Louis D

1. Does your mount have a tracking motor? If not, you'll have to master manual tracking for long exposures. 2. Do want to take short or long exposures? Long exposures are very demanding technically. 3. A DSLR's weight would probably be too much for that mount and focuser. 4. I would start with grabbing snap-shots of solar system objects by holding your cell phone camera up to the eyepiece.

Neither my Tele Vue 1.25" 2x Barlow nor my PBI have compression rings, although neither has a groove for one. The PBI use a brass screw.

You're conflating true field of view with apparent field of view. A telescope's focal length determines it's maximum true field of view. In general, refractors generally have shorter focal lengths than SCTs and especially Maks. Newtonians tend to span all focal lengths. A telescope's true field of view determines the maximum amount of sky visible through it in one view. This has nothing to do with the apparent field of view of the eyepiece used to view that image. An eyepiece has a focal length and an apparent field of view. The focal length determines the magnification. Just divide the telescope focal length by the eyepiece focal length to calculate the magnification for the combination of the two. This determines the image scale. The apparent field of view is how big the image circle appears to the eye, and thus how much of the image at a given magnification is visible in one view. To a first approximation, divide the eyepiece apparent field of view by the magnification to determine the true field of view on the sky of the combined system. Thus, a 40mm eyepiece with a 50 degree apparent field of view would show approximately the same true field of view as a 20mm eyepiece with a 100 degree apparent field of view. The exit pupil would also be half as big in the latter creating a darker sky background.

Some folks just use photographic lenses for wide field imaging instead of telescopes. Others stitch together multiple frames to create wider panoramas.

1. The Bresser is a tabletop Dob, and as such will need to be put on a table or tripod to be usable by anyone but a small child. 2. Bresser is the European marketing group for the Chinese company JOC that is known as Explore Scientific in the US. There is nothing German made about them. 3. I couldn't find a picture of the Bresser in relation to full sized Dobs, but here's one that shows the slightly smaller Orion Starblast 4.5 next to some other telescopes for scale. 4. Here's a tripod mounted version of the Orion 4.5".

I would probably recommend the 5mm, 8mm, and 12mm BST Starguiders. They're very good step-up eyepieces at reasonable prices. If the Celestron X-Cel LXs are basically the same as the Meade HD-60s as many folks claim, they're also a good option. Avoid the original Celestron X-Cel eyepieces on the used market. They had terrible kidney beaning issues. By the way, your scope is a Jones-Bird design. It uses a fast spherical primary mirror and a corrector lens below the focuser.

From what I understand, they're pretty decent scopes. Don't forget to budget for a sturdy tripod to mount it on top of. I'm pretty sure they have a 3/8" tripod socket on the bottom for this purpose.

It's not clear where you are located, but the BST Starguider/Paradigm eyepieces are another lower cost, step-up line of eyepieces. The 5mm for a highest power eyepiece would be a good choice. At the other end, a 32mm Plossl makes for a good widest field eyepiece. You'll probably want some collimation tools for the primary and secondary. I'd recommend the Rigel Aline and a Cheshire eyepiece. Also, read up on Newtonian reflector collimation. It's usually a just a matter of getting it right once and then touching it up before each session.

You check this map to get some idea of you light pollution levels (I centered it on Belgium for you). If you click on your location, a popup will give you statistics about your sky conditions including Bortle level. You generally want to observe under Bortle 6 skies or better (lower number) if possible in my experience.

Texas would mostly be cattle ranches, cotton farms, and oil rigs without A/C systems. Las Vegas and Phoenix would still be empty deserts without them. Washington, D.C., used to empty out every summer due to the oppressive heat and humidity, effectively shutting down much the US government with it. Many parts of the desert southwest and mountain west use "swamp", or evaporative, coolers because the dew points are so low there. They also humidify the indoor air as a side benefit. Given enough global warming, more of Europe may end up needing A/C systems in the future.

It easily breaks down into two very manageable pieces and goes back together very quickly. Here's a link to a video queued up at the point of attaching the main tube to the Dob mount. How far will you be carrying it and where will you be storing it?

Yes, you significantly shortened the optical path length through the eyepiece by removing the prisms. As such, you're having to substitute empty air for that length by pulling the eyepiece out of the focuser a bit. Glad to hear it also significantly improved the view through the eyepiece. Here's a trick to see the secondary shadow more sharply. Pull your eye back from the eyepiece in the daytime, and the secondary shadow should shrink with the field of view and sharpen up in the center. If you move your head left, it should move right and vice-versa.

The terms are right ascension and declination or altitude and azimuth, depending on what coordinate reference you are using. I know there are some apps out there that attempt to use the sensors in your smartphone to help you find targets. I have never used any of them, but it is my understanding you lay the phone along the main telescope tube and line it up to be parallel to it. Because phone sensors are not precise enough to do exact locating, they can only give you a rough idea of where you are pointing at best. However, if you don't know the skies at all, it's better than nothing I suppose.

I just realized that, at least in the summer, a noisy telescope mount isn't going to be any worse than my neighbor's ailing A/C compressor which is so loud that you have to yell to hold a conversation when standing within 10 feet of it. I know because I replaced mine 4 years ago, and the installation technicians couldn't talk to each other every time the neighbor's started up, and the two compressors are within 10 feet of each other. As such, I wouldn't expect any complaints from them about noisy mounts in my backyard being over 30 feet from their house.

If you don't mind disclosing your observing eye prescription, how many diopters of cylinder (astigmatism) correction are you dealing with in that eye? I've got 2 diopters CYL in my observing eye and notice improvement down to about 1mm, although it is subtle at that point, with eyeglasses.

It is an M43 thread for use in digiscoping. As such, I believe a Dioptrx can be attached to it.

Automotive electronics have an operating temperature from −40 °C to 125 °C which is very close to mil spec of −55 °C to 125 °C. Consumer electronics have an operating temperature from 0 °C to 70 °C. Unless otherwise stated by the manufacturer, we have to assume astronomy electronics to be consumer spec rather than automotive spec and treat them accordingly. This not to say they could not be stored at extremes beyond these operating conditions. I know that operating electronics under extreme heat conditions that are not designed for it can lead to permanent failure, typically due to electromigration. Before this happens though, the device typically starts to malfunction.

I think good ventilation is key to avoid massive heat buildup in the summer (at least in Texas and the desert SW of the USA) and dampness buildup in humidity prone areas.

Yeah, this thread has gone a bit off the rails:

Search on Cloudy Nights for some user reports on the ES-62 line. They are very similar to the older 60 degree Meade 5000 Plossls if you want to dive even deeper.

I would pick up the 5.5mm Meade UWA for basically the same money (at least over here in the states, $99 vs $93). Wider field, excellent sharpness by all accounts (it's the newest design of all the Meade UWAs), and good eye relief.

If you don't need the eye relief for eyeglasses, the 24mm Pan is probably the lightest option out there at 8.2 oz with good correction. The 24mm APM UFF is 12.2 oz and the 22mm AT AF70 (2") is 16.8 oz. Since I use mostly Delos/Pentax XL-XW/Morpheus, I'm already balanced for 12 oz to 16 oz eyepieces, so the latter two are not an issue for me. It's when I put the ES-92s in that my balance really goes out.

I would concentrate on star clusters, both open and globular, before heading off to hunt down galaxies in light polluted skies. The only "easy" galaxy in my experience is M31, Andromeda. Even then, it just looks like a fuzzy cigar with a couple of fuzzy companions nearby because all you can see are the bright cores under light polluted skies. I detect most galaxies by putting the scope on them with DSCs and then sweeping the area trying to detect a slight brightening of the background glow at higher powers. It's much the same with comets. To be honest, there's not much satisfaction in it except to say I "saw" it. I enjoy sweeping star fields at lower powers now to see what shows up randomly. It's sort of like getting in your car and going for drive with no particular destination in mind just for the joy of exploration.

I measure the APM UFF 24mm to have a 63 degree AFOV using projection. I measured the effective field stop to be 27.5mm, but it fuzzes out a bit, so it's hard to nail down exactly. It's above the shoulder. The effective AFOV (eAFOV) works out to be 66 degrees if you want to calculate the TFOV from the magnification times the AFOV. Here's an image comparing the view through the 24mm APM UFF to others in that range. And a diagram of the internal lenses (second from right): The field stop is physically 30.2mm, but due to the Smyth lens, it works out to about 27.5mm as I said above. It's a nice lens and all, providing the maximum field possible in a 1.25" eyepiece, but I still prefer the 22mm AT AF70 if I have a 2" focuser handy. The fields are about the same (28.4mm FS for the AF70), but there is none of the fuzzing out at the edge like in the UFF due to the design pushing things a bit too far. Both are equally easy to use with eyeglasses.

Right now, only $53 difference in the states, so not that big of a deal. The XWs only recently dropped in price here. There used to be little to choose between them on price. Tele Vue does put their stuff on sale once in a while here bringing the two closer.