Search found 3309 matches

by Merlin66
Wed Sep 18, 2019 8:56 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: PST etalon repair, decontacted?
Replies: 14
Views: 129

Re: PST etalon repair, decontacted?

Marty,
I don't see the four small spacer flakes???
Are these visible?
by Merlin66
Wed Sep 18, 2019 6:45 am
Forum: Solar Scope Modifications
Topic: New CaK filter assembly.
Replies: 2
Views: 64

Re: New CaK filter assembly.

Some interesting reading on CaK observations (Zirin)
http://adsabs.harvard.edu/full/1974SoPh...38...91Z
by Merlin66
Wed Sep 18, 2019 4:27 am
Forum: Solar Scope Modifications
Topic: New CaK filter assembly.
Replies: 2
Views: 64

New CaK filter assembly.

Just completing a new CaK 2A filter assembly..... This version is based on a 2" Baader Blue CCD filter as an "ERF" give a good UV cut below CaK (393nm) and above about 520nm. Then follows a #1 "Yellow" filter removed from a CaK PST. This has a bandwidth of 2A centred on CaK. The third element is an ...
by Merlin66
Tue Sep 17, 2019 9:55 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: SHG build, Lucky find or not
Replies: 4
Views: 89

Re: SHG build, Lucky find or not

Martin,
Well done!
You should have contacted me... I have a couple of SS slit assemblies which have been used in SHG builds as well as some slit edge plates..
Let me know if I can help.
Ken
by Merlin66
Sat Sep 14, 2019 4:39 am
Forum: Solar Scope Modifications
Topic: Easy PST Module with ERF (non-destructive, no cutting of OTA, & no-black-box rebuild)
Replies: 47
Views: 544

Re: PST, how to replace that black box?

Marty,
I use a SM60 on an ED80 with a PST etalon as a double stack.
I also use a BF10 diagonal....so effectively an ERF up front and a second in the Coronado BF.
No issues, no drama.
Using the PST etalon and SM60 is not to much different from adding a front etalon to a SolarMax II.
by Merlin66
Sat Sep 14, 2019 2:06 am
Forum: Solar Scope Modifications
Topic: Easy PST Module with ERF (non-destructive, no cutting of OTA, & no-black-box rebuild)
Replies: 47
Views: 544

Re: PST, how to replace that black box?

Marty,
Belt and braces....gives some added safety.
You can never be sure of the capabilities of the ERF - some are better than others.
Don’t take the risk.
by Merlin66
Fri Sep 13, 2019 6:14 am
Forum: Solar Scope Modifications
Topic: Easy PST Module with ERF (non-destructive, no cutting of OTA, & no-black-box rebuild)
Replies: 47
Views: 544

Re: PST, how to replace that black box?

Marty,
As you're still using the PST 5mm blocking/sort filter why change the ITF? I would have thought the original built in ITF would have done the job??
by Merlin66
Wed Sep 11, 2019 8:24 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Blocking filters and wintertime
Replies: 17
Views: 262

Re: Blocking filters and wintertime

Mark,
Thanks for that.
I’d be interested to know what the operating temperature of the blocker is v’s ambient temperature during a normal observing session??
Ken
by Merlin66
Tue Sep 10, 2019 1:45 am
Forum: Solar Scope Modifications
Topic: Easy PST Module with ERF (non-destructive, no cutting of OTA, & no-black-box rebuild)
Replies: 47
Views: 544

Re: PST, how to replace that black box?

The blue PST objective is just AR coated - no ERF qualities.
No need to add and upfront ERF etc with the 40mm aperture, the ITF at the rear is all that's required.
by Merlin66
Mon Sep 09, 2019 6:33 am
Forum: Solar Scope Modifications
Topic: Layout of filters in a CaK PST
Replies: 10
Views: 194

Re: Layout of filters in a CaK PST

Thanks guys! May be tomorrow with the spectroscope. Quick visual test...removed the gold tube and the filter capsule ( i.e. using elements #1 to #3 above), looking at a Quartz halogen (bright!) lamp. I can see a central bright green(ish) image of the lamp with three secondary images decreasing in br...
by Merlin66
Mon Sep 09, 2019 1:05 am
Forum: Solar Scope Modifications
Topic: Layout of filters in a CaK PST
Replies: 10
Views: 194

Re: Layout of filters in a CaK PST

OK, The PST CaK arrived, s/n 50059............ There are five filter elements, including the objective (excluding the pentaprism).... 1. The objective has a light yellow (AR?) coating 2. The first filter in the blue ring has a bright blueish AR(?) coating, otherwise clear 3. The second filter is wha...
by Merlin66
Sun Sep 08, 2019 3:29 am
Forum: Solar Scope Modifications
Topic: A big solar newton for ultra narrowband imaging, possible?
Replies: 27
Views: 563

Re: A big solar newton for ultra narrowband imaging, possible?

Christian,
Could you use the IR camera to measure the temperature of a blocking filter diagonal against an ambient temperature.
Ideally on different aperture scopes.
Ken
by Merlin66
Sun Sep 08, 2019 2:00 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Blocking filters and wintertime
Replies: 17
Views: 262

Re: Blocking filters and wintertime

CWL = Central wavelength
This is important to register/ align the filter elements at the same wavelength.
by Merlin66
Sun Sep 08, 2019 1:34 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Blocking filters and wintertime
Replies: 17
Views: 262

Re: Blocking filters and wintertime

Hmmm Found this reference: ""Change due to temperature Temperature changes affect a filter's performance due to thermal expansion and contraction of the materials used to construct them. Most filters are designed and specified for operating at 23°C, and deviations from this value will produce peak w...
by Merlin66
Sun Sep 08, 2019 1:25 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Blocking filters and wintertime
Replies: 17
Views: 262

Re: Blocking filters and wintertime

Hmmm Some Lunt(?)(don't know about Coronado) users are mentioning on CN that the blocking filter seems to loose it's CWL at low temperatures... Hence, I suppose Lunt marketing a $179 heater.... This is something I've never heard before...there will be some residual heat coming through the scope to w...
by Merlin66
Sun Sep 08, 2019 1:10 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: My Setup
Replies: 6
Views: 102

Re: My Setup

Good call! I had an original Solarmax 60 which came with an external etalon (no Rich view tuning etc.) and added a second external etalon for DS. Moved the double stack to the ED80 for better performance. IMG_1542s.jpg IMG_1543s.jpg I now use an original SM60 etalon mounted on a SME60 II (rich view ...
by Merlin66
Sat Sep 07, 2019 11:47 pm
Forum: Solar Scope Modifications
Topic: Easy PST Module with ERF (non-destructive, no cutting of OTA, & no-black-box rebuild)
Replies: 47
Views: 544

Re: PST, how to replace that black box?

Marty,
Just check the baffles and their position inside the OTA....
I had an issue mounting a 150mm long 2" CaK module I constructed into the refractor due the the rear baffle.....
by Merlin66
Sat Sep 07, 2019 11:06 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: My Setup
Replies: 6
Views: 102

Re: My Setup

Looking good!
The SolarMax DS 60 is a great starting point.
by Merlin66
Sat Sep 07, 2019 11:03 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Blocking filters and wintertime
Replies: 17
Views: 262

Re: Blocking filters and wintertime

Re Blocking filter failures.... It's the built in ITF ( the front element) which fails. Both the Coronado and Lunt ITF fail....due to temperature variation affecting the bonding/ seal and moisture ingress. It's recommended that the blocking filters be stored in a seal container with silica gel when ...
by Merlin66
Sat Sep 07, 2019 8:58 am
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: Blocking filters and wintertime
Replies: 17
Views: 262

Re: Blocking filters and wintertime

Interesting subject....
What documented evidence for the temperature effect on blocking filters????
Ken
by Merlin66
Sat Sep 07, 2019 3:53 am
Forum: Solar Scope Modifications
Topic: Easy PST Module with ERF (non-destructive, no cutting of OTA, & no-black-box rebuild)
Replies: 47
Views: 544

Re: PST, how to replace that black box?

BP,
The closer you achieve the majic -200mm the better the performance. Don’t compromise.
by Merlin66
Fri Sep 06, 2019 11:10 pm
Forum: Solar Scope Modifications
Topic: Easy PST Module with ERF (non-destructive, no cutting of OTA, & no-black-box rebuild)
Replies: 47
Views: 544

Re: PST, how to replace that black box?

The removal of the PST black box - is a Stage 0.5 mod. The back focus from the rear lens of the PST etalon assembly is 200mm. You 're looking at a Stage 2 rear end. I have a M50 to T thread adaptor some T thread spacers then a Borg Helical focuser. I use a BF10, but you can use the original PST bloc...
by Merlin66
Fri Sep 06, 2019 7:37 am
Forum: Solar Scope Modifications
Topic: A big solar newton for ultra narrowband imaging, possible?
Replies: 27
Views: 563

Re: A big solar newton for ultra narrowband imaging, possible?

Christian,
I understand....
But I would think many internal ERF applications might give significant heat loads on filters in the optical train.
The point is the actual temperature of the element may not be as critical as assumed.
by Merlin66
Fri Sep 06, 2019 7:02 am
Forum: Solar Scope Modifications
Topic: Layout of filters in a CaK PST
Replies: 10
Views: 194

Re: Layout of filters in a CaK PST

OK. I've already built a CaK filter with a Baader Blue-CCD as the front ERF, then a couple of Omega filters...... works OK. As you know any hope of using a CaK filter visually means you have to be less than 12 years of age ;) won't work for a BoF like me. I'll test all the elements when the CaK PST ...
by Merlin66
Fri Sep 06, 2019 4:59 am
Forum: Solar Scope Modifications
Topic: A big solar newton for ultra narrowband imaging, possible?
Replies: 27
Views: 563

Re: A big solar newton for ultra narrowband imaging, possible?

Interesting stuff.....
I assume the ambient temperatures were around 18 deg? that would represent a temperature increase of around 10 deg for the "ERF"
That doesn't sound too bad to me....
The ambient temperatures down here in Oz in Summer can be up to 40 deg in the shade!