Stub Mandrel

Check it isn't just the worm set too tight. I over-adjusted my backlash and caused exactly those symptoms - but only with the extra weight of the scope on the mount (I assume that the scope is balanced).

Original spider. The paint from The Range, but B&Q etc. sell similar.

I've got the original Dark Star base, just replaced the bottom panel of the top part, if that makes sense. I need to get some 'whole thing' photos. Here's a few mods, a decal to make it pretty, heatproof black paint and an Orion double speed crayford focuser: You can see how black this is by how over-exposed the background is! Heatproof paint, which apparently absorbs IR as well as visible light. Problem with the new focuser is I feel the need to buy a small mirror set to use the old one :-0 P.S. that's my workshop, not my living room...

Tosh! I've been enjoying hearing about yours and @Tonyhaz's scopes. Dark Star Owners of the world unite!

No worries; although I haven't taken any qualifying images I started out with an unguided EQ3 mount and this thread was biog inspiration for what could be achieved with short exposures.

Most images on this thread are with Alt-Az tracking mounts. They can go up to about 30 seconds before field rotation becomes an issue.

It sounds like replacing the thin twist of wire stopping my secondary dropping with a thick clip was a very good idea!

I've seen a magnetic toolrack fitted to a dob allowing weights to be easily positioned, as a set of 3 from toolstation is a tenner (the cheaper screwfix one has bad reviews) taht will happen. Telrad sounds good. With a possible laser pointed and dovetails for two different finderscopes I shoudl be able to find anything (not!)

I've had a sneaky first light: Not much achieved beyond showing my collimation is passable and the focus range is right! As soon as I got anything in view a cloud popped up. I've since added a synta finder shoe. I also need to think about counterweights.

I had to fit a new board to the replace the rotten one at the bottom of the base. I used a surplus cupboard door and replaced the three tiny teflon squares with 25mm teflon furniture gliders.

If you have photoshop the 'gradient exterminator' plugin is excellent for getting rid of any residual vignetting or light pollution gradients, but it has a second trick up it's sleeve. You select all the bright areas such as the clusters or any patches of nebulosity and then invert the selection. If you have 'balance background' as well as a selection for getting rid of gradients, it will fix that sort of colour cast in one step. I've found it worth running it even when there isn't a visible gradient.

A mixture of apathy and apprehension...

I left the mirror in place for two days before removing the spacers and three days before moving it (call me paranoid...) but the scope is now all in one piece. The marks on the mirror, on close inspection, are wiggly knots of lines, so I am pretty sure it is the equivalent of 'lens fungus' etched into the glass. I hope they will prove cosmetic. Instead of moving the mirror up, as suggested, I moved the focuser down by about 3/4" (it needed a much bigger hole so I just placed the top of the new hole at the top of the old one. This meant I needed a new 'stalk' for the secondary. I replaced the rusty 1/4" one with a stainless steel 6mm one which fits fine and secures with the existing brass screw. I made a much more robust steel clip to replace the twist of wire as the safety mechanism to stop a loose secondary dropping on the primary. Looking though my makeshift cheshire (film canister with a hole in it) the secondary almost perfectly matches the mirror. I haven't collimated yet. If it is clear later I will do this on the base, using the laser and follow up with a star test.

Are you sure there is a scope under all that?

Nice one, you can see M32 clearly and hints of M110. You can get away with stretching that more aggressively and pull out more galaxy, as it isn't very noisy.

? I doubt there's any of mainland UK with the nearest city of 250,000 people 80 miles away outside the north-west coast of Scotland.

The downside is you now feel obliged to have eyepiece container cases to keep the 'vaults' pristine...

If I saw that one evening, I'd be looking for large circular burn marks on the lawn and counting my kidneys the next morning.

I'm using an Equinox ED 66 lens. these are crops from the top corners using the OVL flattener without and then with a 1mm spacer, I think I need another 0.5mm (the Ha at bottom is in super pixel mode so they cover the same amount of sensor, more or less):

I've got an OVL flattener. At 55mm it was pretty bad, at 56mm I can barely see anything although CCD inspector said there was still about 1/3 of the curvature at 55mm. But the OVL flattenr is meant for f5 to f6 I'm working with an f6 scope isn't the ED72 an f7.5 scope? The lesson has to be experiment with thin spacers!

I'm about to print a Mk VIII airsoft gun magazine adaptor. Versions II to VII and this one have all been in PETG and take about 4 1/2 hours to print at ~60g a time. The last one was perfect but I had moved a clip to incerase the pressure and when I did so this I thickened it by about 40%. This made it too stiff and it snapped off ? Thoroughly fed up of printing these now! I shoudl have done each test in PLA and just used PETG for the final one. At least I have improved my PETG prints to the point where they are as good as my PLA aside from the odd blemish.

A box! For what lies within....

Mirrors have arrived! Secondary looks OK despite an attempted labrador attack! Primary, better than I expected but I can see one large mark south of centre and a few smaller blemishes. This must be compared to the 'before' image!

Interesting... with an ED 66 and a field flattener I needed a similar size spacer for my Canon 450D which is nominally 55mm spacing. I see you also have an astro modified Canon. I would have expected removing the blocking filter to increase the effective optical path by about 1mm, but perhaps it increases it for flatteners and reducers for some reason?