Gfamily

I use a Celestron 6.1 Ah Powertank Lithium LT for power - holds its charge for ages and works very well with the AZ-GTi https://www.firstlightoptics.com/batteries-powerpacks/celestron-6-1-ah-powertank-lithium-lt.html Though it has to be said there's a lot of fans of the Talentcell power pack here, and it does seem to be a more affordable alternative. I can recommend the use of the AZ GTi with Sky Safari 6 Plus software - once aligned with Synscan Pro, you can then select items in SS6+ and simply "goto" them. It's worth waiting until they have it on a half price deal though.

Thanks all for the suggestions. I was thinking of a straight replacement, but going up to a wider angle field might be an alternative. Hmm, decisions, decisions. We're currently away, and I have an old Skywatcher 10mm kit eyepiece to make do with.

Any thoughts? I have a 127mm Mak, the use of a 70mm f/5 refractor and an 8" SCT that doesn't get out much.

A lot (an awful lot) depends on your skies. I have an AZ GTi that have used at home (Bortle 7/8) for planetary with a 127mak, but at our summer place in a Bortle 4 sky, it's just amazing with a 70mm refractor. Literally, with the darker skies, this (with the 70mm refractor) is the most fun with a scope that I've had, I think because: Nice wide field of view - so Open Clusters look great against the background High Contrast - because using a refractor with no central obstruction I am sure if I am finding my target - with a nice wide field of view, and a nice high contrast - not too expanded area, you can be pretty sure if your 'target' can be seen. I also have an 8" SCT, but I wouldn't bother taking it out unless I wanted to go to a specific dark sky area for a star party or similar.

The solution (for Cartes du Ciel at least) is to use the Setup | Catalog... | Catgen utility. I can download the Bright Star Catalog (9110 stars) from CDS Import into Excel and remove rows that are brighter than Mag 3 Save as a text file and use Catgen to create a binary indexed file. Use this file as the only Catalog for CduC and all the familiar star patterns disappear

With Saturn's return to opposition this weekend, it's worth suggesting that people look out for the particularly bright appearance of the rings due to the effects of backscatter. Also, it's 411 days (to the day) since Galileo first saw the rings through a telescope. Though it took another 49 years before Huygens recognised that they were rings surrounding the planet.

It's mostly the software that allows multiple images to be stacked that makes the difference. This is what allows individual frames in a stream to be assessed for quality,and thus the best x% of frames to be stacked. Then, using wavelet processing to apply Fourier processing to sharpen the image. Yes, the quantum efficiency of our imaging devices has improved, but for planetary, i would say that 70's film tech was perfectly adequate, so it's the stacking that makes the difference.

It's not generally known that the GAIA satellite has problems with getting data for stars brighter than 3rd magnitude. For these, the image 'bleeds' which means that the stars' data needs to be subjected to specific data processing to be able to get data at the same level of precision as for other stars*. I would like to put together a modified sky map, to show what our sky looks like without the brightest 230 stars - but I'm not sure whether it's possible to take the 'standard' catalog for either of these two programs and edit it to remove the brightest stars. Does anyone have any suggestions on how to do this? * We're fortunate in fact, before commissioning, it was thought that GAIA would be limited to getting astrometric data for stars brighter than 5.7 - which would exclude practically all stars visible to the naked eye.

Did that at a star party once, but fortunately only for the second scope. I can recommend the SynScan WiFi dongle, as you can run that from a phone, or a tablet if you've forgotten your phone, and if you've forgotten both you could probably borrow one (people are more likely to have a spare phone than a spare SynScan handset ! ).

Excellent suggestion. To which I'll add Newgrange (or the whole Brú na Bóinne site). A fascinating visit including a guided tour of the Neolithic monuments. When we were there, English Heritage members got free or reduced entry (can't remember which).

Skywatcher are certainly putting out some interesting new products.

Personally, I would be looking for a longer focal length EP rather than a shorter one. Under dark skies, a wide field eyepiece can give lovely punchy images; over-magnification is a real risk if you use a too short eyepiece, and a wider field of view can give you the pleasure of seeing things in relation to each other. I think you have a Heritage 150 - which is an f5 scope. A general rule of thumb is that most of the time you won't get excellent views with an eyepiece shorter than your f ratio - so although a 5mm eyepiece might be useful - a 2x barlow and the 10mm is likely to give you as good a view as an affordable 5mm EP. An alternative to a 2x Barlow is a cheap zoom lens - the SVbony 7-21mm is nice and light, and has a decent range - a relatively narrow view at 21mm, but nice images as the power increases. That and a 32mm Plossl would be my suggestion - of course, other people would have other suggestions. ETA - oh, and M31 is amazing in its ability to underwhelm. It is so broad, and relatively featureless so it just looks like a misty smear in most cases (overall, what you see in photographs is 6x the diameter of the moon, so you only get the central bulge in the eyepiece view, and that's fairly featureless unless you're under a very dark sky when you might be able to make out the hint of some lanes)

One thing to remember is that in the Summer months, the further north you go, the shorter the astronomical darkness (and for much of the UK you get; none at all between June and July) so Cornwall will be better than Kielder. If you can travel later in the year, there's a stunning campsite on the top end of Loch Morlich, below Cairngorm summit. The campsite has low level illumination, but you can walk through some woods onto the beach by the loch and it's as dark as I've seen in UK,

Fforest Fields near Brecon has a very good reputation - particularly what they call 'the upper field'. I've not been myself, but I think I read there are electric hookups there as well. https://www.fforestfields.co.uk/campsite-wales

I would say that launch is probably adequately insured and won't be an issue; however, to me it feels that deployment is the issue - and they're definitely uninsured risks.

Oh good to know the launch has beenput back - we'll nip out to the shops now

As well as the problem with the Dobsonian not being a tracking mount, it is very likely that you can't get the image to focus directly onto the dSLR sesnsor as the focuser doesn't rack far in enough.

Excellent choices there TC - one of my favourites is The Curious Cases of Rutherford and Fry - particularly the Podcast version where you get extra chat between the two. Their chemistry is just great.

I think it's fair to say that there isn't a single formulation of MOND that hasn't been ruled out for one reason or another. There may be new formulations that haven't been tested yet. As I recall, even Milgrom accepts that MOND requires some form of DM to make things work.

Consider you're a goalkeeper standing on your goal line, and the other team's goalie is holding up a 6x4 photo. That's the area of the sky that the XDF image covers.

Those papers discuss long term cumulative damage to the lens and cornea, and it is true that UV does cause damage, but the question in this thread is about the dangers (or otherwise) of observing, where an image is formed at the retina. Just like using a magnifying glass to start a fire, it's the IR light that causes the heating that causes the damage to the retina.

The radio telescope at Nançay (in the Cher Department of central France) is an interesting visit - firstly, as a different way of having a radio telescope - but it also has a good visitor centre. In terms of the Michelin Green Guide, not necessarily "worth a journey", but worth a detour - it's a good two or three hours. https://en.wikipedia.org/wiki/Nançay_Radio_Observatory

Jodrell Bank Discovery Centre is local to us. Smithsonian Air and Space Museum in DC and the Udvar Hazy Centre out by Washington-Dulles International Airport. The Armstrong Air and Space Museum at Wapakoneta, Ohio ( a surprisingly good selection of items and books in the shop)

A friend was observing one of the Galilean moons and saw it emerge from behind Jupiter, move away from the planet and then disappear again as it moved into Jupiter's shadow. This was possible because Jupiter was some way off opposition, so the shadow went off at a fair angle.

I can't see that it would affect your focal length, but it will increase your focal ratio (in that it will reduce your aperture by about 1cm - I reckon about 0.5cm at each edge)