Ruud

Below you see three light cones from f/3.5, f/5 and f/10 objectives. Between these three, it is easier to design an eyepiece for the f/10 light cone because such an eyepiece only has to handle rays that stay within three degrees of the optical axis. The other two are said to have steep light cones. Faster objectives with their steeper light cones pose a more demanding task for the eyepiece designer to deal with them. Delos eyepieces are said to work well in telescopes as fast as f/3.5, showing sharp stars across the entire field of view. Coma matters in a different way. It is more an objective issue than an eyepiece issue. Newtonians have coma and standard SCTs too. A good eyepiece faithfully shows the focal plane of the telescope. If coma is present in the focal plane, your good eyepiece will show you that coma. If that same eyepiece is used in a coma free instrument, it will show a coma free image. A coma corrector can be used to correct the coma present in a telescope's focal plane. Fast Newtonians benefit greatly from them. In Newtonians without a coma corrector, the wider the apparent view of your eyepiece, the more coma you'll see. Coma correcting eyepieces also exist, the Pretoria is an example. You seldom see them though because such eyepieces are designed with a specific amount of coma in mind and they will not work well in a coma-free telescope.

Instead of the 24mm Panoptic I'd choose the 24mm ES 68°. Performance seems identical to me. (My fastest scope is an f/5, there might be a difference between these two at f/4.5. Don't know.)

Hello Dainius,

Aw, sweet! It's a sight that really touches a person, isn't it? Show it to everyone you know. They'll be amazed and at least a few, if not all, will ask you if it's real. Saturn will be better placed in the sky year after year for at least a dozen years to come. Ever higher in the sky, showing more detail at each opposition, till on a good night five moons can be spotted even in a small telescope. About the goto alignment: check your manual, you may find there's something like solar system alignment.

It's very bad for your health if your neighbours burn scrap wood and you get to inhale the smoke. The burning resins, particulates and carbon monoxide, the poly aromatic hydrocarbons and burning embers floating about in the air, all are a hazard to your health. You can install a few smoke alarms and get a garden hose long enough to reach the perimeter of your garden. Give a short warning before you use the hose. Reassure them it will only take a short while before everything turns to normal. Good luck.

I don't know, but it could be a reflection from the sensor back to the Barlow and then back to the sensor again.

It's a wonderful image. Well done!

Excellent non-professional review!

Excellent work!

Awesome!

Thank you guys! It's my most ambitious one so far and I'm really glad you like it. It took me hours to paint, but I ended up with five big, happy craters and a few perky little ones. I'm very happy with how it all turned out. @KingNothing13 I suppose I feel the same about this region, Brett, especially because it has Alpertragius, my favourite crater on the Moon. But I've had many favourites. For example Atlas and Hercules. I discovered them when I was twelve, with my binoculars.

The Bresser 30mm Plössl is around €60, and the GSO 32mm €50. Could you compare them for us in your fast dob? Especially edge performance, general sharpness and scatter would be interesting to know about. About your original question, test the eyepieces, keep the better ones for yourself and sell the rest. For people with only kit eyepieces, most of your collection would mean an improvement. The 66° UltraWide Long Eye Relief ones, btw, are sold under many names.

Or the new focuser is longer than the other. Did you attach the new focuser as far forward as it would go?

Thanks people, for for your kind comments. Hi Fraunhoffer, I make these on my computer with a wacom tablet, Corel Painter and Photoshop. I work from notes and partial sketches that have the details of the features I could see. From them, with the help of a reference, I make an underpainting in Corel Painter on the computer. Then with smearing and scratchy brushes, using pencil, oil paint, acrylic and charcoal (all mixed, whatever works) I make the painting. As I go along I compare the miniature version in the navigator window to the reference. Whenever I go seriously wrong I use undo. Only the larger features in the result are realistic, but that's OK. I feel a sketch should be a personal interpretation and that's what I aim for. Photo realism is for the imagers. The observation takes half an hour or so, the work on the computer takes several more, but it's a nice thing to do. I listen to the radio and a podcast or two while I'm at it. We also have real pencil and charcoal sketchers here and I hope they can provide you with a tip or two. My suggestion would be to draw a rough overview of the scene and several partial sketches at the telescope. After that I'd do the final sketch indoors with good light, sitting at a comfortable desk.

Those are good Moons.

Hi Ben!

Yesterday the Moon was low in the sky (in Scorpius), but he seeing was good and allowed magnifications up to 257x. Gassendi was the most prominent crater on the terminator. Here's a painting of the scene. The small Moon image (Stellarium) shows the location of Gassendi. Thank you for watching.

Thank you Michael, that was a good read. The Monarch sounds like a good choice and I very much like the design. I almost regret that I already have a pair of 8x42s.

Very good stills and that transit, well that is so nice!

Thanks for sharing the story. It's a pity that you don't have the binoculars any more.

Wonderful, Mike, both views. Excellent job!

9 August was a good night for the Moon, so I studied the region from Ptolemaeus to Arzachel at 231x. Especially Alpertragius stood out, with its oversized central mound. It has been suggested that this is a volcanic feature. Herschel too was quite prominent. Thanks for watching.

Great that you joined us, King. Hope to hear a lot from you.

Good luck with the eyepieces, Daz. I quite like the 28 myself. Please tell me: how do I get an email address like that? Or do I have one already?

The Morpheus 17.5 is amazing. I use it at f/5. (£189 at FLO. Of the Morpheus, the best are 17.5, 12.5, 9, and 6.5mm.) ES68 and Panoptics are very close to each other quality-wise. The shorter FLs have short eye relief. I'm very fond of my 20, 24, 28 and 34mm Maxvisions, which have the same optics as ES68. Crisp views at f/5.