jonathan

+1 for giving Goto a miss, unless you can buy the all-singing-all-dancing does-absolutely-everything-for-you which also costs-a-flipping-fortune, then it is going to cause a lot of disappointment for those times when it just doesn't work, or it takes an hour or more to overcome some finnicky setup woes.  Even if you did buy that fancy do-everything Goto, if (or when) that refuses to work properly then you'd likely have even less clue about how to make it go (the more parts it has, the more there is to go wrong).  I've owned a Celestron NexStar Goto, I know they can work well but also they can just not work for no obvious reason, which is deeply frustrating especially for a new-comer.  I now purely use tracking-only, though I have to say even that could be confusing as some of the handsets have button combinations required to set different tracking modes, if you're in the wrong mode then it won't work as expected and it's back to trying to understand the manual by red torch light in the freezing cold.  Not that I want to put you off spending or anything, just be aware that you might still have to spend a lot of time out there with your son even with Goto.

Just looking up the National Geographic Premium 76/700, it looks to be on a basic EQ mount.  I'd say you might have an easier time using an Alt/Az mount, which works just like a camera tripod (up/down, left/right), and if you go for something perhaps around the 100mm - 150mm size (same type of telescope - a reflector) then you'd be able to see a whole lot more than with the 76mm.  Books and charts, a planisphere (even if it's just you using them), and a couple of decent eyepieces and you should be set!  Visual astronomy starts with the Mk I Eyeball, if you know where to look there's a lot to see before you even break out any optical aids, and knowing some simple facts about what you're looking at can be as inspiring as the stars themselves.

1 hour ago, jetstream said:

When collimating we go back and forth between secondary and primary collimation? Try putting the primary dot in the cheshire ring, then go back to the sec, then back to primary etc etc. IMHO.

How do I put the primary dot in the Cheshire ring?  That sentence makes almost no sense to me, sorry.

I did some more fine adjustment to the secondary tilt, looks perfect to me now (near as dammit perfect circle when the Mire de Collimation circles are overlaid).  So I removed the green felt and paper that was blocking the tube, and I'm left scratching my head because my next view down the collimation cap doesn't match Astro-Baby's, and doesn't match what she says (or am I reading it wrong again?)  I don't know how to interpret what's going on here, my collimation looks so far out compared to the photos in the guide, I can't understand why.

First photo is with the collimation cap, second is with the Cheshire (which looks miles out).  I measured the spider vanes meticulously, all the same length.  I spent an age getting the secondary mirror positioned correctly in the focuser tube circle, and making sure it was a perfect circle too.

Can't say that I know the mount, but just as an experiment could you setup the telescope (if it's possible) 'the wrong way around', so that what is usually pointing East is now pointing West.  Run the telescope the 'wrong way around' and see if the error still occurs on the same side of the mount (e.g. if it occurred on the East side, then see if it now occurs on the West side).  This should indicate whether it's something you're doing, something the software is doing, or something the hardware is doing.

If it's still doing the thing on the same side of the mount then I'd say it sounds mechanical, possibly a failing or poorly fitted / adjusted part somewhere, maybe after a year it just needs some maintenance (perhaps a bit of lubrication).

The EQ3-2 is probably not the most precise tracking mount, but for a DSLR and typical fixed or zoom lens it would probably be fine, provided you get the polar alignment accurate (for this you probably need to also buy the optional polar scope, fits inside the mount).  You would have to buy at least RA tracking motor to go with the basic EQ3-2, along with a suitable power supply (6v), and a vixen-style dovetail bar with a camera mount attached.  You might want to have a look at the EQM-35 as a reasonably modern goto version of the EQ3-2.  Quite a few scopes come with a 'piggy back' camera mount for DSLRs, something to consider also (perhaps to make the mount investment more worth while).

Definitely a tripod with 2" tubular steel legs, the 8" SCT isn't all that heavy or long, but a stable tripod is one of the best ways to cut down on vibration / wobble.  After that, EQ5 / AZ5 minimum (in general terms, think of them as keywords).

I would look at getting an A4 (or A5 if available) sheet of very thin polystyrene, it can be bought from model shops or online.  It will have a white translucent look to it, probably a fraction of a mm thick.  I've used this (sometimes building up one layer at a time) to shim moving parts that had too much slack in them, created a perfect fit.  It needs to have a tiny fraction of play for it to operate freely, but it will be barely noticeable.  The advantage of the polystyrene is that it has a very smooth and even surface, usually one side is matt and the other is shiny so you can decide which works best (I'd probably say matt); apply using double-sided sticky tape or a tiny amount of strong contact glue (not plastic glue though, it won't stick to the metal).

Another alternative could be a narrow (like 10mm) strip of very thin stick-on velvet type material, probably get this from a craft shop or haberdashery department.

10 hours ago, AlexK said:

Not sure it's allowed to give a feedback on this "sad" thread (I seem to be ruining the other "happy" thread doing that recently ). Just let me know.
But I used to observe in -30C winters in Siberia and know what that entails very well. So:

1. Refuel. Get a decent piece of high calorie long burning meal (e.g. prior to all day diving in the Pacific I'm taking a serious chunk of well done ribeye with spaghetti for the brunch on the way to the diveshop). That would give you 3-4 hours of good inner heat source. For the short boost a sip of hot chocolate with milk from my 0.75L thermos saved many cold observing nights for me.
2. Warm up. That means obvious vigorous exercises (like sit-ups,  or see here) for about 15 minutes prior to going out to boost your natural "heat distribution hydraulics" and the "engine". Run the "engine" periodically at the scope as well (I do every hour).
3. Keep that heat for yourself. Think about your clothing out of the box. Your body must be insulated much better than for a regular winter walk as you are barely moving at the telescope. However, that might interfere with the 2 above, so the alternative option is (4):
4. Add an artificial source of heat. E.g. an electric blanket wrapped around the body (there are 12V versions available too), chemical heating pads (that's what I have in my outdoors kit, reusable salt crystallization based, just for high altitude cold occasions, the large shoulder one runs for 3-4 hours). The only issue is that if the excess heat escapes uncontrollably it may affect your views if the hot stream of air intersects the light path (which is often the case for a typical Dob). So a windbreaker is a must (even without an artificial heater). You can always open it up to release the excess quickly if feeling really toasted.
5. Reconsider your instrumentation. I saw a nice thread around here about gloves. I'm using fingertip-less gloves with the magnetic flip mitten pocket. Trust me that's the ultimate solution (given 1 and 2). However if your observing flow requires you to do something often with your bare hands, better start thinking how to eliminate that.

All of the above is very rewarding, as below 0C winter nights are commonly reported as clearer, steadier, and longer nights compared to warm summer nights.

Some very sage advice that I'm sure comes from experience.  At the moment I have chillblains (no doubt due to my poor circulation and an incorrect clothing choice when I went out to do some exercise in some deceptively cold sunshine a while ago) so my choices are limited right now especially when it comes to exercise, step at slightly the wrong angle and my toes will be in agony.  The fingerless gloves with mitt covers do sound appealing, however I am dubious of the electrically heated kind for safety, so many cheap knock-offs around it's difficult to distinguish which will have been properly tested, definitely do not want burnt hands from such a device, ditto an electric blanket (and I'm usually running on 6v for my medium mount).  I have some of those chemical heat packs, I just forget to use them!  I usually do wear extra layers (fleece, thick winter coat, woolly jumper) when observing.  No way to erect a windbreak if I'm on the hard driveway though, don't have one anyway.

I find that bare hands are the safest way to setup and take down a scope, the thought of it slipping through a pair of gloves is just... unthinkable.  Unfortunately that means touching very cold metal and can't really be avoided, the tactile feel and grip of bare fingers can't easily be replaced for me; I have tried expensive insulated tactile gloves, they just constricted the blood flow in my fingers such that they turned white.  I have big insulated windproof mittens now but my hands still get cold even in those, and obviously they are useless for doing anything with the hands.  I could be sitting in a room that's about 17-18C and have cold hands and feet, that's just how I am.

But still good advice which I'm sure will be helpful.

Yes, absolutely that's the shadow of the secondary being cast onto the paper, it didn't cross my mind that that's what @malc-c was talking about.

You guys don't think there's tweaking to be done in the NW / SE direction?  Looks like the secondary is still not perfectly circular to me, a couple of small tweaks of the mirror angle might just sort it.

Btw I have black felt on my secondary glass edge, that's why it looks so dark in the photo (in the NW direction).

For various hobbies I've bought direct from the USA, HMRC has different duty cut-offs for different types of goods, the info is all there for the reading on the HMRC website.  Yes, it's a bit of a pain having to pay import duties and maybe VAT as well, but it's not difficult to do and any trader in the EU who really wants to do business overseas will sort out those so they're already paid as part of the price.  Interestingly, never had to pay import duties on goods from China or Hong Kong, dunno how that works but seems to me EU traders could learn a thing or two from how that's done.  Sounds to me that a lot of the problems seem to be on the EU side.

Two factors have brought me back in, well three I suppose: 

1. The moon is bloody bright
2. I've seen what I went out to see (Moon, Mars, Uranus... or what I think was Uranus, so it still counts 😁)
3. It's bloody cold!!!

There's a very keen wind blowing, frequently nudging the scope which is already struggling with the altitude (Mars / Uranus are still quite high just now).  Five minutes and I start to feel my finger ends turning to ice, so cold to touch anything or even have my hands out of my pockets.  Despite several 'get warmed up in the coat room' sessions I just couldn't stand it anymore.  'Feels like' is -3C here according to the Met Office.

6 minutes ago, Mr Spock said:

Mine is out. The mount is over the top of a puddle though. I'll have to remember that when it gets dark.

Yeah, don't put your battery / power cable in it!

I may be viewing things through a 'simple' lens, but I can't imagine it being all that difficult to do.  HMRC works for other countries outside of the EU so that much should be a known quantity, the EU trades outside of the EU so that much must also be a known quantity, am I being too simplistic in expecting businesses to put these two pieces of knowledge together in a timely fashion, like sometime over the past four years?

I've just been out for a reccy (first time outside today), not as bad as yesterday so long as I stay close to the house.  Looks like Moon, Mars, and Uranus will be getting ticked off tonight for me after all.  Hope those who can get out get to enjoy the sight too.

@JamesF That was our garden for the past few weeks, thawed just this week and been very very wet since (with added two days of rain).  It drains very well near the bottom though as we have proper drainage pipes there.

1 hour ago, malc-c said:

A better picture might help, but looking at what you've provided I would agree that it's still in need of a little tweaking to get the secondary more central. 

This is the best I can do with my iPad through the home-made collimation cap (plastic film cannister with a hole in it).

Which screw would I adjust though, or is it back to random guesswork?

I'll need a diagram to explain why it needs moving towards N, I must be missing something.

Trying my best to follow AstroBaby's collimation advice for my Skywatcher 150P reflector...  Would love to hear some advice on whether I should just stop adjusting, or which screws I should concentrate on next as I'm feeling a bit overwhealmed / exhausted by this secondary collimation malarky.  To me it looks like it could do with another turn or two, but I'm not sure which way to do it.

Thanks!

...the garden is like a swamp!

Anyone else got the same excuse?  What's yours?

I'll probably have to stand on the rockery with a pair of bins instead.

+1 for two-star alignment, takes less time and should be easy to pick two bright stars far apart (ones that are easily identifiable in their part of the sky).  If it fails then try a different pair. 

My two pennies: this is one of the main reasons why I gave up using goto at home, doing that star alignment was a pain and very frustrating when it didn't work (my SE mount also had a bad power connector so it would frequently reset, right back to the beginning!)  Manual EQ mount is so much quicker and forces me to learn the night sky more.  Goto is much better when it's on a fixed pier or you have tripod feet markers in the ground so that you don't have to do the alignment every time.  6SE would probably sit fine on an AZ4 or similar mount in case you ever fancied manual.

There are some good quality refractors in stock if you're prepared to pay the extra (they're not the typical starter fare) and don't mind losing some aperture.  Check Altair Astro.  A refractor makes a great grab and go scope, easy to mount (EQ3-2/EQM35 is fine up to 102mm), no collimation to worry about, sharp optics.

I've found that the Baader Hyperion 8-24 zoom is an excellent performer in the 8SE, and the 25mm Plossl is an excellent starter eyepiece (shove that in first while you do setup etc), just beware that the zoom is heavier so you may wish to balance for that before you do setup, or go for a balance between that and the 25mm Plossl.  As Geoff said, don't spend a lot on a single eyepiece for the 8SE, you likely won't get the benefit, look to the Plossl ranges but also consider that the 8SE won't get a benefit from super wide angle eyepieces either (unless you go 2"), usually it will say on the item page what scope it's suitable or unsuitable for.  I was a bit disappointed with Celestron's (non-Plossl) eyepiece ranges in my 8SE, they're not the greatest eyepieces anyway but do seem to have better potential in my other scopes.

I bought the AstroZap 8" SCT Dew Shield and rate it highly, worth the money; nice and thin, strong, holds a really good shape, has a nice finish on the outside and a matt material inside so should be excellent for preventing condensation forming on the inside and also negate any stray light rays.  I also have a few AstroZap dew heater tapes (main OTA, eyepiece, finder), although I found the HitechAstro 4 channel dew heater controller much better than the AstroZap one.  I reckon the dew shield and at least one 8" dew heater tape should be your priority if you intend to observe in anything but dry mild evenings (unsurprisingly rare in the UK!)

On 11/01/2021 at 11:12, F15Rules said:

...and all that is SO why I'm visual only!😂

Mind you, I still had my own problems two nights ago..

- Scope objective frosted over despite 8" long dewshield

- finder scope lens fogged up

- eyepieces fogged up

All the above happened at different times of the session..in the end I whipped out my wife's hairdryer from the house and in doing so I wrecked my night vision acclimatisation..

I then almost tripped over the extension lead I had to use to make the hairdryer reach the scope..

...and that is why I don't tend to go out with a telescope when it's in the sub-zero temperature range!  Also the risk of slipping on ice and landing hard on ice / frozen ground / tangled mess of equipment (which will probably land on top of me as well, somehow).

Do you mean female at both ends then?  I haven't come across such a cable or adapter myself, I'd probably consider buying the appropriate DIY sockets along with some suitable wire and make one.  eBay can usually be a good source of such components in smaller quantities (though I usually buy more just because to buy one or two is very expensive per unit).  There might be such an adapter in the form of an audio accessory.

I don't know the Bresser mounts but perhaps there's a method to reset it to defaults (check the manual or Bresser website support section).  In case you've done any configuration or setup in the handset then try to make a note of such settings first, go through every menu option and make notes of how everything is set.  In the manual there's probably a menu tree diagram so you can take a copy of it and tick off each item as you check it.

Quick piece of advice for you - keep a local copy of all of the text and photos that you upload or write to the blog, keep it organised so that if the blog is ever lost then you can re-upload the information somewhere again.  If the website offers a local download backup option then use that as well.  Local backup is king, cloud storage should only ever be considered temporary or transient (online services come and go, and can change at the drop of a hat).

17 hours ago, Moonshed said:

Draw curtain around lonely broken man standing at the bottom of the garden on heavily frosted ground in the pitch black of night, going numb with cold, head bowed and clutching dead Canon.

This year's showing of The Snowman still haunting you eh?

*slow reprise of The Snowman tune plays, pan out*