Gina

Here is the ASI178MM image from above cropped to represent the coverage of the ASI185MC when the image is shifted appropriately to fit it on the sensor. This shows that the coverage should be quite adequate - I don't need to see the ground below the trees

I shall be interested in seeing how well the ASI85MC and Fujinon fish-eye lens combination work at night. I plan to use it only for dusk to dawn imaging and make up a much cheaper combination for daytime - maybe RPi camera and CCTV fish-eye lens 12mm board camera mount - possibly for web streaming.

This is the full frame of the ASI178MM which shows how the image circle is offset on the sensor. All these cameras seem to have the sensor offset a bit from centre. With the ASI178MM and the sensor covering more than the image circle it doesn't matter - just crop off the unwanted margin. But for the smaller ASI185 it does matter. I therefore propose to design a 3D printed adapter to carry the lens and be attached to the camera. Being plastic this will also thermally isolate the lens from the camera body so that the lens can be heated and the camera cooled. Hopefully small variations in temperature with resulting varying expansion will not result in the image going out of focus.

With the lens in its normal position I get this view. So I think I need a lens support that permits adjustment in the Y direction as well as Z for focus and which holds the lens with its optical axis at right-angles to the sensor.

If I can persuade the lens and camera to line up optimally the sensor will very nearly cover the FOV as can be seen in this screenshot. I have the ASI185MC attached to the Fujinon fish-eye lens and focused by unscrewing a bit. OK so this is focused on the room and not further away on stars or moon or even distant trees. I may try that tomorrow. I would be quite satisfied with this coverage. This image was obtained using SharpCap on my Win7 laptop. I have yet to check it out with INDI and RPi. I just used the quickest way to check the FOV as I haven't got the RPi wired up ATM.

I think I may try the ASI185MC camera and see what it looks like. The resolution is much less both because the camera pixel size is bigger and in going from mono to colour - but OTOH when I was focussing on the moon the lens only seemed to be able to do around 6 pixels of the ASI178MM when I zoomed right in so I might not be loosing anything. If I ever get around to planetary imaging, the ASI178MM would be better than the ASI185MC. This is an image taken back in June 2015 when I was using the Fujinon zoom lens with ASI185MC. The Fujinon fish-eye lens is vastly superior in light transmission.

Looking through my old files and images from earlier versions of my ASC I have to say I much prefer the colour images. I think the Fujinon fish-eye lens would work well enough with the colour version of the ASI178 but I really can't keep buying cameras and certainly not ATM with a big bill on the horizon for repair of my Rayburn (essential equipment). I have an ASI185MC camera not doing anything at present but the sensor on that doesn't quite get all the sky image in. It's close (but no cigar!) The 178 sensor is 5mm high and the 185 is 4.6mm. Here are the comparisons :- ASI178 ASI185 Resolution 6.4 Mega Pixels 3096*2080 2.3 Mega Pixels 1944*1224 Pixel Size 2.4µm 3.75µm Sensor Size 7.4mm*5mm 7.3mm*4.6mm

Of course it actually goes this way up

A couple of photos of the casing fitted to the ASC insides and aluminium tube that forms the mast.

I'll now crawl back into my shell Or get on with something else...

Received the Pine64 today and looked at it - no USB3 port! Couldn't have checked properly - I blame my cold!! I'll return it, normally no problem with Amazon. A bit later... Applied for return and refund which was successful and now have return label to print - return via Royal Mail postage paid

For focus at infinity the lens to camera distance needs increasing by about 2mm (measured as 1.94mm) so either the lens or camera plus supplied adapter is not complying with the C/CS standard. The C to CS adapter which is 5mm really needs to be about 6.9mm. I've getting round this by using a 3D printed washer between camera casing and T2 to CS adapter to stop the adapter going right in. The thread is about 7mm so there's still 5mm of thread to hold the lens which should be quite adequate. If the lens and camera with adapter complied with standards I would not need to adjust focus it should be correct with the lens simply screwed in! I guess I could measure the back focus of the lens but it isn't easy - could do with an optical bench. The lens has no method of focus adjustment other than unscrewing it. TBH I can hardly believe that either lens or camera would be wrong - it's very puzzling! Had a thought... @ChrisLX200 did you have this problem? Am I right in thinking you have the Fujinon fish eye lens DF1.4HB-L1? EDIT :- Going through my threads I found where you sold me the second of two identical Fujinon fish-eye lenses, Chris, as I thought but my memory plays up at times And yes, you did say you had the focussing problem with this lens.

Here's a couple of photos of the casing. Two parts which fit together to allow access to the "works".

Made a bracket to attach pole to the guttering outside the living room window and tried to get an all round view but with the power wires just hanging, one of them broke. So further sky testing will have to wait for the next clear night sky but meanwhile I have plenty to do on it.

Decided to try changing the USB cable and that fixed it Now have camera out of the window though nearly horizontal. Set up a small area of the sensor to speed up downloading and then adjusted the focus to make the moon as small as possible. The best I could do was about 6-8 pixels wide and it still didn't show the phase - came out round with jagged edges. Maybe still too bright. Here is a screenshot of the KStars FITS Viewer back at full size.

Can't think what the problem can be or how to cure it so I guess that's it for the testing tonight. Probably won't do any more on this project tonight - I'm tired now.

Found the buck converter and everything connected up with standard 13.8v power supply. RPi is working as before but there's a problem - camera isn't working. INDI driver recognises the camera alright but the camera is not showing up in KStars (only the Astroberry Board).

There's a nice clear half moon up there to the south that I can focus on If I can find the buck converter to run the RPi. Otherwise I shall have to wire direct to the RPi and supply it with 5.1v from my bench supply. Doubt I'll be able to capture any stars with the moon out but it will be set by midnight if I can stay up that late

Catenary finished with eyebolt reattached to gable end frame and eyebolt at garage end tightened up. There is a bit of a tangle of cable to be pulled up into the loft - I wasn't able to push it up. Not actually tangled but curled - the cable needs untwisting. Job for another day - that will do for today on that project I think unless I change my mind and decide to go up in the loft and sort it out.

Beautiful sunny day and quite warm so I've taken the opportunity to get on with my outdoor job of fastening my fibre optic cable to the catenary cable Took step ladder out and undid eyebolt from house and started wrapping spiral wrap from the garage end. I have now completed the wrap and taking a break before reattaching the eyebolt and catenary to the house.

Ah yes - I see. Yes, I gather CCD are eminently suited to cooling.

Several years ago I carried out experiments with Canon cameras with APS-C sensors, cooling the sensor to various temperatures and at various gain settings but little improvement was gained in signal to noise performance below 0C and nothing at all below -5C which was disappointing. I don't know what modern DSLR sensors are like or Nikon v Canon, they may be different. One thing I do know is that the sensors used in ZWO cameras do benefit from cooling to -30C so there have been developments in CMOS sensors.

New design and now printing ETA 2:15h. That's ABS with 0.6mm nozzle and layer height of 0.5mm and printing speed of 60mm/s.

That's not big enough either so tomorrow I'll have another go

Not enough room in that one so here's another design This should be the whole middle section housing all the electronics. The dome shaped section holds the stepper motor. There is an opening to take the cable from the driver module to the motor.