Telescope

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Telescope

Postby Мастер » Wed Sep 02, 2020 4:23 pm

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Re: Telescope

Postby Enzo » Wed Sep 02, 2020 4:55 pm

Far out. I know nothing of current scopes, but I note includes cell phone adaptor. MAkes sense, but this old guy would not have thought of it.

I also note in red: they cannot ship to your location?
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Re: Telescope

Postby Arneb » Wed Sep 02, 2020 10:30 pm

Not sure. I think several points are questionable.

Generally, if you want a large aperture ("there is no substitute for aperture, except more aperture"), that makes a telescope more expensive. If you want a relatively large-aperture scope to cost, like, $500, the money has to come from somewhere. In the case of the assembly in your example, it seems to come from the rather shoddy-looking mount and tripod and from the very small, narrow-angle eyepieces. You may be in for an unpleasant surprise there.

I'd go about it differently. The first question is always, what do you want to do with your scope? If you want to have a peek at some Moon craters, a bit of structure on Mars, a cloud band on Jupiter, or Saturn's rings from your balcony or a nearby park, you can easily exchange aperture for sturdiness and better eyepieces - Singapore's skies won't give you many opportunities to really get anything out of the difference between 102 or 114 mm aperture, and 130 mm - too much air movement, too much moisture, too much light pollution. If, on the other hand, you want to travel to dark, transparent and calm skies in order to see faint fuzzies, too, you might consider not to buy cheap equipment at all - after a few trips, you'll have paid enough for the trips to dwarf your initial investment in telescope gear. In other words, why take cheap gear on expensive trips?

If your idea of buying a telescope and making a hobby out of stargazing is more than a fad, I'd turn to a good astronomy shop and ask them what they recommend for your specific needs - even if you don't actually walk into the shop. Good sellers will talk to you via e-mail and clarify what's best for your specific viewing conditions and requirements. And it's no problem to enter into these discussions with a firm upper price limit.

I have some specific points on the offer at hand.
1 Crappy mount and eyepieces can absolutely ruin it for you, see above.
2 Why a German equatorial mount? That type of mount isn't easy to set up correctly, it is not intuitive to operate, and it's usually heavier than a simple alt-az (which as an added bonus doesn't require a counterwight). It has one application (for amateurs) where it's indispensable: Long exposure guided photography - not something you do with a smartphone, and if you want to go into that, the wobbly mount is all the worse. Also, if you really want to go there, you'd be better off with a motorized mount anyway.
3 Even in one of the ad images, the counterweight is almost touching the tripod. If you observe from near the equator, the setup of the equatorial mount will almost certainly cause the counerweitht to make contact with the tripod legs during some observations, because the polar alignment leads to the counterweight bar almost pointing straight down.
4 They talk about a high-transmission *lens* in their scope - but a Newtonian doesn't even have a lens, it's mirrors-only (except in the eyepieces, of course). Lens-mirror hybrids exist, but they aren't called a Newtonian. It's just a matter of nomenclature, but coming from a telescope shop, it sounds fishy.

So no, it's not my recommendation. Seems like a future dust-collecting decorative piece for your appartment. And, as they say, the best telescope is always the one that is used most. So if you want to spend $500 on your first Thing To Look Up At the Sky With, here's a radically different proposal. For $150, get a sturdy photography tripod. For $350, get an excellent 10x50 binocular (or 16x70, if you can do with the heavy stuff), and make sure it has a tripod socket. You can take that anywhere, maybe even in your hand luggage, and use it for the stars and for daylight observations and photography, too. If you're generous, make it 200 for the tripod, and 400 for the scope. If after many a pleasant observation night, you feel you want to see more detail, shell out $ 1,000 and get pro advice on how to spend them.

If it has to be a proper scope RIGHT NOW, a 100 mm (even 80 mm) semi-apochromatic wide-field reflector (lens telescope) on a good alt-az mount with two eyepieces will take you a long way. And for a prospective long-term customer, the competent team of your trusted astronomy shop might even throw in a phone adaptor for small $$.
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Re: Telescope

Postby Мастер » Thu Sep 03, 2020 3:06 pm

Obscured by Clouds.

I’m not referring to Pink Floyd, but Jupiter and Saturn.

But about twenty minutes ago, before I went in the pool, I tried looking at them through a pair of 8x42 binoculars. Even with my elbows resting on the arms of the deck chair, I couldn’t hold them steadily enough; both planets did quite a dance for me.

For brief instants, I thought perhaps I could see Jupiter’s moons or Saturn’s rings, but I could not convince myself that that was reality rather than imagination. I have seen Jupiter’s moons before through a 22-power scope (designed for wildlife, not astronomy) mounted on a tripod, and even then they were small, faint, and fuzzy. So I think it was probably my imagination. For Jupiter for sure though, I could tell it had some size, rather than being a pin point like a star.

No sign of either right now, too cloudy. Also no sign of the girl who often comes out around 11pm in what looks like her underwear, so the dog can take a dump.

Will comment on Arneb’s extensive and helpful telescope comments in a separate post.
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Re: Telescope

Postby Мастер » Thu Sep 03, 2020 3:20 pm

Ok, now to the telescope comments.

Sounds like my candidate scope is good on the body (is that a meaningful term), but crappy on the mount and the eyepiece.

I don’t even know what a German whatever mount is, I’ll have to look into it.

Arneb wrote:If it has to be a proper scope RIGHT NOW, a 100 mm (even 80 mm) semi-apochromatic wide-field reflector (lens telescope) on a good alt-az mount with two eyepieces will take you a long way. And for a prospective long-term customer, the competent team of your trusted astronomy shop might even throw in a phone adaptor for small $$.


Will look into it.

You mention travelling, so I guess these things are reasonably portable? The last few years (until this bloody virus hit) I’ve been trying to make a pilgrimage each year to Lake Placid, New York, which is most of the way from New York City to Montreal. Light pollution will definitely be lower there than here. I go to hike in the mountains, but I thought it would be a good observation place. I think the tops of the mountains would also be good, except (1) I’m usually there during the day rather than the night (maybe I can look at the sun), and (2) said equipment would have to be carried up, generally a vertical rise of 1,000 to 1,500 metres, and the trails are quite crappy. Uneven, rocky, often overgrown.

I was also somewhat annoyed that I had absolutely nothing suitable for observation of the total eclipse (a short distance away in Indonesia) or the annular eclipse (here).
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Re: Telescope

Postby Lianachan » Thu Sep 03, 2020 5:16 pm

Мастер wrote:Will look into it.


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Re: Telescope

Postby Arneb » Thu Sep 03, 2020 7:00 pm

An equatorial mount is one in which one of the two axes of the mount is pointed at a celestial pole. That way, you can follow a star across the sky by turning only one wheel, with a constant rate. If you have a motor, ideally, you can place your object of interest in your eyepiece, start the motor, and keep the object centered for arbitrarily long. That's what makes the mount suitable for long-exposure (or time-lapse) photography. Equatorial mounts (the "German" is only the name for this particular way of building one) have this one killer advantage, but you first have to point one of the axes at a celestial pole, which is quite non-trivial at the beginning, and it's heavier because of the counter-weight.

Alt-az (altitude-azimuth) mounts are simpler. One axis is up-down, the other left-right. Following a star, you must always move your scope in two directions. That is difficult to do smoothly (there are modern mounts that can do it, even for casual observers), and the object will slowly rotate even if kept centered, so you can't use those for long exposures. But they are more compact and intuitive. If you aren't into the photography thing, alt-az is fine.

The setup on the Amazon page would be transportable in a small car, easily. But if you go for an 80 or maybe a 100 mm wide field refractor on an alt-az mount and a tripod that is designed for visual observation (as opposed to photographic; needs to be heavier and more sturdy), you might actually take the whole setup on a hike, or take it along a flight as hand luggage.
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