Bugdozer

6 hours ago, Space Hopper said:

I went 12 years straight between 2005-2016 but have not been back since then.

I was disappointed with the 2016 show ; hardly any vendors there and the speaker line up had seemingly been hastily arranged.

I much prefer the PAS / IAS shows and they are a lot closer for me to get to.

I like a day out in London though.

 * One thing of note ; I believe the train drivers are on strike on Saturday 3rd so if you are planning on taking the train, it may put a spanner in the journey plans.*

Fortunately the train companies striking at the weekend aren't the ones in my area - they're doing it on 30th January. Got lucky there. 

I am thinking of going. I haven't been for probably about 15 years! 

Here's a shot of the Moon taken early this morning using my IR modified Nikon D70. This was the first time I had tried with this camera - it's tricky because there is no live view to zoom in on and you can't even magnify the pictures properly on the tiny back screen to check sharpness. I had to go by eye and cross my fingers!

This is a single shot but when I have more time I plan to stack the several that I took to improve the image. The bandpass in this camera is 690nm and above. The main difference to visible light is that there's a little more inherent contrast between the darker and brighter features on the surface. One bit where this is very apparent is the dark floored craters around Mare Australe, which has quite a favourable libration here (I compared this with another photo taken at the same phase in August, you can't see those craters at all in that one!) The downside is that the inherent image quality of the D70 is nowhere near as good as newer DSLRs.

2 hours ago, Mandy D said:

@Bugdozer I can do no better than to give it you from the master himself, Thierry Legault:

http://www.astrophoto.fr/obstruction.html

That's a pretty comprehensive answer, thanks! It's more complex that I had thought.

Can anyone explain this to me? There must be something I am missing but I can't see what. 

There is a limit of resolution for any given aperture. So a larger aperture will give you a smaller limit of resolution. So far, so good. That makes sense. 

However, on a newtonian reflector, you have the spider supporting the secondary mirror, usually with four vanes. Surely the gap between each of these then acts as an aperture in its own right, creating four apertures with around one half of the maximum diameter each? Does this not then decrease the resolution of the telescope? 

As someone who enjoys radiation, I think this is fascinating. The number of strikes you got from the ash versus the control looks too high to be just down to statistical variation. 

Welcome, you will get lots of useful tips here, enjoy your start in exploring the universe! 

I can't comment on Canon, but my elderly Nikon D90 definitely does. One thing that increases buffer time needed in my camera is having its internal noise reduction set to on - you could check you have that switched off which should also give you better image quality overall when stacked. 

7 hours ago, Mandy D said:

OK, the point is that to achieve sufficient inward focus for my Nikon DSLR to achieve focus requires me to wind the focuser in an additional 46.5 mm just to make up for the fact that the sensor is buried so deep into the camera's body. We could, theoretically, achieve this by using a focuser with a lot more travel than you generally see fitted to Newtonians, but, then the focuser would intrude into the tube further and block precious light.

I have absolutely no argument with you about the fact that extension tubes should be supplied where necessary to focus with any supplied eyepieces. But, the end user has the option to buy other accessories (eyepieces included) that require more extension (or none!). Why should the telescope manufacturer supply everything that everyone will ever want to use with the telescope?

Try purchasing an imaging scope, like my RC6. You will rapidly find that accessories are absolutely required beyond those included with the OTA. Hell, it didn't even have a single eyepiece or finderscope included! I bought an additional pair of 50 mm spacers for mine.

I'm guessing that the OP has bought this kit used and does not have all the original accessories. In any case, it is a simple matter to acquire the necessary parts, as I have explained in my reply to him.

I hope this helps.

That explains it a little more clearly. If components are missing from the kit, then obviously third party extras may need to be purchased. However, I stand by my view that if a retailer is selling A Telescope Set as new (i.e. not just components individually such as the OTA or tripod) then it should be usable in its sold state for visual observation, in other words it should contain some sort of mount, an eyepiece, and a means of enabling that eyepiece to be brought to focus. Just like my SCT came with a diagonal, because without it, it's physically impossible to look at anything above a certain altitude. 

The analogy with buying an imaging scope OTA doesn't really apply because the OP appears to have purchased a complete kit rather than assembling one from components. It's reasonable to assume such a kit would be usable as sold. Otherwise you have a case of misleading advertising, unless the seller was explicit that extra items would be required for even the most basic use. 

22 hours ago, Mandy D said:

No, it's not crazy. You cannot gain extra inward focus without re-engineering your telescope. It is for things like imaging with DSLRs and for accessories to be fitted for imaging that require more back-focus.

 

I don't understand your explanation. The OP is trying to use it visually as far as I can tell. By default, the telescope should be engineered to work properly for visual observation. I understand the need for extension tubes etc with things that require a specific distance for the focal plane such as photography, but this doesn't appear to be that situation. Or am I missing something? If a scope requires extension tubes in order to be used for visual observation, then they should come as part of the scope when you buy it, not have to be purchased separately. 

22 minutes ago, Mandy D said:

@takaeri Yes, you often need extension tubes to bring a Newt to focus. If you cannot get focus on the Moon with the focuser fully racked out, try sliding the eypiece backwards out of the focuser. You may need more extension than you have available. You can buy them readily. Get focus on a distant object in daytime first as it is far easier than fiddling in the dark. Then, at night, aim for the Moon as it is bright and easy to work with. Good focus on the Moon will be fine for everything else in the night sky. Start with the 25 mm eyepiece, no barlow. The 10 mm is probably not going to be very good and I would forget the barlow that comes with these telescopes, altogether.

Question: why do manufacturers make telescopes that are intrinsically impossible to focus without an additional device? That seems crazy. 

Welcome! 

On 15/01/2024 at 19:19, Mr Spock said:

Interesting. S&T predictor says 19:10 for both. I got 19:08 for Io and 19:15 for Europa.

Some thin high cloud arriving but Jupiter is still putting on a show. I don't normally see colour on Jupiter but in the 12" GRS is a lovely salmon colour.

That Sky and Telescope moon predictor isn't very accurate. I tried timing it myself with my 5" SCT and estimated 19:09 and 19:14 for the times they were occulted. I was shocked when I then consulted the S&T site and saw 19:08 for both. So I checked Stellarium, which gave a much more likely 19:10 and 19:15.

I have been getting advertising for this. Although the promotional pages are unclear about exactly what it does, as far as I can tell it appears to be like a Dwarf or Seestar but with an 85mm aperture (so better resolution) and an eyepiece you can actually look through. The adverising is terribly vague and doesn't have many details that anyone who is already familiar with telescopes would want to know. 

My daughter and I have often tried to take handheld pics at the eyepiece, and it's always been a massive faff. So I invested in a phone mount and we tested it last night. I was quite pleased with the results, although my phone has quite a crummy camera - daughter's pictures were much better. These were with my 9.7mm eyepiece. 

We did try and photograph Jupiter but couldn't see any features on it. Eventually we got too cold to keep our gloves off and had to stop. 

The sky is going to be dominated by the moon at that time, so I would say that will make an excellent target with some interesting features across the terminator at high power. Familiarise yourself with a moon map beforehand and you can point out things to the kids (that's what I do with my daughter). 

At low power, I would recommend the Pleiades as a bright, pretty cluster they will be able to see well. 

And my third nomination, a bit left field maybe, but a good bright multiple star is Castor, which you should be able to split into three components. 

15 hours ago, dobblob said:

Very nice bug. It's difficult to combine the the two and in spite of the grain it's a fine artistic shot.

I'm an expat from E. Sussex myself. Where are you from if it's not too personal a question ? Please ignore if it is.

No problem, I am in Hastings. For a town of this size it's not bad for observing with comparatively low light pollution on the outskirts, and you don't have to drive far to get to some darker skies. 

19 hours ago, Elp said:

That is an option, but a SW SAGTI "only" costs 500-600, it'll easily take a DSLR and up to maybe an 80mm refractor and has goto, so a much better purchase than a star tracker.

The cheapest commercial star tracker Ive found is the Omegon LX, if you make a barn door tracker yourself it's even cheaper. But from experience, once you have a goto mount you'll wonder why you ever bothered with a star tracker, the goto mount can also be autoguided down the line for even better tracking accuracy.

I use my telescope as a star tracker for my DSLR by literally strapping it on top with a mechanism of my own devising. On the couple of occasions I have done it, this has worked pretty well. 

I was quite pleased to have a clear sky to look at the crescent moon as soon as I got home yesterday evening, and the air was reasonably still too.

Through the scope with a wide lens, the earthshine was very apparent, so I wanted to try and capture a view similar to what I could see by eye. By combining the above picture (single shot taken on Nikon D90 at 1/200s, ISO 600, prime focus on 5 inch SCT) with another of half a second exposure, I got the image below. I appreciate it's grainy and there are some weird colour casts (I think from internal reflection of the lit portion of the moon) but I think it works as a more artistic rather than accurate image. If you look closely there are two 9th mag stars showing up in it too.

I know what you mean. I spent about 70 minutes outside yesterday and then after I came in I was still shivering for the next two hours. I could have put slightly more warm clothing on but I was in a rush to set up and get pictures of the moon (I will post them later, they made it worth putting up with the cold). 

I think you gave the right answer. Because, like marriage, you have to be sure. If you aren't absolutely sure if you want a telescope, you shouldn't get one, because otherwise you won't have enough enthusiasm to work past the difficulties of practical observing. 

I also disagree with Gonariu's idea that you aren't allowed to get a telescope until you have completed the naked eye and binocular steps. But in keeping with my initial comment, most people who are really keen on getting a telescope WILL have done those things already. 

It's been clear the entire day in Hastings! A few wisps appeared around 19.00 but didn't stop me getting great views of the moon and watching Io and Europa disappear behind Jupiter within 5 minutes of each other. Hopefully got some good moon photos too. 

12 hours ago, Jim L said:

I can’t speak to the guitar world and I would not take the reviewer you’ve referenced at all seriously, but my experience contradicts the notion that Americans “are often very convinced that anything made in the USA is automatically superior.” In fact, I don’t think I’ve encountered that particular bias for as long as I can remember, so sometime in the 70’s or there about. It’s not really a thing here.

In fact, as far as Televue eyepieces are concerned pretty much anyone who owns or is contemplating purchasing any knows that they’re made in either Taiwan or Japan, and that none are made in the USA. Manufacture in those countries doesn’t seem to hurt either their popularity or reputation here in the States one bit.

 

 

My wife is from Massachusetts, so I have spent a good amount of time there, able to observe cultural differences. One of the things that struck me from spending time in the USA is how the term "American" tends to carry with it an undertone of "superior" in many of the contexts it's used in, in a way that just doesn't happen in other countries, especially in advertising. For example to a British person, a product advertised as made in Britain is very rarely assumed to be intrinsically the best simply because it's made in Britain. Whereas in America, advertising definitely leans on the angle "this product is better because it's the one made right here in the USA". This will be less perceptible to Americans because it's just "normal" to them. 

Regarding the eyepieces, yes they may not be made in the USA, but the reason that question comes up in an American survey is overall related to Americans putting a higher choice bias on where things are manufactured than most other countries do. It would be extremely unusual for a British company to ask something like that in a survey. 

On 07/01/2024 at 15:33, Don Pensack said:

 

I notice they asked whether we considered it important which country was the source of the optics.  Hmmm.

That’s unsurprising for an American manufacturer. Americans are often very convinced that anything made in the USA is automatically superior to something made elsewhere, with the view that certain countries can't make anything good at all. 

It's extremely prevalent in the guitar market over there. I remember shaking my head reading a guitar review that said "I was going to give this five stars, but then I noticed it wasn't made in the USA, so I'm giving it four". 🙄

Quite a few things seem to have been found by Guillaume Le Gentil (which I think translates as "William the Polite", doesn't it? Olly?)