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Luna-tic

Members

357

1. meridian flip camera angle

What if you orient the camera so that a particular axis is parallel to Right Ascension? When the setup does the Meridian flip, wouldn't it just invert the subsequent images, which would only require inverting to realign with images shot prior to the flip?
2. Common questions astronomers get asked

"How much did this cost?" is one of my top three. When someone asks "How far can you see?", my answer is, "In distance, or time?" Then I explain how the distance of the objects we look at are so far away and the light we see took so long to reach us, that seeing them is like looking back in time. I'll then skew to Andromeda and let them see the fuzzball, then tell them they just looked 2-1/2 million years back in time. They never fail to be impressed., especially when I tell them there are things to look at even farther away.
3. 180 mm Mak or 8 inch SCT EDGE

I'd go for the Edge over the Mak. You may not think you'll use it for AP, but if you're imaging with the frac, eventually you'll want to try the SCT, and it will open up more possibilities. The reducer for the Edge is .7, and is specific for each size of Edge (also much more expensive than the .63 for standard SCT's). I don't know how fast your ED80 is, f/6?, but having both a widefield and narrower field scope to image with is a grand slam, IMO. Plus, if you go completely AP bonkers, you can go the Hyperstar route and image at f/2 with the Edge. Whatever you give up in increased contrast with the Mak, you'll get back in greater versatility with the Edge. I started with a C6, added the .63 reducer, then added the Edge HD 8", then got the .7 reducer. I still wanted something extra wide-field, so I just recently got an 80 APO at f/5.9, with a reducer that takes it to f/4.7. That's pretty much a full spectrum of possible field sizes and exposures. You won't regret the Edge.
4. Is most of the sky this boring?

Well, it IS called the GHOST nebula.
5. First Light with my new frac

Works well, and the rings are removable from the handle if desired. Alternatively, both the handle and dovetailed foot are removable, and WO makes a set of 90mm rings that fit the scope barrel for a different dovetail arrangement. The dovetail foot can be reversed on the barrel, and is also drilled and tapped so a longer dovetail can be attached. This is the route I'm taking, so I can better balance the Dec axis with big EP's or a camera attached.
6. orion

A through D are labeled in the order of their Right Ascension; not sure why E through I are different, unless it's the order in which they were first seen. I really can't say why we could see 'F' and not 'E', but I'm sure it was 'F' we saw. It was next to the brighter 'C', but it was in and out, mostly out. We had a 20mm EP; sure, but I think it was a Nagler (2"). In a Dob with a 3175mm focal length, that gave a magnification of 158X, and with a 25" (635mm) mirror, it was a pretty darn bright image.
7. orion

I could only imagine that since 'F' is slightly brighter, that's why we could see it and not 'E'. Is there info on the period of B's binary companion, which I would assume would vary its brightness dependent on whether the companion is eclipsed or in conjunction or to one side?

Planets, yes, DSO's like the Crab, unlikely, but others, maybe. It's all about aperture and "magnification". With your 20mm EP, you get 50X (focal length of 1000mm divided by focal length of EP, 20mm). You can see things like M42 (Orion Nebula) and even split the Trapezium on a good night, and clusters like M45 (Pleiades), or M2 (globular cluster in Aquarius). Double stars are very reachable with your setup, and the challenge of splitting some of the closer pairs can be fun. As you increase the magnification by inserting the Barlow, or the small 4mm EP, you decrease the brightness of the observed object, sometimes past the point of being able to see it. M1(Crab Nebula) is pretty faint and small. Large aperture would allow you to see it at low to moderate power, but it would be a tiny smudge on the best night. More magnification would make it slightly larger, but at the expense of being more dim as well. Part of the challenge will be how much better your son's eyes might be compared to yours. I find many of the kids at our club viewings can see stuff I can't, or at least they see it better than I can. That's a nice scope for Moon and planets, and I'd opt for a couple of EP's between the two you have, like a 10mm and a 15mm, Plossl's are inexpensive and give a generally decent view. It doesn't hurt to look for anything in the sky, just don't be disappointed if you can't see a particular object. The combination of aperture and the local seeing conditions will make many objects unattainable. "Seeing" has to do with the condition of the atmosphere. High in the sky is better than low on the horizon, because you're looking through less of the atmosphere. Low humidity is better, less water vapor in the air. Calm and clear is better than breezy, and the saints help you if the Jet Stream is locked above you. Moving air makes the image waver and wobble, think of the mirage you see in movies about the desert and how it makes the image move. Have fun with your telescope, the adventure has just begun.
9. Abysmal science reporting

Which is why astronomy club outreach programs are important; the ignorant media reads something about a "conjunction" and makes it into the Second Coming, or hears the phrase "Super Moon" and has people wowing at how big it looks just after rising. They (media) hang onto one thing until someone gives them something new to mis-report.
10. orion

I split the four easily last night at slightly less than 60X with an f/5.9 80 APO, and we had the club's big 25" f/5 Dob out and had "F" in and out, but never saw "E", we were at the limits of the seeing, I suppose.
11. 2 inch Barlow for 2 inch diagonal

I have one and love it. No noticeable CA that I can tell, it's a five element lens. It looks huge, but with the 1.25 adapter out and a 2" EP in it, it's fairly short for its girth. Not sure why it's a 2.5X, but they do (Barlows in general) come in quite a few magnifications, from 1.5 to 5X.
12. Worth the wait

Oh, how I wish it were a bit warmer tonight; I'd be out there doing what you were doing, John. Moonrise here was about 9:45PM EST; I went to our public viewing tonight at the observatory and got first light with my new 80mm APO, split the Trapezium at 60X and called it a night at 8:45. It was only 19* at 7:30, but I would dearly have loved to see some craters tonight.
13. First Light with my new frac

Tonight was one of my club's two public viewings each month, and the first of 2018. It was nice and clear, some light clouds dissipated just after dark, and Moonrise was later, at 9:45-ish. I decided to take my new William Optics GT81 f/5.9 APO and mount it to a manual EQ we have at the observatory. When I got there, several of the club's scopes had already been set up to cool (it was 19*F tonight at viewing time); among them was a C-11, a 12" f/5 Dob, and a 25" f/5 Dob. Great company for optical comparisons. Seeing was pretty good tonight, I'd say above average from 35* to zenith, but the usual LP made anything near the horizon not worth looking at. My GT81 came with a set of finderscope rings mounted to the carry handle, so I used the 9x50 finder from my Edge HD 8. I didn't worry about a polar alignment, just pointed the mount generally North and clamped the dovetail foot into the saddle. East and South are the best directions to view at our observatory's outdoor pad, so I aimed at M45, having inserted a 2" diagonal and a 25mm Plossl to start viewing. The Pleiades were fabulous, and the scope took them to very sharp pinpoints; with the 25mm EP, I could get the entire cluster in the FOV. The two speed Crayford focuser is glass-smooth, and without adding any "hold" with the thumbscrew, it did not budge, holding a very fine focus. Next, I inserted my Luminous 2" 2.5x Barlow and a 20mm Plossl, and skewed to M42. With a 478mm F/L, the Barlow/EP combo gives me 59.75X; That's about as low as my Edge will get with the lowest power EP I have and no Barlow. I focused in on the Nebula, and clearly split the Trapezium. 'B' was just separable from the other three, but I could clearly see all four at that magnification. The Nebula itself was pretty clear over most of the FOV. As it was so darn cold, and another member wanted to use the mount for first light in his Explore Scientific f/7 102 APO, I put mine away for the remainder of the night, got a look through the 102, then climbed a ladder and looked at M31 through the big 25" Dob--WOW! Overall, with just a short look through my new frac, I'm extremely happy with it. Can't wait now for a warmer night when I can put it on my AVX and look around some more, then try some AP with it. I got the reducer/flattener with it, so I can image at f/4.7.
14. Variable Moon Filters

I'll give that a try Tomorrow night. Supposed to be clear, we have a gibbous waning moon, and Orion will be up early. Going to try for first light with my new WO GT81. My statement was based on losing much of my night vision in the eye I was using to view with, for some minutes after ceasing. If I closed the non-viewing eye, I was almost completely night blind, and trying to view things like doubles or open clusters was a waste of time until I regained the night adaptation with my viewing eye.
15. Variable Moon Filters

It won't damage your eye looking at FM unfiltered, but it ruins your dark adaptation for viewing anything else for quite a while. If you go out to observe the Moon, look at everything else that's visible first. Orion's dual polarizer comes in two pieces which screw together, and have a sleeve which allows you to rotate them to add or cut light passage. I've been attaching the coupled pair to my EP, holding it just over the diagonal and adjusting the light, then inserting them. I think I'll try the trick with attaching one to the diagonal or Barlow, and the other to the EP, sounds much easier if you need to adjust the light.
16. Full Moon 01-01-18

Very nice. I wish I'd had skies as clear as they must have been for you. I only hope the weather cooperates on the 31st, when we get a second chance at FM in one month; if you're in the right place, it's a full Lunar Eclipse, too. Quite a bit of special with it: Supermoon, Blue Moon, and total eclipse, all in one. I won't see the eclipse, it's not supposed to start until just after moonset here.
17. My new APO 80mm

That is the red. I really wanted it in gold, but couldn't find the deal with the included flattener/reducer in that color. Only blue or red. Heck, they all look good. The GT71 is the one with the thermometer in the focuser knob.
18. My new APO 80mm

Yeah, it seems a bit over the top, but I suppose it's the best way to allow for most any finder/guide scope the user might want. The rings will remove from the carry handle if you don't want to use them. I may end up buying a set of mounting rings rather than stay with the foot-style dovetail bar, just for more latitude with mounting. I have a dual mount on the way, so I can mount the frac with my SCT. It will still be less than the max weight for the AVX, but probably past the point of good performance for AP. Gonna give it a try, though, before making any more decisions.
19. My new APO 80mm

I just had to show it off; I'd rather be outside looking through it, but too cloudy. First impressions are pretty darn good. It's a beautiful instrument, the fit and finish are superb. This is the 20th Anniversary Edition GT81 f/5.9 81mm APO refractor from William Optics. It has a two speed Crayford 2" focuser, with a 1.25" adapter. It comes with a small "shoe"-like dovetail bar, and a carry handle that also mounts a set of rings large enough to hold a 9x50 finderscope or guide scope. Just to see how it looks, I installed the 9x50 finder from my Edge 8", and will probably leave it on the frac, since I rarely use it on the SCT. The dovetail bar is barely long enough for the two large tightening screws on my AVX mount to grasp, there is no room to move the OTA forward or back on the mount to assist in balancing once all the accessories are attached. It is threaded so a longer dovetail bar can be attached. The telescope is only 17" long with the dew shield retracted, and weighs around 8 pounds. It comes with a soft case with a fitted closed-cell insert, and the William Optics logo is nicely embroidered on the cover. I also purchased the field flattener/reducer for this scope, it makes it a f/4.7 when used, and so far as I can tell, the reducer is for AP only, it comes with an adapter ring for a Canon T-mount, which can be unscrewed; the threads are then correct for a Nikon T-mount, but there is no means to place an eyepiece in the reducer. The reducer is threaded on the end that inserts into the 2" focuser barrel along the last few mm, but it has a broad sleeve with the safety recess that fits very snugly in the focuser tube. With the three thumbscrews snugged against the brass collar inside the focuser, there is absolutely no free play to be had. Very solid. I also tried a variety of my EP's and accessories, they all fit well and without any movement once tightened. I can't wait for a nice, clear night to try out this marvel. I have a side-by-side dovetail bar coming so I can mount this alongside my Edge.
20. No *90mm* ED APO (semi-APO) Refractors?

So, do you like it because it's a 90, or because it's a WO scope, or both? I just bought the GT81 APO, been playing with it this evening because it's too cloudy to use it. If it works as good as it looks, I'll feel the same as you. Seems like once they pass 80mm, the price goes up faster than the aperture size. Even a good 80 bites the wallet pretty hard.
21. Imaging with an 8 inch SCT - some results

Outstanding. Those are as good as I'd ever expect from my own efforts, and to see that they are unguided gives me hope I can do it, too, with some more practice with the Edge. Going to try first light with my new 80APO tonight, see if I can catch the Moon between clouds.
22. Looking for a 2" diagonal for my 80mm triplet - need help

Doesn't GSO sell to dealers who rebrand them? I have a TPO 2" quartz mirror diagonal, very nicely made, 99% reflectivity, and I believe maybe it's a GSO-made.
23. just messing

"Just messing" you say? If I could "mess" like that, I'd call myself an astrophotographer. Nicely done; looking forward to messing my way to an image of M31 that nice.
24. Modifying a finderscope to guide with

Yeah, one of them should work. Is there a site in the US for these? Shipping from the UK will be twice or more what I pay for the adapter.