Geoff Barnes

Hi again @bluesilver, I know you are in Tasmania but even so, not far from me in Melbourne, and with Jupiter and Saturn at 75 degrees altitude I have no problem observing at 300x with my 12 inch SW Dobsonian on good nights of seeing and the views are quite sharp.

Obviously at 200x the images are brighter and a tad sharper but still very good at 300x. I have on a few good nights pushed up to 375x and even 500x on rare occasions and then things become a bit fuzzy.

If you are getting fuzzy views at only 120x or up to 180x it suggests to me that your collimation may be off, or your primary mirror is not at ambient air temperature, I can't think of any other reason, your views should be tack sharp at those magnifications.

I order most of my gear from FLO (it's much cheaper than buying here and much more choice) and as I'm in Oz it can often take up to a month to get here if I choose the cheaper Royal Mail option, though nothing has failed to arrive eventually.

However, using the DHL option almost always gets things here within a week of ordering, so although it costs more it does get here quicker.

Which carrier I choose just depends how quickly I need the item.

Could be the world's smallest man with his 12inch Dob...  

Have you been following Michele Scotti's 800mm scope project in the DIY forum, would have.to be one of the biggest when it gets finished.

I suddenly feel completely inadequate.  

6 hours ago, JamesF said:

Not so much an eyepiece as a headpiece...

James

Indeed, you'd need eyes like Marty Feldman to look through one of those!

7 hours ago, Captain Magenta said:

Thanks both. I’ve seen SW’s current Dob specs at 70mm, but there’s nothing “out there” that definitively states the dimensions for their solid tube any more. But the GSO also at 70mm strengthens the case...

 

Hi Magnus,

I've just been out and measured my SW 305mm F/4.9 Flextube Dob secondary and it is 70mm wide.

Not a solid tube I know, but the specs are identical to yours, so must surely be the same.

It's not much but its polarity does indicate it is a member of incoming Solar Cycle 25.

https://www.spaceweather.com

Tsk, tsk Mark. Going to need a metre square patch of Astro Turf there I reckon!  

Jeepers creepers, you'd die of fright if you were with me in our Aussie garden at night! 😂

(Oh and congratulations on the longest thread title ever seen on SGL.)

Already being discussed here Dave...

Well once you've got the moon centred in the eyepiece it should only take a few seconds to adjust the finder. The moon is really not going to move to any significant degree while you get aligned.

The moon is always a useful target as it's large and bright.

Might pay you to align on it while it is still up at a reasonable hour.

Should look like this.....

A bit off topic and apologies for that, but it was the "orangey orangey" that caught my attention. I was double spotting t'other night and came across 61 Cygni in Cygnus for the first time, a lovely double with 30" separation that to my eyes were both very orangey orangey. 

I was wondering how much of their bright orange appearance was due to their very low altitude, just 12 degrees above our northern horizon, so a lot of atmospheric murk to shine through. They would be presumably very high up in UK locations, are they still "orangey orangey" up there?

On 13/09/2019 at 08:06, johninderby said:

Thanks forthe opinions. Has helped me make up my mind.

Hi John, it's been a month or so now and I'm interested to know your thoughts of the 4.5mm Morpheus in your f5 Dob.

I realise the weather has been particularly uncooperative over the last month, have you had a chance yet.

I'm sorely tempted to get one to compliment my 6.5mm which I love.

Cheers,

Hi Piero,

I replaced my SW Dob springs a few months ago. I simply took one of the original ones off and went down to our local B & Q equivalent (Bunnings in Australia) and bought three of similar length but much thicker gauge steel and replaced them all.

Only cost a couple of dollars each and feels much more solid, holds collimation better now too, just a mimor tweak occasionally.

Frustrating down here. I bought an Astronomik  OIII filter recently purely to have my first view of the Veil.

I only have a small window of opportunity to see it when it emerges from behind our trees and sinks below the horizon.

Its highest elevation is only 20 degrees at about 9pm so a bit lost in the light glow of the city as well.

I've had a couple of goes now with a SW 32mm plossl and the OIII and have to say it has been disappointing. I can see both east and west sections but they are really faint, only just discernable as pale grey smudges, no hint of detail at all.

I will keep trying, I still have a month to see it but time is running out with lighter evenings ahead.

15 minutes ago, kirkster501 said:

Goto will make you bored; press the button... look.... yawn.....  Press the button again....look...yawn...

Stephen my good fellow, I've just been observing Saturn and Jupiter at 375x in great detail with my Goto, both planets perfectly centred in the EP and me not having to touch the scope, just look, concentrate  and enjoy for a long, long time.

If you want to keep nudging your scope every few seconds in the hope of keeping your subject in view at high powers then all power to you.

Me, I love my Goto, it allows me to observe and concentrate at high power effortlessly and for as long as I desire.

Each to his/her own preference.  

I managed to see Triton last night with Neptune just a few degrees away from the nearly full moon.

I hadn't really set out to see it, I was mainly observing Jupiter and Saturn, but as they were disappearing behind the trees to the west Neptune was clearing the tree tops above my head so I thought I'd have a look.

I used the Baader zoom to centre Neptune in the EP and then put in my new TV 3-6mm zoom. First on 6mm (250x) with no sign of Triton I took it right up to 3mm (500x) and there it was!

Very, very faint, almost at the limit of my 12 inch SW Dob, but very definitely there just at 2o'clock to the grey/green planet and mostly with averted vision.

Amazing really, as there was considerable glare from the adjacent moon, I think in a dark sky I could aee it fairly easily on a good night.

Go away Moon!

I was doing a bit of Googling of astro images as you do, and came across an image that had been posted on this Astro Forum...https://www.popastro.com/main_spa1/?sid=98dd0a491f4ad3fb9c783c45718311e0.

Does anyone on SGL ever visit this site? It's forum doesn't seem to be all that active and certainly doesn't rival SGL in any way.

It got me wondering how many other astro sites and forums there are out there. SGL would easily be the biggest (and best) in the UK.

12 hours ago, FLO said:

This photo is doing the rounds on social media. Apparently it shows two prototype ED doublet refractors, a 62 and 82mm, that will sit somewhere between Sky-Watcher's Evostar ED doublets and Esprit triplets. Currently we don't have specifications, guide prices or an ETA. 

(I would like to credit the photo but have no idea where it originated. If I find out I will edit this post). 

Never a dull moment... 🙂 

Steve 

Steve, have you right clicked on the original photo to explore its properties and origin?

I've tried from my end but nothing comes up. Even opening in a new window the page is blank. Encrypted I suspect.

Ha! I'd call that a real "Grab and Go-Nowhere". 🤣

Cleaning a primary mirror is relatively easy if you just follow some simple common sense rules.

Have a look at Steve Kirk's article on cleaning his 12 inch mirror, it's very well done and simple to follow.... .https://www.sjkastro.com/cleaning-12-dobsonian-mirror/

Hi Fraunhoffer,

Have you considered sitting your Dob on a dolly board like this, it works really well for me. You just wheel it about until you  find a level spot with a spirit level on the base.....