happy-kat

SketchUp is alright on the tablet I just have to occasionally rotate the tablet to get to the button I want, mainly the one to select the template to use at the beginning. I didn't like 123D it worked but didn't rate it as good as SketchUp. I've changed my design since I started this project but all is good now is the best time to make design changes.

SketchUp does not look like it like my 10 inch tablet so now downloading 123D from AutoDESK to see if that is happy to run on the tablet it didn't like XP either much like SketchUp.

The good news is out might be human error, hope so. Took the diagonal out and just used the 25mm eyepiece, nice round light circle on the test card. Re attached with the diagonal and adjusted how it sat and the shape improved, not perfect but better. This gives me confidence that a pepper center square back will be fine. I shall carry on with the current endeavor can I make it focus close then 30 feet away depending on position of the diagonal.

Thank you for testing. Mine has always been very hard to use so feel fairly confident it was always there as eye position has always been very hard. The cardboard is for testing. I will design a back and get it 3d printed that is the plan. Unless you intend to remove the prisim you won't need an adaptor.

Finder bracket, nice idea, I'll probably add a red dot though I think mine will get more day time use. That looks neat how you mounted that bracket. The mak looks the same. When I can get a single bright object in view then either side of focus it is still round not that I see all of it. Confusing... Could you test please the shape you get through your one I used a 25mm and a 16mm both have the fan and not a circle.

I have always found putting my eye in exactly the right place very annoying. Tonight I thought I would do an exit pupil test. Looks like there is a problem that is a fan shape. Colimating the heritage is easy compared to what I think this might be! I am still going ahead with the changes as I believe this issue has been here from day one. Before I twiddle the screws can anybody confirm please if a fan shape is normal for a Mak?

Just had a test, can focus on the stars and there is loads of focus travel left so I am reducing the number of card board rings and going to test again with the hope I can then focus on the bird feeders which are quite close in the garden. Though I have assumed to shorten might find out it was the other way!

Initial test shows that the optics all line up as I could see my vegetable bed some 20 feet away but as expected far too close to reach optimun focus

There are 6 collimation screws on the back of the C70 in three pairs of two.

Removed the inbuilt prisim held on with three small screws. Made a cardboard test of the back so that I can test if focus is still possible on distant objects. The cardboard is holding the 1.25 eyepiece adaptor.

The rear element was held on by two small alen keys. There is a lens in the rear element as well as the prisim in the back of the C70. I am very hopeful that removing all this lens stuff and replacing with a more typical diagonal will improve the view. Next job is remove that prisim it is held with a couple screws. Then I hope to fashion a cardboard back for my diagonal and an eyepiece to test focus.

Took the rubber sleeve off today it is quite thick. The tube is plastic. The rear prism looks to be two torx head screws holding it on. A crude measurement does look promising that a diagonal will be in the same place for presenting the eyepiece.

Seeing as maks have to cool down for optimum use does make me question the thick insulating rubber sleeve!

So whilst the American version (or perhaps a year or two older model) sports a metal body under the rubber mine is plastic. Made a start today to understand how the C70 is covered. It is a rubber sleeve which is in two parts, the orange metal band covers the join. The sleeve has been stuck with a very hard dried glue down the centre seam. This could proove very hard to break the glued seal. Have been trying to pry the rubber sleeve with a plastic splodger seeing as the tube is actually plastic I don't want to use a metal splodger. One side has much less glue and lifted with a bit of a fight but did lift. The other side has a wider glued area (about 1cm) and it does not want to bodge. The plastic body fels quite strong it does not buckle. The length of my diagonal looks to be the same as the inbuild affair so I am not too concerned about focusing once the changes are done. Due to finding a plastic body I may have to rethink the end design but I will decide once it is all exposed.

Thank you for replying. The c70 is not a mak like it's big brothers and the rear end does not have the expected arrangement. The c70 has after the back plate an inbuilt correct image 45 degree prism. My plan is to remove the inbuilt prism and replace with a diagonal of my choice. The c70 comes with the ability to use 1.25 eyepieces and I hope to use the adaptor fixed to a new piece of rear plate. There should be enough focus travel as I an swapping an inbuilt item to a separate item. The c70 lives is a moulded rubber sleeve that incorporates the prism I am just striping it back to reveal the mak. I will add photos as I go which should explain things.

My winter project (well one of them) is to modify my Celstron c70 so that it loses the inbuilt 45 degree erecting prisim thing and I replace the back of it with a new flat plate and directly mount the 1.25 eyepeice adatpor to it. I have seen this done on a archived for sale thread on another forum. I have a friend who can make me the flat back plate but can't do the cutting a thread to make a male fixing for the adaptor. Are there any ideas on how I could get the right thread cut please so that I can screw the adaptor in? This is the 1.25 adaptor showing the female thread. (the adaptor is upside down) Very crudley the back plate would be round with a hole in it. The side view idea is if I made a raised area, could I then afterwards get a thread cut into it?