Niall Saunders

Home made Wedge and Pier

Niall Saunders — Thu, 21 Feb 2008 02:17:08 GMT

Home made Wedge and Pier

Who needs a 'Mitty' wedge when you can have a '$hitty' wedge instead? (No offence intended, please - I just needed a wedge 'right now' - and so an immediate trip to my local scrap metal dealer had to be arranged.)

The whole lot cost about $20.00 - and took about three hours to smack into shape. And most of that $20 was in weld-wire and Argon gas for my MIG welder, although you could probably add another $20 for miscellaneous stainless steel hardware as well.

And I haven't even bothered with a coat of paint. I don't need to - after all 'rust' is a colour, isn't it ?!!

The BEST add-on you can have for your LX90 !!

Niall Saunders — Wed, 20 Feb 2008 22:16:03 GMT

The BEST add-on you can have for your LX90 !!

Apart from the Peterson Engineering upgrade for the LX90 focuser itself - this is the ONLY thing you need to add to your LX90 to give ultra-precise focusing (well, maybe I need to add a $0.10 Hartmann mask made from a discarded cereal box !!)

And even this 'mod' can be upgraded - providing you can afford to purchase a toothpick (preferably un-used, and un-chewed - we are supposed to be scientists after all). Stick one end in anywhere on the circumference, and you have instantly created a 5:1 reduction 'gearbox' for your focuser. And all with NO image shift.

Yes, I really mean that - I have absolutely no detectable image shift whatsoever when I focus - even at f/20 with a Barlow. I use a second toothpick (yep, no expense spared) to act against the first when I want that final critical adjustment.

Motorised gizmo-justers - who needs them?

DSI-II(C) and DSI-IIPro - my main imaging/guiding cameras

Niall Saunders — Wed, 20 Feb 2008 22:09:38 GMT

DSI-II(C) and DSI-IIPro - my main imaging/guiding cameras

I am mostly using the LX90, at f/10, as the guide-scope for the ED80, imaging at f/6.8.

I swap between the two DSI-IIs as needed, no longer using the DSI-IC as a guide camera now that I have the second -II (although it did a perfectly good job when I did use it).

I tend to work two PCs - a desktop one (1.3GHz, ancient) for gathering the actual images, and a P4 3.4GHz notebook for guiding (just because it gets the downloaded image processed much faster). I also use the notebook for the DSI-IC 'finderscope' camera - when needed.

I have regularly run all three cameras off the notebook, with no problems, even when guiding. And that is without any form of external supply or powered hubs (other than a mains supply to the notebook PC itself). I use high quality USB2.0 extension cables (5m) between the PCs and the top of the pier, and then 2m cables up to the cameras themselves.

However, I am about to add a pair of (powered) hubs to the top of the pier - just to simplify the cabling nightmare. This will also allow me to add a USB RS232 emulator to each hub - again to simplify getting the AutoStar connected to either PC. (Both PCs have 'true' RS232 ports - I would NEVER buy a PC that didn't have this level of 'legacy' compatibility - so this enhancement is purely 'cosmetic').

DSI-IC as an ultra-widefield 'finder' scope

Niall Saunders — Wed, 20 Feb 2008 21:59:34 GMT

DSI-IC as an ultra-widefield 'finder' scope

My first DSI camera, now several year's old. Almost destined to the scrapheap (or eBay) now that I have the two -II models.

And then I remembered that the second DSI-IC that I had bought had come with a cheap C-mount lens and T-thread adaptor. So these have now been pressed into service as a wide-field finderscope. Simple, but effective.

I am also planning to machine up a (set of) 1.25" eyepiece adaptor(s) for the original Meade 8x50 finderscope - which will allow me to use the stock LX90 diagonal, and a cheap Kellner EP, or even the DSI-IC as well. I'm not over worried about the rubbish focuser on the finderscope - it will serve it's purpose.

So, all I need now is a bracket somewhere up at the front end of the scope to hang my Olympus e500 DSLR on (when not attached to the ED80 or LX90) and I think I will have most focal lengths covered !!

My home made 3-D balance system - total cost $10 at the scrap metal dealer

Niall Saunders — Wed, 20 Feb 2008 21:50:47 GMT

My home made 3-D balance system - total cost $10 at the scrap metal dealer

I just refused to buy into a commercial balancing system - most of them don't look that sturdy anyway. So, I bought a bunch of 'end-cuts' of 2" brass bar-stock - readily available from any good scrap metal dealer. Some aluminium 2" x 1/8" flat bar (again, scrap ends) and some 1/2" 'Unistrut' (again, scrap). A few lengths of M10 and M8 rod and bolts (Stainless steel - cheap at good hardware outlets) and some M8/M10 nuts, bolts and washers - and an M8 tap. Job done.

Took about a year to plan, and about two hours to implement - having TOTALLY abandoned the 'plan' altogether, because I couldn't be bothered firing up the Milling machine ! (see the "3D Balance System - Engineer's Plan" image)

Me and my LX90 8" SCT (and its friends)

Niall Saunders — Wed, 20 Feb 2008 21:32:44 GMT

Me and my LX90 8" SCT (and its friends)

In response to a request from Matt Taylor I took this picture of my imaging setup - mostly because I finally got my 3D balancing system fabricated. And, boy does it work!! Why I waited so long to make this I don't know. Even with all that 'stuff' hanging off the LX90 OTA, I can release the clutches ANYWHERE, and the scope just doesn't shift. And, at last, I am back to using full High Speed slews!

M51 LRGB DSI-IIC and DSI-IIPro

Niall Saunders — Tue, 19 Feb 2008 15:44:31 GMT

M51 LRGB DSI-IIC and DSI-IIPro

This is the first image that I have completed using two cameras. I used the DSI-IIPro to capture 13 frames at 120s, and the DSI-IIC to capture 12 frames, again at 120s.

The imaging scope was a Moonfish ED80 APO at f/6.8, although I also left in place an Atik 0.5FR when using the DSI-IIPro - as it helps keep the CCD 'sealed' ! This meant that the two sets of images were slightly different in scale, but I was able to overcome that. The ED80 was riding piggy-back on my 8" LX90 Classic, being guided by my old faithful DSI-C. All guiding was done at 2s exposures, on a second PC, still running Envisage.

All images were saved as FITS, normal, un-combined - with no auto-dark subtraction. All image calibration (Darks, Flats and FlatDarks) was carried out in AIP4WIN (Flats and FlatDarks were with a lightbox on the ED80, exposing at 2s). Calibration runs were 20 images for each data type, and for each camera.

For the DSI-IIC, I collated the individual R, G, B and Lu frames into separate sub-directories, and then processed each group as a 'mono' image. The original Lu data from the -IIC was processed to evaluate the colour image in general, but was not used in the final processing.

In AIP4WIN, I median combined the Darks and FlatDarks and Average combined the FlatDark-corrected Flats. I used the 'square pixels' function, and 2x Upsample when stacking the Lights, and applied a 3.3 Pre-scale and 1.0 Noise Filter before registering on two stars for a final Average stack of the calibrated and registered Lights.

I then aligned the R, G and B images to the Lu image, using AIP4WIN, which applied the appropriate Scale, Translation and Rotation to each colour frame - and yes, I should have been more careful about the rotation I let creep in when I swapped cameras !! (And, I should have removed the 0.5FR as well - life would have been simpler, and I would have ended up with a larger image, better framed).

I then applied a Gaussian Blur, at 1.2, to each of the colour frames, before using AIP4WIN to create a final LRGB image - which I then took over to PixelInsight LE (that last, free, version) for Histogram and Curves work.

I started out by cropping the usable image from the rotated mess, and then carefully Curved and Histogrammed, through several small iterations (HUGE lesson learned here !!) before using the SBGNR function to smooth out some of the background colour noise.

I felt that the image could still be sharper, so I split it into L.a.b frames, and threw away the L data. I brought the original Lum frame back and Histogrammed and Curved it, and then reassembled my colour image using the old a and b images, and the new L image. MUCH better!!

I then scaled it back down to 775 x 577 pixels - which is the 'natural' size of a 'square pixel' DSI-II image.

And that is what I have posted.

It's not spectacular, but it does represent the first image created from an 18-month learning curve, based on photons that always seem to be above a cloud layer here in NE Scotland !!

Thanks for looking.

Niall Saunders
Clinterty Observatories
Aberdeen, SCOTLAND