Peter Drew

Welcome to solar UK!

A lucky clear patch at 11.30am gave me a first view of the oncoming new AR. Looks very promising, at 11.35 it was showing a thin fragmented line of erupting material similar to a WWII line of tracer shells.

I have dismantled some of all of the various PST incarnations and all of them had cemented doublets. It's true that if you offer up an eyepiece to one of these in isolation it does give some weird chromatic effects confirming that there is an added correction of some kind to optimise the Ha performance. @Macavity, you can place your 90mm ERF internally to safely utilise a donor telescope of suitable F ratio up to 150mm aperture.

CoC...

You could well be right Ken, just shows that the advertising script could be even more misleading?. Reading it again from your perspective perhaps it would have said "stacked" instead of "stack" if there was an internal etalon as supplied. If you are correct, it's even less of a deal!.

SW, Tak, Tasco, AP, Seben, Meade, it's jus another tube to me. As long as it makes a practical improvement, "off with its head".

Yes, 10mm off My reading of the advertising is that it is a 70mm aperture short focus achromat with an internal small etalon. To the front of the objective is a 60mm external type etalon which double stacks the internal one albeit operating as a 60mm overall Ha system. The price reflects the high cost of a 60mm etalon and a BF15. There is a distinct difference between external and internal etalons, the former has to be (usually!) a full aperture to suit that of the objective and designed to accept parallel light, the latter configured to accept converging light, not directly interchangeable.

Excellent shot of the prom at its most active, I was just just focusing for my first look this morning as it clouded over. By the time I was able to try again it had changed dramatically.

My last viewing was around 6.15pm. Good seeing and great detail, the prom was one of the most detailed I've seen, like fine gossamer. A challenge for any sketcher!. The very windy conditions with the wind blowing directly into the solar observatory making it impossible to increase my baseline 150x.

Just had a clear patch between heavy downpours. the large prom seems to have fragmented now and fainter than earlier, very complex structure. The main AR is spreading out as it draws towards the disc centre, superb detail, should be well placed on eclipse day.

Agreed.

The extra weight bearing down on the complete system can improve the stability, look at all the recommendations for hanging an extra weight on the tripod.

At times today, under high magnification, the prom on the right of your image resembled the radio telescope dish at Jodrell Bank.

I know it's a different set of circumstances when you actually live in America and if I did and was going to be away for a few nights the thought of taking a telescope for some night time viewing would be attractive. However, if the venue is badly light polluted then I think it might not be worth the bother, there would be nothing to see that you could not do better elsewhere, anytime. For a total eclipse I would take a pair of solar glasses for the partial phases and a 10x50 binocular for unfiltered views of the totality. Anything else is a distraction! Good luck.