Roog

I shall do this, thanks, it will be interesting to see what I get back

I take your point @Pompey Monkey I will weigh my Astro gear once I have bought some Astrophotography gear in the mean time I did weight my Dob on its trolley it came out at 50kg! Needed to check for my back door lift capacity. :0) no I wasn’t thinking of a person stash of data more a collective built up by a group with similar interests, like this very fine forum.

Oddly I assumed that this might be something that loads of astro geeks might have done?

Does anyone know of a published/accessible schedule showing weights of astro gear please? I ask because lots of manufacturers just seem to quote the shipped weights which often come out much higher than I would expect.

I have a similar challenge as I am looking for a scope to take with me camping and space weight capacity is limited. I recall seeing a nice looking Altair scope of about 100mm aperture.

Nice option thank you both, I will give this serious consideration

Its all good if a little bewildering, thank you everyone. It would be really nice to get a high quality 4" refractor, but I notice the price rises very quickly once you get North of 80mm including the increased size and weight for a portable camping scope. I will keep an eye on the used ads and torture my self trying to choose! Thank you

Interesting, I have not heard this one before, is this generally accepted and if so why does this come about? Do lenses transmit more light than mirrors for a given aperture or is there another characteristic in action here ?

Of course you make a very valid point and for me it’s hard to define, I used to take my guitar in its case and a small practice amp with me on our camping trips buy that has been displaced by our two dogs and all of their stuff! Ideally a 300 x 200 x 900mm case plus tripod, but in practice it will be what space is left for my “non essentials” so that will be as small as possible

Thank you everyone, so many responses I’m going to struggle to respond to each of you individually. I take the point that I could transport my Dob in the motor home, but I think my wife might have something to say about it joining us! And getting it in and out through the narrow door with quite a drop would be a worry. I guess my anxiety is that having used a 10” Dob for visual I might be very disappointed by a much lesser aperture for visual, ultimately I should seek to find a compromise and in the absence of personal experience it is a little of your wealth of knowledge I seek. I have been watching videos of enthusiastic 150mm Newtonian owners managing to carry out AP effectively with this gear, but I have to confess it does look quite challenging as a travel rig. I think perhaps I need to prioritise future use for AP and accept that visual astronomy will be significantly compromised. I might be naive but I have a vision of a 80mm ED refractor in a case as a manageable travel scope.

Hi I have been exploring the skys from my back yard for nearly a year using my 10" Dobsonian and I think its great, but i have also been taking my 20 x 80 binoculars with me on my camping trips, (I have a very modest and old motorhome) and I have began to wonder if a portable scope might be more rewarding. So looking through the ads for refractors I began to wonder whether I could kill two birds with one stone and get a physically smaller scope which I could use for direct viewing that might be suitable as a gateway into astrophotography in the future? accepting that I would need to get a suitable guided mount, laptop, software, camera, etc etc. Sorry if this is a dumb question but is this possible or sensible? or am I asking too much from one scope? I am wondering whether a 150mm Newtonian might be a more sensible choice for dual use? I was looking to refactors in an attempt to keep the bulk down for travelling. I would appreciate your guidance, Cheers

It did seem a little alien to me to have a heater in a scope where keeping every thing cool seemed to be the order of the day, but based on my limited experience the trade off of keeping things clear vs possible heat ripple and distortion of the secondary seems to be in favour of the heater so far. I must figure out how much power i am dissipating in the heater too, based on my desk top experiments out of the scope it is very likely to be much less than the full rated output of the heater, may be 1/5 or 1/4 of full?

Nice one @tomato, I stumbled upon a similar DIY idea, I have been using a 'tool holder' magnetic strip like the one in the link below, with lead sheet glued to the back. I have added a thin polyethene layer on the magnet face to minimise scratching of the telescope tube, it can be slid up and down the tube to improve balance. I don't like to add too much weight to the scope so I normally work with just one and add a second only if I attach my SLR . https://www.screwfix.com/p/smith-locke-magnetic-tool-holder-black-380mm/6951j I have added with

It can up as well.

Of course you make a very good point @Louis D the simplest solutions are the best and a ramp was my first thought, but my inner geek fancied a motorised lift, in fact I would have asked for one that made a quarter of a turn clockwise at the same time as lowering just to ease the telescope exit from the platform, but I sensed I'd made the brief complicated enough already, MkiV version perhaps? I expect 'Brian' being the engineer that he is did check what the requirements would be to make a compliant lift such as the one pictured in your post, I recall he did ring me to ask "how safe do you want this telescope accessory to be?" I decided that I would own the risk. I'll do a toe count at the end of the year.

I think that you are quite right @adyj1 I have no reason to be coy about its worth, because all credit goes to my mate and ex-colleague 'Brian' who very kindly designed and fabricated it for me. I have another video of it going up too, although it is very similar :0)

Bang on the money, this was his, (lets call him 'Brian' because that is his name), first idea, until I asked if it could be remote controlled as I wasn't sure that i could get out through the back door once I had loaded the telescope on the platform. It retrospect I think a removable handle would have worked well. As for the battery conversion this is my next task.

Its good enough for my purpose, and when not in use it is just a deck of wood outside the back door with all of the lifting apparatus unclipped and put in the shed. When I went to collect it, its designer and maker expressed much frustration that it could have been improved, but as he said to me, "I had to stop changing things and start welding at some point" so this is what i ended up with. He has gone off to think about MKii and MKiii versions! It has got me thinking that there must be a need for a similar low cost device, if somewhat developed to make it safer, to help less ambulant people in and out of their homes.

Ok, that wasn't too difficult. Lift "Going Down" is here!

Ok, I'll check, File is 195Mb. I think I have a Gmail account, but have never up loaded a video to youtube

Thank you , but it really is a very dull watch! But in order that others can suffer, do you have any ideas as to how this could be posted?

In my first post I mentioned that i have a small but never the less irritating challenge to get my '10" Dob on a trolly' out of my back door and down one step into my back garden. Well after much discussion and designs I happened to mention my challenge to an ex-colleague. I was only expecting to hear back from him with a few ideas as i know him to be a very experienced mechanical engineer. I became a little alarmed when out of the blue he began to send me animated linkage stress analysis run on his computer. Next he announced that he had bought him self a fancy pants Mig Tig Arc welder and a welding tent. He continued to send me updates including some videos to show progress. To put it mildly I was a little alarmed at the money he was spending on my behalf. Anyway in the early part of this month he announced that 'it was ready' my back door step lift was ready to collect. And, here it is, it simply sits on the floor, no need for fixing down. The square deck section remains outside the back door when the lift is not in use and has a low profile. The rest of the mechanism, including the metal arms to the rear and the electric actuators clip into place when needed and can be assembled and removed without tools. It operates from a small 12V 7Ahr sealed lead acid battery (early tests used a lab power supply) and takes about 50 seconds to travel the single stop of one step. It is very quiet and smooth in operation. It is designed for a 60Kg load but manages 1.5 times this. In fact the electrical linear actuators and battery are not the limiting factor the gauge of steel in the construction is. It was getting dark when I shot the picture which is not the best. I do have to finish the woodworking off by shaping the edges to act as short ramps (wedges) and will add one to the front edge to minimise the risk of topping off the front lip. I am going to get a shower resistant box in which to install the battery and I may also change the wired remote controller over to a wireless remote which should reduce the wiring and make operation a little more flexible. I have a short video too, but i am not sure that I can up load such a large file to this site, TBH it isn't very interesting but does show how quiet and smooth the operation is. (Edit: I have broken new territory in that i have now managed to uploaded my first ever video on youtube, see link in later post!)

I ended up buying a PCB based dew heater from FLO, by 4tronix, I had the choice of 2 sizes, one for 8" or for 12". As a have a 10" Dob and given that I didn't want the heater to overhang the mirror I opted for the heater intended for the 8" scope. It is a very tight fit on the secondary mirror support on my 10" scope and i bravely, or is that stupidly opted to file a small amount of PCB away from the inside of the 'C' shaped board, I had several fingers crossed that I didn't kill it by cutting through any tracks in the process. Anyway I managed to bond the heater on to the back of the secondary mirror without great difficulty, although it would have been nice if the heater kit had included some cotton gloves to protect the mirror from my sweaty fingers, cables routed along one edge of the mounting star and I was nearly ready to fire it up! I made up a fused 16V battery pack from 4No. laptop batteries and bought a PWM small DC motor controller to manage the heater power and connected it all up. From my initial dry tests I have power ratings for 0 up to about 2.4W. Having not used such a device before I was concerned that the heat might debond the secondary mirror, so I started off with low power. In real use I have found that the fog has gone, it runs at very low power perhaps in the order of 0.5 to 0.75W and my 1.8Ahr battery lasts for ages, certainly longer than I can stand out in the cold. It seems that this was a good investment for my Dob. and until I find otherwise it seems to have put and end to my sessions being ruined by dew.

Thank you for your reply @Mike Q, yes is did check "DIY dew heaters" in Google and found the resistor ladder one, and also nichrome wire too, I have used both these methods to make small heaters in other hobbies and whilst both are doable, its the packaging in a safe to use package which I find most challenging.

Hi @Mike QI note that you emphasised (Store bought) as being expensive, out of interest, is there a popular way of making these amonst amature astronomers?