Peter Drew

I think you will find that once the objectives have been removed the problem will prove to be between the two optical components. These will most likely be cemented, if so, separating them and re-cementing them raises the difficulty of a repair considerably. 😟

A degree of your problem could be due to the eyepieces. TV eyepieces are probably better corrected than the ES equivalents, specially if the ES's are wider field than the TV's. The Paracorr is also optimised for TV eyepieces, particularly the wide field ones. 🙂

I'm in the loathe camp! 😡

I would try the unit out first before considering whether it would be worth replacing the scratched dome. Polishing out a scratch would require quite a bit of material loss in the area and would likely introduce optical distortions. 🙂

I have a number of zoom eyepieces ranging from cheap to very expensive. The best cheapest version I have is the Seben 8mm-24mm. Avoid the cheaper Seben 7mm-21mm unit, very poor by comparison. 🙂

Four wheels and a horse for dark sky trips? 🙂

I think you are now on the right track. The good news is that it can eventually be sorted out by patient adjustment. Nothing is broken! 🙂

Oh dear, that looks about as far out as it gets!, some further attention is needed. The focuser tube also looks to be encroaching on the light path if the view is in focus at that setting. I wold start from scratch by fixing crosshairs of white cotton accurately across the tube opening then stand back and see if their reflection overlaps, when it does you can be sure that the mirror is reflecting centrally up the tube. Next, look through the empty focuser and adjust the secondary until you can see the image of the primary mirror central in the secondary mirror. The result of this won't be perfect but it will be a lot closer than you show, it will be a better base to do more precise adjustment. Good luck! 🙂

My experience has been that larger blocking filters only enlarge the field of view, they don't increase the "sweet spot" of good Ha on band performance, this is determined by etalon diameter and focal length of the telescope. I have 5mm, 10mm and two 15mm blocking filters, the 5mm gives the best image in conjunction with a 2x Barlow and binoviewers at a minimum magnification of 150x on my 150mm solar refractor. 🙂

@ S & S. All my EAA work was with video captured on VHS yet the results were just as good as computer based imaging albeit in monochrome which I actually prefer. I went through an ever upgrading sequence finally settling on the Watec 120n+. This was a highly sensitive camera with theoretically infinite integration, realistically limited by mount and setup accuracy. One minute exposure with a 5" refractor showed the "Pillars of Creation". I believe that this camera has now been superseded by the 910HX, however this camera has on screen display for functions, a system I dislike. 😀

I have a 30" Dob and EAA equipment (not intensifier tube type). Used in conjunction with a 12" SCT at F3.3 it easily outperforms the 30" used visually on DSO's. We have a 42" pre- generated ceramic blank, that cost nearly 5K several years ago!

These were also my thoughts but not as brave as Geoff to post them! 😀

I think the difference in finish would eliminate this one as a suspect. Good price for a Clarkson though. 🙂

Even less chances of actually seeing it! 😥

I'm not happy with the original suggestions for the 8" CC not operating at full aperture. If a 8" CC has an 8" mirror it will operate at full aperture provided that the secondary is the correct size. Where the effective aperture comes into question is when the loss due to secondary obstruction and/or reflectivity is taken into account, both apparently minimal in this case. The diagrammatic explanation also puzzles me as for the two different focal lengths the convex secondary would not occupy the same place in the light path, as far as I can see the diagram would indicate a plane secondary.

You can always smear some Marmite on them if they're too sweet for you Olly. 😃

You've not seen me with my make-up on Mike. 😍

I have 4 of these, two each as two binoscopes. I have been very pleased with the performance. 😀

I live in Bacup. Says it all really!. 👀

I would have reservations about an "elbow" pier, even when fairly massive, ones that I have seen "ring" at the slightest touch. The very large stock one made for the Meade 16" SCT was particularly poor in this respect, too much weight hanging off axis. 🙂

The complete front cell and corrector unscrew. At a pinch, you can carefully warm the secondary baffle with a hairdryer and when the glue softens slightly you can carefully slide the baffle back to its correct position. I've had to do this on the Meade 7" Maksutov. 🙂

And yet, beginners still seem to be keen to get into imaging! 😀

I would also post this on CN, there is an active antique section on there and I doubt thieves would chance offering the telescope on a UK site any time soon.

I think Venus is brighter when in the crescent phase because the planet is nearer then and giving a larger image with more apparent surface area. 🙂

Gutted to hear of this, I know more than most how this feels having had a large number of telescopes stolen some years ago. Happy as others to keep an eye out but several of mine were unique and none ever appeared for sale. ☹️