Peter Drew

It's an Astrosystems (Luton) 8.5"(?) Newttonian circa late 70's. It will have David Hinds optics of premium quality. 🙂

I would expect that the flange unit will be a decent fit to the main tube once the sawn off material is removed. If the flange is to be glued back on you can adjust the squareness by placing a well collimated laser unit into the eyepiece holder and making sure that the beam exits through the centre of the objective. Don't use superglue or any other instant variety! 🙂

If it was my telescope I would cut it off. You would only lose a few millimetres of tube length. You could then be more aggressive with removal of the remaining material. 🙂

I'm beginning to think that I should have bought up a number of disposable barbeque kits whilst they were going cheap. 🙂

Bear in mind that a white dome will reflect solar heating better than a green one, although green might well be a personal or environmental consideration. 🙂

I purchased two of the Celestron 70mm StarSense Explorer telescopes to cannibalise the push to units. The telescopes, including the cheap looking diagonal and eyepieces were surprisingly good. It's just a pity that at the price point, a better mount can't be provided to a similar performance, it makes the operation of the whole package difficult for a beginner to realise the potential. ☹️

Welcome back Ron.

I think it is just attention grabbing, as it says, "price to be determined." 🤔

Unfortunate but maybe not as bad as it looks. The optical power of the corrector is quite weak, just enough to balance the aberration of the primary mirror, as long as it is intact it may still function properly, give it a try. The retaining ring screws should be turned until they stop, no further pressure. If the telescope still works ok you might want to black out the crack. Check the tightness of the retaining ring and back it off if necessary, if too tight it might propagate the crack further.

No mirror clips on my 30" mirror either. It has a 3" central hole that sits on a 3" boss, a front cover plate sandwiching a rubber O ring prevents it from falling off. No mirror clips on SCT's or Maks for similar reasons. 🙂

This is exactly what keeps me motivated to do outreach during the last 40 years. 🙂

And they were all flying from Denmark to the UK as we had similar conditions. 🙂

I don't think that anything of this nature is impossible, but it takes time. Technology is quickly catching up with traditional skills and automation will produce reliable repeatability. Hopefully providing top quality at lower prices. 🙂

What I was alluding to was the complexity of the high end wide field eyepieces. Some have up to 8 lenses, several of which have different optical signs or meniscus in profile. All have to be good optically, correctly centered and spaced and not least of all each surface multicoated for maximum transmission. To do all this to the expected high standard is not cheap. 🙂

Anyone querying the cost of a top of the range ultra wide eyepiece should take one apart before posting. 🙂

Hello Bb, welcome to SGL. What power source are you using, batteries or poor connections can cause havoc with an 8se. 🙂

Some good suggestions so far that should prove successful. If in doubt about the ability to do this I would advise leaving well alone if the OTA is otherwise working well. Removing the optics, necessary for panel beating could lead to protracted efforts to replace them and perform the collimation. If it was my OTA, because I can and have some experience in these matters and not least have the facilities, I would cut two wooden formers, a convex and a concave of the correct radius, support the OTA on the concave former and then tap the inner convex former until the dent was removed. Good luck. 🙂

I have a 19mm and 7mm Luminos eyepiece. They work well enough in a 16" SCT and a 20" F3.5 Dob with a Parrcorr. Certainly heavy! Wide angle eyepieces, particularly 2" fit versions need to have large bodies to house the large lenses to give the wide field of view. 🙂

I have only a standard DSLR lens, a mosaic would look suspicious. 🙂

I know this thread is not a competition but FYI I must have at least 100 eyepieces, mostly 2nd hand or donated. Mostly low to mid range, notables are a 16mm Clave Plossl, TV 3-6mm zoom, Leica zoom and 42mmLV. Also have some antique brass RAS thread orthos, Tolles and Monocentric versions. 🙂

If your version has a tripod attachment facility you could screw on a dovetail rail and then fit it to a SLT goto mount or similar. 🙂

Planetary imaging is enhanced by aperture so the larger Skymax instrument would be better. Either would do well on a HEQ5. 🙂

This version was an attempt to provide a factory set collimation with no need for the entry level beginners to alter the settings. The David Hinds primary mirrors had their backs ground flat parallel to the optical surface so no wedge to correct for. The secondary, as mentioned, could be adjusted up and down and for rotation. The tilt of the secondary could be adjusted by loosening the screws holding the secondary support and using the clearance holes to move it as necessary. Once done it should remain set almost indefinitely. I have one which must be pushing 40 years old now and still in good collimation. The David Hinds aluminising is still good as well. HTH. 🙂

The images and animations that I've seen so far really don't do the event justice, either too fast or too small scale. I was using a 150mm Ha telescope at 150x and viewed the activity for an hour. The main object was like a thermo-nuclear fireball and the elongation from the solar limb was approaching a solar radius before fading. I was very fortunate to witness this event. 🙂

If it's any consolation I have two 16" SCT's, some nights they are fit for the bin, on others they can give awesome views. Too early to panic, large SCT's take a while to tame. 🙂