My first light a disapointment

[Gemini2544]

Last night with a crystal clear night I took my new 8" reflector outside for first light. Well the collimation was so bad the stars looked like the uniform badges in Star Trek.

I discovered the main mirror was way off and levelled it via the adjustment screws by eye & played around with the prism a bit too. I have managed to improve the image by about 80% but still can't nail that last 20%

Any ideas guys? :shrug: or is someone with more experience in the area of Marnoo able to help. :thanx:

[mental4astro]

Do you have an old photo film canister around? If so you can make a make shift cheshire collimating eyepiece. Let me know if you do and I'll chase down the instructions and post them and how to use the film canister.

[Gemini2544]

Hi Alex yes I do, Ones on my desk with loose screws in it.

Thank for the help.

[mental4astro]

This will only get you to about 90% collimated until you get a proper collimation EP. Take your time, it's a little tricky but not difficult. You will make something resembling the 'Anatomy' diagram.

You will need some fine wire, masking tape, and be able to make a tiny hole in the canister's base, and piece of aluminium foil jammed into the canister set roughly at 45deg, and a torch.

*Make a tiny hole, about 2 or 3mm diameter in the base of the canister.

*cut out an opening in the side of the canister near the base about 2/3 the diameter of the canister

*Pack the foil into the canister and set to the rough 45deg to the big opening so that light shone into the canister via the large hole will reflect out the main opening.

*Pierce the foil so that you can see the cross hairs through the tiny hole in the base.

*Make a set of cross-hairs with the fine wire across the opening of the canister and fix with the tape. The tape will also add some resistance to the cylinder. You may need to trim off the lip of the opening as this end needs to be fit into the focuser (1.25")

*Fit the canister into the focuser upto the but not covering the hole in the side and have a look into the hole.

*Check that the secondary is properly centered in relation to the "eyepiece". The spot on the primary should intersect with the eyepiece cross-hairs, figs 2 & 3.

*Shine a torch into the side hole. The idea here is that the cross hairs will be sillueted against the foil, making them visible in the primary. As long as you can see them it's OK. This is called the Annulus.

*With the secondary properly centered, now adjust the primary until the Annulus is centered with the cross-hairs fig. 4.

Good luck.

[dannat]

if you want to avoid the film cannister i removed the glass elements from a totally useless 4mm ep i got with a scope..works very well

[Gemini2544]

Thanks Alex for the info, I had a go at it yesterday before dark & had slightly better results. The view is sort of good with the 30mm EP but go to a 10 or 15mm EP and the stars look like a mercede benz symbol minus the circle. I also looked at Jupiter with the 30mm EP and due to the brightness Jupiter was distorted.

All in all it's a learning curve & it's slowly getting better. I feel like a kid with a new musical instrument that's out of tune & I can't play it anyway. :confused2:

What I need is a Iceinspace member that live in either Stawell, Horsham, Donald or St Aruand area where I can fix this myself with someone looking over my shoulder, A big ask I'm sure.

[Gemini2544]

Just an update on this thead, I can't get the collimation good enough so I bought a laser collimator from the UK that has a alignment target in the 45 deg reflector part of the collimator. I'll let you all know how well it worked once I've got it.
Cheers