Sun H-Alpha 23.04.17

[Macavity]

Sun(day) 12:30! As ever, Lunt 50 Single Stack + DMK41, "bag flat" etc.

Full is disk now *rotated* to align Solar North at the top -- Or so I claim.
(Conveniently, rotating smooths out a few minor image glitches too!)

And now (non-rotated) 2x Barlowed quadrant:

[michael.h.f.wilkinson]

Lovely results!

[Davey-T]

Really nice images Chris.

Dave

[David Smith]

Nice work Chris

[Macavity]

Thanks folks! I'm happy enough too... I might wish that the individual images
didn't require QUITE such *individual* treatment (and quite such time too!)

It's tantalising... I sense I am getting near to the resolution limit of my Lunt 50?
The 60mm (+ bigger) ones seem to give significantly more? Idem the Quark(!) 
At my commitment level too expensive. Aside: In retrospect waiting for funds
for bigger apertures is probably good advice re. any field of Astronomy, but!

Still pondering "Frankenscope" ideas! Sufficiently versed of the SAFETY aspects? 
I have a B600 Lunt.  Maybe a (75mm D-ERF) stopped-down 600mm 4" Achromat:
http://www.rothervalleyoptics.co.uk/skywatcher-102mm-dual-speed-guidescope.html

Guess I will EVER wonder if a modest increase in aperture: 50 --> 75 --> 80(+)
(Noting f/7 Etalon limit?) Frankenscope might gain me something significant???
Or would it just be *even more* hassle? As ever, just more "pie in the sky"! 

[james_screech]

22 hours ago, Macavity said:

Sun(day) 12:30! As ever, Lunt 50 Single Stack + DMK41, "bag flat" etc.

Can you explain what a bag flat is?

[Macavity]

45 minutes ago, james_screech said:

Can you explain what a bag flat is?

Yes. It's a method of producing some sort of FLAT field frame for
Solar (especially H-Alpha) imaging. The main problem is that the
initial field is often far from flat (Large bright central solar object!)
Simply pointing scope at random part of faint sky won't work. 

Aside: Some functions of a Flat is to remove chip pixel variations
and dust motes on the surface. This by *division* of the "light"
frames on a pixel-wise (matrix) basis. There is also the need for a
normalising factor based on overall brightness of the flat etc.  

SO we need some way of diffusing / blurring light across a frame.
For images without any edges, "almost transparent" material e.g.
as cling film (placed across the objective) works OK. For FULL solar 
disks (with a lot of dark space around the image!) you need a bit
denser material -- Typical supermarket "fruit & veg" bags work.

Just attach a bag over the end of the scope with a rubber band.
That said, much is still open to experiment, plus some LUCK!

[james_screech]

30 minutes ago, Macavity said:

Yes. It's a method of producing some sort of FLAT field frame for
Solar (especially H-Alpha) imaging. The main problem is that the
initial field is often far from flat (Large bright central solar object!)
Simply pointing scope at random part of faint sky won't work. 

Aside: Some functions of a Flat is to remove chip pixel variations
and dust motes on the surface. This by *division* of the "light"
frames on a pixel-wise (matrix) basis. There is also the need for a
normalising factor based on overall brightness of the flat etc.  

SO we need some way of diffusing / blurring light across a frame.
For images without any edges, "almost transparent" material e.g.
as cling film (placed across the objective) works OK. For FULL solar 
disks (with a lot of dark space around the image!) you need a bit
denser material -- Typical supermarket "fruit & veg" bags work.

Just attach a bag over the end of the scope with a rubber band.
That said, much is still open to experiment, plus some LUCK!

Thanks for that, great images by the way.

[Pete Presland]

Lovely set of images.