Lunt 70mm f6 & LL & X2 mono

[f15p5]

Here are some short exposure images taken with x2 mono in 70mm Lunt ED, no post processing, no guiding on my G11 mount.  First try with this scope piggybacked on my 10" RC. M31 misslabeled. No filters.

Richard

[Macavity]

Great stuff! Just shows... one needn't be afraid of small ED APOs.

(Excellent "tight" stars - And, of course, you get nice wide fields...) 

[Martin Meredith]

Hi Richard

Great to see some apo shots -- thanks for posting. I have a feeling this scope would do a good job on some of the larger dark nebulae.

Out of interest, did you use the nonlinear modes for the M31 pic?

Martin

[f15p5]

Hi Martin,

No, just linear. I find sliders to touchy to use non linear modes, or images get washed out?

Thanks,

Richard

[arkosg]

Richard,

Some very nice results indeed!  Well done!

I have a colour Lodestar X2C, and was playing with a generic 90 mm refractor the other night.  I had also looked at M31, 

but didn't have anywhere near the small, sharply defined stars that you have in your images; rather, I noticed some star

bloat, especially on longer integrations.  My seeing on that night was less than perfect, but still....

Were you using any sort of filter?  Or is this just the mono vs. colour issue?  Or are your ED Doublet/sky conditions just better than mine?

Cheers,

- Greg A

[Martin Meredith]

Hi Richard

I wondered about that. Using one of the nonlinear modes will help desaturate the core while preserving details in M31's arms. If you find the controls too sensitive, it may be that you have the brightness setting at the wrong point. I find that sweeping the brightness slider slowly there comes a point where the response is very rapid. You need to be either side of that point I think to get the best of the nonlinearity. (You can spot this point without examining the display, just by looking at the histogram). I also find the contrast setting is best set quite low to start with then adjusted after finding the brightness 'sweet spot'.

I find the nonlinear modes invaluable nowadays… hope this helps for you.

Martin

[f15p5]

Hi Greg,

I think it may be a few things. The mono is higher resolution, my tracking was a bit better, and I have decent seeing (usually 1.5 arc sec or better), better than my 70mm (1.65 arc ses) can use up. Also my exposures were probably shorter and I keep white level all the way to the right, black all the way to the left, and bring the signal to the left as fae as I can without extreme clipping.

Richard

[f15p5]

Hi Martin,

Thanks for the info, I will try it out!

Richard