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What's more likely, an error in a theory that has been demonstrated to conform to observations for: Earth based experiments Orbit of Mercury precession Shapiro effect Deflection of starlight during eclipses Binary Pulsar orbit decay Gravitational lensing Scale of anisotropy of CMBR or We can't see everything in a galaxy?

The maximum altitude for 'fixed' objects (stars and DSOs) will be the same regardless of the date - so if you select an object, the information provided will include the time of transit. If you then hit F5 and set that time , the information will give you the altitude at Transit.

My first piece of advice would be to get yourself a decent Planisphere, for example the Philips one (though not the gimmicky 'glow in the dark one') as that will give you a 'whole sky' view of what is up at the moment and has the brighter stars named. Second suggestion is that you try the Level and North alignment on the handset (I appreciate you didn't get on with it, but it's worth sticking with IMO) , you don't really need to know the names of the stars, as the stars selected should be amongst the brightest ones, and if your initial estimate of Level and North is close, then it should be pretty obvious which star it's meant to be pointing at.

Just a quick update for anyone who does a search on the A5000 camera. I found out today, that if you choose any of the 'Continuous' shoot modes, then the camera doesn't apply the Noise Reduction. The best mode to use is the Continuous Bracket mode - as this allows the use of Bulb mode for longer exposures than 30". If used on Bulb it doesn't actually do any Bracketing, it just takes the one exposure.

All Saints Church's wartime role is also mentioned here http://www.petershamvillage.org/history1.html

Two updates on the research: #1 I have found a contact in the Friends of Richmond Park - apparently a US Professor asked the same question back in 2011 so I've asked the chair of FRP if anyone was able to help him. #2 Independently though, a 2007 copy of the Richmond Historical Society Journal (issue 28) has the following article, so it seems very likely that this is the site used. You can buy a back copy for £5

In case people didn't read the full thread on why you shouldn't buy the A5000, the main issue raised is that the Noise Reduction (dark frame image) can't be switched off, so any long exposure is followed by the same length of 'processing', so a 1 minute exposure on Bulb will be followed by a 1 minute dark frame exposure before you can take your next image. However, this is not actually the case, as there is a Continuous Bracket mode which doesn't do the Noise Reduction. In fact, none of the continuous modes does NR, but only Continuous Bracket mode works with Bulb.

One of my astro club members mounted a TS 60 scope + dSLR on the Star Adventurer and used a repurposed 6x30 finder as a guidescope (mounted on the counterweight bar). Might be do-able within budget.

Hmmm, I have a Meade LS and I'm pretty sure it would be loud enough to be audible by the neighbours on a warm summer night if they had their windows open ! But Meades have a bit of a reputation for this. Fortunately, it's one I only really use at star parties or out in the middle of nowhere these days.

The NWAF is online this year, currently on YouTube https://m.youtube.com/watch?v=8l4RECl5Wq8

I think that's 6lb rather than 6kg, so should be easily within the capacity for the AZ GTi (According to here) .

I'm surprised you don't have an Identify button. Do you have the latest version? On my version (Android v1.17.0) the Identify button is inside the Utility menu.

You shouldn't need to tell it that you've manually moved to Betelgeuse, the Freedom Find encoders should have kept track. Once you have moved it, what happens if you go straight to the 'Identify' command on the app? It should tell you that you are on Betelgeuse (or near it at least), if so, then it's working as expected.

As has been said, it's not really a valid statement to say "an image has a magnification" However, if you know the diagonal size of the sensor, you can say the field of view is roughly comparable to that size of eyepiece. So, for example, the ASI 120mm camera has a sensor size that's 4.8mm x 3.6mm, so has a diagonal of about 6mm. If you were imaging Mars with that camera, then it would have a similar field to that you would get with a 6mm eyepiece. Yes, it's not an exact match, but as a rule of thumb, it'll do

I'd second the recommendation for the Heritage 150p. We have the very similar 130p scope, which is very well put together and gives very good results. Yes, look out for apps for your phone to work alongside it - Stellarium and Sky Safari are both very popular (personally, I prefer Stellarium, but YMMV). However, what I would really strongly suggest is that you get yourself a proper planisphere. These are made up of two discs that allow you to match up the date and time and they will show you what is visible in the sky all in one go, so you can see how constellations relate to each other. One thing that a planisphere does is show how the sky changes hour by hour across an evening, and also how it changes month by month across the year. You can often get one for less than £10 from places like The Works, either by themselves or with a 'guide to the night sky', and they are really useful for learning your way around the night sky.

That's interesting. I wonder how it's related to the 'Core Cusp Problem', which (as I understand it) says that for small galaxies, the Dark Matter should have high density knots, that we don't see. This recent report seems to be a complementary problem affecting assemblies at the other end of the galaxy cluster scale. https://en.m.wikipedia.org/wiki/Cuspy_halo_problem

Hi, I've been loaned an Altair Lightwave, and am trying to find out more about it. I have to say it's a beautiful scope to use under dark skies. Mounted on my AZ GTi it gave me great views of clusters, nebulae and the planets we were looking at earlier in the year. It's the first scope I've really been able to use with my 6.4mm eyepiece, so I'm beginning to see why people love their 'fracs. I can't see any references to it being on sale any more, so what would be its current equivalent?

When using a list for planning, you still need to consider surface brightness, as some things disappear as your skies get more light polluted, and many galaxies (for example) just get lost away from dark sky sites. This is a mock up of the difference seen between a Brecon Beacons dark sky site and my home skies (outskirts of a town). It's M13 which is one of the easier objects to pick out under urban skies, so you can see that fainter DSOs could well be more or less invisible.

I think the poster separated the illuminator and crosshair disc and flipped it, so that it went in back to front. If you have perfect vision, the final image is meant to be at infinity (otherwise you can get eye strain), but for people with uncorrected short sightedness, the final image needs to be closer than that. To move the image of the crosshairs hairs closer, you need to shorten the distance between the crosshairs and the eyepiece, and I think lack of focus adjustment made that a problem. I'd want to know more about the distances involved to be sure, but that's my best explanation from an 1970s A level physics standpoint.

I can concur with this. I've borrowed a 72mm refractor and when we were out in France at a relatively dark sky site, that scope on the AZ GTi was the most fun I've had with the scope in a long time - all GOTOs were spot on, and the dark sky meant that the targets were all easily seen. However, having tried the same set up here at home, it's clear that light pollution makes that 'small refractor' approach far less rewarding. It's good to hear that the scope can manage a larger refractor though.

The downside of the SkyMax is that it has a relatively narrow field of view, and a long focal length, which has two effects. - the narrow field of view means that you need to be spot on with your alignment or otherwise you could find your actual target is outside your field of view - the long focal length can reduce the contrast of extended faint objects There's a lot to be said for the Az GTi as a mount, and with a light weight scope it works really well - however, my experience of using it with the 127 Mak is that it's not always spot on with finding its targets, and not hitting the targets can be extremely frustrating (believe me, I know this !!) I would suggest going for a lower tech solution, and would suggest you start with a Heritage 130p manual dobsonian scope. It has a nice wide field of view, and gives excellent images of clusters, the Moon and planets (with a Barlow lens to give the extra image size). One advantage of this is that your son will be able to get it out and use it by himself. One feature of the Heritage over other 'table top' telescopes is that optics can be removed from the table-top mount and mounted onto the AZ GTi, which will give you the advantage of freedom find and wifi controls. Now, in fairness I have to say that I do have a 127Mak and it is generally the first scope I go to for observing - but I often get frustrated with it, and I can see how people can be put off when it doesn't work as well as I thing it ought to. In short, rather than risking you and your son getting frustrated by the tech, start by going for something that allows a simpler, lower tech approach to whet your interests. Hope this helps

I fear that many things included on 'Tonight's Best' tours are likely to come under the category of 'faint fuzzies', and if you're looking under moderate levels of light pollution, they may be much less obvious than you might expect. If you want to check out your scope's capabilities, start with things that are not going to be swamped out. So my suggestions would be... Start with Mizar and Alcor as it shows the power of the scope to clarify what you can just make out with the naked eye. Albireo in Cygnus - is worth looking at as a double star with different colours Epsilon Lyrae (the double double) is worth examining under higher magnifications, as it can help you determine the quality of your image - how well can you identify that each of the 'double' is also a double? Messier 13 in Hercules, should be visible under moderate levels of light pollution, but it will look better if you can get to a dark sky site. https://www.lightpollutionmap.info/#zoom=11.41&lat=51.7710&lon=-2.1932&layers=B0TFFFFFFFFFFFFFFF And, of course there are the two early evening planets, Jupiter and Saturn - if you can get to a location with a good South/West aspect in the early evening, it'll be rewarding to observe them telescopically. All the best with this - and clear skies.

If you're unsure, the SyncscanInit App on your (android) phone will give you the location and the time/zone data to enter into the handset in exactly the right format

As well as using apps as others have suggested, it can be an idea to take a pair of binoculars out with you as the wider field of view can make it easier for you to get a better idea of where the scope needs to be pointed. They can be used as an intermediate stage between 'naked eye' and 'finderscope' You can also build your own star hop charts to try to familiarise yourself with how to move between the bright stars and your targets. Attached is one I prepared for hopping to M81 & M82 using Cartes de Ciel and MS Word Word

I know Mercury's best evening visibility is in February, so it's a question of whether it is still reasonably possible to observe it a few weeks later, when it's good for the Messier Marathon.