Peter Drew

A standard 2x Barlow will permit focussing with a binoviewer but will create a higher magnification than a glasspath component. You could try fitting just the lens cell of the Barlow to the nose piece of the binoviewer, if this comes to a focus the magnification increase will be reduced. 🙂

That's interesting. I wasn't sure as to who currently owned Meade so I did a search on the internet and it came up with "Meade and Celestron are both owned by Synta. 🙂

Quite likely, but keys can snap from poor tempering, too hard and they can become brittle. 🙂

Meade are owned by Synta and most likely don't make the telescope, just rebrand it. 🙂

Good luck with trying to drill into the end of an at least reasonably hardened 1.5mm Allen key. The face may be sloping and no easy way to produce a centre punch spot. Could end up with a broken drill bit sharing the space with the key. 😧

They are most likely M3 or M4 thread size. Cap head screws have a knurled head which makes them a suitable replacement. Should be available on line or a hardware shop. 🙂

Strong magnet? 🙂

Change of focus or shapes across the field of an image is usually the result of tilt either in the optics of the telescope or any supplementary optical components including the camera. My money is still on tilt somewhere in the system. 🙂

The mirror will have enhanced coatings so a recoat (Hilux?) would need to be of a similar standard to retain the performance. I would have thought that slightly less than the going rate for a 9.25" of that vintage as well as less the cost of a recoat might tempt a purchaser, specially as the issue will have little affect on the performance. 🙂

It looks like a tilt issue to me. One degree tilt could be enough to spoil a fast refractor image, specially one with a complex lens system. 🙂

The lens cells might well be interchangeable but as mentioned, you would need to shorten the Helios tube by around 400mm. Also, what is the problem with the Helios lens? 🙂

I think spherical mirrors, as an optical shape are too easily dismissed. If not for the fact that a sphere, on a Foucault test presents a null result to a knife edge rather than the harder to judge parabolic shadows, it would be almost as difficult to produce a high quality sphere. At a suitable focal ratio, I'd sooner have an excellent spherical mirror than a poor parabolic one. 🙂

Sounds to me to be a power issue, something to check first. Welcome to SGL. 🙂

I would second Alex's suggestion, an alternative possibility would be to utilise a screw on the backplate to hold a bracket mounted focusing motor that could be coupled to the micrometer barrel with a drive belt. 🙂

There are few "bad" telescopes these days but unfortunately many bad mounts. There is little difference between a bad telescope on a good mount or a good telescope on a bad mount. A StarTravel 80 on an AZ3 mount would be a good compromise and an upgrade from your current telescope. Welcome to SGL. 🙂

I think that was known as the "lensless Schmidt", described in detail in an issue of Sky & Telescope many years ago. 🙂

True, but poor collimation will make matters worse. 🙂

A "fixed" collimation Newtonian like the Heritage 76 theoretically shouldn't need subsequent collimation. However, at F4, if the factory setting is not very close to perfect, images will suffer at higher powers. There are three screws securing the end unit that contains the primary mirror, if the unit is removed and the three clearance holes are slightly slotted then the complete unit can be carefully adjusted by hand and then the screws tightened in place. I fine tuned a Heritage 114mm to good effect by doing this. 🙂

Don't forget that the OP is located in India which makes some of the advice challenging. 🙂

First for me as well. Took advantage of a rare sunny morning to have a look in Ha with my 150mm. Good variety of details, a hedgerow prominence, thin detached pillar, extensive filaprom, active areas around the sunspot groups and a good selection of filaments. Seeing was surprisingly good considering the seasonal low altitude. Excellent start to the year. 😀

There are times when only the best will do. 🙂

Just got in from viewing the Uranus occultation, previous cloudy sky cleared just in time. Only scope available at home was my Meade 90mm Maksutov on an AZ3 mount using a Baader zoom giving 150x. Seeing very good but Uranus quite faint and would be difficult to see emerging from the bright limb. First successful observation in 2023. 🙂

I believe it is glued on. With other mounts that have glued on covers it usually helps to warm them with a hair dryer before prising them off, so worth a try. 🙂

Baader film for me, you can use an orange filter if you want a coloured Sun. 🙂

Whatever you get, make sure it has motion controls, push-pulling for solar is a pain. 🙂