globular

Nice report John I had a similar session. I was mainly trying out my ES92/12. It was giving me 178x and just about fitted the whole of The Moon's disk in it's lovely wide field. I'm really liking the EP. I 2x powermated it to 355x for a while too and got quite a few WOWs from Mrs Globular! (Both at the size of the stack and the views through it ). I stuck with that EP for Mars too - it couldn't really take any more magnification - and got some nice glimpses; nothing like previous sessions though; you're right about seeing conditions being quite poor. Then everything went foggy and I realised the power to my dew heater controller had run out of juice! Can't believe I forgot to charge it up!

Enjoy

The formula calibrated by regression from actual readings will naturally already have 'average' transparency built in... so it may need adjustment to allow for this.... or accept that matching the formula will give you average transparency and bettering it will be above average.

Isn't that where the value of this will formula shines through? The formula tells you what the brightness should be on a given night. And the difference between that and an actual reading is a measure of transparency?

So bringing this all back on topic for you @johnturley; In your F/5 scope you should get a big contrast improvement over your Meade 56mm (which has an exit pupil of 11mm) by using a shorter fl eyepiece with a wider AFOV. You should perhaps target something around 4 to 5mm exit pupil = focal length of 20 to 25mm. Maybe you can push it to 6mm pupil = 30mm fl as you have such a large aperture? To give a similar TFOV to your Meade they would need to be hyper wide - which makes them heavy and expensive. A better compromise is probably to give up a little TFOV to save weight and cost.

Seems to fit. The 21 Ethos @ F/5.3 is 4mm exit pupil, the 31 Nagler @ F/6.5 is 4.8mm. Aero ED 40 would give 7.5mm and 6.2mm pupils in those scopes, so unless the skies were very dark you'd get washed out views.

I've been working along the same lines... but at a slightly higher figure of 5mm max exit pupil because my skies are not that highly polluted. My XW40 in my F/10.5 scope gives exit pupil of 4.8mm and looks great to my eyes in my garden. So that seems to fit. If John finds 21mm Ethos and 31 Nagler are the limit then I guess that means he must be using scopes around the F/6 mark and/or more polluted skies.

What's the mechanism at work here? Is it the larger exit pupil in the Aero ED 40 that caused the skies to appear brighter? So with a different F ratio scope the Aero ED 40 could give a nice dark sky? Or is it the magnification? So with a different focal length the Aero ED 40 could work better? Or is it something within the eyepiece design. So this eyepiece is doomed to give poor contrast?

By better to you mean wider or less aberrations? (I imagine you want both!) I can say a bit on FOV (but not on optical quality). I think your Meade 56mm probably has a field stop of around 46mm and so will give you around 1.48 degrees TFOV in your 14" F5. Your Baader 36mm is (if the 72 AFOV is accurate) giving you around 1.45 degrees. The maximum TFOV you can get with a 2" barrel is an eyepiece with a 47mm field stop - like the Masuyama UltraWideField 32mm which would give 1.51 degrees. A lot more magnification but only slightly more sky than the Meade. It weighs 450g so is quite light. As I say, I can't speak for it's optical quality. Larger than 47mm field stop and vignetting will occur - meaning the extra sky on display will not be worth looking at anyway. The next biggest (usable) field stop is 46.5mm and these include Pentax XW40 and Masuyama 60mm. They will give you 1.50 degrees. All other 2" eyepieces have a field stop at or below 46mm (most quite a lot below) and so give you no more sky than your Meade. Eg the Tele Vue Plossl 55mm has a 46mm field stop giving you 1.48 degrees. In summary you are not likely to get more sky at your eye with another eyepiece - but you can certainly get the same amount of sky at higher magnifications and probably better optically corrected too - but I'll leave other more knowledgeable SGLers to advise on that.

Pretty good here in Shrophire - fairly stable atmosphere and little to no cloud; so clear in fact that the temperature has dropped below freezing. 🥶 Wonderful to have a nice long session - first one in far too long.

Most houses on our road face the road directly and are clearly displaying their number. Others, of which ours is one, are set back down long driveways, so we do take a bit more seeking out. We're number 33 and our driveway falls between 31 and 35 which are both clearly visible as you drive down the road. Not rocket science to work our we're down there but when this is missed our problems start. (We do have a sign with the road name and house number on it!). Our road turns into another one with a different name without warning (i.e. without a junction or obvious physical change - there are large clear name signs!) and both have the same numbers on them - so we sometimes get their mail and they get ours. This was not the issue this time. The odd numbers are one side of the road and even on the other (fairly standard in UK) but they do not run opposite each other (less common). Sometimes a delivery driver will find the house 1 away from ours (34 perhaps) and then just deliver it next door to, or directly opposite, them. This is rarer but has happened. This was not the issue this time. Our number is 33 and one or more of the 3s are sometimes confused with 5s or 8s. We've had mail delivered to or from all permutations over the years we've lived here. This was not the issue this time. I'm not sure what happened this time - I can't think of any reason why the house it was left at was chosen. Just a genuine mistake perhaps. Or maybe just picked a house at random when ours didn't jump out and grab them. p.s. from the above it sounds like this is a big problem here. It isn't that bad. We've been here over 20 years and have had thousands of deliveries over that time with only a small number of mistakes - mostly when we get a new postman!

Enjoyable read, it was like I was there. Thanks for sharing

Peter Drew's comment on a possible water variant also deserves this thread's resurrection.

I cringe at the noise of my Celestron Evolution goto "coffee grinder" too - but at 10pm or so I just reduce the slew speed down to about 30% of max and it's nice and quiet and neighbour friendly.

Thanks @DaveL59. Nail varnish tip duly noted! Dismantling I think will likely be tricky. Breaking it off and taping/gluing it back on would be next option, albeit a poor second best. Failing that I'll just add thick black tape to mask off the unwanted LEDs and apply layer(s) of red to the outside over the remaining ones.

One each end of the rod will probably do the trick... bit brighter and more uniform. Good luck 👍

Thanks Mark. I'll give it a go. Have you tested yours since the mods?

Can I ask your advice? I don't have the skills to make things from scratch and was wondering if I started with something like this.... https://www.amazon.co.uk/dp/B07WMQQZ6M .... could I disconnect all but one of the LEDs? And paint the clear plastic cover over the LEDs with some red paint of some kind? And then use it on the 20% dimmed setting?

I'm after an ES92/17 (some of you may have noticed ) but the retailers won't give me the time of day.

Looks a lot dimmer overall and without too much glare from the rod. I'm not sure the unevenness of the illumination over the page will be too big a problem; it's amazing how your eyes even things out. I think the key is not to have any really bright spots. Give it a test drive before you try a whole new concept.

Very nice. Thanks for sharing.

Do you think the clouds will be fooled by the mis-delivery and plague my neighbour rather than me? It was raining when I picked it up and it's raining again now so I'm not so sure.

It seems very flat to me rather than lovely and spherical in earlier observations; but I think I remember it being round 🤔. Going to have to look out for that now.

If you want to get something new maybe go for a different type of telescope that excels in an area different to your SCT? And keep the SCT too! You'll then have two complementary scopes which will probably give you a much more noticeable improvement than getting a spanking new like for like replacement.

When I was sharing my observations of Mars with my wife I kept referring to it as The Moon and then I got all cross when she seemed dismissive of their being dust storms 🤡x2