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Sunday: For hours I tried repeatedly to get Registax on my PC to open my solar videos from the SSD but it refused. I had to move a video from the SSD to the PC desktop before it finally opened.
The results of my labours were strange indeed! AR2738 had the distinct appearance of having been burnt by a magnifying glass focusing the sun's image on paper. It was still glowing! Very odd! Judge for yourselves:
This the result of running an H-alpha colour video from the ZWO120 through Registax. It looked just like that on the live laptop screen as well.
This the result of running an H-alpha colour video from the ZWO120 through Registax. It looked just like that on the live laptop screen as well.
Today's promised sunshine is a dud. Heavy grey overcast instead of sunny periods. I shall have to get on with mounting the new focuser. I am being driven [all too slowly] by the desire to focus properly and remotely. So I don't have to touch the telescope. At these high magnifying powers the long and heavy telescopes exaggerate their own natural nodding frequency in the wind. Or when excited by a touch of the focuser knob.
I still have new ideas about stiffening up the 20mm thick base fork with another, sturdy, 16mm cross stud. I don't think the pyramidal pier is responsible for image movement. The laptop shelf is mounted directly onto the pier and the image doesn't move when I touch the shelf or the mouse or type on the keyboard.
I brought down the 7" OTA and removed the objective, tailpiece, handles, weight rail and Vixen focuser. Then shortened the main tube by 150mm/ 6". The FTF is about 30mm longer than the Vixen both at minimum length. The turned base ring adds another 20mm. So I added 50mm to the difference. This should allow me to reach focus with the 2" Lacerta prism and binoviewer. It is very easy to add 2" extenders but far more difficult to reach inward focus.
A slight worry is the great difference in weight between the two focusers. Weight at the tail end means moving the OTA up through the rings. There isn't an an awful lot of clearance now. So I'll just have to move the offset weights for the 6" H-alpha 'scope to the top of the 30" long saddle. I already had weights up there but moved them down to the focuser end. This was to balance the added weight of the offset 6" mounted, via tube rings, on the saddle.
After spending so much time on the backplate I changed my mind. I have decided to sandwich the original [saucepan] tailpiece with the focuser collar and base ring. This required I turn a shoulder on the custom base ring. Meanwhile I shall be looking for another saucepan with much less taper.
I put the laminated plywood internal rings back in the lathe and turned the outer surface to better match the saucepan's curve. Then I was able to make use of the original collimation springs in the shorter gap. I reconsidered the sandwich when I realised that I was merely duplicating the FTF rotation system. The custom base ring needs to be firmly anchored to the saucepan base. Then the FTF collar can do its thing. Springs are probably a bad idea with such a heavy focuser on an equatorial mount. It would tend to sag around the optical axis in all positions. So I need to add push screws for locking the collimation as well. All this would be far better done on a straight-sided pan base.
I now have the 7" refractor in pieces just as the sky clears. The Moon is high in the south, the sun has an interesting spot and my new camera is sitting uselessly on my computer desk.
I still have new ideas about stiffening up the 20mm thick base fork with another, sturdy, 16mm cross stud. I don't think the pyramidal pier is responsible for image movement. The laptop shelf is mounted directly onto the pier and the image doesn't move when I touch the shelf or the mouse or type on the keyboard.
I brought down the 7" OTA and removed the objective, tailpiece, handles, weight rail and Vixen focuser. Then shortened the main tube by 150mm/ 6". The FTF is about 30mm longer than the Vixen both at minimum length. The turned base ring adds another 20mm. So I added 50mm to the difference. This should allow me to reach focus with the 2" Lacerta prism and binoviewer. It is very easy to add 2" extenders but far more difficult to reach inward focus.
A slight worry is the great difference in weight between the two focusers. Weight at the tail end means moving the OTA up through the rings. There isn't an an awful lot of clearance now. So I'll just have to move the offset weights for the 6" H-alpha 'scope to the top of the 30" long saddle. I already had weights up there but moved them down to the focuser end. This was to balance the added weight of the offset 6" mounted, via tube rings, on the saddle.After spending so much time on the backplate I changed my mind. I have decided to sandwich the original [saucepan] tailpiece with the focuser collar and base ring. This required I turn a shoulder on the custom base ring. Meanwhile I shall be looking for another saucepan with much less taper.
I put the laminated plywood internal rings back in the lathe and turned the outer surface to better match the saucepan's curve. Then I was able to make use of the original collimation springs in the shorter gap. I reconsidered the sandwich when I realised that I was merely duplicating the FTF rotation system. The custom base ring needs to be firmly anchored to the saucepan base. Then the FTF collar can do its thing. Springs are probably a bad idea with such a heavy focuser on an equatorial mount. It would tend to sag around the optical axis in all positions. So I need to add push screws for locking the collimation as well. All this would be far better done on a straight-sided pan base.
I now have the 7" refractor in pieces just as the sky clears. The Moon is high in the south, the sun has an interesting spot and my new camera is sitting uselessly on my computer desk.
Click on any image for an enlargement.
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