Rob Sellent

Been here for about 8 weeks and to be honest SGL seems like a huge family from all over the world. There are lots of specific sections to dip into, many helpful, knowledgeable and very talented folk to bounce questions off, the mods are welcoming, sort without a fuss any problems and activily participate in the discussions themselves without a hint of pretension or affectation . The site is extremely generous in its bandwidth, as also with the type of threads that can be set up (just take a peek at the lounge!) and categories in general . In short, SGL is probably the best astronomy site in the world and until Fermi's paradox is significantly addressed, no doubt the best in the known universe. I'm thoroughly enjoying my stay and glad I came aboard. I just have a couple of questions/suggestions: the profile page has a category called "day's won". What does this mean? How does one win more days? And can one lose days? would visual observers be interested in something similar to the imagers challenges and competitions? Not to clutter or make more sections, but within the observer's sections, say? (tricky double stars of the month challenge, awkward lunar feature or sketch challenge of the month etc) would a section on reviews be amiss (books, films, docus, shows, star parties, software, podcasts etc), related, of course, to astronomy & science? Not something like, 'this is worth seeing/reading' but actually a short review. Again, thanks for everything . Rob - - - - - Welcome to SGL @Theoldboy You're very fortunate to have no light pollution and neighbours to boot . Can't go wrong with a 10". I thnk a 10" or 12" are kind of the goldilocks of Dobs. I look forward to meeting you on the boards.

Sure, but the stars will be above them

Dan, I wrote as much the other day, but a similar idea will also suffice here. If possible take your time. Try to appraise your gear first and then you'll have a better idea of where you want to go and how you want to get there. I feel you ought not to upgrade or buy anything until you know you are missing something that is essential to your astro-sessions. If you're a relative beginner, slow down, for it's going to be tricky to make a sensible and informed decision. Regardless of the excellent advice you'll get here at SGL. Moving on...for general observing, that is pretty much everything but planets, moon and double stars - I tend to just stick to 3 quality eyepieces and from time to time a decent x2 Barlow. With something like an 8" f6, I'd like to work with a low power wide field between 20mm to 24mm (depending how dark my skies are), a middle power wide field around 13mm to 14mm and a tad higher power wide field around 10mm. That way - including the Barlow - I've got about 50x, 90x, 120x, 180x and 240x. The lower focal length eyepiece is nice for general hunting and framing largish objects, the middle grounds for globs, galaxies, nebulae, the higher powers for Saturn, Jupiter and Lunar work and the 240x for those exceptional nights with the planets, Moon or tighter double stars. If you got yourself a Baader solar filter from FLO, your 50x would also double up nicely for white light solar observations. In general, in this hobby you get what you pay for. Like scopes and mounts, some eyepieces are considered to be better than others. Needless to say, my general percept when it comes to buying stuff is to buy once and make it count. Although initially expensive, premium eyepieces such as TeleVue, Pentax XW etc will turn out to be the cheaper option in the long run and are never going to be a waste of money. When buying premium you only cry once. Or again, paradoxically speaking, "a poor person cannot afford not to buy premium." Let me explain. Generally speaking, premium eyepieces - unlike scopes - become lifers, you never have to upgrade again or you can always re-sell them without losing much money, especially if you have bought them already secondhand. Premium eyepieces hold their value more than cheaper ones. They also offer an important psychological benefit. After a session, you are not left with any nagging feeling of 'what if...', for you know that this end of your optical system is about as good as it is going to get. If the view was poor, if you didn't get the expected detail, it will not be due to the eyepiece itself. This ties in with what was said at the beginning. All you really need for your 8" f6 are 3 decent eyepieces and a decent Barlow. And there is no hurry in accumulating them. Spend your time scanning the secondhand market, for if you start out buying cheap, you'll either lose a significant percentage of money when trying to resell, or you'll eventually end up upgrading and again lose money, for in this case, not only are you buying the upgraded eyepiece, but you've already spent a load of money on the cheaper eyepiece. So, for the moment don't spend your hard earnt cash. Get to know your kit a little more. Oh, and welcome to SGL and I look forward to meeting you on the boards

I have a homemade cap but never found it of much use. If you want to make a cap, you can either follow this type of description, or just get yourself an empty 35mm film canister, cut the bottom off, then drill a hole in the center of the cap (where the dimple is). However, Moonshane's tip-top-tip milk carton washer thing and collimation guide is the business . And not a mention - if I recall correctly - of caps. Suffice to say, the Cheshire should be fine for collimating a Dob.

Dan, just a quicky, what is it that you want to upgrade on? Field of view, eye-relief, field stop, possible sharpness and contrast across the field, dodgy aberrations that you've noted in your aforementioned eyepieces, brand name? What do you think you are missing that is essential to your astro-sessions?

Can't add to what others have already said but just to add voice to the discussion. If field of view and eye relief isn't a big concern, then for good quality planetary eyepieces, I've found Baader Genuine Orthos a good move. Indeed, the quality of image is as good as something like a Delos. I have also used Tele Vue's Plossls and have found the quality of image as good as Tele Vue's more expensive glass. However, I find eye-relief with them more uncomfortable than with the Orthos and personally wouldn't recommend going less than 11mm. Like @alan potts, I have a couple of TV plossls in a box but haven't used them a great deal.

@mikeDnightI'll let you in on a little secret, Mike. Doing a bit of research I came across a post you had made about an old Vixen 4". How it turned you onto fluorite and how you ended up with the gorgeous Tak. So in effect, since around the end of 2018, I've had 3 options. Save hard for a Tak that you, @John, @Stu have all enjoyed. Save for the SW 120ED but also budget for a bigger mount/tripod or look for an old Vixen fluorite. And in this three way limbo I sat for around 8 months. Then around August I saw an advert at APM selling an old Vixen FL102s. I went back to your post explaining how great the scope was. I returned to a few other posts (such as those by @F15Rules) mentioning how good old time Vixen refractors were and I figured, it's now or never. As soon as I put in a bid at APM and got the thumbs up from Marcus, I joined SGL . The only thing bugging me know, Mike, is did you paint your AZ4, or did it come in that gorgeous colour?

First of all, I'd like to congratulate you on your new telescope . The 8" Dob should last you many many years, if not a lifetime. Now, I appreciate that nights can get cold ⛄ and on those occassions there's no harm done viewing from open windows but whenever possible try to avoid this option. As @John has already explained, looking from inside the house through open windows causes drafts 💨 and general air disturbance 🌪️ which will seriously compromise seeing. You may think, 'well, I'll just close the window.' And although a reasonable conclusion, again, it's not really going to help. The window's optical quality cannot match those of your mirror or eyepieces, so you're degrading the image once again. I'm going to put on my lectuer's cap on for a moment . If possible take your time. Try to appraise your gear first and then you'll have a better idea of where you want to go and how you want to get there. I feel you ought not to upgrade or buy anything until you know you are missing something that is essential to your astro-sessions. If you've hardly used your scope, it's going to be tricky to make a sensible and informed decision. For general observing, that is pretty much everything but planets, moon and double stars - I tend to just stick to 3 quality eyepieces and from time to time a decent x2 Barlow. There are as many tastes and budgets as there are colours, so it's tricky to say, x, y and z are the eyepieces you need, but for me, with something like an 8" f6, I'd like to work with a low power wide field between 20mm to 24mm (depending how dark my skies are), a middle power wide field around 13mm to 14mm and a tad higher power wide field around 10mm. That way - including the Barlow - I've got about 50x, 90x, 120x, 180x and 240x. The lower focal length eyepiece is nice for general hunting and framing largish objects , the middle grounds for globs, galaxies, nebulae 🤩, the higher powers for Saturn, Jupiter and Lunar work and the 240x for those exceptional nights with the planets, Moon or tighter double stars. If you got yourself a Baader solar filter from FLO, your 50x would also double up nicely for white light solar observations. As it stands, then, I wouldn't recommend 6mm for your scope 😕. Maybe when you've got to know your kit and skies a tad better, you may feel the need for a dedicated high power but understand that 200x will probably be your maximum mean power during a given year, is not particularly suited for things like galaxies or nebulae or open clusters and seeing conditions will not always allow such magnification. It's a bit of dilemma to advise what's best because some prefer no filter, some prefer an ND filter, some prefer a variable polarising filter, some prefer Moon & Sky Glow filter, some prefer using colour filters, some prefer a neodymium filter, and so on. However, there is some good news 🤗. I find the intensity of light isn't so much based on the scope itself, but rather what phase the Moon is in. So, again, lecturer's cap on, before going any further, it might be a good idea to observe the crescent Moon 🌜and see how you get along. If you still don't like the light's intensity, you'll probably need to experiment a little. Borrowing filters from an astro-mate is a possibility not many of us can enjoy, so failing that purchasing and trying out the filters is realistically the only way you will be able to find out what works best for your eyes. Personally, I wouldn't bother with a Moon filter but if you did find the need, try to double its work 😅. For example, purchase a polarising filter for the Moon and Sun (with the solar filter, of course!), or purchase the neodymium filter with an eye also on Jupiter and Mars as well as the Moon, and so on. I find that in general in this hobby you get what you pay for 🤑. Like eyepieces, like scopes and mounts, some Barlows are considered to be better than others. Needless to say, my general percept when it comes to buying stuff is to buy once and make it count. Although initially expensive, premium eyepieces or Barlows will turn out to be the cheaper option in the long run and are never going to be a waste of money. When buying premium you only cry once 😫. Or again, paradoxically speaking, "a poor person cannot afford not to buy premium." Generally speaking, premium eyepieces/Barlows - unlike scopes - become lifers, you never have to upgrade again or you can always re-sell them without losing much money, especially if you have bought them already secondhand. Premium Barlows or eyepieces hold their value more than cheaper ones. They also offer an important psychological benefit. After a session, you are not left with any nagging feeling of 'what if...', for you know that this end of your optical system is about as good as it is going to get. If the view was poor, if you didn't get the expected detail, it will not be due to the eyepiece or Barlow in itself. This ties in with what was said at the beginning. All you really need for your 8" are 3 decent eyepieces and a decent Barlow. And there is no hurry in accumulating them. If you start out buying cheap, you'll either lose a significant percentage of money when trying to resell, or you'll end up upgrading and again lose money, for in this case, not only are you buying the upgraded eyepiece, but you've already spent a load of money on the cheaper eyepiece. Again, this ties in with what has already been mentioned. Get to know your kit. Get to know what you are missing that is becoming essential to your astro-sessions. Then you can set up threads here on SGL and get some tip-top advice 🤪. This is the type of collimator I used for more than a decade before getting into Howie Glatter's dream collimator for a faster dob. The former is a good tool and as @Trikeflyerhas already stated, will do its job just fine. I'm not sure of the exact science involved but it seems that most astronomy gear, especially when it's new, emit Moiston molecules. Moistons group together to form huge clouds. The full Moon is capable of absorbing Moistons and thus giving us relatively clear nights on full Moon nights but reemits them as it ebbs towards becoming new again 🌚. Moistons also collect inside unopened telescope boxes and are released into the atmosphere whenever a newly purchased telescope (secondhand or not) is opened. This is the reason why companies such as FLO supply their telescopes with the warning, 'may contain clouds'. Here are a couple of pics which better describe the situation:

@mikeDnightThank you for the great advice and information. I was out last night and noticed that in conditions of good seeing the frac wasn't running out of puff around 150x, so as you say, a 5mm would be a good bet here. I've read many posts and seen many sketches here on SGL and have noted that you don't appear to have a problem with short eye relief. You're either a brave man or have bionic eyes I think you're right to point out to not be afraid. As you say, if it works, use it. What I'll do it is either go for a dedicated 5mm XW or Barlow the 10mm and 14mm Delos I already have and purchse a 6mm Delos. I'll also see how I get along with higher magnifications and if I'm comfortable, I'll definately look into those Vixen HRs. Thanks again, Mike

Due to chronic weather in Spain, it’s been almost a month since I’ve been able to head out and observe the night sky. However, forecast for Tuesday night was spot on and I was able to enjoy a good session on an extremely warm and still autumn evening. With the Vixen fluorite already cooled, I decided to focus attention around Cassiopeia and Perseus, mainly concentrating on objects within that part of the Perseus Arm which stretches across the sky from Cassiopeia through Perseus and later on in the season down to Auriga and Gemini. As can be seen by the following image this area of the night sky is a rich source of targets for the amateur astronomer. I started with NGC 957, a loose open cluster around 7,200 ight years away and the pretty yellow pair of stars known as h2143. From here I then spent quite a while with the famous Double Double (NGC 884 & 869). Visible in the night sky as an indistinct smudge of light, enough has been written about this pair to know that it is a gorgeous expanse of blue-white supergiant stars sparkling amid a scattering of cooler red supergiants. The 19mm Panoptic spilled over with stars and the more I spent at the eyepiece the more stars came into vision. At a similar distance from Earth to NGC 957, the Double lies over 7,000 light-years away and each of its clusters are several hundred light-years apart. Guided by a paved arc of stars, pausing only to view the easy double Struve 230, I was greeted by Stock 2 or the Muscleman Cluster, about two moons wide and made up of around fifty or so icey blue stars. Hard as I tried I couldn’t see the headless muscleman and whilst not as showy as the Double Double, Stock 2 does have its own delicate beauty. Other clusters picked up around this area were: NGC 743, 744, 957, 654, 663 and 659. NGC 663 otherwise known as the Lawnmower cluster, is a particularly stricking cluster worth hunting out. In the 4” there is a rich grouping of stars at its centre whilst dozens of other brightly lit stars gleam across its surface. At about the same distance from Earth as the other clusters we’ve seen, if viewing with more than a degree of field of view, one is also able to pick out the fainter cluster, NGC 659. Moving up I spent a moment or two with the wide open cluster M103 before finishing my cluster evening with NGC 743 and the Owl cluster NGC 457. A good three hours had passed by. I said goodnight to Pleiades rising above the garden’s gate and the princess of the autumn skies, M31 or the Andromeda galaxy. As a final note of interest, the star light that was enjoyed this evening, left those gorgeous gems around the time the human race was getting on with the agricultural revolution. A revolution which introduced the necessary ingredient that would make civilisation and culture possible and with it the fruits of complexity, science and art but also all the problems we still face today, subjugation, warfare and endemic disease.

Cracking image @astroavani and glad to see you had time to put together such a gorgeous image

Outstanding image, @MartinFransson. Thank you for sharing your photography with us

@Rodd I apologise if I don't visit the imaging section that much - do imagers check out the sketchers section etc? - but I just wanted to say I find your photography outstanding and a joy to see. The two images supplied in this thread are absolutely gorgeous

Thanks for the lunar links @Stuand your insights into the binoviewers. I can appreciate that Barlowing long focus length eyepieces would probably make life easier and probably double up quite well without the Barlow for solar viewing. I'll keep my eyes peeled on the secondmarket and if a pair come up, I'll probably go for it and have a little play . Thanks for the eyepiece suggestions @John. I've been playing with the Orthos and feel I definately need something around the 5/6mm range. In my younger days I never had a problem with Orthos but either due to age or being spolit by more comfortable eyepieces, I find it difficult to use the shorter focal lengths. I'm split at the moment between the XW at 5mm or the Delos at 6mm. A nice position to be in

Ohh, this sounds like a good test for the Vixen. Clearly, I'm a very poor lunar observer for I've never seen the Rille, Stu . Do you know when the best time to do so would be? And here or elsewhere, it would be nice to hear how your 8" planet killer gets on and how you think it compares to your fluorite

@Stuthat's excellent advice and words of wisdom, Stu It's both your own and @Johnposts about binoviewers that have kept me on the fence but I think when funds allow, I'll just have to get on with it and bite the bullet. You're right about being able to push more than 1mm and in this case it's not so much the optics which run out of puff and not always the seeing conditions which limit high powers but the eyes. The snag is although - as you so rightly point out - aperture is the antidote to tight exit pupil, I prefer viewing planets and the Moon and the star fields etc in the 4" than I do in the bigger 250mm scope. It's just a pretty picture @BGazingthank you for your help and thoughtful post, Bgazing and I think you're right about the 6mm. It'll give a perfect 150x and isn't horrendous regarding exit pupil. The seeing here is often good but I feel anything less than 5mm will be compromised by my eyes. The floaters will become just a little too annoying. I've never heard about the ZWO ADC, so thank you for pointing that out. I'll have a read and look into it. I'm down in Spain, so I figure the planets are just a tad higher than they are for our northern European friends. Sadly, Jupiter and Saturn are dipping down now before I can get out to view, but this is also good news for it'll give me chance to work through my kit and see what we can come up with before next year and the return of Mars 😀

It's interesting you mention binoviewers, Louis. I think when I've had a little more use of the FL102, I might look into it. The thing holding me back is not only price but of the mixed reports, some folk enjoying their use, others who simply can't get on with them. I'd take the risk in the UK with the fluid secondhand market, but here in Spain there's really very little activity. Regarding exit pupil, at the moment I'm 'comfortable' down 0.6mm/0.7mm. Below that, I just can't blink away the floaters.

Welcome to SGL, Cary . Great idea about the bins to get a grounding on the night sky. Look forward to seeing your sketches and artwork

Thanks for going through that @Ruud I appreciate that you're putting in a lot of work but from the results of your sketches, it's definately worth it. I'm blown away not only by the way you have figured out a phenomenal way to sketch the Moon, but from that foundation the way you go about layering in the features and tweaking detail. Amazing stuff. I think your artistic temperament to go for the evocative, impressionistic approach as opposed to some kind of extreme realism pulls of a treat. The latter can leave one a tad 'cold' whereas your own leaning realises the moonscape in all its parched and desolate beauty. Again, thanks for taking your time and going over this, Ruud. Much appreciated and won't be forgotten

I think it would be a lovely idea of some of the active sketchers on SGL could give a little insight and tips into their art. @mikeDnight, @Ruud, @kuvik, @Wiu-Wiu, @Mike JW, to name a few, are all currently active and produce outstanding work

Absolutely amazing sketch, Ruud . I've just a couple of questions I hope you don't mind me asking? What mediums were you using? It looks like chalk, it looks like brush work. I just can't figure what you've done other than a spectacular drawing . What scope were you using for the evening's view? Also, how do you think your TV 4" compares with the 6" SCT? Sure, I understand they're different beasts but I have a little TV 76 and found it outperformed a Mak127 on everything except frustration in use and was wondering what your own opinions were with the 6".

Got it, @LDW1 It looks like the calculator's 'optimum' power range is based on exit pupils between 4mm to 2mm correspondng to the aforementioned 36mm to 18mm eyepiece focal length. Your own millage may differ but regarding exit pupil, I've found: 6mm - 4mm - nice for star fields and large open clusters. 4mm to 3mm - nice contrast, good on star-fields. 2.5mm to 1.5mm - nice for most DSOs and casual lunar/planetary viewing. 1.6mm to 1mm - nice contrast and resolution on planets, Moon and globs. 1mm to 0.5mm – finer detail on planets, lunar, tight doubles - dependent on seeing conditions. 0.5mm to 0 – super tight doubles but really not much call for use. Needless to say, my enquiry was mainly about that 1mm to 0.5mm range where even a 1mm difference in an eyepiece's focal length makes quite a bit a difference. It'll be interesting to hear about your own experience with exit pupil and how it compares with the little table above

Olé That looks the absolute business, Stu You must be super chuffed finding that gorgeous looking place, quintessentially Andalucian El Gastor is part of the White Village route and is known as, The Balcony, which is just another way of saying you're going to get some spectacular views and the entire area will create a lovely backdrop while you're sipping on your chilled white wine and zooming in on Jupiter. Not only that but you're in fine reach of some amazing towns like La Ronda etc. The outstanding guitarist and one of the fathers of modern Flamenco, el Gastor is from the village . I imagine you'll be driving down from the north, so any further tips or help I can offer, just let me know

Thank you, JG. Since the report above I haven't been able to give the frac much play. Being such an old scope, it must have been chocked with moistons, for we've had almost a month of nonstop cloud, intermingled with unprecedented floods and freak electric light storms. I'm crossing my fingers for a clear night on Tuesday. The Vixen SD range look the business and by all accounts have outstanding optics. I was almost on the verge of purchasing the newer Vixen 4" when the old fluorite was spotted and I figured I'd take the risk. You mention 1990. Those years seem like yesterday but they were almost 3 decades ago . Where did all those years go?

Stu, I've visited the Cadiz area on a number of occassions - camping, Spanish Hostels (not to be confused with UK ones), and even posh hotels 😀 However, the last visit was possibly just under a decade ago, so any information I give might be a little out of date. Along with the coast around Almeria, the Cadiz area has some of the finest 'wild', non-built up beaches in southern Spain. The main differences are that the Cadiz beaches are rockier and windier. As such, although amazing places to visit and chill out, I'd be wary of carrying my optics down to the coast. If you're into your coasts, your seas and beaches, and havens of peace and quiet, you have to pop along to some of these: Los Caños de Meca Bolonia Zahara de los Atunes Call me a snob, but not a skyscaper or drunken lout in sight If you fancy a number of white washed abodes and some tasty food, El Puerto de Santa María and Sanlúcar de Barrameda are both worth a visit. They'll be packed in July with Spanish families but such is the nature of things. Other places to visit in a day would be, Arcos de la Frontera, Jerez de la Frontera, Vejer de la Frontera, Medina Sidonia, La Suara National Park, and Doñana National Park. I really can't comment on whether it'll be best to rent a villa in the mountains or down nearer the coast. Rather than focus on astronomy, I'd keep an eye on what activities you were wanting to do during the day and early evening. The coast will have a lot more going on but will be pricier. The mountain areas will be more relaxed, perhaps cheaper and more secluded but you may feel a little cut off. I'd also like to comment on timetables. Often tourists will come over and yet continue with their home timetable but I feel this is an error - as if I could come to the UK and continue with my Spanish timetable! Typically, in the summer, you'll have your breakfast and enjoy the morning, then around 2pm, if you're eating out, you want to order 'el menú del día' not 'a la carta'. The menu should give you 3 plates, bread, and wine all included in a very reasonable price. After lunch only fools head out. It's just too hot. You want to stay indoors, or near the pool until around 7pm or 8pm and then enjoy the evening with light snacks/tapas. Again, in the evening there is no 'menú del día', so if you do order 'a la carta' expect to pay handsomely. If there's anything else I think of, I will continue to add here, but for now I have to go to lunch