Tiny Clanger

Simple physics isn't it ? I find it fascinating the way that some things like this fall outside general 'common sense' and loved working out how to explain it to the small folk I used to teach. Heather

It will be no surprise to anyone who reads the beginner kit threads on here that I'm going to chip in with great enthusiasm for the heritage 150. It ticked all the boxes for me as a first 'scope : price, aperture, ease of storage, I could not find anything to compare with it. If you've read around on here about the heritage, you'll know all about making a light shroud and doing the easy plumber's tape mod on the focuser, you will also want to think about a good stable stand, base or small table to raise the little dob to a workable height. Get the dob, and spend some of the money saved on a copy of 'Turn Left at Orion' an 8mm BST starguider eyepiece (to replace the horrible stock 10mm skywatcher bundles with every reasonably priced 'scope, the bundled 25mm is OK though) and a 32mm plossl to use as a wide view and 'finding stuff' eyepiece. Go on, get buying before the xmas gift rush snaps up all the good, well priced stuff ... Heather

1) to an extent. It will help, and delay dew condensing, but it's not perfect . It is, however, cheap and easy to make, so why not do it ? 2) I've not checked my sources , in fact I've no idea where I read it, but somewhere I came across a suggestion that the max. length for a dew shield (i.e. before it started to vignette the corners of the view) was 1.5x the aperture . Ha, I've found my bookmark, there's a formula in post #6 https://www.cloudynights.com/topic/486858-dew-shield-length-how-long-is-too-long/#entry6374801 3) Foam works fine, I started with cheap camping mat , but when I ordered some closed cell foam to make a shroud for my heritage dob I bought enough of the thin black closed cell foam to make a dew shield for the little dob and one for ny 127 mak, which is very dew - prone . The thin foam works really well. I looked at proplex, (or corriflute) which is essentially like corrugated card, but made of plastic (estate agent's signs are often made of similar stuff) but for a small diameter tube I didn't like the way it creased along the channels rather than making a smooth curve (sorry Wickes, that was me experimentally cracking the top sheet in the stack...) I also wondered if the open channels in the proplex might hold moisture. So, I went with this stuff https://www.efoam.co.uk/closed-cell-polyethylene-foam.php It is closed cell, so does not absorb water, is opaque, dark and dull, so will help avoid extraneous light as a bonus. I used 3mm thick , but for a larger diameter aperture 'scope I'd suggest going up to 5mm or more to avoid it being a bit floppy if there's a breeze. I did a bunch of experiments to find out how best to glue some velcro onto it , and the best glue I found was hot melt glue gun stuff, which surprised me as I has expected the hot glue to melt the foam ! A year on, and all the things I made are still going strong. I found the self adhesive velcro stuck to itself far better than it did to the foam., total waste of money, simple velcro + the correct glue for the job is far better. Heather

On here second hand BSTs usually go for around £35 , they don't hang around long , get in fast if any become available. At that price they are a risk free investment, anyone buying one and wanting to upgrade in the future can sell it on again easily. I wasn't confident that I'd see any improvement over the stock skywatcher eyepieces by spending more, so tried a skywatcher 17mm plossl , which gave far sharper views than the 10mm stock one, albeit at a lower magnification (the 25mm stock ep is actually OK though, don't rush to replace that) . Convinced by my personal experience in my 'scope (at the time, the heritage dob) I tried a sw 12.5mm plossl, hated it, bought an 8mm BST and saw how much better , sharper and more detailed a view it gave than the stock 10mm or 12.5 plossl . The BST's eye relief and 60 degree field of view are greater than a plossl too. Heather

Something just struck me ... despite being never further than arms length from a DSLR (well, except when in the bathroom ) , and having at least two adequate tripods not actually occupied with telescopes available to deploy, it didn't even cross my mind to try and photograph the aurora , I was too fascinated with just looking. I think I'm innately safe from the dangers of the astro photo money pit 🙂 Heather

Aaargh, mils & radians ... I've come across particularly mind mangling geocaching puzzles using those , set by an ex forces guy who became a fire fighter and had a fondness for hiding the containers you needed to find to complete the puzzle high up trees or in small caves in a quarry wall ...

A lot depends on what equipment is available in India, how much you have to spend, how much light pollution you have to contend with , how much storage space you have, where you hope to observe from ... I'd suggest you contact some amateur astronomers with more local knowledge, for example https://www.go-astronomy.com/astronomy-clubs-global.php?Country=India http://www.amateurastroclub.in/ http://agc-astro.org/astrolinks/amatclub.htm https://bas.org.in/

Well, I was just getting my feline overlord in at 1am before heading to bed when I got a text from a friend in the city of Leicester (which is to the north of me ) saying there was a red aurora alert and they thought they saw a greenish tint to the sky from their high vantage point. Ragged clouds blasting across the sky gave brief clear patches, but I couldn't discern anything but light pollution from outdoors, so headed upstairs to keep watch out of a north facing bedroom window . At 1:50 am I was rewarded with a fortuitous low clear patch of sky, which showed an absolutely distinct narrow band of green, pulsing and rippling above the distant rooftops, which continued to be visible until 1:58, when more cloud rolled in. Wow, my first view of the aurora, not exactly spectacular or scenic , but impressive nonetheless ! 🙂 Heather

Eyepieces , almost too much choice .... First way to cut down the (probably thousands of) possibilities : how much money do you feel it is reasonable to spend ?Under £100 in total ? up to £2 or 300 ish ? More ? If you have £200 = to spend per eyepiece there are plenty of possibilities , which I'm sure the big boys can explain, but are way out of my experience, so I'll stick at the bargain end of the range , because that's where I (mostly) am. Next , you do a little maths . Your 'scope has an aperture of 130mm, the general rule of thumb is double the aperture in mm is the max. magnification it is reasonable to expect an instrument to manage. So max mag = 260x, but as has been mentioned , you won't often get that in the UK, so investing in an eyepiece to give you that won't give you a lot of use for your cash, better to think n terms of 200x as an eyepiece which will give you observing time . To calculate the mag. of a 'scope/eyepiece combo, you take the focal length of the 'scope , 650mm in your case, and divide it by the focal length of the eyepiece. So, your stock 10mm gives you 650 divided by 10 = 65x , while your 25mm yields 26x . To get 200x, you would need a 3.2mm eyepiece, while a 4mm would give a decent 162.5x . On my setup, in slightly above average seeing conditions I use an eyepiece which gives me 187x , and if less good, drop back to 125x (which for you would be a 5mm) There are topics on here about eyepiece choice , do a search in the box (top right) for 'eyepieces the least you need' to see the sort of gaps between mm folk recommend , but as you are , at the moment, mainly thinking of planets, I'd suggest buying one or two in the higher magnification range I've explained above to start off with, and maybe adding a simple 32mm plossl ( £30 , https://www.firstlightoptics.com/astro-essentials-eyepieces/astro-essentials-super-plossl-eyepiece.html ) to use as a low magnification, wide view eyepiece for scanning around, finding stuff, and admiring things like the Pleiades. I've no experience of the 5mm and 3.2mm BST starguiders, they would be too much magnification in my setup, but I do use the 8mm and 12mm(and the 15mm and 18mm ones ) and they are great, I've not heard any complaints about the shorter focal length ones being less good. If you are happy to spend £50 per eyepiece, they are probably your best choice https://www.firstlightoptics.com/bst-starguider-eyepieces.html I'm a cautious spender, so would go for the 5mm (and a 32mm plossl) , see if the 5mm gave me what I wanted, maybe try it with the 2x barlow you have to see in principle if more mag is actually useful , and only if I thought I needed it, go for the 3.2mm If your spending plans are higher, the OVL Nirvanas have a good reputation, and I love the 16mm I recently bought, they are around £80 and the small range includes a 4mm ( https://www.firstlightoptics.com/ovl-eyepieces/ovl-nirvana-es-uwa-82-ultrawide-eyepieces.html all out of stock everywhere at the mo., believe me, I've looked ... ) the next stage up for me would be the explore scientific 82 deg, range at around £150 each https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-82-degree-series-eyepieces.html By the way, is your 2x barlow one which lets you unscrew the bottom bit, with just the lens(es) ? I f so, you unscrew it, screw it on the bottom of the eyepiece in the filter threads, and increase the mag by not 2x, but 1.5x, which would make 5mm BST plus 1.5x Barlow cell = a rather handy 195x ... Heather

I thought about it , but never got beyond the thinking stage ! One of the more random thinks went like this : the bigger the circle, the more accurate it would be , yes ? A setting circle CARPET would be better than a little A3 thing on the dob base then ... why have it attached to the 'scope at all ? I observe from the garden, often right over the spot where the rotary drier socket is let into the grass, it's obviously away from obstructions ... So , how about turning the entire garden into a giant setting, er , rectangle , by marking the fences at, say, 10 degree intervals ... worked out empirically by observing a star at the required az, according to stellarium, panning the 'scope down, and marking the fence with glow in the dark paint, or glow in the dark cord, or reflective material ...

You might find it useful to read up on exit pupil, the thread below specifically deals with eyepieces for DSOs

"couldn't find anything beyond "averted imagination" " A perfect description of many of my attempts 🙂

Well, apart from the convenience of the slo mo,and the less agricultural focuser ( OP thinks their 130p focuser is cheap and crude Ha ! try the heritage one ... ) I had problems with viewpoint on the dob too , with tall fences around a small garden and low planets I often found I needed a higher viewpoint than I could comfortably manage with a 'look in the side of the front opening' newt, so I needed something with a diagonal behind it, I couldn't just get away with putting the heritage on the AZ5. The quality of the view in the heritage is undoubtedly good, but I confess I've hardly ever used it on the AZ5 , for some reason it seems too unbalanced to me , so I can't say how the two 'scopes compare without the practicalities of their different mounts intruding. It was the tantalising views last autumn of Mars whizzing across and out of my view with an 8mm BST at a bit under 100x that had me looking for an alternative !

The skywatcher 127 mak is what I have, Maks focus in an entirely different way to newts, in a mak the whole inner mirror moves forward & backward within the tube, which is closed at the front by a thick front glass plate. the focus on the 127 is a small knob you turn on the rear plate, I have a high precision focus adapter on mine, it's a plastic clothes peg 🙂 , offering fine , fingertip adjustment at the right price !

Wikipedia reckons it's true https://en.wikipedia.org/wiki/Fictitious_entry "By including a trivial piece of false information in a larger work, it is easier to demonstrate subsequent plagiarism if the fictitious entry is copied along with other material. An admission of this motive appears in the preface to Chambers' 1964 mathematical tables: "those [errors] that are known to exist form an uncomfortable trap for any would-be plagiarist".[7] Similarly, trap streets may be included in a map, or invented phone numbers in a telephone directory. "

Quite right 3d was thrupence 🙂 , 6d a tanner , 1/- a bob , 2/- a florin or two bob, 2/6d half a crown. When I was small , I thought my Yorkshire born & bred gran was calling people (affectionately) a silly monkey when she said what sounded to me like 'Daft apath ' , but later I realised it was a contracted version of half pence worth , ha'penny worth , (h)aypath ! 🙂

Chains ? Important to some people ? Sounds a bit dodgy to me, I expect those tables were copied , which for some reason reminds me, my Dad told me that the books of log tables had at least one deliberate mistake in them, intended to betray any copyright flaunting imitations . I've no idea if that was true or not . Heather

OK, so the extra detail there means I actually might have something useful to contribute ! I started out with (and still use by preference for wide field DSO observing etc) a 150mm heritage dob, but found it's shortish focal length (750mm) and the need to 'nudge ' it frequently at high magnifications made it awkward to use for Jupiter, Saturn and Mars, which are the planets where you can reasonably expect to see detail . So I bought a 127 mak and an AZ5 , twice the focal length (1500mm) and slo mo controls so no careful nudging at high powers. With the mak I can get 187x magnification fairly often , which shows some detail on those targets, and beautiful detail on the Moon, but pushing the magnification beyond that is almost always pointless, as the 'seeing' the atmospheric stability which goes with our famous British weather is the limiting factor. I've managed 250x maybe a handful of times (on anything apart from the Moon) in the year since I got the mak. That said, the mak works really well on the AZ5, so if you already have that mount and a decent tripod, it may be worth considering, the only problem you may find is that the maks need time to cool down , mine goes outdoors at least half an hour before I am going to use it. Targeting those planets I mention above is easy because they are naked eye objects. However, the ice giants, Neptune and Uranus, appear far dimmer and are less easy to locate, certainly in my suburban sky . I've seen both through a 'scope, but it was a struggle over many sessions to find Neptune , and when I did it was a faint unremarkable dot , as was the easier to find, somewhat brighter and distinctively coloured Uranus. I found them not with the mak, but using star patterns in stellarium to compare the actual view through the eyepiece with the computer view . Not join the dots, but identify the dot ! Features on either of those planets are out of range of reasonably priced amateur kit. If you have a suitable smartphone there are apps which have a 'push to' capability, i.e. , you use them on the 'scope tube as a sort of electronic viewfinder, while steering the scope normally by hand. I've not used it myself (my smartphone is too stupid) but SkEye is one for android 'phones which looks interesting. I've had some success (notably with Neptune !) tracking elusive objects down by using a cheap little AA cell powered electronic level which sits on my heritage dob tube with the handy magnet on the level's base, and helps me pion the tube up to whatever alt (altitude) angle I have got from stellarium for my target. It's then a matter of scanning horizontally using a wide eyepiece until I find whatever I'm after. The little levels are often referred to as wixys (or something similar, wixies ? ) in older posts on here, worth having a look for threads about them , they certainly help cut down the uncertainty, and mine cost around £15 last time I checked on amaz. in the DIY section. Heather

I rather enjoyed teaching the eminently sensible metric system to the pupils in my charge, then , when a small person inevitably bought up the topic of the 'funny marks on the other side of the ruler that came in my new pencil case' , impressing them with the insanity of the whole 12"= 1 foot, 3 foot = 1 yard, 1760 yards = I mile . They always wanted to know why those numbers, rather than the sensible 100x , 1000x relationships of the metric measures, and I had to say, er, it's a jumble of history, probably something to do with human foot length and paces . And the Romans. it's always the Romans. And if you think that's crazy ,children, how about furlongs , acres, rods, poles perches , ells, gills , fathoms, nautical miles , lbs, stones and hundredweight (which in Imperial is a mind melting ... 112 lbs ?!) and the whole host of weird stuff which actually used to be printed for reference on the back of exercise book covers ? More marvelling at the weirdness of 'olden times' was to be had when we studied the Victorians and I made them try some calculations involving £ shillings and pence, with extra annoyance in the form of guineas and halfpence/farthings thrown in for the maths geniuses. Blew their minds. It's not just the US, North Korea and Liberia don't do metric either. Interesting company to be in ... Heather

Oh, and I forgot to say, welcome ! If you post in the 'welcome' area and introduce yourself , plenty of folk will respond . Heather

I very recently bought a second hand Berlebach Castor , which is an option you have not mentioned https://www.teleskop-express.de/shop/product_info.php/info/p7605_Berlebach-Castor-Alt-Az-mount.html It comes with one clamp, and TS say it can handle a 7kg telescope if counterweights are used. I've only used mine so far with a 3kg 'scope, and no counterweight, but for a relatively light and compact mount the Castor appears to work really well. The Castor fits any 3/8" standard photo tripod screw. You should buy the sturdiest tripod you can , it needs to be strong and not prone to vibrations , not light weight , and not cheap ! Heather

Everything in this game is a compromise, there are diametrically opposed forces to be assessed and balanced out to make the best compromise for your specific situation . Maybe the first most obvious is overall cost vs quality, but then there's visual vs photo use, aperture vs OTA size and weight, high magnification planetary use vs wide field DSO use, tripod lightness and portability vs tripod rigidity , altaz mount simplicity and speed of setup vs eq astro photo possibilities .... I could go on. You've seen for yourself that the tripod and mount are going to be a limiting factor on any telescope you put on top , and for what you intend to spend you simply will not get a sturdy tripod, well made head , and a good telescope ( not new, anyway, you might come close if you are very lucky with second hand kit ) and that's not even taking in consideration the eyepieces, finder etc you will find you want to supplement the 'get you started' low grade stuff the 'scope manufacturers bundle with their kits to make them theoretically complete . My suggestion is that you consider a planned upgrade path, start off with some kit you will expect to keep , some which will be upgraded from , or relegated from 'the kit' to 'the portable kit' , and think only of visual astronomy to start off with. The visual aspect is not exactly cheap , but it it far cheaper than the photography aspect ! Many folk on here own more than one 'scope , at least partly because that huge lovely light bucket Dobsonian takes some effort to shift outdoors, the complex , cable festooned , heavy astro photo set up needs carrying out, probably in several journeys, assembling, aligning and connecting up, but the small, lightweight refractor or newtonian on an alt az / tripod combo which is sturdy enough for the minimal weight of that OTA can be carried outside as one , parked on the lawn and be in use in moments, and when there is an hour's window between clouds, it's really cold , there's work or school tomorrow, or other calls on your time intrude, that's an important ability. Please don't be put off, this is a fascinating hobby, and you can buy , for example, a heritage dob for under £250 https://www.firstlightoptics.com/telescopes-in-stock/sky-watcher-heritage-150p-flextube-dobsonian-telescope.html which will show you fantastic things (but will be rather limited for photography) , or I'd agree the AZ4 mount/tripod combo for £190 and an explorer 130p https://www.firstlightoptics.com/telescopes-in-stock/skywatcher-explorer-130p-ds-ota.html for £230 , £20 over your budget, but the 'scope could be used later on a more expensive mount for photography if you want ... Heather

The perils of rural navigation using a sat nav ! Just grabbed the chance for a quick 15 minutes 'getting the hang of it' viewing session, it worked well with the 102mm Bresser and after a few minutes I wasn't even noticing the mount, which to my mind means it's really good ! I'm hoping to spend some more time with it later if the clouds stay away after midnight, when every other street light round here goes off, and my suburban skies improve considerably 🙂 Heather

Courtesy of @HollyHound , a Berlebach Castor and extras, all in excellent condition and beautifully packed . It only took seconds for me to PM that I wanted to buy it when HH put the ad. up, but it's taken rather longer for parcelforce to find where they were supposed to collect it from , but they managed it in the end ! Heather

Because my tripods are photo ones, with no bracing triangle , I lose some rigidity but gain the ability to fold the legs in , actually I generally just fold one tripod leg in to ease my way through doors, and carry the setup as one, with the 'frac locked in a vertical position so I have a tall but fairly narrow thing to carry . It helps that the bresser 102 has a handle on its rings, a very useful thing I find 🙂 I close the leg sections down for storage ('scope still on top) , and the clip locks allow me to hold the setup one handed, have the sections unlock one at a time and drop with gravity, then lock them in place quickly with the other hand. I do the same process for the 127 mak/AZ5 setup which has it's own photo tripod . I've no idea if your new tripod could have the bracing loosened or removed to fold the legs in, but if so that may be less faff than taking the 'scope on and off. My kit gets used plenty, so I'd not pack it away , I want it convenient and ready for quick deployment !