Upgrade Options (Long but Contains Images!) :P

[Macavity]

In my (our collective?) never ending quest for "better" images,
I have arrived at a point where I'm not sure what to do next!
I suppose my ultimate would now be to produce a *close-up*
disk animation -- like some of the fine examples shown here!

I don't think I'll be in the market for a £k's larger Solar Scope.
Idem re. the Quark: Nice idea... but too much dosh in one go.
Whatever it's merits or no, my trusty Lunt50 will have to do!
(I don't think I have found the "right" camera (DMK41) tho...)

I am quite pleased with the ST120 FrankenScope experiment.
I'll post some comparison images to show where I'm now at?


Full Disk "Barefoot" Lunt 50 (No flat to show the dodgy pixels)

 

Lunt 50 Barlowed 2x (Beyond this I sense the 50mm aperture is limiting?)

 

Frankenscope "86mm" (ST120) Barlowed 2x  (Beyond this the ST120 Achromat is not the best?)




Same as above only a bit "better" processed? (I can always work on my processing skills!)

BAD FORM to discuss money? lol. But if I look at the cost of the Frankenscope
I paid £350 for the 90mm Baader ERF (and £250 for the ST120)! But I will be
using the ST120 as a "push-to" visual (night!) scope on my Sky-Tee mount. 


So, if YOU were looking at ca. £500 upgrades over time what would YOU do? 

1. Replace the ST120 in the Frankenscope by a ED100? They seem a bargain
    at £350 and it I would also upgrade my Altair ED66 for White Light work!

 **  I have some evidence that the ST120 (fast achromat) is not ideally suited
    for H-Alpha work. An ED APO of even slightly less aperture must be better?

2. Replace the DMK41 Camera. Despite lack of Newton's rings and being a fair
   "work horse", I'm still having to do FLATS to get rid of the dodgy pixels.
   
 ** Or REVERT to using my ZWO120MM camera exploring the possibility of 
   *tilting* it properly? It has 3.75 mu pixels (compared to the DMK's 4.4)
   so could give a better resolution... If I can banish the Newton's Rings!

 
3. Be happy with what I have! Buy myself that much-needed comfy chair! 


No detailed response needed (lol)! But if you pick up on ANY of the above
I would be happy! It may even sow the seeds for others' upgrade ideas?

 

P.S. latest FrankenScope incarnation (For those who are still with this!) lol

[johnfosteruk]

I am (eventually) going to buy a quark. It's on my list of things to do with savings, below a better mount and a better camera. This is because although I love to fettle as much as the next man I can't bring myself to butcher gear to the extent needed to make a frankenscope.

However, seeing as you are already in deep with the butcherment, I think I'd go with option 1 if I were you

HTH

[Macavity]

Thanks John... Yeah, just the sort of input that is appreciated!
I think I am at the stage (age?) where most of my projects are
reasonably complete + thinking of non-Astro things as well.

The Frankenscope is awkward (at present), but I have some
ideas re. improving the "quick release" scheme. I will get the
bits made (OTA bung, ERF cell) by someone with real skills!
It will mostly only be assembled for the "special occasions".
(Everyone seems to at least *try* an ED80 at some stage). 

The camera issue is more uncertain. Smaller pixels, No NRs,
faster interfacing (I'll need a USB3 Laptop!), more sensitive?
I continue to watch the choices / fortunes of others here...

[Peter Drew]

Looking at your progressively improving results I would suggest that your first (and cheapest) route would be to stick with what you have at the moment and continue to hone your capture and processing skills. Your latest images show that there is little in the way of potential detail  missing, just needs refining. Eventually, an even better Frankinscope would give you more high resolution possibilities along with the basic LS50 for full disc solar imaging.  Newton rings can be mitigated by using a tilt adaptor for the camera.   

[Pete Presland]

They are very nice images.

I would also be tempted by option 1 as well.

As an alternative  have you considered keeping a look out for 2nd hand double stack maybe? 

[Macavity]

On 10/7/2017 at 17:05, Peter Drew said:

Looking at your progressively improving results I would suggest that your first (and cheapest) route would be to stick with what you have at the moment and continue to hone your capture and processing skills. Your latest images show that there is little in the way of potential detail  missing, just needs refining. Eventually, an even better Frankinscope would give you more high resolution possibilities along with the basic LS50 for full disc solar imaging.  Newton rings can be mitigated by using a tilt adaptor for the camera.   

So right, Peter! (My) Solar Astronomy acquires a certain "momentum" 
which may benefit from a modicum of thought / practice sometimes?

Anyway, it's been an interesting little project and I thank YOU and Ken
(Merlin66) + others for providing encouragement to have a go at it!  

I do find some of the Frankenscope designs quite inspiring, whatever
I may do eventually. lol  Here's a nifty idea for avoid tube currents... 

https://www.flickr.com/photos/w0lvy/10851442273/
(Paolo Procellana -- 150mm "Truss" HA Solar Scope)

 

[Peter Drew]

@Macavity,  Paulo has modded the skeleton tubed 6" Istar which was introduced by Istar as an alternative to their very heavy standard tube offering rather than send it to WW. This, and other Istar telescopes are now no longer being made, abandoned in favour of just supplying optics. I'm not convinced by the claim for tube current reduction and suspect that the open tube could introduce reflections for solar work although his images are excellent. My 6" Istar mod has a full, oversized diameter tube weighing less than the skeleton model and produces similar visual performance.