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13 May with Omega Ha

Posted: Tue May 14, 2019 3:34 pm
by RodAstro
Hi just a crude mosaic with the Omega Ha filters from yesterday
sadly the QHY5 is hit and miss with vertical lines but I will stick with it until I get a better filter system

Re: 13 May with Omega Ha

Posted: Tue May 14, 2019 6:46 pm
by marktownley
Good result for the Bob filters! a PST mod would be the next stage up.

Re: 13 May with Omega Ha

Posted: Tue May 14, 2019 6:50 pm
by MalVeauX
Hrm,

I'm genuinely curious the bandwidth of that filter(s). If it's around 1A it could be a very interesting option as the 2nd filter after an etalon....

Very best,

Re: 13 May with Omega Ha

Posted: Tue May 14, 2019 11:03 pm
by RodAstro
Thanks Mark
I will have to work on my processing but it is coming along.
You are quite right I am going to try a PST mod next, I have been working on one with Andrew on a vixen 110mm so will transfer that to the Zeiss the only problem will be the small sweet spot tof the PST etalon at 2250 focal length.
If that doesn't work I will probably go for a Quark combo as starting with a f15 scope the combo should be ok.
If anyone has a combo and fancy a day trying it on my very special Zeiss scope, one only three I know of working in the west, they are quite welcome.

You are quite right Marty we are going to try the filters after the PST etalon instead of the 5mm blocker, in theory they should work as they are narrow enough for the comb filter and two may work as a double stack. Not as narrow as two etalons but may improve the contrast a bit and have a much bigger output the same as a quark. The only thing is they will have to be tilted to bring them on band and this may cause banding, although a flat should remove that.
I will give an update on this experiment.

Re: 13 May with Omega Ha

Posted: Wed May 15, 2019 3:13 am
by Valery
RodAstro wrote: Tue May 14, 2019 11:03 pm The only thing is they will have to be tilted to bring them on band and this may cause banding, although a flat should remove that.
Pretty much useless flat field in this given case. The problem is not in a different brightness (like vignetting) but also that at brighter area your filter is already out of H-a and even if you will equalize the brightness, you will not help to get back the H-a details contrast loss.


The best way I see for your scope (if to save money) is TV PowerMate 2,5x and Quark combo this will yields final F/37.5 . Or use a weak focal reducer made of small achromatic lens (with 0,67x power) and then use a standard Quark Chromosphere which yields final F/43.

Valery

Re: 13 May with Omega Ha

Posted: Wed May 15, 2019 7:51 am
by RodAstro
Hi Valery
I get your point
My biggest problem is seeing though and I think at f40 I will be pushing it.
Science building the observatory UK planning laws have relaxed, I did have a lovely clear horizon to the west but now I have a house to the west almost on top of me so limited to 30 degrees above the horizon in the summer over a house that has been heated all day, that is my best seeing.
I really need to see what a Quark Combo can do around f15 or with the scope stopped down.
A PST etalon may also be a problem as I think it may have to go inside the scope because there is no way to shorten the tube.
Not defeated yet though as what I have learnt from the Omega filters is what in theory is optimum is not always best when you have other parameters involved.

Re: 13 May with Omega Ha

Posted: Wed May 15, 2019 11:23 am
by Montana
That's a lovely panorama Rod :bow

Sorry to hear about the house, I bet you bought your house because of that astro view and some selfish person ruined it. I have exactly the same with 100 houses now on my lovely view which used to be 1st grade agricultural land and grow wheat. It is amazing how in the UK it is impossible to build houses on brown field sites but planning permission is grated first time on food producing land. I guess we don't need food now or in the future.

Alexandra

Re: 13 May with Omega Ha

Posted: Wed May 15, 2019 3:41 pm
by RodAstro
Thanks Alexandra for the positive comments.

Your quite right about the house building in the UK. The reason we moved here was to get away from the light pollution. the interesting thing is on the plans for four houses the builders put in garages across the access to the fields behind and then they never built the garages so we expect a new housing estate will come next, all green belt. A hundred yards down the road is useless land for farming reclaimed from the old coal pits, no one wants to build there.
Sad for my lovely telescope. It seems the englishman's home is not his castel any more.