exe_hibit

Hi Jim, i've done all-sky brightness checks of various places on Exmoor, the last one I did was after the first lockdown but before this current one (so reasonably current). As a general rule of thumb for Exmoor the darkest views right down to the horizon are to be had to looking to the South and West (this is assuming you don't have any localised light pollution problems near you within the park). Everywhere else don't expect any miracles below about 15degrees altitude, especially from the North West round to the East where there is a pretty much solid and continuous light curtain of white and yellow light (from various origins). For Exmoor's case specifically it is such a small and light-vulnerable national park that zenithal sky brightness (often quoted on light pollution websites and dark-sky associations) is not representative of what you see as a visitor/resident. Let me know if you need any more info, I probably can give you a more definitive answer if you want to pm me your location. Kind Regards.

Many thanks, good spot Likes: Nice reference book with a good balance of theory and reality. I like the diagrams and photos, they are really clear and straightforward. I like the licence (https://creativecommons.org/licenses/by/4.0/) for if you want to use the material for other purposes (e.g. astronomy club presentations). Dislike: I can see it has been peer reviewed but my main gripe with it is the complete lack of referencing of where the source material was collated from. If this is the first edition of a document which is going to be updated it would be good to see the references added in the future. I guess it will depend on who the authors are aiming it at.

Hi, does anyone have any experience of observing along the coastline between roughly Salcombe/Soar and Newton Ferrers. We are thinking of moving house in that direction and was looking for some opinion on the 'perceived' darkness of the 'whole visible sky' (i.e. not zenithal opinions/SQM readings), ideally with the opinions either compared with other dark parts of Devon/Cornwall (or compared with well-known dark observing locations in the UK/abroad). I know its a dark area (possibly some if it darker than the darkest parts of Exmoor) but with the past 7 months of almost constant cloudiness plus now not being able to get out there at the moment because of the CV has put paid to testing it, Also does anyone know if there are any plans to protect/recognise its darkness? Many Thanks

Hi Rudd, thanks for the reply I don't use glasses and my last visit to the optician came out all clear for both eye clarity and focus, etc. Yes all fine with seeing at infinity. Age wise, just assume roughly a 5mm exit pupil (currently more because I want an image brightness at least as good as my current setup than because of my age, but also I am planning on keeping the scope for life so still best to stick with around 5mm)

Hi, I am looking to purchase a wide-field refractor to use with my existing Nagler 31 eyepiece. I am looking to get approx 6 deg field of view with approx 5mm exit pupil, and my two shortlisted scopes which will achieve this are the William Optics GT71 and the Takahashi FSQ85. Both are good scopes but one is more than triple the cost of the other. I can see from various online reviews and tests that the FSQ85 in visual use (rather than astrophotography) ticks the boxes for field flatness (in visual mode), but i can't find the same anywhere about the GT71. Note that I can't fit the field flattener in visual mode. So my question is: i) What is the field flatness/curvature like using the GT71 in visual mode with long focal length eyepieces (what sort of percentage of its field of view could I expect to 'feel' flat with pinpoint stars)? Evidence-based opinions would be appreciated please Many thanks in advance

The annual sky measurements and light pollution modelling show the darkest skies are in the vicinity of the area called Blue Gate/Deer Park/Drybridge Coombe, approx 2km SW of Simonsbath, but like everything in life it comes with trade offs (horizons, some hedges, etc). It also doesn't mean other places on Exmoor are bad; a number astrophotographers prefer the south-western side of the park (imagine an area bounded by B3223 to the East and B3358 to the North).