modded 11cm Meade Newt + Lodestar-C
Posted 23 July 2014 - 10:39 AM
The Newt mirror is spherical and produces spherical aberration but not too severe as you can see from the main Altair shot in 10s exp recording stars to mag12 and fainter. Some earlier mono shots with a aperture mask on a spike show sharper results here with an explanation as to why.
Results last night were curtailed when the battery died but the M57 shot [right] is a single frame as the stars traversed the field of the now static scope - quite pleasing to watch! An overhaul of drive with replacement batteries is in order for next try.
My video clip here
- RightWill likes this
Posted 24 July 2014 - 01:49 AM
Posted 26 July 2014 - 01:58 PM
Posted 26 July 2014 - 02:47 PM
To put things into perspective, such a fast spherical mirror probably delivers something like a full wave (if not more) of departure on the wavefront. For prime focus work with larger pixels, a diffraction limited system is certainly not a requirement.
Interesting, so maybe those ebay scopes with spherical mirrors and one of the lower priced video cameras would go a long way.
Posted 05 August 2014 - 02:50 PM
I've dumped the idea of using the little Meade on its erratic alt-az mount and piggybacked the OTA on my 12" LX200 - awaiting some clear skies to test it
Posted 05 August 2014 - 04:21 PM
That little scope will be a lot happier riding on a better tracking mount.
Knowing your desire to not move cameras around too much it will be interesting to see which camera spends the most time on which scope (lower sensitivity color vs. higher sensitivity mono). I didn't get much discussion on that subject when I posted about it a few months ago.
Love the graphic on the relative sizes of the fovs.
Edited by mclewis1, 05 August 2014 - 04:21 PM.
Posted 05 August 2014 - 04:45 PM
Thanks Mark - the OSC Lodestar-C via SX s/ware will go on the 11cm Newt initially then maybe the L-Mx2 IF I get a Ha filter. We're due for some much needed rain tomorrow for the parched gardens ! Then perhaps more imaging as the evenings 'draw in'
Edited by nytecam, 06 August 2014 - 04:56 AM.
Posted 07 August 2014 - 05:15 AM
Fair conditions last night - drifting thin cloud initially and gibbous moon due south [snapped in 1ms [=1/1000s] under SX sware] eg first colour images via the 11cm f/4 piggybacked modded Meade Newt with spherical primary.
Had some collimation issues that I couldn't solve whilst grabbing first images so right hand side of image cropped on this occasion. Had hoped to use the aperture mask before scope to sharpen images but they seem fairly good anyway.
Altair field in 1x10s exp recorded mag 12 stars
M57 in 1x2m exp
M27 in 1x1m exp
m13 in 1x1m exp thro thin cloud
Pleased with initial results from the scope with a spherical mirror
Edited by nytecam, 07 August 2014 - 05:17 AM.
Posted 14 August 2014 - 12:12 PM
Achieving this with a cheap little scope tells ma that these small sensors used in near-live electronic observing work with any optics as long as it is fast. I feel sorry for those, who spend thousands of dollars on fancy Edge or RC tubes to use them with 1/2 or 1/3 inch sensors.
A question: I notice that you are using SX software. Does LL not work with the non-X2 Lodestars or does it not work with color?
Posted 14 August 2014 - 01:12 PM
Thanks Dom for your and your wife's interest. Although colour in celestial objects is muted [and virtually completely absent to the eyeball] I expect more from my camera!
Paul [of LodestarLive=LL] has concentrated with the video-like options with his LL but its colour is too muted for my liking hence my use of SX s/ware which has a saturation range of 1-9. I would estimate LL has [currently] a fixed colour value ~1 so barely ok on terrestial subjects.
Truer star colours comes from oversampling via large DSLR etc. The small CCDs used in video or Lodestar etc tend to undersample eg the stars falling on too few pixels which may then display spurious, if pleasing, star colour. Hope that helps