Gina

I've a reasonable head for heights but I don't know about that high step ladder in the dark!! Particularly if there's a breeze!

Magnificent machines Chris!! Wonderful engineering! I can practically feel your loss for your dear friend!! My most sincere condolences for you and your family and Marc's wife and family, of course. <<<HUGS>>>

Cross-posted with James.

Goodness me - that looks to be some serious damage! Hope it's not as bad as it looks. That upside-down apex roof lying on the fence reminds me of when my observatory roof blew off in a storm and landed on the boundary fence. Damage wasn't too bad. The fence suffered more than the roof. Your damage looks a lot worse.

Same here - found both very good to date.

Very sad indeed. The telescope is a grand tribute!

That is so true!!!

I think one way to look at it is that this is an image of the hydrogen nebulosity and therefore the stars are not part of it. The fact that stars emit hydrogen wavelengths is irrelevant.

I'm no longer sure about using the C-Beam and Gantry Plate system in view of the cost mainly though if I decide to change the Z axis on the Concorde I would have most of the parts to transfer from Concorde to Giant. The Concorde printer Z drive system does not appear to be performing as well as I had expected though I'm not sure the rail system is the cause, I have some investigations to do.

Looking now at the angular resolution required to give pixel accuracy :- Pixel size for the ASI1600MM-Cool camera is 3.8µm. Focal length of longest lens I have that I could use in a dual imaging rig is 200mm. By geometry, 1px subtends an angle given by tan(A) = 1px and for these very small angles tan approximates to the angle in radians. So angle in radians = 3.8µm / 200mm = 3.8 / 0.2 x 10^-6 = 19 x 10^-6 A radian = 2 x π degrees so angle in degrees = angle in radians x 2 x π Angular resolution required = 19 x 10^-6 x 2 x π = 119.4 x 10^-6° or 1.194 x 10^-4. Near enough 1 x 10^-4 degrees. Returning now to the resolution we should get with the drive system above :- 3200 x 1408 / 360 µsteps of a standard NEMA17 motor turns the RA axis by one degree. Thus each µstep turns the RA axis by 360 / (3200 x 1480) ≈ 0.8 x 10^-4 degrees. Just about enough though I might prefer to use the 0.9° step size motor and get 0.4 of a pixel resolution.

Largest diameter pulley I can 3D print ATM is 290mm OD though will be more when I have my Giant printer working again if it's accurate enough. For the moment though I'll work with 280mm OD to give some leeway. Looking again at the calculations for the RA drive :- Final drive large pulley = 280mm OD. Final drive small timing pulley will have 20 teeth with a GT2 timing belt. Circumference of large pulley = π x D = 879.64mm Timing belt tooth spacing = 2mm so teeth per 360° = 439.82. Near enough 440. This give a final drive ratio of 440:20 = 22:1 Primary and intermediate reductions will have 120t and 15t timing pulleys giving a reduction ratio of 8:1 each. Overall reduction ratio from motor to RA axis will be 22 x 8 x 8 = 1408. NEMA17 stepper motors have either 200 or 400 full steps per revolution. 16x microstepping can be used giving 3200 or 6400 µsteps/rev. Taking the standard 200steps/rev gives 3200 x 1408 µsteps per 360° = 3200 x 1408 / 360 µsteps per degree Enough brain straining for the moment...

If my astro imaging enthusiasm is still intact in a year or two when I have the second pier/observatory up and running I might consider buying another cooled mono CMOS camera for use with smaller DSOs such as galaxies and MN190 scope but one with a smaller sensor and pixels such as the ASI 183MM-Cool.

Firstly, the widefield rig. I currently have a single imaging rig with 8 position EFW. For a dual imaging rig I could add another camera and lens together with the ZWO EFW Mini 5 position. For use on the EQ8 the two separate imaging rigs can be mounted on an aluminium plate, side by side, with the plate mounted on the dovetail. However, when I have the second pier and miniature observatory done, I shall want something smaller and lighter to use with my DIY mount. For this I could perhaps have a fixed filter for one camera and the EFW Mini for the other. This is shown in my Blog - Widefield Narrowband Dual Imaging Rig. This would cater for my longest focal length pair of lenses of 200mm f4. The advantage of having the second pier etc. is that the EQ8 can be kept for telescopes and save humping heavy scopes or dual scope rigs on and off the EQ8. Anyway, I have always liked the idea of building my own mount and the miniature observatory will make a great 3D printer project.

Meteor showers have always been a disappointment for me too. Think I may have caught the odd one with my all sky camera.

This mount will have remote PA as mentioned elsewhere so I can set up PA from indoors. The mount and imaging rig will be contained in a miniature observatory with no room for anything but the equipment. I haven't finally decided whether this will be dome or clamshell type - it won't be a ROR shed, I'm pretty sure. I think a clamshell would be easiest to implement but that's another project. Altitude PA control can be a NEMA 17 stepper motor with single-start trapezoidal screw as used in 3D printers for the Z drive. A similar system could be used for the azimuth with a lever to translate the linear movement to a small rotation. This is easier than timing belt or gearing for the very small angle required for PA adjustment. I already have the design for the RA axis drive using multiple timing belts and pulleys running off a NEMA17 stepper motor and will look at a similar system for DEC having rejected the tiny 28BYJ-48 stepper motor. Having designed a complete precision 3D printer in CAD this will be the next complicated thing to design, I think. I don't think imaging rigs will need this level of intricacy apart from the design of brackets and focus gears etc.

That's an interesting idea but tricky for a dual imaging rig. I think I'll stick with a standard design fork mount but I don't think I shall use a 28BYJ-48 stepper motor for the DEC drive as they are very fragile. Alright for the light-weight job of focussing but ...

Could be but the roof was dry. Anyway, not enough to worry about. Considering the horizontal heavy rain lately it's surprising the inside is so dry!

Since it's on top of a rubber mat I assume it must be wet coming down.

I found a damp patch on the floor of my scope room when I went out to open up this afternoon - no sign of anywhere there was wet coming in though.

Boot/shoe polish certainly works - used it myself,

I have Muck boots for outside work in winter - excellent. Not just for winter either actually. Very hard wearing and long lasting.

Last time I saw Mars it was orange.

Mine are mainly hazel too.

The colour receptors in the eyes (cones) are less sensitive than the mono ones (rods) and only the rods are used in very dim light. That's why moonlit scenes look black and white. It therefore seems irrelevant which colour of light is used - only the intensity. For seeing charts either weak white light or green light would seem best. This is from the scientific POV - since I don't observe I have no practical experience.

I've struggled with ASCOM in the past! Getting everything working together was a headache. Good luck Dave. Of course, things may have improved since then. Should be plenty of people who can help though. ASCOM is an open source thing so plenty of support. Developing any system to a set of specifications is complicated. I've worked with many such systems. You need to be a programmer!