Stub Mandrel

Thanks, I'll take a look at this! Neil

These could become collectors items...

New focuser: None More Black: New Decal:

"It is solvent free and bonds to timber, concrete, brick, glass, plaster etc." The ingredients are the same silanes as used in other silicone adhesives. It's more expensive than aquarium silicone - and it comes in a smaller tube! What I like is that this is specifically a flexible adhesive, aquarium silicone may not be as rubbery. The 19mm MDF of the cell had spilt horizontally where the screws go in, probably because the screws were fitted with too-small pilot holes. I filled the cracks with aliphatic adhesive under pressure (Super Phatic - I once repaired a plate with it and it survived a year of use including going through the dishwasher). To ensure no further split risk I have drilled out 6.5 mm holes, then cross drill 10mm for the same sort of 'barrel nuts' used to assemble MDF and chipboard kitchen furniture. These will hugely reduce the stress on the MDF. Oddly, the three fixing holes in the tube were very poorly positioned so fitting the cell was distorting it quite noticeable. This was probably why the original focuser had a tick washer under one corner... Some simple maths and three equi-spaced holes and the mirror cell now sits centrally. I was advised to move the mirror up by an inch to allow use of a filter wheel. I've achieved the same effect by moving the new focuser down a bit, also I have a low-profile 2" to 1" adaptor so I should have no focus problems.

Thanks Nigel, That's how I'd expected to do it - I removed the mirror with a guitar string to cut the blobs, and I was planning to use spacers as you suggest. Your priming idea is good, especially as this will key into the surface. The Evo Stick mirror adhesive is silicon based and is permanently elastic as well as having high adhesive strength so it should work at least as well as ordinary silicone adhesive. You can use it to fix mirrors to ceilings if you are so inclined (sic). www.farnell.com/datasheets/1489819.pdf https://www.anglo-adhesives.co.uk/wp-content/uploads/2018/.../mirror_adhesive.pdf

Yes, but I appreciate that they range me up to explain the situation. The mirror was held in place (on the MDF cell) by three generous blobs of silicon. I've sanded down to remove every trace of the silicon. I've bought a tube of Evo Stik mirror adhesive, is this the best thing for fixing it in place?

How do you think I feel? Apparently it has a few percent of 'dull' spots where the old coating wouldn't come off. He said 'they may bond to the new coating in time and come off when it's next recoated, or they may be poor patches on the glass'.

A reminder, the mirror before recoating:

Well said. I will say the one thing that would make it more useful and that no other apps appear to do: a graph showing the relative sky darkness at 15-minute intervals, if you could add an estimate of your local light pollution level it would show the point when your skies are unlikely to improve further.

I have a flu jab ?

Very pretty, although I read Zeiss Tormentor the first time round! Mars is nice this evening, hopefully I have some decent images coming...

My mirror has been done. Unfortunately the main mirror wouldn't strip completely with a few bad patches, and the edges of the secondary were similar. The coaters say this is unlikely to be enough to have any observable effect, but I suppose bit disappointing. Understandable given the state of the mirrors as received I suppose - the primary looked like a map of Mars - without the dust storm. It must be better than it was and it gave me impressive views on first try ? Should be with me in a few days.

I hate to say this but... it doesn't do very much does it? I get the same from Clear Outside app and that tells me the weather as well.

When I got hold of an ED 66 lens cell, I realised it would need a field flattener. It took me a lot of digging before I found some posts here that suggested the OVL flattener would work. The ED66 is f6.06 and the OVL flattener is for f5-f6 'or telescopes just outside this range'. It does not change the focal length, which mattered to me as I specifically wanted a 400mm set up as I already had a 400mm tele lens and find this this suits lots of targets really well used with an APS-C sensor. I'm posting this so if anyone else fancies using the Equinox ED66 for astrophotography, they can know the OVL flattener does work. Initially I had bad stars in the corners with the appearance of coma. I added a 1mm spacer between the flattener and the canon t-mount adaptor and although DDC inspector said there was curvature present, it was reduced to the point where it's very hard to see in the image. I will experiment with a slightly thicker spacer, but for the record: The OVL flattener does correct the ED66 right across the field. You may need to increase the spacing to get better results and a very small change (about 2%) in spacing can make a dramatic difference. I got my flattener from @FLO https://www.firstlightoptics.com/reducersflatteners/ovl-field-flattener.html

Looks like a spacer has made a big difference. Before: After: Although the difference looks modest the difference in the appearance of stars is huge with the 1mm spacer. I will try adding another 0.5mm next time.

Thanks, a generous offer! 42mm - but to be honest I have a well-equipped workshop so once I have the right spacing I can make my own permanent one. Save your spares for someone not able to do so. This is my latest - still off-centre, but stretched in all four corners. P.S. - I've just checked a Ha sub of the veil and it appears that the corner most affected in previous images is OK with a printed 1mm spacer, but of course the camera is not in the same orientation, so we will see...

Helps me. For my second session I took care to make sure I eliminated tilt as far as possible. The effect is now less marked, but is like your image 1 - too close. Better than too far! I will 3D print a 1mm thick spacer for between the flattener and the T-mount adaptor and try again. Let's hope it doesn't take too many tries.

Which one did you go for?

I can't say I've ever had problems holding my 450D (with built on cooler) on the stock 130P-DS focuser and CCD inspector says my tilt is 0.1 arc-seconds.

I bet none of them have plastic lenses though ?

Here we go, some high-density foam arrived today. I filed a sharp end on the aluminium tube from a defunct pop-up display and spent ten minutes cutting out holes. They are a nice tight fit! Only thing missing from here is my cheap Bresser diagonal and a barlow. Despite the impressive number of things (where did they all come from) I'm confident the total cost was considerably less (~£130 spent, not including the four that came with scopes) than most of you folks have spent on a single EP! Skywatcher UWA Planetary 2.5mm, 5mm (via SGL classifieds, only used briefly - too strong for the small scope I tried them with, meant for my bigger scopes) Series 500 4mm Plossl (awful, from ebay) Skywatcher Super 10mm, Super25 long eye relief (the standard Skywatcher pair, came with my 150PL, both work fine) Circle-T 18mm Orthoscopic (came with my 10" Dob) Datyson 8-24 Zoom (possibly one of the many clones, a bit rattly, not tried out yet) Opticstar 25mm Plossl (dead cheap, bought for a guidescope and fitted with cross hairs. Give worryingly good views...) Celestron 32mm Plossl (came with C90 Mak, very comfortable to use and shows zillions of stars) Svbony 40mm Plossl (Another ebay cheapy, but very pleasant to look through). Celestron amici prism diagonal (to turn C90 into a spotting scope but I like the very natural views of the moon etc.) Datyson x5 barlow (not had much joy with this, very hard to get focus). Revelation Astro x3 ED barlow (spanking results used for planets in the dob). Even I am too proud to stick cheap Huygenian EPs etc. in there! One plan is to make a few EPs from odd lenses I have around. First attempts worked OK, but I want to make a better job of them.

I had a close look in daylight, and tightening one screw forces the flattener out of alignment by about a millimetre. I will sort the new adaptor this evening and try with that first. Another option is an adaptor screwed on both sides so the flattener screws direct to the focus tube, guaranteeing alignment.

Dremel printers. Not cheap, but aimed at schools, but PLA only, custom spools and no heated bed. But excellent results out of the box with broken filament recovery.

No, the ED66. The field flattener seems to a have a wide full diameter section before the taper section, and the fixing screws seem to line up with the 'step'. I suspect this is tilting the camera and field flattener. This is one from the 130P-DS. I assume this isn't perfect but is far better than the other one, and suggests my camera itself (same one for both images) has no major issues?:

Sorry to gatecrash, can anyone help me interpret this - it looks bad!