news is that Lunt appear to be replacing their Blue BG38 filters free of charge upon request.
by Merlin66
Tue Dec 31, 2019 9:45 pm
Forum: This is SolarChat !!
Topic: The Solarscope in winter!!!!!
Replies: 13
Views: 248

Re: The Solarscope in winter!!!!!

Alexandra,
Well done!
Nice to see your DSF100 set-up.
by Merlin66
Tue Dec 31, 2019 10:44 am
Forum: This is SolarChat !!
Topic: Solar Activity 27th Dec 2019
Replies: 13
Views: 211

Re: Solar Activity 27th Dec 2019

Thanks Alexandra.
Unfortunately we've not yet started our normal fire season....it may get a lot worse before it get better.
The loss of life is devastating to many communities....

I'm observing from 20 mtr altitude, about 400 mtr from the seashore....hence the terrible seeing.
by Merlin66
Mon Dec 30, 2019 9:51 pm
Forum: This is SolarChat !!
Topic: Solar Images 29/12/2019
Replies: 12
Views: 215

Re: Solar Images 29/12/2019

Franco,
Yes, Zirin is a wealth of knowledge...
I would comment, some of the reference images he uses don't stand up well against the current amateur capabilities! Our images in most cases are better ;)
by Merlin66
Mon Dec 30, 2019 8:00 pm
Forum: This is SolarChat !!
Topic: Solar Images 29/12/2019
Replies: 12
Views: 215

Re: Solar Images 29/12/2019

Martin,
Well done mate!
Hopefully the fire conditions will get better.....
Zirin is one of the solar "Bibles" - a very interesting read.
Take care.
by Merlin66
Mon Dec 30, 2019 10:16 am
Forum: This is SolarChat !!
Topic: Solar Activity 27th Dec 2019
Replies: 13
Views: 211

Re: Solar Activity 27th Dec 2019

Maurits,
There’s a description in one of the earlier threads....basically a Baader Blue CCD filter as an ERF then a series of Omega Bob’s narrowband filters and a #1 “yellow” filter from a CaK PST.
I use it with a stopped down ED80- 60/600.
by Merlin66
Mon Dec 30, 2019 3:10 am
Forum: This is SolarChat !!
Topic: Solar Activity 27th Dec 2019
Replies: 13
Views: 211

Re: Solar Activity 27th Dec 2019

Martin,
Thanks mate!
by Merlin66
Mon Dec 30, 2019 1:52 am
Forum: This is SolarChat !!
Topic: Solar Activity 27th Dec 2019
Replies: 13
Views: 211

Re: Solar Activity 27th Dec 2019

Thanks Franco, appreciated!
The seeing down here on the coast is never very good....
When I get more "practise" with processing hopefully they look better.