SolarChat!

JohnM

I've always had excellent results with a TV 2.5X Power Mate. A friend of mine has a telecentric barlow from Siebert he swears by.
Since the ERF is going to be the single most expensive part I'll have to buy and I had poor results using a 25A filter, I'm going to wait and go all out with a Baader.

JohnM

I like how you went with your assembly too.
What is that great looking piece of brass you used for your ERF cell?
Did you use the Baader DERF?, I'm hoping to be able to get one ordered next month.

JohnM

Seems like everyone has their favorite method for getting Solar flats. I just find a blank area on the surface and shoot an AVI at the same settings as my regular one except for defocusing slightly. Since I don't often change my rig around once I get it right I save the flats and darks too for later...

JohnM

Looking good! Did you use flats and darks?

JohnM

Sounds right, I thought I had saved a link to his site in HK because it was good stuff, but I can't find it.

JohnM

There was a guy in Hong Kong who had doubled up PST etalons mounted on a scope and was producing fantastic images with that set up. I recall he also commented on the difficulty of getting those tuned. I've been trying to remember his name, Seems like I saw him make a few posts here. He used to post ...

JohnM

Yup. When I finally save up enough for a Baader DERF I may finally get to the point of a good operable 100mm Ha scope! Been a long road.

JohnM

I've only ever seen one person who swears there no difference between a stage 1 and a stage 2, I have better things to do than deal with that.

JohnM

I see you finally made your way to the Yahoo PST tech group.
Some of us here have been members of that group for a long time.
Spend some time digging through the available information.
Too much to try and enumerate here in a few sentences.

JohnM

That build is giving you most excellent results.

:

JohnM

If you used both and couldn't see the difference, I'll leave it to others to carry on.

JohnM

OK, there's a major advantage to getting rid of the Black Box of the PST and in particular getting that penta-prism out of the light train.

JohnM

I do not see any advantage between them if your PST is working well; it is another story if the PST is not giving of it's best.

There's one major advantage. It opens you up to the world of large aperture Ha telescopes.

JohnM

I forgot to post a pic of what I use to hold this creation on the mount.
A couple rings for a 50mm finderscope and an old 8" dovetail fits that PST tube perfectly.

JohnM

I missed this one somehow. A couple more great ideas to rid the PST of the old "Black Box". An inexpensive first step which improves the performance of that little 40mm tube many fold. Be nice if we could get all these "mimi" stage 2 mods in a common thread to show what a little ...

JohnM

There's an existing thread.

JohnM

Why don't you just do a mini mod like I did to mine for now.
All you need to get it done is an SCT focuser, 2 1/2" SCT thread extensions, and an old 2X1.25" adapter and 3 pan head machine screws.
Performance of the PST is outstanding when you get rid of the funky black box.

JohnM

This is an old thread. A lot of work and tests done and posted in newer threads since this one.
All the issues and problems associated with trying to use these filters have proven to be the case.

JohnM

Thanks all. Being far from any town There's great vistas in all directions and no houses close. 2 paranoia lights visible at night some miles off.
Looks like I'm going to be clouded out today, wanted to try a Baader #5 film yet for WL. First image was with my old #3.8.

JohnM

Well sure, isn't everybody?

Fresh snow falling in spots up high already.

It doesn't snow down here in July very often.

JohnM

The views from the yard are nice.

JohnM

I live on the east slope of the Wind Rivers in Wyoming.
My house is at 6000 feet. Rest of the rock is piled 13,000 feet plus on 3 sides.
Down slope atmospherics are a bear here.

JohnM

Given late afternoon seeing here in the mountains I'm pleased with it.

JohnM

Just great WL images.

:
I'm going to change over my new 102mm to WL and see what it will do today.

JohnM

So it WAS really faint. I thought part of my problem was all the smoke I was shooting through.

JohnM

Yesterday was another day of trying to tweak some presentable images out of that 25A ERF. To make it even tougher, smoke from all the nearby forest fires was pretty thick. I did finally get this prom, it was extremely dim and it took some gain, hence all the noise, to get it. That 25A filter seems t...

JohnM

Read through some of this stuff by the late Jan Timmermans. Lot of good basic PST info here. How to tune your penta-prism and how to make sure your tuning ring is doing all it can. http://www.thefirmament.nl/astro/main_screen.html?ini_equipment.html&2 All this stuff is scattered around here too,...

JohnM

How are you going to see granulation in Ha?

JohnM

Granulation? With an Ha scope? You can't see it. It's in the photosphere, a WL subject.

JohnM

Give up on all those wild ideas and just stick a barlow in it.
Generally a PST can handle 2-2.5X without a problem.
I used a TV2.5XPM 99% of the time, even after I built the mini stage 2.
Or look at the special camera adapters Siebert Optics offers.

JohnM

There's only about 18mm between the cell holding the mini ERF and the threads needed to make the connection to the EP holder. You go cutting that part to shorten it and try to make a sleeve to joint the parts together again you get into some limited operating room. A "sleeve" would have to...

JohnM

Most excellent Walter!

JohnM

This is the mini ERF holder that screws into the black box. Leave it alone. This is the eye piece holder, it's what holds the eye piece, it screws into the tube that holds the mini ERF. This one has been shortened and a second lock screw added. I read where you had ordered a short nose piece for you...

JohnM

The human eye is much more forgiving than the camera.

JohnM

Should have shot enough AVIs to put together a mosaic of that one.
It took me sort of unawares.

JohnM

So you use it visual and don't try to image with it?

JohnM

Very strange behavior. If I drop down to f10, 1000mm, that bright area comes back unless I move the filter back in close again. Rotating, changing tilt angle has no effect. It all has to be related to that filter. Wave front error? I'm not sure if I've actually seen any images posted here by people ...

JohnM

The mornings test shots.
2000mm/DMK21
#1 0.25" gap
#2 1.25" gap
#3 2.25" gap
Each with it's own flat, identical processing in AS2

Hmmm. OK

JohnM

Really?, that's interesting.
I plan on doing some more comparisons tomorrow.

JohnM

I'm using a 25A for an ERF, maybe that's the problem?

JohnM

True enough, these were from too widely spaced time periods. I'm clouded out now as usual for the PM. I'm going to do some comparisons tomorrow, got this spacing change down pat now :) From what I was seeing at my end with processing and all I think I'm about as close as I'll get with that 25A. Then...

JohnM

This with an air gap of ~.25"
Improvement?

JohnM

I was going to play a bit more with the 4' mod, then tear it down and gor back to my mini stage 2 that I thought did a better job.
But, I don't think I can get stuff like this with that little 40mm

Maybe I better play with it some more.

JohnM

What a difference. I reduced the air gap from ~1.5" to ~.5" It's not much of an image, the seeing with the Sun as low as it is is always terrible here and I'm still off on etalon tuning, but the bright area seems to have gone. Might try closing the air gap down to about .25" First ima...

JohnM

Depending on circumstances, barlows, etc., I often get newtons rings while imaging I try to find a Solar field showing nothing prominent and defocus slightly, the "slightly" can take a couple trials sometimes, I don't always hit it right :) Then I shoot the AVI. I use AviStack2 to create a...

JohnM

Alexandra! You are doing some of the most outstanding work!
That is just superb

:

JohnM

Has anyone noticed if there is an optimal separation between the OG and the ERF filter element? Building this stage 2 mod I had originally placed an 82mm 25A filter internally. Focus was less than desired, but illumination was even across the field. Then I made a simple cell and mounted it out in fr...

JohnM

Hmm. OK, thanks Mark, I'll try that first. Have to be tomorrow, storms have moved in and covered us again. I was thinking maybe something with the etalon that wasn't so apparent with my mini stage 2 using the 40mm PST OTA, but really showed with the 102mm OTA. If it is that Lumicon filter I'll just ...

JohnM

Back to this one again.
Walter, anyone, care to venture an idea where that bright area, ghosting is coming from?
I had a bit of Sun earlier, I'm still getting it, same area.
I just took apart the etalon and checked things and went back together with it waiting for Sun again for another run.

JohnM

Walter,
I've got recent posts on this 4" stage 2 from the last few days in the mod section and in the photos section. You've been replying to some

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