Improving contrast on a Daystar... double stack?

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
User avatar
marktownley
Librarian
Librarian
Posts: 24536
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: Improving contrast on a Daystar... double stack?

Post by marktownley » Sun Mar 22, 2015 7:06 am

Valery wrote:
marktownley wrote:Try it with a naked PST etalon Frederic, this will give better results (I find) than the Bob filters which I also have. I use this wih my quark on the output side of the telecentric beam.
Have you tested the Quark coupled with the Bob's filter?

What is the bandpass of your Bob's filter?

Is the improvement with Bob's filter worth to make it?


Thanks,


Valery.

Hi Valery,

Yes I have tried it on the Quark, I have no idea of bandpass, I have his 0.7a and 1.5a version and both are a waste of time, the PST etalon showing way more detail than both. To answer you last question, a straightforward no in my experience.

Mark
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

User avatar
marktownley
Librarian
Librarian
Posts: 24536
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: Improving contrast on a Daystar... double stack?

Post by marktownley » Sun Mar 22, 2015 7:19 am

fjabet wrote:
marktownley wrote:Try it with a naked PST etalon Frederic, this will give better results (I find) than the Bob filters which I also have. I use this wih my quark on the output side of the telecentric beam.
I tried Mark, but it's dim as well.
This solution (the 1,5A etalon) is the best I tested up to now and it is very nice visually.
But my goal is to get rid of the Daystar.
I managed to get a nice result visually from both the Lunt and the PST. I know that the best combination would be the 2xLSFHa. Even if Lunt etalon is not top notch, when DSed it does the trick.
But I am plaggued with 2 parasite reflections for one very nice DS image. Reflections are far from focus and present themself has large high background areas.
I need to try again with some linear polarazing filter as reflections should be polarized.

I tried also two PST, but it was dim again, and lacked homogeneity.
Unusual, shows how different etalons are different! Completely opposite to what I found. The Bob filters I have showed both uneven illumination and also uneven bandpass across their field of view. With the PST etalon in the Quark i'm only loosing 2 stops of light (compared to quark on its own), which for me is an acceptable compromise, the Bob filters lost more light still. I have no idea what the resultant bandpass of the Quark/PST is, but it is tighter and more contrasty than any other scope I have looked through. I always thought my doublstacked coronado 40 had a tight bandpass, but then last year I looked through a double stacked Lunt 60, which was tighter still, the double stacked 100mm solarscope I viewed through was in the similar levels of contrast to the Lunt, but, have to say my Quark/PST blows them away, when I image there is no need to stretch contrast in post processing etc, I just tuck in both ends of the histogram and sharpen.

My next mission, and I started this briefly before winter set in, is to try different blocking filters on the quark to try and get a bit more light through, some success initially, but then winter came and cut the experiment short. Shorter exposures is always good when imaging...
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

User avatar
Valery
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 3053
Joined: Sun Nov 18, 2012 3:13 pm

Re: Improving contrast on a Daystar... double stack?

Post by Valery » Sun Mar 22, 2015 7:20 am

marktownley wrote: the PST etalon showing way more detail than both. To answer you last question, a straightforward no in my experience.
Thanks, Mark

I understand that PST etalon is a way better than Bob's Omega H-a filters.

I will test the PST etalon with Quark again any of these coming days with sunshine and good seeing.
All necessary adaptors were made by a machinist.

I will let public know the results with photos.

However what I have found in my Quark is that it:

1. very narrow - better than 0,4A
2. very low contrast vs PST etalon + BF10 filter

IMHO, it just need a better blocking filter and then all will be OK. And I consider Bob's 1,5A as DS + Blocking filter which will improve the contrast
in the Quark. Frederic's experience confirms this my guess.

One very well known and experienced guy now also experimenting with 1,5A Bob's filter as an additional blocking filter for his DayStar etalon.


Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

User avatar
Valery
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 3053
Joined: Sun Nov 18, 2012 3:13 pm

Re: Improving contrast on a Daystar... double stack?

Post by Valery » Sun Mar 22, 2015 7:28 am

marktownley wrote:


My next mission, and I started this briefly before winter set in, is to try different blocking filters on the quark to try and get a bit more light through, some success initially, but then winter came and cut the experiment short.


Shorter exposures is always good when imaging...

Mark some of us (if not many) are looking for your findings with Quark improvement at least in light through ! So, please, continue your experiments.

Yes, the shorter exposure, the better seeing freezing.


Valery.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests