Search found 3610 matches

by Merlin66
Sat Jan 09, 2021 7:22 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Prism or mirror diagonal best for solar Ha?
Replies: 22
Views: 264

Re: Prism or mirror diagonal best for solar Ha?

Only if you want to use polarized filters to attenuate the light throughput.
by Merlin66
Sat Jan 02, 2021 7:49 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: SM2 to SM3 stacking question answered
Replies: 36
Views: 671

Re: SM2 to SM3 stacking question answered

I may be Scots by birth, I’m Australian by choice. 🇦🇺
by Merlin66
Sat Jan 02, 2021 3:25 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: SM2 to SM3 stacking question answered
Replies: 36
Views: 671

Re: SM2 to SM3 stacking question answered

James,
The Pommie Marmite is a poor copy of our Vegemite ;)
You'll find fitting a drive well worth the effort.
by Merlin66
Sat Jan 02, 2021 2:09 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: SM2 to SM3 stacking question answered
Replies: 36
Views: 671

Re: SM2 to SM3 stacking question answered

James,
Sounds like you need to buy some Vegemite!
I've used the Vegemite lid drive for over ten years....well worth trying. Certainly makes life much easier.....
by Merlin66
Fri Jan 01, 2021 5:00 am
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 302

Re: Evaluating the PST etalon with a neon bulb

Bob, Looked at your images.... I think to collect and analyse useful data a more robust and repeatable set-up is needed. Too much variation at the moment . Measuring field angle?? The attached shows the ring spacings and the FWHM of the rings. (The second image was not good enough to properly analys...
by Merlin66
Fri Jan 01, 2021 4:32 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: SM2 to SM3 stacking question answered
Replies: 36
Views: 671

Re: SM2 to SM3 stacking question answered

KISS...... I make use of the Skywatcher/Orion electronic motors and controllers. Cheap and effective. Use them belt geared for all the focusers (six at the last count!) The nominal 9V SW controller also drives the micromotor (variable speed). https://www.ebay.com.au/itm/DC-6V-12V-5RPM-10RPM-Full-Met...
by Merlin66
Thu Dec 31, 2020 10:07 pm
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 302

Re: Evaluating the PST etalon with a neon bulb

Building a high resolution spectrograph is not difficult, or necessarily expensive, but it does require some attention to detail and careful workmanship. An adjustable slit, a couple of binocular objectives from Surplus Shed and a reflective diffraction grating from Optometrics are the main componen...
by Merlin66
Thu Dec 31, 2020 5:14 pm
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 302

Re: Evaluating the PST etalon with a neon bulb

Bob, I designed and manufactured the original Spectra-L200 Littrow spectrograph. This is capable of achieving up to R=10000. I also have a couple of Classic spectrographs, an "MG80" spectrograph made from readily available commercial components and various spectroheliographs. Unfortunately the only ...
by Merlin66
Thu Dec 31, 2020 7:53 am
Forum: Solar Scope Modifications
Topic: Advices needed on doublestacking Daystar Quark Chrom and PST Etalon
Replies: 9
Views: 202

Re: Advices needed on doublestacking Daystar Quark Chrom and PST Etalon

The PST etalon will be OK behind the ERF.
It may be better getting both etalons on a NR if the PST was up front....don’t know but well worth trying.
by Merlin66
Thu Dec 31, 2020 7:48 am
Forum: This is SolarChat !!
Topic: White Light imaging with narrowband filters
Replies: 11
Views: 167

Re: White Light imaging with narrowband filters

Correction...
The Baader K line filter is a wide band “continuum “ which also covers the CaK.
by Merlin66
Thu Dec 31, 2020 4:41 am
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 302

Re: Evaluating the PST etalon with a neon bulb

Bob, OK. I have a few (!!!) spectrographs which are capable of resolving down to 0.26A but for this experiment it may not be necessary... If a reference wavelength (Ha) is used and we image the F- P rings we could determine both the spacing and the FWHM by accurately recording the spacing and FWHM i...
by Merlin66
Thu Dec 31, 2020 12:35 am
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 302

Re: Evaluating the PST etalon with a neon bulb

Bob, Interesting. As the CWL will vary with tilt (or Rich view tuning, or pressure tuning) and we do want occasionally to record the solar features off-band, what's the relationship of the data you collected to the FWHM performance? There's a review of commercial etalons: https://www.researchgate.ne...
by Merlin66
Wed Dec 30, 2020 7:06 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: SM2 to SM3 stacking question answered
Replies: 36
Views: 671

Re: SM2 to SM3 stacking question answered

James, Using the SM60II etalon adds a new dimension to the tuning of the DS. The original SM60 etalons were both null tuned to the red wing, is meant that once they were tuned together they effectively became a “solid” narrow band filter. Any tilt tuning of the pair seemed to maintain the CWL of eac...
by Merlin66
Tue Dec 29, 2020 10:29 pm
Forum: Solar Scope Modifications
Topic: Advices needed on doublestacking Daystar Quark Chrom and PST Etalon
Replies: 9
Views: 202

Re: Advices needed on doublestacking Daystar Quark Chrom and PST Etalon

The Quark is tuned by heating only, there’s no cooling option. I can’t remember the on band temperature (30 deg C?) but if the ambient temperature is higher there well may be a problem. When I looked at getting a Quark for use here in Australia, the temperatures can easily get to 45 deg plus, Daysta...
by Merlin66
Tue Dec 29, 2020 10:04 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: SM2 to SM3 stacking question answered
Replies: 36
Views: 671

Re: SM2 to SM3 stacking question answered

Talking about DS set-ups....
I used a pair of SM60 etalons on the ED 80 for many years. They worked well for me.
Sold one....then regretted that!!
Replaced it with an SM60 II etalon. The old SM60 screws directly to the front of the SM60 II.
No issues so far.
by Merlin66
Tue Dec 29, 2020 9:45 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Solar image size affected by focal extenders/reducers
Replies: 9
Views: 302

Re: Solar image size affected by focal extenders/reducers

Most of the generic 0.5 reducers seem to work OK.
I use an ATiK reducer and also have a GSO version.
by Merlin66
Mon Dec 28, 2020 5:08 am
Forum: Solar Scope Modifications
Topic: Evaluating the PST etalon with a neon bulb
Replies: 15
Views: 302

Re: Evaluating the PST etalon with a neon bulb

A very interesting post. I think the wide spread of the neon spectrum is not ideal for this sort of evaluation. (See attached) neon2.gif Possibly a laser pointer with a defined emission wavelength would be better. I use Bass Project (https://groups.io/g/BassSpectro) for all my spectral processing. I...
by Merlin66
Fri Dec 25, 2020 4:59 am
Forum: This is SolarChat !!
Topic: AR2794 WL 22/12/2020
Replies: 13
Views: 223

Re: AR2794 WL 22/12/2020

Martin,
Well done mate!
SPOD you deserved it.
Have a great and safe Xmas and festive season.
by Merlin66
Tue Dec 15, 2020 12:40 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Solar Spectroscopy
Replies: 17
Views: 471

Re: Solar Spectroscopy

Just a hint to new SHG users..... How do you know if your slit gap is at the focus of the telescope? Normal method is to check the top/ bottom edges of the solar spectrum being recorded. When in focus, they should appear tight and crisp. A quick way to get you close.... Use a finder to look through ...
by Merlin66
Mon Dec 14, 2020 10:19 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Solar Spectroscopy
Replies: 17
Views: 471

Re: Solar Spectroscopy

You could use (with a significant light loss) a Baader ND3.8 solar filter on the aperture. Then you have absolutely no issues with possible heat loading. An alternative would be to stop the aperture down to 60mm with a card disk/ ring. The SimSpec SHG V1.3 allows you to assess the probable performan...
by Merlin66
Mon Dec 14, 2020 5:58 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Solar Spectroscopy
Replies: 17
Views: 471

Re: Solar Spectroscopy

Rainer,
No ERF used.
The telescopes used are generally smaller refractors 100- 120mm.
We want to get as much light as we can through the very narrow slit gap and use very fast frame rates.
The heat build up on the slit plate doesn't appear to be an issue.
by Merlin66
Mon Dec 14, 2020 2:42 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Solar Spectroscopy
Replies: 17
Views: 471

Re: Solar Spectroscopy

Any slit spectrograph can be used to obtain a solar spectrum. Just need to point it to a bright sky - no telescope required. Add it to a telescope and you have a spectroheliograph. To obtain spectrogram images, you scan the slit across the solar disk, select and isolate the line of interest ( CaK, F...
by Merlin66
Thu Oct 29, 2020 1:29 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: my new old spectroscopy book
Replies: 12
Views: 354

Re: my new old spectroscopy book

Whoooo That's a great and very useful find! (There's a eCopy available: https://ia803207.us.archive.org/12/items/spectrumanalysis00sche/spectrumanalysis00sche.pdf ) The dispersion of a prism is directly related to the base length - either a very (very!) large and expensive prism, or the addition of ...
by Merlin66
Fri Oct 16, 2020 10:34 am
Forum: Solar Scope Modifications
Topic: Basic question about PST etalon to focus spacing.
Replies: 39
Views: 1194

Re: Basic question about PST etalon to focus spacing.

Andrew,
Interesting, but I think you're over thinking the issue.
What do the results look like?
by Merlin66
Wed Oct 14, 2020 12:17 am
Forum: Solar Scope Modifications
Topic: Basic question about PST etalon to focus spacing.
Replies: 39
Views: 1194

Re: Basic question about PST etalon to focus spacing.

KISS The PST etalon assembly is designed for an f10 input beam and to get optimum functionality/ performance the front lens of the etalon assembly should be placed at -200mm inside the prime focus of the telescope. That's it. (if you're using something like a SCT you can quickly determine if the eta...