Bugdozer

It's like cooking. Sometimes you are just hungry and a microwave ready meal is better than taking half an hour making something from ingredients. Other times you want to experience the satisfaction of having made something from scratch.

What is a shorty Barlow?

That’s what I was wondering. I think I have experienced this using my Celestron 25mm Plossl with the Celestron 2x Barlow - weirdly enough both items being supplied with the telescope, so you would expect good compatibility, but it could be that I just didn't adjust my eye position properly to account for the increased eye relief produced by the Barlow. It's a combination I rarely use, I prefer to just switch to a higher power eyepiece.

Does anyone know if using a Barlow lens can change the eye relief for a given eyepiece, or affect the shape of the exit pupil plane?

The downside of this is that the thing you're trying to find needs to either exist in the pages of TLAO or else you have to have a laptop or phone out with Stellarium or similar on it, which isn't convenient if you're also running anything like Astrohopper on your phone or don't want to lug a laptop outside into a wet field etc.

I have nothing against dobsonians, they're great. But there are very few threads where people have asked what scope they should get without at least one person recommending one. I am highlighting that the "there is no ideal all round scope" quote persists alongside dobs being recommended for almost everything (including areas like planetary where they aren't always the best choice). I offer no judgement about which view is correct, merely that the two views are incompatible.

I don't understand. You can see an amazing amount with an 8 inch scope of any kind. You have used scopes before so you are familiar with the main drawback of a Dobsonian, which is actually pointing it at something you otherwise can't see, so that won't be much of a barrier. You can see some incredible sights with such a scope.

Shh! Don't let the Dob Squad hear you! 😁

Interesting. I also found what causes this effect. Basically I wasn't accounting for refraction or for the elliptical orbit of the earth. This link explains it well: https://skyandtelescope.org/astronomy-resources/astronomy-questions-answers/daylight-hours/ I think I have had about the same number of clear nights as last year. Including tonight when I was finally able to try out my new 32mm Super Plossl I got for Christmas.

That’s not moving the goalposts. That's what I suggested from the beginning. In the summer half of the year, the time to reach astronomical darkness is greater nearer the pole than towards the equator. In the winter half of the year, the time to astronomical darkness is less great nearer the pole than towards the equator. These balance exactly for any given latitude, the only difference with latitude is the magnitude of the effect, being greatest at the poles and smallest at the equator. At least, that is my understanding. If that IS the case, then you can see why I remain unable to understand why the poles would have more daylight and less darkness overall, which was your original assertion. As I said, I am happy to be proven wrong, but so far no explanation of why my understanding is incorrect has been given.

I am happy to accept that, if you can tell me a date after the autumn equinox but before the spring equinox, on which a location of your choice in Norway gets a shorter period of astronomical darkness than a location of your choice in France. My understanding is that doesn't happen, but I will accept I might be wrong. If we were to take today as an example, Norway has a greater length of astronomical darkness than France does.

The numbers were just made up as an example, my overall point being that there are as many hours of astronomical darkness per year in both locations, they are just concentrated into a smaller number of days the closer you are to the poles. The cloud cover is a separate issue.

Except what you describe is balanced out by astronomical darkness happening much earlier in the evening and lasting longer in the morning during the winter half of the year. For example, in November, there are more hours of astronomical darkness in Helsinki than there are in Hastings. You are neglecting to factor in that a night which is 17 hours long gives you more opportunities to observe than a night which is 14 hours long. What the axial tilt giveth in the summer, it taketh away in the winter.

I don't follow this - yes you have a smaller amount of darkness in the summer, but this is exactly balanced by a much greater amount of darkness in the winter, isn't it? So the total hours of darkness per year are identical for everywhere on earth, just distributed differently.

This is a bit hard on GoTo mounts. I have never had any problems with using mine, in fact I have cried more in frustration at not being able to find an object by manually hunting about than I ever have at setting up my scope to automatically find things.

Hello there, welcome!

Hello there, welcome!

Are there any particular objects in the sky that image particularly well in the 700nm infrared range, or thereabouts?

Astro Essentials 32mm eyepiece, now all I need is a clear sky! Update: finally got to test this out tonight, not ideal with a bright moon but seems to perform excellently, very happy with it!

No binocular or telescope is fundamentally better than another at combating light pollution. There are filters designed for telescope eyepieces but these often can't be used with binoculars. By viewing from inside through a window, you will also be deteriorating the view.

Welcome, nice to know the tinies still love space.

Speaking from my experience of working with radiation for 19 years as a radiographer, and having studied it at degree level, with individual sporadic captures of this kind, it's virtually impossible to determine the source. It could be a cosmic ray, it could be radon in the air, it could be a single atom of a radioactive substance stuck to your shoe that just happened to decay at the right time. Radioactivity and ionising radiation are everywhere to a greater extent than most people realise. Regarding ash versus wood: per unit of mass, ash is more radioctive due to the higher carbon concentration (carbon occurs more commonly as a radioactive isotope than hydrogen does). However, the amount of activity from ash cannot exceed that which was present in the wood initially, as long as the absorbtive properties of the wood are discounted. Try leaving a banana next to the camera. They are generally more radioactive than their surroundings due to the high potassium content.

The 6SE is a goto scope. You should be able to point inherently with a reasonable degree of accuracy. I have the 5SE which uses the same software and although it's nit always bang on, it's pretty close nine times out of ten.

One thing not yet mentioned in this thread is what these features actually look like compared to the rest of the planet. It helps to know what it really looks like. The GRS is not the big dark red blob you imagine it to be. It's a pale salmon pink colour and crucially it is very close in brightness to most of the rest of the surface, it's mostly the colour that differentiates it rather than the brightness. However, it does push into the darker south equatorial belt, so the easiest way to spot it is that it makes the belt appear narrower at that point. Shadow transits look to me exactly like a very tiny black pinhole on the surface, easiest to see when they're not right by the edge. I can see these things in my 125mm scope at around 130x magnification, although depending on seeing a higher magnification can show more. As others have said, letting the scope cool properly makes a difference, and so does practice at observing these things. Over time you will see more.

I don't think I stand a chance. I made the mistake of trying to look at Sirius after my eyes were dark adapted last time I was out, it was like being stabbed by a flashing laser. No way I could see the companion.