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to set up a 15mm CPL I would need a 43mm secondary with an obstruction close to 21%. we are at one and a half times what I had in mind :D
Unfortunately Atmos I know how to use very little, just enter the data for the newton simulation. I understand what you mean, but keep in mind that I am not looking for the photographic tool for large fields but, given the peculiarity of the mirror, a tool 99% visual and 1% whim shot with asi 120MM or MC. As for the parabolic, I don't think that with a 1.4mm deflection the mirror can be parabolic, but I don't know about mirror processing (even if I have 4 calcium sodium discs 203mm thick 20mm doing nothing that inspire me a lot but I wouldn't know where to start…..)
keep in mind that I would only use it for the planetarium, then ortho con 42-45 degrees of campo.Ora we think about it well.
Andrea
now I have to decide whether in the fully illuminated field to put 0 (visual only) then fitting a 31mm minor axis secondary with a 14,8% (practically a refractor) or whether to do it photographically by putting 6mm with a 36mm secondary and obstruction from 17,3%. In the first case I would do a Dobsonian, in the second I would equip it with a bar and rings.
let's try this way…..eccoilfile
Hello Giulio I simulated the newton Atmos free:
focale 1827mm
diameter 203mm
optical axis + the focal plane is given by the sum of the focuser (105mm) + the radius of the tube that is 250mm (then 125mm) total 230mm
field in bright light 6mm (sensor size of shooting)How can I upload the file?
Completely redone the calculations, tube diameter 250, height 105mm focuser, field in bright light 6mm, result of 35mm minor axis.
hello Giulio,
Unfortunately, the tube is often only 5mm then rinforzerò inside pasting 4 rings (one every 40cm) multilayer thickness 25mm diameter 220mm, so it should not flex. I thought then tighten 2 of these inner rings Vixen the bar so as not to have outer rings. With regard to the calculation of the secondary, I did put 6mm of field in bright light (the diagonal of my shooting Sensor) but that may be my mistake to make calculations, try to enter data with 6mm. The focuser will be a 2 inchhello Giulio,
it is the very particular optical, I thought to realize a square tube in multilayer 6mm until I have not found and received as a gift a cardboard formwork often (those for concrete cast of the columns) long 3 meters with an internal diameter 250mm and thickness 5mm. It weighs 7,8kg then once a measure will weigh on 4,40kg, I thought to stiffen it with glass fiber and polyester resin, according to you could go? Considering that the tube is free (resins part) I thought to try and control the flexure then back to the maximum on the multilayer, definitely more robust. For the focuser I have an old rack and pinion (I love to the detriment of crayford) and the spider autocostruirei sheet metal along with portasecondario. The secondary on balance will be 28mm (minor axis)
