wulfrun

9 minutes ago, Louis D said:

Thanks.  There's an equivalent supplier here (Foam Factory).  What sized sheet did you end up going with before cutting to size for your Heritage 150P?

I'd need to look it up but I think it was 1m x 2m, way more than actually required. There was only a small price increase for 2m vs 1m so I went for it, gives me plenty spare for re-makes if I rip it. Plus I made a dew shield for my RACI. There's certainly plenty over but it was easier than not having enough!

Telrad, Rigel, RDF or, if you want a home-made thingy, how about this:

http://www.jerryoltion.com/Split_pupil_finder.htm

9 hours ago, Louis D said:

To put this back on topic, what material have other folks been using to make their light shrouds for the Heritage scopes?  I'm thinking I might get one someday as a travel scope.

I used 3mm thickness of this (as recommended to me by @Tiny Clanger)

https://www.efoam.co.uk/closed-cell-polyethylene-foam.php

Probably not that useful a link to you over the pond but I'm sure you can source something similar. At the risk of stating the obvious, it needs to be thick enough to be rigid but not so thick it'll start obstructing the light path.

Good result! The thing with the Heritage 150 is that even if in the future you end up with something bigger, better, with go-to or whatever it'll remain a capable grab-and-go for the future. Not a purchase to regret  🙂

For the first time ever, I've just managed to clock the ISS going over (well, OK, an hour ago!). Spotted it by chance, had time to grab the binos and follow it. Blimey it's bright! Faded to yellow then red then suddenly gone as it went past about 40 degrees up in the easterly direction. Might even get the next pass!

From the wording, I'm reading it that you intend to run the cable from the 12V output for 10m? You have two factors to consider, the safety rating of the cable and the voltage drop caused by it. In free air, 2.5 sq mm mains cable is rated at 27A, so you're probably just about OK from a cable safety perspective. In terms of voltage drop, you'd lose approx 0.15V per amp (you have 10m there on the "live" and 10m back on the "ground"). Add up the peak powers of your devices and see how that looks. Not speaking from personal experience but it may not be acceptable in terms of spikes and glitches it could cause.

It's never easy to transfer significant current at low voltage over distance. Can you not supply mains over the distance and limit low voltage to short leads? As long as you do that safely it's the better option. If not, I'd be tempted to use 4 sq mm at least. The other option would be some kind of smoothing/filtering at the remote end but that starts to get complex and possibly expensive.

35 minutes ago, Robindonne said:

Lets hope it doesnt get knocked accidentally in our direction😬

My thoughts too but I rather hope they've thought about that!

I'm not a refractor owner so can't comment on those but if you're looking at the 150P, the PL version would suit planetary/lunar/doubles better. You'd sacrifice some maximum field-of-view, so a bit less "all-rounder" but it would be better at higher powers. If you're happy with a dobsonian mounting, the PL version tube is what comes on the 150 size. There are also the Messier and StellaLyra equivalents, both dobsonian.

On 19/11/2021 at 00:04, malc-c said:

...but in order for the pins to register a pulse that must mean that they are held high through the transistor, which as there is no current flowing to its base will be turned on (its a PNP type)...

It'll be turned OFF by lack of base current when SW1 is "open". There is no bias until SW1 closes, so the transistor is effectively not there. It's a bipolar transistor not a FET, so no base current = no collector current. PNP and NPN are opposite polarity but work the same way.

First proper night in a month, damn weather! Went out early with the binos but a great wedge of cloud wandered over and I came in for Dr Who. Clear again after that and promising so the 150PL came out first.

Since a lot has come back into view, I visited some old/returning favourites. Started on Jupiter since it would soon be gone over the neighbour's rooftop. Seeing was fairly steady but a haze kept detail low, not an exciting view but hey, better than nothing.

Had a while on the Owl/ET cluster, Pleiades (which don't quite fit the max FOV) & Hyades (ditto). Almach was looking good and I just managed to see Andromeda's core, despite the bright moon and haze. I had a look at Albireo before it went over my rooftop, interesting how similar to Almach it appears, visually, although it splits at much lower mag. Split Castor despite it being relatively low, not very cleanly though at x75.

The moon being higher by now and very bright, I popped the variable polariser in and spent some time on it. It looked very steady and, as per @Ags above, Petavius was fascinating.

Next came Orion, nice to see it accessible at a sane hour! The nebula is something I never tire of. I did notice the haze meant I only got three stars in the trapezium with the fourth appearing/disappearing. Popped in a UHC and the nebulosity came out better, despite the hazy conditions.

Last was to swap out to the Heritage 150 and compare on the Orion nebula, just for fun. The view I got seemed exactly the same (different EPs, of course) but I've never tried the Heritage on the Altair Sabre before, so I did learn that it plays very nicely.

Came in at a quarter to midnight, very cold (quite a frost on the shed) but very happy after a month being clouded out!

9 hours ago, JamesF said:

Thanks for pointing out that I'd forgotten how PNP transistors work, btw.  I'd completely missed that

I often find it difficult to visualise. Mentally, I turn the circuit upside-down, so that "ground" is the real positive supply and now I have an imaginary negative "power rail".

Yes, "105" would be 10 with 5 noughts after it i.e 1-meg.

EDIT: Definitely a BC557 (pnp) not BC547 (npn)?

That's a wierd circuit. However, your transistor logic is the wrong way round - it's a pnp. With S1 open, the base is held at 3V (supply) via 10k, so it does not conduct. Hence the output is at 0V via the 1-meg resistor (strangely high value?). If S1 is closed, the base drops to (47/(10+47))*3=2.47V. That leaves 0.53V across the base-emitter junction, hardly going to turn it into full conduction to give 3V at "out"? Are you sure the bias resistor values aren't the other way around?

Unless I'm missing something! (It's late being my excuse).

It would be helpful if you tell us a bit more. What things are you trying to observe? In what way is the view not good? Where are you using it from (dark skies, urban garden etc)? Is the scope on a steady platform? Did you let it cool down outside before using it? Have you checked the scope's collimation is OK? Does it have a shroud fitted, to exclude stray light (if needed)?

The 25mm SkyWatcher supplied eyepiece isn't too bad but the 10mm is not good quality. Most people would advise replacing that with something like a BST Starguider eyepiece or similar, assuming you're on a budget. There's a 12mm or 8mm in that range, they are the nearest to your 10mm. Your scope has a focal length of 650mm so a 12mm gives a magnification of 650/12=54, the 8mm gives 650/8=81. The supplied 10mm gives x65. Those magnifications are well within the scope's capabilities.

I have one of the collapsibles, similar to @wookie1965's OP. I got it cheaper (£10 ish less, at the time) off fleabay than Amazon. As a stool it's great, certainly packs down to almost nothing. It doesn't go all that high though, so it's of limited use as an observing seat. If you have a longer Newtonian it probably isn't useful beyond a perch while waiting for clouds to pass. Might be more useful for a short Frac or Mak but I own neither so can't confirm.

45 minutes ago, Mr Spock said:

LOL, this is turning into a 'show us your TMB' thread 

Identical to mine, assuming it says "Planetary" on the side, with a "II" through it. Performs well enough, to my eye anyways.

Courtesy of the classifieds and @Sirius Biznessand in spotless condition, postie delivery me this. It'll fill a gap in my EP lineup nicely:

I've accumulated a few hours looking at Jupiter & Saturn over recent months and concur with the above. Focus on the moons or a nearby star then leave the focus alone and watch and wait. If there's a lack of detail, it's almost certain to be atmosphere (unless it's a rubbish EP) and hard luck, no point fiddling with focus since you'll probably make things worse. Give up if bad enough or sit patiently for the fleeting moments of clarity. Patience is required! I can usually get up to 130-150x mag and sometimes a bit more (and sometimes less!). Rare to get much higher without it all going mushy but it can happen.

51 minutes ago, Marvin Jenkins said:

It just gets worse! Re built the mower engine using metric tools on Imperial fixings. Had to give the head bolts my best guess as to torque by watching a guy on YouTube do it till he grunted!!! In American!

I have a torque wrench (just realised we call them torque wrench, not torque spanner) but all the info for the motor is foot/pounds. This is what I have, a confusing mix which if used on anything other than a mower could cause untold harm on a large scale.

Seems the head and associated fittings are Imperial but the torque settings are metric. I feel very uncomfortable and have decided to never fly again, never drive anywhere and stop cutting the grass.

Marv

Just occurred to me...sockets and drivers are invariably imperial sizes, regardless of the actual socket size. 3/8", 1/2" and 3/4" drives being the common ones.

2 hours ago, johninderby said:

 

I've always assumed that "strimmer" is just a contraction of "string trimmer", even though they use a nylon line rather than actual string.

2 minutes ago, DAVE AMENDALL said:

I am in the process of inventing a gizmo which measures the ammount of light pollution,  and if high, gives out a continueing beep beep until the offending light is switched off. It isn't perfected yet. When it is, I hope to  place it on my house roof.  

Great idea but unfortunately it relies on the owner of the offending light having the mental capacity to link the light to the bleep. Experience suggests most folk are dimmer than their offensive lights.

9 minutes ago, Louis D said:

Why haven't time units gone decimal?

Don't say that too loudly 😉

Probably because 60 and 24 are more sensible in terms of how they divide.

EDIT: Compare with degrees and their decimalised version, Gradians. No-one sane uses Gradians.

Just now, wookie1965 said:

I have bought a power bank with two usb`s giving 5v 2.1amps so not sure if I could use one of those thanks.

Yes but the output is then going to be around 0.8A at 12V, using a boost (step-UP) converter. Might not be enough? Just an idea.

If you already have 12V dew heaters, you could probably also find a 5V-to-12V boost converter. If you did, make sure that it can supply sufficient amps and also be aware it'll draw more than twice the current from the 5V supply than it delivers at 12V.

3 minutes ago, Pixies said:

Has the scope cooled down properly? I het 5 or 6 spikes (4 vanes) when the scope is warm. That or a telephone line is in the way!

The scope is kept in the shed, so certainly cooled by the time I've set up. However, you might have hit on something with the "telephone line" idea...or more specifically, washing line! It might just be in the line of sight, I'd have to re-check that one.

Thanks for all the suggestions so far...