Luna-tic

I wish I had the head for the higher math, but this has been an interesting discussion. I'm trying to get back in to astronomy after a 3 year hiatus due partially to the pandemic. We're doing comparisons here to telescopes with a disparity of f/stop and aperture. How does the math work in this instance, with these conditions: 8" Edge HD with a F/7 reducer, compared to a 80mm refractor using a 1.5x Barlow (in this case a William Optic GT81 which is f/5.9 in its native focal length). Given that the imaging camera is the same for either setup (pick whatever pixel size you want), which would be the better one to image with for deep space objects?

I re-greased my AVX with Lubriplate 130-A. It isn't temperature sensitive (at least not within the bounds a human can survive or is willing to endure). It clings well to gears without being "sticky". I use it on the trigger assemblies and bolts of my semiauto rifles. https://www.lubriplate.com/PDFs/PDS/3_14-130-Series.aspx

Very nicely done power supply, looks great and nicely laid out.. I just finished mine, will deliver 12VDC or 115VAC with included inverter. I'm using a 96 amp/hr deep cycle wet cell lead-acid battery. Very true. Generally, the heavier and more basic a battery is, the less it costs per amp/hr. capacity. As you go up in capacity, up in technology (AGM or Lithium)or down in weight, the prices climb correspondingly. Choose your priorities in weight, technology and capacity, then look at what's out there. As a very broad rule of thumb, you can figure it that way, but you can only count on about 80% of the total capacity to be useful, and that depends on several conditions. A 12 volt battery delivering 16 amps only gives you 192 watts, according to Ohm's Law, and that is at 0.75 ohms. You'd get 3600 total watts over 18.75 hours at that voltage and load. Now, if you were at 220VAC and drawing 16 amps, you be using pretty close to 3600 watts. A telescope mount of moderate size will draw anywhere from 0.25 to 0.75 amps during tracking. At full speed slew that will increase to 3-6 amps. If that is all you have to power, you can run most of the night on a 20 amp-hr. battery doing observation. I can run a dew heater at full power, my mount, a laptop and two cameras at less than 7 amps total continuous draw. So, for 6 hours, I'd use about 42 amp/hrs. Realistically, it would be longer than that, because the 7 amps is maximum, (during slewing) and drops about 2.5 amps during tracking. Part of the draw is from the inefficiency in converting 12VDC to 115VAC through an inverter, which part of my gear runs through.

English is my native language, and you're doing a better job than I do most times.? Of course, I live in the US South, so our English can be a little.....different.

Can I join the club? My EQ6-R Pro arrived today, along with a Stellarvue FG50 guide scope which I'll install on my GT81. I have an AVX that I really like and unlike some, get good service from. I'll keep it for mainly visual, and grab-n-go service. I may even image with the GT81 on it, but the EQ will definitely get the Edge 8 for AP. Plans are also to use a tandem dovetail saddle and use the GT81 as a guide scope for the Edge. All I've done so far is unbox the Skywatcher and put it together, stand back and admire it. I've looked through the Synscan manual, looks like there's quite a few differences (none too serious, though) between it and the Nexstar/Starsense HC's and operations. Hope I get a few decent nights this week and weekend, I'm headed to the Green Bank Star Party mid-July, and want to be familiar enough with it so I don't waste half the night setting it up. One of my clubmates bought one of these mounts a couple of months ago and has been doing some fantastic AP with it and a f/7 102 APO. I fell in love with it immediately; he's going to tutor me in its finer points.

I saw that thread as well. The one thing the optician can't do with an optics machine (and it changes the comparison between the eye and a telescope) is measure how the brain is compensating for visual aberration, and that varies with the individual because part of it is interpretive and can't be quantified. I look at SCT manufacture as a compromise between absolute optical perfection and what someone can reasonably afford. With today's technology, I'd rather have a finely tuned instrument made on an assembly line than a hand configured, although more optically perfect, instrument, because the likelihood of repairing the hand configured one back to its original specs if a major lens or mirror was damaged, is close to nil, without a huge cost involved, both of time and money. The hand configured one will be prohibitively expensive (to me at any rate) to begin with. The commercially manufactured ones are of course subject to tolerance ranges determined by by the limitations of the equipment used to make them. So, each and every primary mirror will vary within their tolerance limit, each and every secondary mirror the same, as well as the correctors. The optical qualities of each item can be individually checked by computer, and those computer readouts used to match the items in the most optically "perfect" combinations. When the parts are matched, further fine tuning can be done by hand; this could be as simple as rotating the secondary and /or corrector orientations with the primary once the tube is assembled, to hand grinding/polishing of one or more parts to more closely match them with each other; the degree of which will determine the price range of the item, since the more hand work performed, the greater the cost. Even with an instrument that tests "perfect" within the tolerance range of the test equipment, once sold, it will depend on the acuity of the user's vision as to just how good it is. You could have a user with average acuity and a telescope where everything fell precisely into place, and said user could not fully appreciate how good his scope was. You can also have someone with perfect vision and a perfect scope, and how they rave at the quality of the views they get; there's also the guy with perfect vision who happens to have the scope at the lower borders of the tolerance range, and how they complain that they'd never buy another product of that company, as well as a guy with poor vision and a poor scope, who can't see anything. Consumer products aim at price points and they are built to provide a level of quality that matches that. The better you want, the more it will cost; a level is reached where the cost is prohibitive to the point of nobody buying it and no manufacturer will approach that. Can't make a living that way.

Pretty close, I think, except your eye will give a much wider FOV with peripheral vision, but your central vision would be close to what a 50mm lens gives. I think that is why 50mm is so commonly used for standard prime lenses. Not sure if that was directed at me(with all the quotes flying around), but my D3400 Nikon has a crop sensor.

Took the camera off the scope and made this silhouette, while viewing and shooting the Supermoon the other night. Orion is rising. The misty clouds shut down the viewing shortly after this was made.

"Magnification" is all relative to a baseline size. I think you're asking "how much bigger will the picture image look at prime, versus naked eyeball, and telephoto lens at XXmm ". All I can do is give some comparative photos which might give you an idea. You'll have to consider the focal length of the telescope used; at "prime" focus, it would be like having that focal length lens on the DSLR. In my case, the telescope used for comparison has a focal length of 2000 mm. 1st picture: Nikon D3400. 18mm lens, 1/4 sec, f/3.5 at ISO3200 Same camera used in all pictures 2-Nikon D3400. 300mm lens, 1/4 sec, f/6.3 at ISO 3200 3Nikon D3400. EYEPIECE PROJECTION, Edge HD 800, 25mm EP (40x magnification) 1/160 sec at ISO 100 4-Nikon D3400. PRIME FOCUS, Edge HD 800 (2000mm F/L) 1/60 sec at ISO 400 See the relative difference in size of the Moon? Frame size is the same in all four photos. These were all taken the same night, so relative Moon size is the same. This was last week's Supermoon from the SE USA.

Try these settings: auto white balance; MANUAL mode, aperture open as far as the lens will go, focus at infinity; ISO 1600, shutter speed varied from 5-25 sec. Mount on a tripod and use a remote release. You can experiment by varying ISO and shutter speed, but something along those lines should get some images, if light pollution is not too bad (sky looks black). If the picture is still washed out at lower ISO and faster shutter speeds, you're probably too light polluted. I have a D3400, it's just the latest version of your D3200 (with the D3300 in between). I get great results with the pictures I'm taking. If you plan to step up, go at least to the D5600 or D7500; the D500 is the top of the DX line. Canon seems to be the go-to for astrophotography, you may want to look at some of their offerings.

I am so envious. I spend a lot of time around Orion, but the seeing here, mainly due to LP, just won't let me see much other than M42 and 43. Even trying for a 20-30 second exposure at ISO 6400 won't give me much. Night before last, I got just enough of the Flame to make out the general shape, with a 45 second exposure. Forget visual (Edge HD 800 and 25 and 40mm EP's), it just wasn't happening. Great post, I felt like I was there.

I thought that might be the case. I'm getting there, too. I'll be 70 in 2024, hope I'm not blind, or worse, by then. Maybe the old-folks' home will have an excursion so I can go see it (2024 eclipse). Maybe I can design a clamp to mount my telescope to my walker for the occasion. Patagonia that far south is so far off the beaten track you can barely see it from there. Never been there myself, but from looking at Google Earth, it's just one step removed from the Moon. My daughter has been to that part of the world (works on a cruise ship), she says that southern Chile is nice, at least the areas along the coast she's seen, but southern Argentina is pretty desolate. Certainly it would be an adventure to go there, eclipse or no. Hope you can work it out. Here's a couple more shots I made, to further whet your appetite:

Are you particularly wanting to see a total eclipse in South America (once in a lifetime trip), or just wanting to see a total solar eclipse? The terrain in that part of South America east of the Andes is pretty much desert. The Argentinian coast from Viedma to about 30 miles south of Las Grutas might be the only decent area in Argentina to view. West of the Andes is a bit greener and more populated, although that's a relative term. Only three cities of note in Chile in the path of totality: Temuco, at the northern edge of the path, about 262,000 population. More in the path center are Nueva Imperial, population 29K, and Petrufquen, population 21K. My choice would be somewhere near one of those cities, or along the Chilean coast from Isla Mocha to Nueva Tolten. If you want more viewing options for a total eclipse, why not wait to 2024 and come to the States? Longer period of totality, much, much longer path to choose a site from. And English is (sort of) our first language. I was only a 2 hour drive from the path of totality back in August; I'll have to drive about a day to get to the one in 2024, but I plan to be somewhere in the path. Took these shots through a C6 back in August.

Exactly. Because it's bright, it's one of the first DSO's people try, and why I also tried it. Stacking and processing is the only way to get even lighting and a full image of it; I knew that going in, but I'm taking 'baby steps', looking at exposure times and ISO to gauge tracking accuracy without guiding (I'm using a long F/L scope). I took over a dozen images of M42 at exposures from 20-40 seconds and ISO from 1600-12800. It's easy to see in the combinations where tracking becomes an issue and noise starts becoming prominent and where lighting is enhanced or inhibited. I've also played with less-bright objects like M1, M31, M13 and some of the open clusters. Once I get a feel for this, I plan to start stacking images and playing with them in Registax and Lightroom, using filters, etc to improve coloration and visibility. Now that I've photographed a rather large-field DSO, I know what to expect with FOV and my longer F/L and a DSLR's sensor size. Hopefully, Celestron won't take the remainder of my lifespan to get their reducer availability issue worked out. Then I can open up my field a bit. Fastar and f/2 is further down the road. As for the grin, I still have it, several days later. This is FUN.

Interesting, but what's your point? I'm using an EQ mount. Just haven't started stacking and processing yet.