Peter Drew

Congratulations John, you are one of a select few whose posts I always read regardless of the topic.

I get the feeling that the mass of a 2" version of a wedge might handle the heat issue more comfortably. What intrigues me more is the obsession with the care taken to ensure thermal equilibrium of optics for night time use versus the full heat of the Sun being introduced into the OTA when a wedge is in use yet the instrument still being capable of sub arcsecond resolution on a good day . 🤔

I've used my 1.25" Lunt wedge and a 1.25" Lacerta wedge on a 8.5" refractor without problems. A 2" wedge would be better, the Lacerta is about the size of a 2". 🙂

This is the problem with entry level equipment, even at these prices! There is a manufacturing tolerance which results in a variable example lottery. The PST etalon used in my 150mm Ha telescope was the best one out of a dozen or so. A friend once brought along a 60mm model which proved to be unexceptional, when fitted with a double stack unit, for someone noted for his low key persona, the outburst of expletives on looking through it said it all. 🙂

Users of single stack units will probably have noticed the significant enhancement of solar disc contrast which occurs when thin cloud passes over the image. This is very similar to the effect of double stacking in appearance. Pity it's so expensive to achieve properly. 🙂

Sad as it is for science, spare a thought for the local community for which the telescope was a huge economic benefit through tourism and services. Many livelihoods will have been affected as well as those of the scientific elite. ☹️

Definitely a contrail, often a good indication of air stability as you suggested. Aircraft in and out of airports don't leave contrails, they're nowhere near high enough. 🙂

Hello Andy, welcome to SGL. A pretty comprehensive list which should satisfy your interests. Main caveat would be that the CPC versions are pretty heavy as the components don't dismantle for set up and take down. It's not so much the carrying as the need to carefully place it accurately on its tripod whilst supporting the weight, you won't be 53 for ever. 🙂 I would personally go for the 11", the planets are not well placed for some time and there are countless DSO's for which the 11" will do better on. An after market additional focuser is very beneficial from the start, you shouldn't need any counterweight as the CPC's are fork mounted, the heited dewshield is essential. You will probably get recommendations for a completrly different telescope! 🙂

It really depends on what represents the best image for your interest. Double stacking enhances the contrast of surface features albeit with a dimmer image visually which detracts from prominence visibility, a hood or cover over the instrument improves this. I personally find the prominences more dynamic and interesting. 🙂

There still seems to be excessive "rock" between the wormwheel teeth and the worm, as though the mesh needs adjusting, I would expect no visual movement if all was well. One of the design shortcomings of the GEM is the relatively small area of contact support to combat the inertia imparted to the RA axis, relying on just the worm bracket and a few gear teeth. When I built the "scrap box" mount for my 8.5" F12 refractor I adopted the polar disc modification, this gives much wider contact support, the effective bearing diameter is over 12". My worm and wormwheel RA drive isn't on the RA shaft, a relatively small wormwheel is attached to the substantial main housing and drives the East bearing roller that co-supports the disc. Both RA and Dec gears are permanently adjustably clutched and the telescope can be finger tipped in any direction even when driven. Most users are surprised how easily moved and backlash free the system is, none more surprised than me!

Certainly makes you jump if you're using an eyepiece at the time! 🙂

These things do happen, I once rebuilt a Velocette Venom engine and was surprised it had no compression when I tried to start it. I suspected a valve lifter malfunction until I noticed a spare pair of pushrods I didn't have beforehand. 🙂

I looked hard at the photo to see which one of us had made it but the resolution wasn't quite good enough to see the difference. On the attachment knobs on mine I used to turn a little recessed styling whereas Rob left his flat. Being that it was sold by Rob I'm pretty sure it was one of his. 🙂

Perhaps we should start a SW150ED users thread. Thursday early evening was the first time I'd had anything like decent seeing conditions since I got mine a few months ago and at last was able to see something of which it was capable. Certainly stands 400x given the opportunity. 🙂

Bit of work to do there I think! 🙂

I think I would be looking at a along term solution. Once such things are out of the house, well you know the rest! 🙂

Should be ok, the astro branded ones are usually more expensive 🙂

I have a recent 150ED, in the limited opportunity to use it so far I've been pleased with it's performance. Its mounted piggyback on a 16" SCT to easy to do comparison observations. Apart from the obvious light grasp superiority of the SCT there is little to choose between the two for lunar and planetary detail. All the usual benefits of refractors over other types can be taken advantage of. The tube is slightly larger in diameter than the 150 F8 achromat but not significantly heavier, it looks heavier than it is. It's considerably front heavy so would need a tall tripod or extension. The dual speed focuser on mine is excellent and in no need of upgrading. I certainly wouldn't spend a considerable amount more for something "better". 🙂

Having the reducer in the wrong place relative to the camera is possibly what is causing the unexpected extension to the focused position. I would suggest trying it in the correct position before ordering anything, you may find that you have an opposite problem. Welcome to SGL.

Most likely a focusing issue although the reflection from the filter suggests that it might be a little tight, the film needs to be completely relaxed and floppy. 🙂

Best night for a long time for me regarding seeing stability but very foggy. During the brighter moments a crisp outlined image of Mars at 500x on the 16" SCT and 400x on the 150ED. Trial purposes only, better viewed at 400x and 300x respectively, pity things were not so steady at opposition. Conditions got more foggy, Mars barely visible to the naked eye. Tricky drive home! 🙂

The best one we've found so far is the Celestron NexYZ. 🙂

For days we had a sunny forecast for today, what do we get? fog and cloud!. No Sun forecast for the next 2 weeks. ☹️

I was treated to a view of the Sun, Moon and Mars today but the seeing was rubbish, still at least a look at the sunspot array. 🙂

15 minutes, that's longer than our visual allowance in these parts! 😀