Search found 3277 matches

by Merlin66
Sat Aug 17, 2019 7:02 am
Forum: Solar Scope Modifications
Topic: PST Blocking Filter modification unit by AOKSwiss
Replies: 6
Views: 108

Re: PST Blocking Filter modification unit by AOKSwiss

Beat was very quick with a reply. I'll post it here for the benefit of the group: "" Your right, but most regular refractors have not 200 mm back focus. So the most users will not cut the tube; also because it's not easy and you will made many scratches normally with this..... well it's right, but t...
by Merlin66
Fri Aug 16, 2019 7:33 am
Forum: Solar Scope Modifications
Topic: PST Blocking Filter modification unit by AOKSwiss
Replies: 6
Views: 108

Re: PST Blocking Filter modification unit by AOKSwiss

I’ve sent an email to Beat asking about the optical length of his rear adaptor.
As we know the standard PST etalon assembly focuses 200mm behind the rear lens.
by Merlin66
Thu Aug 15, 2019 1:28 am
Forum: Solar Scope Modifications
Topic: PST Blocking Filter modification unit by AOKSwiss
Replies: 6
Views: 108

Re: PST Blocking Filter modification unit by AOKSwiss

A worthwhile addition to the "PST Mod"....
I wonder if adding this diagonal immediately behind the etalon assembly (as suggested) will provide the optimum 200mm spacing to the focus?
by Merlin66
Tue Aug 13, 2019 1:20 am
Forum: This is SolarChat !!
Topic: Two PST etalons doublestacked
Replies: 11
Views: 171

Re: Two PST etalons doublestacked

As I've mentioned before - double stacking PST etalons isn't the easiest challenge to attempt.
I'm currently using the SM60/ED80 with a PST etalon as a double stack system, with good results.
(The SolarMax II DS is basically the same arrangement but with the RichView tuning)
by Merlin66
Thu Aug 08, 2019 2:33 am
Forum: Solar Astronomy Shop and Swap
Topic: SME 60 external etalon
Replies: 0
Views: 43

SME 60 external etalon

Still looking for a SME60 etalon with Tmax tuning.
Can you help??
by Merlin66
Tue Aug 06, 2019 11:02 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: it seems that my Quark is not reaching the working temperature
Replies: 13
Views: 307

Re: it seems that my Quark is not reaching the working temperature

Roman, When the Quark was initially released, I seriously considered purchasing one... but had some concerns about the high ambient temperatures we experience here in Oz - above 40 deg C is not unusual. I contacted Daystar at the time and was told - yes could be an issue, and to request a Quark whic...
by Merlin66
Sun Aug 04, 2019 11:26 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: SHS at stellafane VT 2019
Replies: 11
Views: 182

Re: SHS at stellafane VT 2019

John,
Very impressive!
Good to see that the SHS is still recognised as a unique instrument and that it is still capable of producing great views of the Sun.
by Merlin66
Sun Aug 04, 2019 11:23 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: it seems that my Quark is not reaching the working temperature
Replies: 13
Views: 307

Re: it seems that my Quark is not reaching the working temperature

Roman,
Could be it reached "operating" temperature without the heater....
What did the views look like?
by Merlin66
Wed Jul 31, 2019 11:33 pm
Forum: This is SolarChat !!
Topic: June 2019 Sky&Telescope (US Edition) wanted
Replies: 2
Views: 128

Re: June 2019 Sky&Telescope (US Edition) wanted

Franco,
PM sent....
Many thanks, appreciated!
Ken
by Merlin66
Tue Jul 30, 2019 10:16 pm
Forum: This is SolarChat !!
Topic: June 2019 Sky&Telescope (US Edition) wanted
Replies: 2
Views: 128

June 2019 Sky&Telescope (US Edition) wanted

I don’t know what’s going on with S&T, but for the second time in six months my magazine has not arrived!!
They now say that it’s out of stock!!
To maintain my complete collection of S&T I need a clean complete copy of the June 2019 issue.
Can you help??
by Merlin66
Mon Jul 29, 2019 10:15 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Long focus singlet lenses-Surplus Shed
Replies: 6
Views: 153

Long focus singlet lenses-Surplus Shed

Surplus Shed have a special running at the moment on long focus lenses- 2500 to 4000+mm with apertures of 150mm.
These sound ideal for anyone considering building a spectrohelioscope.
by Merlin66
Fri Jul 26, 2019 8:24 am
Forum: Solar Scope Modifications
Topic: Planning my first PST mod and need some help
Replies: 68
Views: 1755

Re: Planning my first PST mod and need some help

Please,please, listen to the experienced advice your are being given.
Your safety and that of others following this thread is paramount.
We do not support any unsafe modding of the PST or any other commercial solar scope.
by Merlin66
Sun Jul 21, 2019 3:26 pm
Forum: Solar Scope Modifications
Topic: Planning my first PST mod and need some help
Replies: 68
Views: 1755

Re: Planning my first PST mod and need some help

If the donor is faster than f10, the etalon assembly will act as an aperture stop and give an effective f10 system. If the donor is >f10 then the beam is not affected by the etalon assembly and will still give a system >f10. Example: an f8 say 100/800mm will become a 80/800mm system; an f12 say 100/...
by Merlin66
Wed Jul 17, 2019 4:47 pm
Forum: This is SolarChat !!
Topic: Quark Combo at low focal lengths
Replies: 7
Views: 178

Re: Quark Combo at low focal lengths

Jack,
Don’t over think the issues....
Just go for the Chromo standard Quark, use it with your achromat with a suitable ERF and enjoy!!
by Merlin66
Sun Jul 14, 2019 5:06 pm
Forum: Solar Scope Modifications
Topic: Planning my first PST mod and need some help
Replies: 68
Views: 1755

Re: Planning my first PST mod and need some help

The front AOK adaptor is just a means of mounting the PST etalon to the donor scope.
The rear adaptor will need addition spacers to bring the the final focus to a position 200mm behind the PST etalon assembly.
by Merlin66
Sat Jul 13, 2019 4:27 pm
Forum: Solar Scope Modifications
Topic: Planning my first PST mod and need some help
Replies: 68
Views: 1755

Re: Planning my first PST mod and need some help

The most successful and probably easiest PST mods are where the donor OTA is adapted (focuser removed and OTA cut) to correctly position the PST etalon assembly at the design -200mm inside the prime focus.
Many other options are fraught with problems and difficulties.
Keep it simple, and safe.
by Merlin66
Wed Jul 10, 2019 7:17 pm
Forum: Solar Scope Modifications
Topic: Planning my first PST mod and need some help
Replies: 68
Views: 1755

Re: Planning my first PST mod and need some help

As well as the above important comment from Mark, remember you don’t need a focuser in front of the PST etalon. Once the etalon is correctly positioned at the -200mm in front of the prime focus it should not be moved. Any focusing behind the etalon to accommodate the eyepiece/ camera can be achieved...
by Merlin66
Sat Jul 06, 2019 6:11 pm
Forum: Solar Scope Modifications
Topic: Planning my first PST mod and need some help
Replies: 68
Views: 1755

Re: Planning my first PST mod and need some help

I think you need to review the basics of the PST mod. 1. The front of the etalon must be positioned near as possible at -200mm inside the prime focus of the donor scope. 2. The final focus will then be very (very) close to 200mm behind the etalon assembly. Check your fitting/ settings to see how clo...
by Merlin66
Thu Jun 27, 2019 10:21 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: question on Young's F line image
Replies: 4
Views: 220

Re: question on Young's F line image

Nothing as distinct as Young shows.
We may have to wait until we see more activity.....
by Merlin66
Thu Jun 27, 2019 8:24 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: question on Young's F line image
Replies: 4
Views: 220

Re: question on Young's F line image

I simplistically think in terms of Severny’s moustaches as described and shown on p 82 and p83.
by Merlin66
Thu Jun 27, 2019 7:38 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: question on Young's F line image
Replies: 4
Views: 220

Re: question on Young's F line image

These were distortions seen in the Spectral line. A fine slit positioned over an active area.
See recent discussions and links from Peter Z.
by Merlin66
Mon Jun 24, 2019 12:19 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: A 19th century PST
Replies: 5
Views: 195

Re: A 19th century PST

I have some illustrations back home..... Basically a multi prism spectroscope with adjustable slit mounted on an excentric rotating adaptor which fitted the telescope. The adaptor could be rotated to bring the slit onto the edge of the Sun and when proms were found, the slit opened to allow a full v...
by Merlin66
Sat Jun 22, 2019 3:08 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: A 19th century PST
Replies: 5
Views: 195

Re: A 19th century PST

Browning made many solar spectroscopes which could be mounted on any refractor to allow observation of the proms using Huggin’s method.
More like a Quark than a pst.
by Merlin66
Thu Jun 06, 2019 1:06 pm
Forum: Solar Scope Modifications
Topic: How do I know my Stage 2 is 200mm?
Replies: 5
Views: 198

Re: How do I know my Stage 2 is 200mm?

The distance from the rear lens of the etalon assembly to the focus should be very close to the Majic 200mm.
It’s probably easier in some cases the find the prime focus position of the donor scope and then position the front element of the etalon assembly at -200mm by measurement.
by Merlin66
Sat Apr 27, 2019 10:25 am
Forum: Solar Scope Modifications
Topic: help with stuck threads
Replies: 11
Views: 482

Re: help with stuck threads

Brian,
Not sure I can help at this stage.....
I’ve successfully use a smear of boot polish on all the treads before using them, It’s worked well for me for over ten years.