Ruud

Do you already have Stellarium? https://stellarium.org

Hi Seb, welcome.

You can get rotating mounting rings but they are expensive. Ouroboros is right. Here is a DIY project with photo's: http://www.astro-baby.com/articles/rotating rings/Rotating Rings Project.htm

About the upper limit: This is determined by the effective field stop of an eyepiece. The stop can't be wider than the barrel. In a 1.25" barrel you can fit the field stop of a 32mm 52° eyepiece, or that of a 24mm 68° one. Both are at the upper limit of what will fit. See the diagram. The eyepieces on the blue line all show the same maximum true field of view that can be obtained from a 1.25" focuser. Any combination of focal length and afov on and below the blue line will fit a 1.25" focuser. Combinations above the blue line blue line need a 2" focuser (or larger). Occasionally you'll come across a 1.25" eyepiece that lies above the blue line, like say a 30mm 60° eyepiece. Such an eyepiece has an excessive amount of pincushion distorting due to positive angular magnification distortion (amd) which blows up the apparent field of view. I love the Morpheus and Delos. Their angular magnification distortion is very close to zero. A small amount of positive amd (5%) is often used by designers because this makes it easier to correct an eyepiece for astigmatism. The 24mm ES68 and 32mm GSO Plössls are examples. I've taken this into account when calculating the blue line. If you know the size of the field stop you can very accurately calculate the true field of view of an eyepiece. The first sheet of the attached spreadsheet is for the 200p and calculates true fields of a few eyepieces mentioned in this thread. ScopeCalculator-2019-06-16.xlsx Scope Calculator Formulas.pdf I plan to make a new version that runs using macros. This will be more versatile and self explanatory. In the current version (no macros), put the cursor over the commented cells in the spreadsheet to read the explanations there and consult the pdf if you want to know what is calculated and how. Edit only the yellow cells.

That's the best image I've seen yet (excluding NASA). It is fantastic! I saw nothing of the transit myself. We had clouds and rain all day.

Hi Deisler, it's personal, but I'd say 1) no PM. A decent Barlow is just as good as a PM. 2) no zoom. These zooms have very small fields of view at lower magnifications. 3) BST is okay. With a Barlow instead of a PM you might have enough money left for a 32mm GSO Plössl. --- Above 3x magnification factor, a PM is a better choice than a Barlow. Otherwise I am fully content with my Barlows.

It is Autumn of course, and there's climate change as well. Familiar with the meteoblue astronomical forecast? It might help a bit for planning around the clouds: https://www.meteoblue.com/en/weather/outdoorsports/seeing/colchester_united-kingdom_2652618

The blue snowball looks pale blue in a 4". In a 6" it has an obvious cyan hue. For me it is the only nebula that shows any colour. It's a very compact nebula. That must help. Here is a finder chart for it from https://freestarcharts.com/ngc-7662

Oh, I just edited my previous post. Without a 2" adapter, anything 2" might end up crooked with the screw pushing the 2" accessory to one side in the wider section. Do you have an adapter?

That is the case normally. But I believe that some telescopes have focusers that are neither suited directly for 2" or 1.25". These require two separate adapters, one for 2" and another for 1.25" accessories. EDIT Tried to find a manual, but failed. Looking at your image B I get the feeling that a 2" eyepiece couldn't go in deep enough if that opening is 2" wide at the end. I guess it is wider and that a separate 2" adapter probably came with the telescope.

Short adapters with grub screws exist too: you want a low profile 2" to 1.25" adapter. Google for that and you'll find plenty. The one I linked to is really short. If you chose that one, I suppose you'd keep it on permanently. The TV in-travel has a negative profile, but again no grub screw: http://www.televue.com/engine/TV3b_page.asp?id=23 This one is also pretty short, but is still a cm long. It has a grub screw though: https://www.teleskop-express.de/shop/product_info.php/info/p281_TS-Optics-adapter-from-2--to-1-25----2--filterthread---compression-ring.html

What I linked to is intended to replace this: The replacement would be 1mm deep instead of 3cm, which you have now. Alternatively, you could get a 2" nosepiece for your T-ring, if that fits in this ring.

That's a really long adapter. This one is just 1mm long: https://www.teleskop-express.de/shop/product_info.php/info/p4218_TS-Optics-Adapter-from-2--to-1-25----only-1-mm-length.html

Hi Andrea!

That's great one Mike. Your sketch is a masterpiece. It has an amazing amount of detail. It would take me several hours to record this much and turning it into a painting would require at least a two evenings. I notice that your Gassendi is more or less circular. My craters too, even when they are close to the edge of the lunar disk, tend to come out as circles. It's like the mind compensates for them being on a spherical body, interpreting the shape that it really ought to have instead of how they actually appear. I was thinking (as I was scanning and combining my partial sketches, morphing circles into ovals etcetera and doing the brushwork to make the painting) that I have strayed far from my original intentions. When I started off I meant to 'express an observation'. Now I feel I have become obsessed with detail and try to make ever more realistic representations. I even considered getting a 180 mm Maksutov to make better use of those rare, perfect nights and collect better detail. I want to go back to what I did before: coarse, harsh brush strokes with dramatic contrast, giving expression more priority than detail. I enjoyed that better. Here's my Gassendi from three month back Taking liberties with the details gave me room to put my heart in the scene and even though this Gassendi is less lifelike than my latest one, it feels more alive and more real. At least to me it does.

Very dramatic, with that cloud threatening to engulf the planet.

Aw, that is sweet. It's going to be cloudy here with rain in the afternoon.

Suiter must be wrong. How does the diagonal matter more than the eyepiece? I can easily see an IQ difference between eyepieces, but find the difference between diagonals is very hard to see if at all. Also, Suiter splits up the telescope in component parts and gives them all a place in the list, yet he completely forgets aperture. There's more that's wrong with his list: Points 1 and 8 are irrelevant to the quality of any setup. Eyepieces matter, I use mine in three telescopes and if they weren't any good I'd notice that in all of them.

Awesome!

It's been a while since I've had a clear view of the Moon but yesterday I got lucky. Gassendi stood out and formed an interesting comma shape with the northwestern edge of Mare Humorum. The seeing was far from ideal but with a bit of patience quite a few smaller craters, ridges and rilles could be found. Of course I forgot that once corrected for left-right reversal the scene doesn't resemble a comma at all, but still, here it is. Hope you like the result.

Ah, that's pretty!

Cables for D-type connectors always work themselves loose. This looks much better! Maybe you can drill a second hole opposite the screw holes in each cable, so that you can use Meade's pins?

The cross hairs should in the focal plane of the eyepiece. That is the same place where the field stop is (at least, where it should be: if the field stop is not sharp if it is not in the focal plane of the eyepiece). Plössl eyepieces have an accessible field stop, Kellner, König and Erfle too. You can glue the hairs to the field stop. There are more. See here: Lord-Eyepiece-Evolution-Tree.PDF Also see here: Google Books Search

That's a good one. Love it!

Oh wow, that is amazing! Perfectly detailed and excellent light control. What a wonderful view!