JOC

Mind you there are plenty of targets that aren't planets or the moon for which you actively don't want such a large amount of magnification, for example Pleiades star cluster won't give you the 'wow factor' if you are too close in.  Also, I've found that some double stars are not ideal at really high magifications and have actually split more cleanly at lower mags - that might again come down to atmospheric conditions I guess.

It looks like a big project - are you costing it vs. buying the mount?

20 hours ago, Atomic_ said:

However I'm confused about the Minimum/Optimum and Maximum Magnification, the minimum magnification for the telescope being 171x and the eyepieces magnification being 60x and 96x for the 20mm and 12.5mm. What does it mean to have a eyepiece magnification lower than the minimum magnification of the telescope? I'm assuming it just means the minimum 'useful' magnification for details.

The maximum magnification is easy - in theory the most magnification you can get to before things don't look right.  However, it is only a mathemetical/theoretical determination.  I've got exactly the same scope (I'm guessing you have something like a skywatcher 8" flextube) and a 4mm would give x300 - divide tube length in mm by EP size in mm = magnification.  In reality, in the UK at least, we have a battery of atmospheric conditions which consipire such that it might sometimes/rarely be possible for me to use a 5mm (x240), but practically not much more and the sweet spot is around a 7mm approx x171, for clarity on most nights.  

On 08/05/2024 at 21:42, happy-kat said:

If you are handy at making things you could make a dobsonian base at home for a telescope

That ^^^ was also my thought when I read the enquiry, but OTA's for larger Dobs are not that small even flex-tubes like mine.

Mind you unless the OP wants the light grabbing potential of a larger mirror to go chasing feint fuzzy's I also wondered if they could make as much progress improving what they have?  The reviews I read on the scope suggest that the OTA/Optics are quite useable, but let down by the mount.  Would the OP be better off spending their cash and load allowance on a better folding tripod for it, for example a good heavy duty camera tripod.  I own a Manfrotto 055 (MT055XPRO3 2nd hand off MPB if you get that chance) that looks to me well up to taking a telescope and would fold to go into a tall rucksack (and I bet the others on here will have better suggestions).  It must be possible to buy a top mounting arrangement that would take the existing scope and maybe invest in 3 nice EP's to go with it, possibly a better focuser if it is changeable.  

Sooner or later it will dawn on folks that there are many of us enlightened enough to NOT do Facebook!

4 hours ago, Don Pensack said:

So you have 6mm, 8mm, 16.5mm and 23mm.

You lack an eyepiece in between the 16.5mm and 8mm.  Beyond that is merely personal taste.

11mm would be ideal, but 10mm would be fine as well.  The best choice would be a 10mm Ethos.  With ultrawide fields,  the choices at 10-11mm are limited, but the 11mm Explore Scientific 82° is a possibility, or, if you could find one, the 11mm Tele Vue Type 6 Nagler.

If talking used eyepieces like the 11mm T6,  the ultimate is the Tele Vue Apollo 11, but a 10mm Ethos would be cheaper.

Don, how about a Baader Morpheus too, the 12.5mm would be almost in the middle of the gap, then they also do a 9mm or a 14mm.  They are fairly wide field, good eye relief and a little easier on the wallet!

I don't use the telescope a great deal, but do wear glasses and have the full Morpheus range, I haven't had any huge problems viewing through any of them with or without my glasses on.  FWIW unless you dealing with extreme astigmatism (and I deal with a modest amount) I often find no problem with taking my varifocal glasses off to view through the telescope, which after all contains a reasonable modicum of bits and bobs to focus any image to any viewer.

Clouds can be quite useful too.  When we had the solar eclipse in the UK all those years ago we did all trooped out of our laboratory to watch it do the 3/4 thing that we got in Essex.  Without solar eclipse viewers which we didn't have we thought we would need to view a shadow on the ground, which seems rather 'meh!' - as my kids would put it.  However, when we went out there was just sufficient cloud cover to clearly see the sun disk sufficiently diffuse through the clouds, but also clearly through the clouds.  It stayed like that for whole time and we remain people that have been able to directly watch a solar eclipse with our plain eyes and see the moon advance across etc. all in plain sight and without filters.

Nice!,  that's a real comety looking comet!

5 minutes ago, mcrowle said:

The anatomy of the eye is the difference, the rod cells being responsible for night vision but not seeing colour. Only the cone cells, for day vision, see colour. Therefore, the aurora only registers to our eyes in colour when it is bright enough. The camera sensor doesn't have that limitation, and colour is registered regardless of how bright the light is. No doubt I'm over-simplifying things, though 😃.

Nope - that makes sense as does this:

6 minutes ago, ONIKKINEN said:

There is also the fact that our dark adapted eyes see in monochrome, so if the aurora is faint enough for our eyes to stay dark adapted then colour is not seen.

I recall a school homework for biology being asked to go home and watch outside whilst it got dark and then they we would be quizzed on what happened.  Not one class member spotted that colours disappeared and that only shades of grey remained due to only the rod cells firing in the eye due to the darkness.  However, that lesson, entirely explains why these explanations above also make sense 😄  It's amazing the odd stuff you can recall after far too long, but I remember the homework assignment.

It's most interesting, so what is the camera recording that our eyes aren't?  Is it just down to the longer exposure and more photons hitting the camera sensor (like when you use longer exposures and/or stack exposures) or is the camera actually seeing more light wavelengths than our eyes do in the same way that a mobile phone camera can show the infrared? light from the TV remote that you can't see with your naked eye.  

1 minute ago, Shimrod said:

Glendale app is a good one to see if others are reporting sighting of aurora, although it does get overwhelmed with traffic at times. https://aurora-alerts.uk/

Now that's a nice example of how the internet should be used 🙂

I'm under Bortle 4  skies here which I understand aren't the best, I reckon roving 'white' bits are what we would see.  I wonder how many people book those aurora trips on the promise of photos of all those spectacular colours only to be disappointed by the actuality.  It's kind of like the deflation you seem to get when many new deep sky observers are hit by the realisation that they aren't going to see all the colours in the pictures, and that the Orion nebula is just a grey wisp in the sky to the naked eye.

I think I will go and charge the tablet up, that is supposed to have decent onboard camera capability and I will have the large screen.  There is a posting elsewhere on SGL that suggests there is a chance of seeing it tonight around midnight?

53 minutes ago, Carbon Brush said:

Take a look here....

Really interesting - and thanks for the pointer to that thread.  Perhaps I don't feel quite so disappointed to have missed it, I thought people were seeing all the colours.  However, it does make me wonder if my mum and I saw something the next night.  We were out looking at the right time and either side of the moon (which was a tiny sliver) it was as though there were clouds wisps appearing and disappearing in arcs around the edges of the moon.  I wonder if I had known to hold up a phone if there would have been the colours.

So I've just had an interesting discussion with my Bro who Did see that spectacular aurora display last week.  He and a group of friends were at a festival.  However, he reports that without exception all those watching reckonned that they only 'naked eye; saw the spectacle showing as white lights in the sky and that it took photographing them with only some of the mobile phones (the others wouldn't take the display at all) before they saw all those spectacular colours.  Does that sounds par for the course, do the eyes only see these things in whites and grey and if so what is going on please?  I guess perhaps it is this persistance of vision that a camera gives - like when you have a longer exposure and do some stacking to see more stars.   I assumed that we would see all the spectacular colours with the naked eye, but on bro's report that would not appear to be the case??

We've given up.  Sat outside 2230- 2320 nothing.  Fippin' amazing, yesterday biggest astronomical event in the last 20 years and I miss it :-(

I know of 3 groups that are watching ATM  :-(

Which direction is best to look please, we are assuming North?

Look even I have managed to take some pictures of it - I've got a T ring for the camera body and it just slots into the focusser on the OTA.  These seem good enough for an amateur effort I think 🙂

I've just got the telescope out for the first time in a year and am delighted to report that we have enjoyed seeing the sun flares,  I checked that my cover was securely fastened around the gap in the flex tube and double checked my home-made Bader solar filter which I keep in a special box to keep it safe for pinholes and put it all together with a 9mm Morpheus EP lovely view and my bro was also really interested,  We first held the film up in front of our faces (it is in an 8" cyclinder style holder so quite safe, and can confirm it is indeed a naked eye object with a certified solar film protection, and then viewed with the telescope and can see the whole cluster of little dots - super, thanks for the heads up - an unusual blue sky day here so a nice clear view 😄

FWIW have you tried the scope back to manufacturers configuration, no heavy additional objects, esp. heavy EP's.  I find my goto Dob is esp. prone to not functioning well i.e. slipping if I put anything too heavy at one end of the OTA or the other.

On 30/04/2024 at 16:33, Tiny Clanger said:

You might be able to find either a window clamp or a hide clamp intended for birdwatchers etc spotting 'scopes that would suit whatever form the balcony rail or barrier takes

Ducatigaz has some mounts that fit over his opened car window and clamp to the inside of the car - they then take his camera.  You could probably make such a thing work by adding a couple of boards each side of the balcony railings with a couple of nuts and bolts.  Then add a standard tripod plate to the bottom of the small telescope, like I did here, by knocking up a little plate and a couple of nuts and bolts to mount onto this tripod below.  Also don't forget the possibility of a triangular plate mounted across the corner of the balcony to provide a 'table'

14 hours ago, Louis D said:

Or, build your own suitcase Dob:

Isn't that dinky 😄

I have travelled with my baby Vixen, it and it's 'folding all inside itself mini tripod' all fit into a tiny plastic tool box I bought for it.  Here it is in action when I took it to Scotland

I have also sat it onto a proper tripod 

and I was respectably impressed with its performance the night I viewed Saturn with it at home.  It was at that point I realised that most apparent magnification seems to come from the EP that is deployed rather than the width of the mirror - which seems to come into play more if you go chasing feint fuzzies.  B.t.w. I like the little wheeled adjustment links to do the tracking with - they were so easy to use compared to shifting a Dob.

Astrobabys guide to collimation is the most recommended on sgl https://www.astro-baby.com/astrobaby/help/collimation-guide-newtonian-reflector/

It uses a 200p skywatcher as the example so very close what you have.  do it to letter no matter how odd the instructions sound and you won't fail.

I have the same flextube telescope.  I first tried a laser collimator then got a cheap Cheshire and it is much easier with the Cheshire. 

Finally, Just a word to the wise - make sure you draw the flextube apart TWO clicks!  It is very easy to think you are there at the first set of stops, but you must pull it again and get it to the second clickstop to make it long enough to use.  It will not work at the first stop, take it from one that knows!  Oh yes, also make sure you have removed the big plastic cover too, sometimes it gets plonked down on the second stage and you forget to remove it!