DaveL59

bigger as the secondary is now lower into the light cone if you see what I mean

if you consider the primary as the base of an isoscelese triangle and the secondary sits near the point where the long sides meet, the line across parallel to the edges forms a plane of a certain length. Moving the primary up is much the same as lowering the intercept point nearer the base, resulting in a wider plane at that new point. Yes I know the secondary isn't parallel but the result is much the same, closer the secondary gets to the primary, the wider the light cone hitting it...

Not a great pic but might illustrate what I mean, if you consider upper and lower red lines as where the mirror was/is tho in the Tal it won't be that big of a difference  

thinking about it simplistically and I may be off the mark, but having moved the primary up the tube (I've done the same), you're effectively intercepting the cone of light earlier at a slightly wider point. So a slightly larger secondary might make a bit more of the image the primary is projecting, no?

Not sure if the later Tal-1's with shorter tubes used a different secondary to allow for that, perhaps someone else here with one would know or be able to measure and let you know. Alternatively you could always get the secondary re-coated.

what may help is exposure to UV as that'll at least cull the mould hopefully, so it doesn't spread. A UV lamp and a decent exposure time would do if the sun doesn't want to help, don't point it at the sun tho!

As for cleaning it off, a soak with some hydrogen peroxide added perhaps? tho I've no idea how that'd aflict the mirror, others with more experience than me may be able to advise better re that. Might be fine with just the usual soapy water routine after a UV session to kill it off, but give the internals of the casing a treatment as well to remove any spores that might still be lurking.

could be fine then 🙂 It is a problem now for shipping LiPo cells, being they can be quite "volatile" so can imaging it's not so easy to source if there are no local suppliers around.

does seem pricey but may well do the job, has mains inverter output which is likely why, do you really need that?

so long as it doesn't auto-shutdown with a low-drain load it could work, tho using the AC outlet will reduce runtime quite a bit I expect. I have a LiPo car jump-start pack that's smaller but similar rated power and use the Cig socket adaptor to hook up to a Buck converter to deliver 12v out to the SynScan, seems to work just fine and cost around £65 all in. Just be sure you check the DC output  voltage before you hook up the scope as  they can be a lot more than you'd see off a regular 12v lead battery, mine showed 16v which is more than the 15v max for the goto, hence the buck converter.

The old TAL scopes came in a plywood box and I've been thinking along the same lines myself, as my smaller Tal-M has the box but the Tal-1 and 100RS do not. Problem I see will be the weight and bulk which won't be helped by the added weight of the box. I'm thinking along the lines of adding decent sized wheels at one end so it can be towed along more easily, esp given the 100RS+EQ5 weighs in around 50KG. I guess another option would be a fold-up sack barrow to strap it onto while moving it around

hopefully it'll be fine then 🙂 I know some have used hot-glue to secure prisms in binoculars so I'd go that route rather than general purpose/cyano-acrylate stuff for any optics having seen the effect it had on a torch reflector one time.

Enjoy the Tal, I travelled from Kent to Coventry to collect the 100RS I have, love how well made they are and the views it gives are fabulous to my eyes, not that we've had the skies to do much of late...

yikes I'd not have used superglue, it outgasses and can leave a nasty residue on optics, hope you left it open a good while before you sealed it all back up 😮 

Well done on getting it all back aligned tho 🙂 

is that with the laser in the diaganol? Do you get the same with the diaganol removed, that'd confirm the focuser and lenses are or are not the issue.

I've tended to use treetops around 150m away, centre in the scope then set the finder a smidge above which seems to work reasonably well for me. Fun when its a windy day tho and the trees swaying about. After that I'll tweak a little if needed once looking at the stars but found in the main little need to do much tbh

can't say if they're the same but no harm in asking RVO as they'll likely know the answer...

13 minutes ago, PhoTenix said:

I wanted to try binoculars but I cannot hold my arms up for long at all  (as silly as it sounds) unless I had a table under my elbows, due to the crap that I have ! 

But seeing Jupiter's moons must be awesome. I have a fascination with Jupiter ☺️

A monopod and bracket for the bino can help a lot and not add much cost or weight if you want to try the bino route first

A parallelogram rig for binos can make things even better tho at a cost, of course.

Add a lounger type chair so you aren't craning your neck esp now its getting colder and you're started out at reasonable budget till the right scope comes along...

I'll be honest here and say I'm new to scopes myself so not long into the hobby, moved up from binoculars after collecting and restoring a few (lot). But a chunk of reading, looking at what's out there and checking forums and reviews, then taking a punt based on that... Most of mine are TAL, they're v solidly made and low cost with some restoration needed on the reflectors (paint in the main). The refractor on the other hand is in v nice condition, all are 2003 vintage or earlier and likely in 20+ years will still be going strong. I'm sure the skywatcher will be fine too but feels so thin in comparison lol.

Another thought springs to mind, not wanting to be too personal or intrusive, but have you considered the tripod legs relative to your situation? Could be that they get in the way a bit for comfortable access to the eyepiece where a pier type mount may work better for you?

depending on how high you are seated relative to the scope, a refractor/SCT/MAK may suit better then, tho a refractor can have a big range of movement when looking higher toward azimouth, depending on the length of the OTA. My refractor is 1M long so essentially 45-50mm from the pivot point to the eyepiece to give an idea. MAK/SCT are much shorter so less of a range to swing through.

you often see pics on the bay where the little finder scope is fitted pointing the opposite way from which it should be. The finder should be the other way round from what's shown in that pic 

see that so often lol

Otherwise, probably a nice scope but I've no experience of the dobs. Quite a way from you tho. Depends how much of a hurry you're in really, some decent binos might help tide you over till something more local turns up, perhaps. You can pick up good 10x50 waterproof porro's for good money from time to time, I landed a pair of minolta's that were under £25 and mint, for example.

23 minutes ago, PhoTenix said:

I'd love to be in a position to do that, but am disabled without transport, and most of them are far away 😕

only thing in that case would be how well its packaged up and then the carrier handling it "nicely". Any loose items in the package might find their way into the OTA and damage the mirror, or for a refractor the main objective. Assuming the seller has the original packaging it was shipped in you might be ok but it does increase the risk. Disputing condition when it arrives makes it your word against theirs etc. Bear in mind that a scope plus tripod is large and heavy, not to mention the OTA can be quite long (1m) so shipping may not be cheap. Insured shipping may not cover any optical gear either. Given that, best to get a quote from the seller first then decide, might be better to go new from FLO or another where you'll have warranty if it gets damaged in transit.

Where are you based tho? could be worth waiting until something nearby comes up, all but the TAL100RS I was lucky to find not so far away, that one was a v long round trip but one I felt was worth making.

3 minutes ago, John said:

I suggested a look at FLO's website to give an idea of what decent scopes to look out for

I've bought a few good things from e.bay as well but I've been in the hobby for 35+ years so I know what to look our for (and what to avoid !).

wasn't aimed at you john, in fact you replied as I was writing mine

Agree about looking at FLO and others to see what's good and get a general idea of what may suit, also helps to better know if the bay price asked is reasonable or not. Seen quite a few ads for scopes where its not much less than new with warranty, but claimed to be unused even if a year or more old. 

can understand why many would prefer to go elsewhere than ebay, but I've bought all mine from the bay with no issues, but I did collect each of them in person so they were transported home with care. I've not tried AP via the scopes so far other than mobile to eyepiece, fiddly to achieve a nice image so will one day sort something to fit the EP to go further.

I've the skywatcher 130EQ2 with clockwork drive that seems to track fine for visual, and also a Tal100RS on EQ5 with SynScan which is nice to use. The 130 can be had for under £100 often, the TAL  was quite a bit more but I had to have it  

Probably best if you want to go ebay/classifieds route to stick with better known brands like skywatcher/celestron and aim for larger aperture (mirror/objective lens) but the short tube reflectors maybe less useful for AP? Others who know way more than me can advise better on that front but they tend to have a corrector lens  in the focuser to compensate the shorter tube length and not sure what that does for the image with a camera rather than a regular eyepiece. Makes collimation fun too I gather.

Should add - if you are able, go check the equipment before bidding or committing to buy, check for fungus on optics, scratches on mirrors, that bits that should move do and all the components are present etc (not that I did lol, but did exchange messages with the sellers to verify stuff beforehand)

I have 2 EQ5's, one sticks here and there on RA where the other runs freely. So I transferred the SynScan gear across to that one so it works smoothly. Not got around to stripping the other EQ5 down yet so can't say what the internals are like, suspect it'll need cleaning out and new grease to get it running smooth once more.

Does yours run free without the motors installed or was it always that way?

I guess if the SynScan is working fine and tracking accurately it may be fine as-is and perhaps have less slop than if the axle was looser. On mine where the RA catches the motor sure didn't make nice noises and would just stall.

general concensus is anything higher than 10x will be harder to hand hold and keep steady, most go for 8x or 10x, avoid zoom ones. You might be able to go to 12x but more you'd need a means of stabilising (mono/tripod). There are stabilised binos but they're pretty expensive and heavier.

Choice will be between porro or roof designs, if roof find ones that are phase coated prism for sharper image if you go above 8x mag, also largest aperture objective you can afford if you plan to use at night or low light.

yeah hence am sorta following that route too, I have a thread "El cheapo sky camera" if you can find it, shows what I put together.

I'd say at £96 that one's pretty expensive for what it is, given a cctv IP board camera is in the £24 region with a fisheye lens, would just need the housing. OK you can't pan/zoom but would you need to? Mine stay in a fixed aim unless I decide to adjust that manually and give 150-170 degree view from a 2.5mm or 2.1mm  lens. That lens likely would only go to 120 degree and the extra elements to enable the zoom range would probably not be good for astro, too much loss if nothing else.

If that one is something you think worth a go, factor in swapping out the dome for a clear one if you can find a suitable one, else you'll see almost nothing at night  

9 minutes ago, CedricTheBrave said:

slightly on / off topic

anyone tried using one of these as an all sky camera? https://www.amazon.co.uk/LEFTEK-3072x1728-3-5-10-5mm-Distance-Weatherproof-white/dp/B0785J1H6V?ref_=fsclp_pl_dp_2

i guess it depends on what control of the camera you have?

Would depend what you'd like to see, daytime sky or night and stars. Likely it'll not be able to slow the shutter below 1/25s so would need video capture and stacked to get much of an image. 3.5mm won't give a wide fisheye and the lens likely will be relatively slow (f2.x or slower). Add that the dome is tinted and that'll wipe any chance of capturing stars other than the really bright ones at best.

Also and perhaps more importantly, CCTV domes aren't intended to be used dome upward, even if IP66 rated, so you'd probably need to adapt it to suit to ensure it resists water ingress. I rebuilt a pendulum dome type and so far that's working pretty well, tho the smaller dome similar to this is now showing condensation inside after I moved it recently, one more job when weather permits.

saw that one too and was tempted for a brief moment, tho for the Tal100RS I'd need to buy a diagonal too. Given funds are tight at the mo and that likely the tal 40mm 1-1/2 EP I have would be more than enough somehow sanity took over for a change and I passed  

not bad, bargain price even, tho I'd think an extra layer of foam might be needed to stop them moving about , but that's not expensive to do